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Diffstat (limited to 'src/migration/rdma.c')
| -rw-r--r-- | src/migration/rdma.c | 3516 |
1 files changed, 3516 insertions, 0 deletions
diff --git a/src/migration/rdma.c b/src/migration/rdma.c new file mode 100644 index 0000000..dcabb91 --- /dev/null +++ b/src/migration/rdma.c @@ -0,0 +1,3516 @@ +/* + * RDMA protocol and interfaces + * + * Copyright IBM, Corp. 2010-2013 + * + * Authors: + * Michael R. Hines <mrhines@us.ibm.com> + * Jiuxing Liu <jl@us.ibm.com> + * + * This work is licensed under the terms of the GNU GPL, version 2 or + * later. See the COPYING file in the top-level directory. + * + */ +#include "qemu-common.h" +#include "migration/migration.h" +#include "migration/qemu-file.h" +#include "exec/cpu-common.h" +#include "qemu/error-report.h" +#include "qemu/main-loop.h" +#include "qemu/sockets.h" +#include "qemu/bitmap.h" +#include "qemu/coroutine.h" +#include <stdio.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netdb.h> +#include <arpa/inet.h> +#include <string.h> +#include <rdma/rdma_cma.h> +#include "trace.h" + +/* + * Print and error on both the Monitor and the Log file. + */ +#define ERROR(errp, fmt, ...) \ + do { \ + fprintf(stderr, "RDMA ERROR: " fmt "\n", ## __VA_ARGS__); \ + if (errp && (*(errp) == NULL)) { \ + error_setg(errp, "RDMA ERROR: " fmt, ## __VA_ARGS__); \ + } \ + } while (0) + +#define RDMA_RESOLVE_TIMEOUT_MS 10000 + +/* Do not merge data if larger than this. */ +#define RDMA_MERGE_MAX (2 * 1024 * 1024) +#define RDMA_SIGNALED_SEND_MAX (RDMA_MERGE_MAX / 4096) + +#define RDMA_REG_CHUNK_SHIFT 20 /* 1 MB */ + +/* + * This is only for non-live state being migrated. + * Instead of RDMA_WRITE messages, we use RDMA_SEND + * messages for that state, which requires a different + * delivery design than main memory. + */ +#define RDMA_SEND_INCREMENT 32768 + +/* + * Maximum size infiniband SEND message + */ +#define RDMA_CONTROL_MAX_BUFFER (512 * 1024) +#define RDMA_CONTROL_MAX_COMMANDS_PER_MESSAGE 4096 + +#define RDMA_CONTROL_VERSION_CURRENT 1 +/* + * Capabilities for negotiation. + */ +#define RDMA_CAPABILITY_PIN_ALL 0x01 + +/* + * Add the other flags above to this list of known capabilities + * as they are introduced. + */ +static uint32_t known_capabilities = RDMA_CAPABILITY_PIN_ALL; + +#define CHECK_ERROR_STATE() \ + do { \ + if (rdma->error_state) { \ + if (!rdma->error_reported) { \ + error_report("RDMA is in an error state waiting migration" \ + " to abort!"); \ + rdma->error_reported = 1; \ + } \ + return rdma->error_state; \ + } \ + } while (0); + +/* + * A work request ID is 64-bits and we split up these bits + * into 3 parts: + * + * bits 0-15 : type of control message, 2^16 + * bits 16-29: ram block index, 2^14 + * bits 30-63: ram block chunk number, 2^34 + * + * The last two bit ranges are only used for RDMA writes, + * in order to track their completion and potentially + * also track unregistration status of the message. + */ +#define RDMA_WRID_TYPE_SHIFT 0UL +#define RDMA_WRID_BLOCK_SHIFT 16UL +#define RDMA_WRID_CHUNK_SHIFT 30UL + +#define RDMA_WRID_TYPE_MASK \ + ((1UL << RDMA_WRID_BLOCK_SHIFT) - 1UL) + +#define RDMA_WRID_BLOCK_MASK \ + (~RDMA_WRID_TYPE_MASK & ((1UL << RDMA_WRID_CHUNK_SHIFT) - 1UL)) + +#define RDMA_WRID_CHUNK_MASK (~RDMA_WRID_BLOCK_MASK & ~RDMA_WRID_TYPE_MASK) + +/* + * RDMA migration protocol: + * 1. RDMA Writes (data messages, i.e. RAM) + * 2. IB Send/Recv (control channel messages) + */ +enum { + RDMA_WRID_NONE = 0, + RDMA_WRID_RDMA_WRITE = 1, + RDMA_WRID_SEND_CONTROL = 2000, + RDMA_WRID_RECV_CONTROL = 4000, +}; + +static const char *wrid_desc[] = { + [RDMA_WRID_NONE] = "NONE", + [RDMA_WRID_RDMA_WRITE] = "WRITE RDMA", + [RDMA_WRID_SEND_CONTROL] = "CONTROL SEND", + [RDMA_WRID_RECV_CONTROL] = "CONTROL RECV", +}; + +/* + * Work request IDs for IB SEND messages only (not RDMA writes). + * This is used by the migration protocol to transmit + * control messages (such as device state and registration commands) + * + * We could use more WRs, but we have enough for now. + */ +enum { + RDMA_WRID_READY = 0, + RDMA_WRID_DATA, + RDMA_WRID_CONTROL, + RDMA_WRID_MAX, +}; + +/* + * SEND/RECV IB Control Messages. + */ +enum { + RDMA_CONTROL_NONE = 0, + RDMA_CONTROL_ERROR, + RDMA_CONTROL_READY, /* ready to receive */ + RDMA_CONTROL_QEMU_FILE, /* QEMUFile-transmitted bytes */ + RDMA_CONTROL_RAM_BLOCKS_REQUEST, /* RAMBlock synchronization */ + RDMA_CONTROL_RAM_BLOCKS_RESULT, /* RAMBlock synchronization */ + RDMA_CONTROL_COMPRESS, /* page contains repeat values */ + RDMA_CONTROL_REGISTER_REQUEST, /* dynamic page registration */ + RDMA_CONTROL_REGISTER_RESULT, /* key to use after registration */ + RDMA_CONTROL_REGISTER_FINISHED, /* current iteration finished */ + RDMA_CONTROL_UNREGISTER_REQUEST, /* dynamic UN-registration */ + RDMA_CONTROL_UNREGISTER_FINISHED, /* unpinning finished */ +}; + +static const char *control_desc[] = { + [RDMA_CONTROL_NONE] = "NONE", + [RDMA_CONTROL_ERROR] = "ERROR", + [RDMA_CONTROL_READY] = "READY", + [RDMA_CONTROL_QEMU_FILE] = "QEMU FILE", + [RDMA_CONTROL_RAM_BLOCKS_REQUEST] = "RAM BLOCKS REQUEST", + [RDMA_CONTROL_RAM_BLOCKS_RESULT] = "RAM BLOCKS RESULT", + [RDMA_CONTROL_COMPRESS] = "COMPRESS", + [RDMA_CONTROL_REGISTER_REQUEST] = "REGISTER REQUEST", + [RDMA_CONTROL_REGISTER_RESULT] = "REGISTER RESULT", + [RDMA_CONTROL_REGISTER_FINISHED] = "REGISTER FINISHED", + [RDMA_CONTROL_UNREGISTER_REQUEST] = "UNREGISTER REQUEST", + [RDMA_CONTROL_UNREGISTER_FINISHED] = "UNREGISTER FINISHED", +}; + +/* + * Memory and MR structures used to represent an IB Send/Recv work request. + * This is *not* used for RDMA writes, only IB Send/Recv. + */ +typedef struct { + uint8_t control[RDMA_CONTROL_MAX_BUFFER]; /* actual buffer to register */ + struct ibv_mr *control_mr; /* registration metadata */ + size_t control_len; /* length of the message */ + uint8_t *control_curr; /* start of unconsumed bytes */ +} RDMAWorkRequestData; + +/* + * Negotiate RDMA capabilities during connection-setup time. + */ +typedef struct { + uint32_t version; + uint32_t flags; +} RDMACapabilities; + +static void caps_to_network(RDMACapabilities *cap) +{ + cap->version = htonl(cap->version); + cap->flags = htonl(cap->flags); +} + +static void network_to_caps(RDMACapabilities *cap) +{ + cap->version = ntohl(cap->version); + cap->flags = ntohl(cap->flags); +} + +/* + * Representation of a RAMBlock from an RDMA perspective. + * This is not transmitted, only local. + * This and subsequent structures cannot be linked lists + * because we're using a single IB message to transmit + * the information. It's small anyway, so a list is overkill. + */ +typedef struct RDMALocalBlock { + char *block_name; + uint8_t *local_host_addr; /* local virtual address */ + uint64_t remote_host_addr; /* remote virtual address */ + uint64_t offset; + uint64_t length; + struct ibv_mr **pmr; /* MRs for chunk-level registration */ + struct ibv_mr *mr; /* MR for non-chunk-level registration */ + uint32_t *remote_keys; /* rkeys for chunk-level registration */ + uint32_t remote_rkey; /* rkeys for non-chunk-level registration */ + int index; /* which block are we */ + unsigned int src_index; /* (Only used on dest) */ + bool is_ram_block; + int nb_chunks; + unsigned long *transit_bitmap; + unsigned long *unregister_bitmap; +} RDMALocalBlock; + +/* + * Also represents a RAMblock, but only on the dest. + * This gets transmitted by the dest during connection-time + * to the source VM and then is used to populate the + * corresponding RDMALocalBlock with + * the information needed to perform the actual RDMA. + */ +typedef struct QEMU_PACKED RDMADestBlock { + uint64_t remote_host_addr; + uint64_t offset; + uint64_t length; + uint32_t remote_rkey; + uint32_t padding; +} RDMADestBlock; + +static uint64_t htonll(uint64_t v) +{ + union { uint32_t lv[2]; uint64_t llv; } u; + u.lv[0] = htonl(v >> 32); + u.lv[1] = htonl(v & 0xFFFFFFFFULL); + return u.llv; +} + +static uint64_t ntohll(uint64_t v) { + union { uint32_t lv[2]; uint64_t llv; } u; + u.llv = v; + return ((uint64_t)ntohl(u.lv[0]) << 32) | (uint64_t) ntohl(u.lv[1]); +} + +static void dest_block_to_network(RDMADestBlock *db) +{ + db->remote_host_addr = htonll(db->remote_host_addr); + db->offset = htonll(db->offset); + db->length = htonll(db->length); + db->remote_rkey = htonl(db->remote_rkey); +} + +static void network_to_dest_block(RDMADestBlock *db) +{ + db->remote_host_addr = ntohll(db->remote_host_addr); + db->offset = ntohll(db->offset); + db->length = ntohll(db->length); + db->remote_rkey = ntohl(db->remote_rkey); +} + +/* + * Virtual address of the above structures used for transmitting + * the RAMBlock descriptions at connection-time. + * This structure is *not* transmitted. + */ +typedef struct RDMALocalBlocks { + int nb_blocks; + bool init; /* main memory init complete */ + RDMALocalBlock *block; +} RDMALocalBlocks; + +/* + * Main data structure for RDMA state. + * While there is only one copy of this structure being allocated right now, + * this is the place where one would start if you wanted to consider + * having more than one RDMA connection open at the same time. + */ +typedef struct RDMAContext { + char *host; + int port; + + RDMAWorkRequestData wr_data[RDMA_WRID_MAX]; + + /* + * This is used by *_exchange_send() to figure out whether or not + * the initial "READY" message has already been received or not. + * This is because other functions may potentially poll() and detect + * the READY message before send() does, in which case we need to + * know if it completed. + */ + int control_ready_expected; + + /* number of outstanding writes */ + int nb_sent; + + /* store info about current buffer so that we can + merge it with future sends */ + uint64_t current_addr; + uint64_t current_length; + /* index of ram block the current buffer belongs to */ + int current_index; + /* index of the chunk in the current ram block */ + int current_chunk; + + bool pin_all; + + /* + * infiniband-specific variables for opening the device + * and maintaining connection state and so forth. + * + * cm_id also has ibv_context, rdma_event_channel, and ibv_qp in + * cm_id->verbs, cm_id->channel, and cm_id->qp. + */ + struct rdma_cm_id *cm_id; /* connection manager ID */ + struct rdma_cm_id *listen_id; + bool connected; + + struct ibv_context *verbs; + struct rdma_event_channel *channel; + struct ibv_qp *qp; /* queue pair */ + struct ibv_comp_channel *comp_channel; /* completion channel */ + struct ibv_pd *pd; /* protection domain */ + struct ibv_cq *cq; /* completion queue */ + + /* + * If a previous write failed (perhaps because of a failed + * memory registration, then do not attempt any future work + * and remember the error state. + */ + int error_state; + int error_reported; + + /* + * Description of ram blocks used throughout the code. + */ + RDMALocalBlocks local_ram_blocks; + RDMADestBlock *dest_blocks; + + /* Index of the next RAMBlock received during block registration */ + unsigned int next_src_index; + + /* + * Migration on *destination* started. + * Then use coroutine yield function. + * Source runs in a thread, so we don't care. + */ + int migration_started_on_destination; + + int total_registrations; + int total_writes; + + int unregister_current, unregister_next; + uint64_t unregistrations[RDMA_SIGNALED_SEND_MAX]; + + GHashTable *blockmap; +} RDMAContext; + +/* + * Interface to the rest of the migration call stack. + */ +typedef struct QEMUFileRDMA { + RDMAContext *rdma; + size_t len; + void *file; +} QEMUFileRDMA; + +/* + * Main structure for IB Send/Recv control messages. + * This gets prepended at the beginning of every Send/Recv. + */ +typedef struct QEMU_PACKED { + uint32_t len; /* Total length of data portion */ + uint32_t type; /* which control command to perform */ + uint32_t repeat; /* number of commands in data portion of same type */ + uint32_t padding; +} RDMAControlHeader; + +static void control_to_network(RDMAControlHeader *control) +{ + control->type = htonl(control->type); + control->len = htonl(control->len); + control->repeat = htonl(control->repeat); +} + +static void network_to_control(RDMAControlHeader *control) +{ + control->type = ntohl(control->type); + control->len = ntohl(control->len); + control->repeat = ntohl(control->repeat); +} + +/* + * Register a single Chunk. + * Information sent by the source VM to inform the dest + * to register an single chunk of memory before we can perform + * the actual RDMA operation. + */ +typedef struct QEMU_PACKED { + union QEMU_PACKED { + uint64_t current_addr; /* offset into the ram_addr_t space */ + uint64_t chunk; /* chunk to lookup if unregistering */ + } key; + uint32_t current_index; /* which ramblock the chunk belongs to */ + uint32_t padding; + uint64_t chunks; /* how many sequential chunks to register */ +} RDMARegister; + +static void register_to_network(RDMAContext *rdma, RDMARegister *reg) +{ + RDMALocalBlock *local_block; + local_block = &rdma->local_ram_blocks.block[reg->current_index]; + + if (local_block->is_ram_block) { + /* + * current_addr as passed in is an address in the local ram_addr_t + * space, we need to translate this for the destination + */ + reg->key.current_addr -= local_block->offset; + reg->key.current_addr += rdma->dest_blocks[reg->current_index].offset; + } + reg->key.current_addr = htonll(reg->key.current_addr); + reg->current_index = htonl(reg->current_index); + reg->chunks = htonll(reg->chunks); +} + +static void network_to_register(RDMARegister *reg) +{ + reg->key.current_addr = ntohll(reg->key.current_addr); + reg->current_index = ntohl(reg->current_index); + reg->chunks = ntohll(reg->chunks); +} + +typedef struct QEMU_PACKED { + uint32_t value; /* if zero, we will madvise() */ + uint32_t block_idx; /* which ram block index */ + uint64_t offset; /* Address in remote ram_addr_t space */ + uint64_t length; /* length of the chunk */ +} RDMACompress; + +static void compress_to_network(RDMAContext *rdma, RDMACompress *comp) +{ + comp->value = htonl(comp->value); + /* + * comp->offset as passed in is an address in the local ram_addr_t + * space, we need to translate this for the destination + */ + comp->offset -= rdma->local_ram_blocks.block[comp->block_idx].offset; + comp->offset += rdma->dest_blocks[comp->block_idx].offset; + comp->block_idx = htonl(comp->block_idx); + comp->offset = htonll(comp->offset); + comp->length = htonll(comp->length); +} + +static void network_to_compress(RDMACompress *comp) +{ + comp->value = ntohl(comp->value); + comp->block_idx = ntohl(comp->block_idx); + comp->offset = ntohll(comp->offset); + comp->length = ntohll(comp->length); +} + +/* + * The result of the dest's memory registration produces an "rkey" + * which the source VM must reference in order to perform + * the RDMA operation. + */ +typedef struct QEMU_PACKED { + uint32_t rkey; + uint32_t padding; + uint64_t host_addr; +} RDMARegisterResult; + +static void result_to_network(RDMARegisterResult *result) +{ + result->rkey = htonl(result->rkey); + result->host_addr = htonll(result->host_addr); +}; + +static void network_to_result(RDMARegisterResult *result) +{ + result->rkey = ntohl(result->rkey); + result->host_addr = ntohll(result->host_addr); +}; + +const char *print_wrid(int wrid); +static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head, + uint8_t *data, RDMAControlHeader *resp, + int *resp_idx, + int (*callback)(RDMAContext *rdma)); + +static inline uint64_t ram_chunk_index(const uint8_t *start, + const uint8_t *host) +{ + return ((uintptr_t) host - (uintptr_t) start) >> RDMA_REG_CHUNK_SHIFT; +} + +static inline uint8_t *ram_chunk_start(const RDMALocalBlock *rdma_ram_block, + uint64_t i) +{ + return (uint8_t *)(uintptr_t)(rdma_ram_block->local_host_addr + + (i << RDMA_REG_CHUNK_SHIFT)); +} + +static inline uint8_t *ram_chunk_end(const RDMALocalBlock *rdma_ram_block, + uint64_t i) +{ + uint8_t *result = ram_chunk_start(rdma_ram_block, i) + + (1UL << RDMA_REG_CHUNK_SHIFT); + + if (result > (rdma_ram_block->local_host_addr + rdma_ram_block->length)) { + result = rdma_ram_block->local_host_addr + rdma_ram_block->length; + } + + return result; +} + +static int rdma_add_block(RDMAContext *rdma, const char *block_name, + void *host_addr, + ram_addr_t block_offset, uint64_t length) +{ + RDMALocalBlocks *local = &rdma->local_ram_blocks; + RDMALocalBlock *block; + RDMALocalBlock *old = local->block; + + local->block = g_new0(RDMALocalBlock, local->nb_blocks + 1); + + if (local->nb_blocks) { + int x; + + if (rdma->blockmap) { + for (x = 0; x < local->nb_blocks; x++) { + g_hash_table_remove(rdma->blockmap, + (void *)(uintptr_t)old[x].offset); + g_hash_table_insert(rdma->blockmap, + (void *)(uintptr_t)old[x].offset, + &local->block[x]); + } + } + memcpy(local->block, old, sizeof(RDMALocalBlock) * local->nb_blocks); + g_free(old); + } + + block = &local->block[local->nb_blocks]; + + block->block_name = g_strdup(block_name); + block->local_host_addr = host_addr; + block->offset = block_offset; + block->length = length; + block->index = local->nb_blocks; + block->src_index = ~0U; /* Filled in by the receipt of the block list */ + block->nb_chunks = ram_chunk_index(host_addr, host_addr + length) + 1UL; + block->transit_bitmap = bitmap_new(block->nb_chunks); + bitmap_clear(block->transit_bitmap, 0, block->nb_chunks); + block->unregister_bitmap = bitmap_new(block->nb_chunks); + bitmap_clear(block->unregister_bitmap, 0, block->nb_chunks); + block->remote_keys = g_new0(uint32_t, block->nb_chunks); + + block->is_ram_block = local->init ? false : true; + + if (rdma->blockmap) { + g_hash_table_insert(rdma->blockmap, (void *)(uintptr_t)block_offset, block); + } + + trace_rdma_add_block(block_name, local->nb_blocks, + (uintptr_t) block->local_host_addr, + block->offset, block->length, + (uintptr_t) (block->local_host_addr + block->length), + BITS_TO_LONGS(block->nb_chunks) * + sizeof(unsigned long) * 8, + block->nb_chunks); + + local->nb_blocks++; + + return 0; +} + +/* + * Memory regions need to be registered with the device and queue pairs setup + * in advanced before the migration starts. This tells us where the RAM blocks + * are so that we can register them individually. + */ +static int qemu_rdma_init_one_block(const char *block_name, void *host_addr, + ram_addr_t block_offset, ram_addr_t length, void *opaque) +{ + return rdma_add_block(opaque, block_name, host_addr, block_offset, length); +} + +/* + * Identify the RAMBlocks and their quantity. They will be references to + * identify chunk boundaries inside each RAMBlock and also be referenced + * during dynamic page registration. + */ +static int qemu_rdma_init_ram_blocks(RDMAContext *rdma) +{ + RDMALocalBlocks *local = &rdma->local_ram_blocks; + + assert(rdma->blockmap == NULL); + memset(local, 0, sizeof *local); + qemu_ram_foreach_block(qemu_rdma_init_one_block, rdma); + trace_qemu_rdma_init_ram_blocks(local->nb_blocks); + rdma->dest_blocks = g_new0(RDMADestBlock, + rdma->local_ram_blocks.nb_blocks); + local->init = true; + return 0; +} + +/* + * Note: If used outside of cleanup, the caller must ensure that the destination + * block structures are also updated + */ +static int rdma_delete_block(RDMAContext *rdma, RDMALocalBlock *block) +{ + RDMALocalBlocks *local = &rdma->local_ram_blocks; + RDMALocalBlock *old = local->block; + int x; + + if (rdma->blockmap) { + g_hash_table_remove(rdma->blockmap, (void *)(uintptr_t)block->offset); + } + if (block->pmr) { + int j; + + for (j = 0; j < block->nb_chunks; j++) { + if (!block->pmr[j]) { + continue; + } + ibv_dereg_mr(block->pmr[j]); + rdma->total_registrations--; + } + g_free(block->pmr); + block->pmr = NULL; + } + + if (block->mr) { + ibv_dereg_mr(block->mr); + rdma->total_registrations--; + block->mr = NULL; + } + + g_free(block->transit_bitmap); + block->transit_bitmap = NULL; + + g_free(block->unregister_bitmap); + block->unregister_bitmap = NULL; + + g_free(block->remote_keys); + block->remote_keys = NULL; + + g_free(block->block_name); + block->block_name = NULL; + + if (rdma->blockmap) { + for (x = 0; x < local->nb_blocks; x++) { + g_hash_table_remove(rdma->blockmap, + (void *)(uintptr_t)old[x].offset); + } + } + + if (local->nb_blocks > 1) { + + local->block = g_new0(RDMALocalBlock, local->nb_blocks - 1); + + if (block->index) { + memcpy(local->block, old, sizeof(RDMALocalBlock) * block->index); + } + + if (block->index < (local->nb_blocks - 1)) { + memcpy(local->block + block->index, old + (block->index + 1), + sizeof(RDMALocalBlock) * + (local->nb_blocks - (block->index + 1))); + } + } else { + assert(block == local->block); + local->block = NULL; + } + + trace_rdma_delete_block(block, (uintptr_t)block->local_host_addr, + block->offset, block->length, + (uintptr_t)(block->local_host_addr + block->length), + BITS_TO_LONGS(block->nb_chunks) * + sizeof(unsigned long) * 8, block->nb_chunks); + + g_free(old); + + local->nb_blocks--; + + if (local->nb_blocks && rdma->blockmap) { + for (x = 0; x < local->nb_blocks; x++) { + g_hash_table_insert(rdma->blockmap, + (void *)(uintptr_t)local->block[x].offset, + &local->block[x]); + } + } + + return 0; +} + +/* + * Put in the log file which RDMA device was opened and the details + * associated with that device. + */ +static void qemu_rdma_dump_id(const char *who, struct ibv_context *verbs) +{ + struct ibv_port_attr port; + + if (ibv_query_port(verbs, 1, &port)) { + error_report("Failed to query port information"); + return; + } + + printf("%s RDMA Device opened: kernel name %s " + "uverbs device name %s, " + "infiniband_verbs class device path %s, " + "infiniband class device path %s, " + "transport: (%d) %s\n", + who, + verbs->device->name, + verbs->device->dev_name, + verbs->device->dev_path, + verbs->device->ibdev_path, + port.link_layer, + (port.link_layer == IBV_LINK_LAYER_INFINIBAND) ? "Infiniband" : + ((port.link_layer == IBV_LINK_LAYER_ETHERNET) + ? "Ethernet" : "Unknown")); +} + +/* + * Put in the log file the RDMA gid addressing information, + * useful for folks who have trouble understanding the + * RDMA device hierarchy in the kernel. + */ +static void qemu_rdma_dump_gid(const char *who, struct rdma_cm_id *id) +{ + char sgid[33]; + char dgid[33]; + inet_ntop(AF_INET6, &id->route.addr.addr.ibaddr.sgid, sgid, sizeof sgid); + inet_ntop(AF_INET6, &id->route.addr.addr.ibaddr.dgid, dgid, sizeof dgid); + trace_qemu_rdma_dump_gid(who, sgid, dgid); +} + +/* + * As of now, IPv6 over RoCE / iWARP is not supported by linux. + * We will try the next addrinfo struct, and fail if there are + * no other valid addresses to bind against. + * + * If user is listening on '[::]', then we will not have a opened a device + * yet and have no way of verifying if the device is RoCE or not. + * + * In this case, the source VM will throw an error for ALL types of + * connections (both IPv4 and IPv6) if the destination machine does not have + * a regular infiniband network available for use. + * + * The only way to guarantee that an error is thrown for broken kernels is + * for the management software to choose a *specific* interface at bind time + * and validate what time of hardware it is. + * + * Unfortunately, this puts the user in a fix: + * + * If the source VM connects with an IPv4 address without knowing that the + * destination has bound to '[::]' the migration will unconditionally fail + * unless the management software is explicitly listening on the IPv4 + * address while using a RoCE-based device. + * + * If the source VM connects with an IPv6 address, then we're OK because we can + * throw an error on the source (and similarly on the destination). + * + * But in mixed environments, this will be broken for a while until it is fixed + * inside linux. + * + * We do provide a *tiny* bit of help in this function: We can list all of the + * devices in the system and check to see if all the devices are RoCE or + * Infiniband. + * + * If we detect that we have a *pure* RoCE environment, then we can safely + * thrown an error even if the management software has specified '[::]' as the + * bind address. + * + * However, if there is are multiple hetergeneous devices, then we cannot make + * this assumption and the user just has to be sure they know what they are + * doing. + * + * Patches are being reviewed on linux-rdma. + */ +static int qemu_rdma_broken_ipv6_kernel(Error **errp, struct ibv_context *verbs) +{ + struct ibv_port_attr port_attr; + + /* This bug only exists in linux, to our knowledge. */ +#ifdef CONFIG_LINUX + + /* + * Verbs are only NULL if management has bound to '[::]'. + * + * Let's iterate through all the devices and see if there any pure IB + * devices (non-ethernet). + * + * If not, then we can safely proceed with the migration. + * Otherwise, there are no guarantees until the bug is fixed in linux. + */ + if (!verbs) { + int num_devices, x; + struct ibv_device ** dev_list = ibv_get_device_list(&num_devices); + bool roce_found = false; + bool ib_found = false; + + for (x = 0; x < num_devices; x++) { + verbs = ibv_open_device(dev_list[x]); + if (!verbs) { + if (errno == EPERM) { + continue; + } else { + return -EINVAL; + } + } + + if (ibv_query_port(verbs, 1, &port_attr)) { + ibv_close_device(verbs); + ERROR(errp, "Could not query initial IB port"); + return -EINVAL; + } + + if (port_attr.link_layer == IBV_LINK_LAYER_INFINIBAND) { + ib_found = true; + } else if (port_attr.link_layer == IBV_LINK_LAYER_ETHERNET) { + roce_found = true; + } + + ibv_close_device(verbs); + + } + + if (roce_found) { + if (ib_found) { + fprintf(stderr, "WARN: migrations may fail:" + " IPv6 over RoCE / iWARP in linux" + " is broken. But since you appear to have a" + " mixed RoCE / IB environment, be sure to only" + " migrate over the IB fabric until the kernel " + " fixes the bug.\n"); + } else { + ERROR(errp, "You only have RoCE / iWARP devices in your systems" + " and your management software has specified '[::]'" + ", but IPv6 over RoCE / iWARP is not supported in Linux."); + return -ENONET; + } + } + + return 0; + } + + /* + * If we have a verbs context, that means that some other than '[::]' was + * used by the management software for binding. In which case we can + * actually warn the user about a potentially broken kernel. + */ + + /* IB ports start with 1, not 0 */ + if (ibv_query_port(verbs, 1, &port_attr)) { + ERROR(errp, "Could not query initial IB port"); + return -EINVAL; + } + + if (port_attr.link_layer == IBV_LINK_LAYER_ETHERNET) { + ERROR(errp, "Linux kernel's RoCE / iWARP does not support IPv6 " + "(but patches on linux-rdma in progress)"); + return -ENONET; + } + +#endif + + return 0; +} + +/* + * Figure out which RDMA device corresponds to the requested IP hostname + * Also create the initial connection manager identifiers for opening + * the connection. + */ +static int qemu_rdma_resolve_host(RDMAContext *rdma, Error **errp) +{ + int ret; + struct rdma_addrinfo *res; + char port_str[16]; + struct rdma_cm_event *cm_event; + char ip[40] = "unknown"; + struct rdma_addrinfo *e; + + if (rdma->host == NULL || !strcmp(rdma->host, "")) { + ERROR(errp, "RDMA hostname has not been set"); + return -EINVAL; + } + + /* create CM channel */ + rdma->channel = rdma_create_event_channel(); + if (!rdma->channel) { + ERROR(errp, "could not create CM channel"); + return -EINVAL; + } + + /* create CM id */ + ret = rdma_create_id(rdma->channel, &rdma->cm_id, NULL, RDMA_PS_TCP); + if (ret) { + ERROR(errp, "could not create channel id"); + goto err_resolve_create_id; + } + + snprintf(port_str, 16, "%d", rdma->port); + port_str[15] = '\0'; + + ret = rdma_getaddrinfo(rdma->host, port_str, NULL, &res); + if (ret < 0) { + ERROR(errp, "could not rdma_getaddrinfo address %s", rdma->host); + goto err_resolve_get_addr; + } + + for (e = res; e != NULL; e = e->ai_next) { + inet_ntop(e->ai_family, + &((struct sockaddr_in *) e->ai_dst_addr)->sin_addr, ip, sizeof ip); + trace_qemu_rdma_resolve_host_trying(rdma->host, ip); + + ret = rdma_resolve_addr(rdma->cm_id, NULL, e->ai_dst_addr, + RDMA_RESOLVE_TIMEOUT_MS); + if (!ret) { + if (e->ai_family == AF_INET6) { + ret = qemu_rdma_broken_ipv6_kernel(errp, rdma->cm_id->verbs); + if (ret) { + continue; + } + } + goto route; + } + } + + ERROR(errp, "could not resolve address %s", rdma->host); + goto err_resolve_get_addr; + +route: + qemu_rdma_dump_gid("source_resolve_addr", rdma->cm_id); + + ret = rdma_get_cm_event(rdma->channel, &cm_event); + if (ret) { + ERROR(errp, "could not perform event_addr_resolved"); + goto err_resolve_get_addr; + } + + if (cm_event->event != RDMA_CM_EVENT_ADDR_RESOLVED) { + ERROR(errp, "result not equal to event_addr_resolved %s", + rdma_event_str(cm_event->event)); + perror("rdma_resolve_addr"); + rdma_ack_cm_event(cm_event); + ret = -EINVAL; + goto err_resolve_get_addr; + } + rdma_ack_cm_event(cm_event); + + /* resolve route */ + ret = rdma_resolve_route(rdma->cm_id, RDMA_RESOLVE_TIMEOUT_MS); + if (ret) { + ERROR(errp, "could not resolve rdma route"); + goto err_resolve_get_addr; + } + + ret = rdma_get_cm_event(rdma->channel, &cm_event); + if (ret) { + ERROR(errp, "could not perform event_route_resolved"); + goto err_resolve_get_addr; + } + if (cm_event->event != RDMA_CM_EVENT_ROUTE_RESOLVED) { + ERROR(errp, "result not equal to event_route_resolved: %s", + rdma_event_str(cm_event->event)); + rdma_ack_cm_event(cm_event); + ret = -EINVAL; + goto err_resolve_get_addr; + } + rdma_ack_cm_event(cm_event); + rdma->verbs = rdma->cm_id->verbs; + qemu_rdma_dump_id("source_resolve_host", rdma->cm_id->verbs); + qemu_rdma_dump_gid("source_resolve_host", rdma->cm_id); + return 0; + +err_resolve_get_addr: + rdma_destroy_id(rdma->cm_id); + rdma->cm_id = NULL; +err_resolve_create_id: + rdma_destroy_event_channel(rdma->channel); + rdma->channel = NULL; + return ret; +} + +/* + * Create protection domain and completion queues + */ +static int qemu_rdma_alloc_pd_cq(RDMAContext *rdma) +{ + /* allocate pd */ + rdma->pd = ibv_alloc_pd(rdma->verbs); + if (!rdma->pd) { + error_report("failed to allocate protection domain"); + return -1; + } + + /* create completion channel */ + rdma->comp_channel = ibv_create_comp_channel(rdma->verbs); + if (!rdma->comp_channel) { + error_report("failed to allocate completion channel"); + goto err_alloc_pd_cq; + } + + /* + * Completion queue can be filled by both read and write work requests, + * so must reflect the sum of both possible queue sizes. + */ + rdma->cq = ibv_create_cq(rdma->verbs, (RDMA_SIGNALED_SEND_MAX * 3), + NULL, rdma->comp_channel, 0); + if (!rdma->cq) { + error_report("failed to allocate completion queue"); + goto err_alloc_pd_cq; + } + + return 0; + +err_alloc_pd_cq: + if (rdma->pd) { + ibv_dealloc_pd(rdma->pd); + } + if (rdma->comp_channel) { + ibv_destroy_comp_channel(rdma->comp_channel); + } + rdma->pd = NULL; + rdma->comp_channel = NULL; + return -1; + +} + +/* + * Create queue pairs. + */ +static int qemu_rdma_alloc_qp(RDMAContext *rdma) +{ + struct ibv_qp_init_attr attr = { 0 }; + int ret; + + attr.cap.max_send_wr = RDMA_SIGNALED_SEND_MAX; + attr.cap.max_recv_wr = 3; + attr.cap.max_send_sge = 1; + attr.cap.max_recv_sge = 1; + attr.send_cq = rdma->cq; + attr.recv_cq = rdma->cq; + attr.qp_type = IBV_QPT_RC; + + ret = rdma_create_qp(rdma->cm_id, rdma->pd, &attr); + if (ret) { + return -1; + } + + rdma->qp = rdma->cm_id->qp; + return 0; +} + +static int qemu_rdma_reg_whole_ram_blocks(RDMAContext *rdma) +{ + int i; + RDMALocalBlocks *local = &rdma->local_ram_blocks; + + for (i = 0; i < local->nb_blocks; i++) { + local->block[i].mr = + ibv_reg_mr(rdma->pd, + local->block[i].local_host_addr, + local->block[i].length, + IBV_ACCESS_LOCAL_WRITE | + IBV_ACCESS_REMOTE_WRITE + ); + if (!local->block[i].mr) { + perror("Failed to register local dest ram block!\n"); + break; + } + rdma->total_registrations++; + } + + if (i >= local->nb_blocks) { + return 0; + } + + for (i--; i >= 0; i--) { + ibv_dereg_mr(local->block[i].mr); + rdma->total_registrations--; + } + + return -1; + +} + +/* + * Find the ram block that corresponds to the page requested to be + * transmitted by QEMU. + * + * Once the block is found, also identify which 'chunk' within that + * block that the page belongs to. + * + * This search cannot fail or the migration will fail. + */ +static int qemu_rdma_search_ram_block(RDMAContext *rdma, + uintptr_t block_offset, + uint64_t offset, + uint64_t length, + uint64_t *block_index, + uint64_t *chunk_index) +{ + uint64_t current_addr = block_offset + offset; + RDMALocalBlock *block = g_hash_table_lookup(rdma->blockmap, + (void *) block_offset); + assert(block); + assert(current_addr >= block->offset); + assert((current_addr + length) <= (block->offset + block->length)); + + *block_index = block->index; + *chunk_index = ram_chunk_index(block->local_host_addr, + block->local_host_addr + (current_addr - block->offset)); + + return 0; +} + +/* + * Register a chunk with IB. If the chunk was already registered + * previously, then skip. + * + * Also return the keys associated with the registration needed + * to perform the actual RDMA operation. + */ +static int qemu_rdma_register_and_get_keys(RDMAContext *rdma, + RDMALocalBlock *block, uintptr_t host_addr, + uint32_t *lkey, uint32_t *rkey, int chunk, + uint8_t *chunk_start, uint8_t *chunk_end) +{ + if (block->mr) { + if (lkey) { + *lkey = block->mr->lkey; + } + if (rkey) { + *rkey = block->mr->rkey; + } + return 0; + } + + /* allocate memory to store chunk MRs */ + if (!block->pmr) { + block->pmr = g_new0(struct ibv_mr *, block->nb_chunks); + } + + /* + * If 'rkey', then we're the destination, so grant access to the source. + * + * If 'lkey', then we're the source VM, so grant access only to ourselves. + */ + if (!block->pmr[chunk]) { + uint64_t len = chunk_end - chunk_start; + + trace_qemu_rdma_register_and_get_keys(len, chunk_start); + + block->pmr[chunk] = ibv_reg_mr(rdma->pd, + chunk_start, len, + (rkey ? (IBV_ACCESS_LOCAL_WRITE | + IBV_ACCESS_REMOTE_WRITE) : 0)); + + if (!block->pmr[chunk]) { + perror("Failed to register chunk!"); + fprintf(stderr, "Chunk details: block: %d chunk index %d" + " start %" PRIuPTR " end %" PRIuPTR + " host %" PRIuPTR + " local %" PRIuPTR " registrations: %d\n", + block->index, chunk, (uintptr_t)chunk_start, + (uintptr_t)chunk_end, host_addr, + (uintptr_t)block->local_host_addr, + rdma->total_registrations); + return -1; + } + rdma->total_registrations++; + } + + if (lkey) { + *lkey = block->pmr[chunk]->lkey; + } + if (rkey) { + *rkey = block->pmr[chunk]->rkey; + } + return 0; +} + +/* + * Register (at connection time) the memory used for control + * channel messages. + */ +static int qemu_rdma_reg_control(RDMAContext *rdma, int idx) +{ + rdma->wr_data[idx].control_mr = ibv_reg_mr(rdma->pd, + rdma->wr_data[idx].control, RDMA_CONTROL_MAX_BUFFER, + IBV_ACCESS_LOCAL_WRITE | IBV_ACCESS_REMOTE_WRITE); + if (rdma->wr_data[idx].control_mr) { + rdma->total_registrations++; + return 0; + } + error_report("qemu_rdma_reg_control failed"); + return -1; +} + +const char *print_wrid(int wrid) +{ + if (wrid >= RDMA_WRID_RECV_CONTROL) { + return wrid_desc[RDMA_WRID_RECV_CONTROL]; + } + return wrid_desc[wrid]; +} + +/* + * RDMA requires memory registration (mlock/pinning), but this is not good for + * overcommitment. + * + * In preparation for the future where LRU information or workload-specific + * writable writable working set memory access behavior is available to QEMU + * it would be nice to have in place the ability to UN-register/UN-pin + * particular memory regions from the RDMA hardware when it is determine that + * those regions of memory will likely not be accessed again in the near future. + * + * While we do not yet have such information right now, the following + * compile-time option allows us to perform a non-optimized version of this + * behavior. + * + * By uncommenting this option, you will cause *all* RDMA transfers to be + * unregistered immediately after the transfer completes on both sides of the + * connection. This has no effect in 'rdma-pin-all' mode, only regular mode. + * + * This will have a terrible impact on migration performance, so until future + * workload information or LRU information is available, do not attempt to use + * this feature except for basic testing. + */ +//#define RDMA_UNREGISTRATION_EXAMPLE + +/* + * Perform a non-optimized memory unregistration after every transfer + * for demonstration purposes, only if pin-all is not requested. + * + * Potential optimizations: + * 1. Start a new thread to run this function continuously + - for bit clearing + - and for receipt of unregister messages + * 2. Use an LRU. + * 3. Use workload hints. + */ +static int qemu_rdma_unregister_waiting(RDMAContext *rdma) +{ + while (rdma->unregistrations[rdma->unregister_current]) { + int ret; + uint64_t wr_id = rdma->unregistrations[rdma->unregister_current]; + uint64_t chunk = + (wr_id & RDMA_WRID_CHUNK_MASK) >> RDMA_WRID_CHUNK_SHIFT; + uint64_t index = + (wr_id & RDMA_WRID_BLOCK_MASK) >> RDMA_WRID_BLOCK_SHIFT; + RDMALocalBlock *block = + &(rdma->local_ram_blocks.block[index]); + RDMARegister reg = { .current_index = index }; + RDMAControlHeader resp = { .type = RDMA_CONTROL_UNREGISTER_FINISHED, + }; + RDMAControlHeader head = { .len = sizeof(RDMARegister), + .type = RDMA_CONTROL_UNREGISTER_REQUEST, + .repeat = 1, + }; + + trace_qemu_rdma_unregister_waiting_proc(chunk, + rdma->unregister_current); + + rdma->unregistrations[rdma->unregister_current] = 0; + rdma->unregister_current++; + + if (rdma->unregister_current == RDMA_SIGNALED_SEND_MAX) { + rdma->unregister_current = 0; + } + + + /* + * Unregistration is speculative (because migration is single-threaded + * and we cannot break the protocol's inifinband message ordering). + * Thus, if the memory is currently being used for transmission, + * then abort the attempt to unregister and try again + * later the next time a completion is received for this memory. + */ + clear_bit(chunk, block->unregister_bitmap); + + if (test_bit(chunk, block->transit_bitmap)) { + trace_qemu_rdma_unregister_waiting_inflight(chunk); + continue; + } + + trace_qemu_rdma_unregister_waiting_send(chunk); + + ret = ibv_dereg_mr(block->pmr[chunk]); + block->pmr[chunk] = NULL; + block->remote_keys[chunk] = 0; + + if (ret != 0) { + perror("unregistration chunk failed"); + return -ret; + } + rdma->total_registrations--; + + reg.key.chunk = chunk; + register_to_network(rdma, ®); + ret = qemu_rdma_exchange_send(rdma, &head, (uint8_t *) ®, + &resp, NULL, NULL); + if (ret < 0) { + return ret; + } + + trace_qemu_rdma_unregister_waiting_complete(chunk); + } + + return 0; +} + +static uint64_t qemu_rdma_make_wrid(uint64_t wr_id, uint64_t index, + uint64_t chunk) +{ + uint64_t result = wr_id & RDMA_WRID_TYPE_MASK; + + result |= (index << RDMA_WRID_BLOCK_SHIFT); + result |= (chunk << RDMA_WRID_CHUNK_SHIFT); + + return result; +} + +/* + * Set bit for unregistration in the next iteration. + * We cannot transmit right here, but will unpin later. + */ +static void qemu_rdma_signal_unregister(RDMAContext *rdma, uint64_t index, + uint64_t chunk, uint64_t wr_id) +{ + if (rdma->unregistrations[rdma->unregister_next] != 0) { + error_report("rdma migration: queue is full"); + } else { + RDMALocalBlock *block = &(rdma->local_ram_blocks.block[index]); + + if (!test_and_set_bit(chunk, block->unregister_bitmap)) { + trace_qemu_rdma_signal_unregister_append(chunk, + rdma->unregister_next); + + rdma->unregistrations[rdma->unregister_next++] = + qemu_rdma_make_wrid(wr_id, index, chunk); + + if (rdma->unregister_next == RDMA_SIGNALED_SEND_MAX) { + rdma->unregister_next = 0; + } + } else { + trace_qemu_rdma_signal_unregister_already(chunk); + } + } +} + +/* + * Consult the connection manager to see a work request + * (of any kind) has completed. + * Return the work request ID that completed. + */ +static uint64_t qemu_rdma_poll(RDMAContext *rdma, uint64_t *wr_id_out, + uint32_t *byte_len) +{ + int ret; + struct ibv_wc wc; + uint64_t wr_id; + + ret = ibv_poll_cq(rdma->cq, 1, &wc); + + if (!ret) { + *wr_id_out = RDMA_WRID_NONE; + return 0; + } + + if (ret < 0) { + error_report("ibv_poll_cq return %d", ret); + return ret; + } + + wr_id = wc.wr_id & RDMA_WRID_TYPE_MASK; + + if (wc.status != IBV_WC_SUCCESS) { + fprintf(stderr, "ibv_poll_cq wc.status=%d %s!\n", + wc.status, ibv_wc_status_str(wc.status)); + fprintf(stderr, "ibv_poll_cq wrid=%s!\n", wrid_desc[wr_id]); + + return -1; + } + + if (rdma->control_ready_expected && + (wr_id >= RDMA_WRID_RECV_CONTROL)) { + trace_qemu_rdma_poll_recv(wrid_desc[RDMA_WRID_RECV_CONTROL], + wr_id - RDMA_WRID_RECV_CONTROL, wr_id, rdma->nb_sent); + rdma->control_ready_expected = 0; + } + + if (wr_id == RDMA_WRID_RDMA_WRITE) { + uint64_t chunk = + (wc.wr_id & RDMA_WRID_CHUNK_MASK) >> RDMA_WRID_CHUNK_SHIFT; + uint64_t index = + (wc.wr_id & RDMA_WRID_BLOCK_MASK) >> RDMA_WRID_BLOCK_SHIFT; + RDMALocalBlock *block = &(rdma->local_ram_blocks.block[index]); + + trace_qemu_rdma_poll_write(print_wrid(wr_id), wr_id, rdma->nb_sent, + index, chunk, block->local_host_addr, + (void *)(uintptr_t)block->remote_host_addr); + + clear_bit(chunk, block->transit_bitmap); + + if (rdma->nb_sent > 0) { + rdma->nb_sent--; + } + + if (!rdma->pin_all) { + /* + * FYI: If one wanted to signal a specific chunk to be unregistered + * using LRU or workload-specific information, this is the function + * you would call to do so. That chunk would then get asynchronously + * unregistered later. + */ +#ifdef RDMA_UNREGISTRATION_EXAMPLE + qemu_rdma_signal_unregister(rdma, index, chunk, wc.wr_id); +#endif + } + } else { + trace_qemu_rdma_poll_other(print_wrid(wr_id), wr_id, rdma->nb_sent); + } + + *wr_id_out = wc.wr_id; + if (byte_len) { + *byte_len = wc.byte_len; + } + + return 0; +} + +/* + * Block until the next work request has completed. + * + * First poll to see if a work request has already completed, + * otherwise block. + * + * If we encounter completed work requests for IDs other than + * the one we're interested in, then that's generally an error. + * + * The only exception is actual RDMA Write completions. These + * completions only need to be recorded, but do not actually + * need further processing. + */ +static int qemu_rdma_block_for_wrid(RDMAContext *rdma, int wrid_requested, + uint32_t *byte_len) +{ + int num_cq_events = 0, ret = 0; + struct ibv_cq *cq; + void *cq_ctx; + uint64_t wr_id = RDMA_WRID_NONE, wr_id_in; + + if (ibv_req_notify_cq(rdma->cq, 0)) { + return -1; + } + /* poll cq first */ + while (wr_id != wrid_requested) { + ret = qemu_rdma_poll(rdma, &wr_id_in, byte_len); + if (ret < 0) { + return ret; + } + + wr_id = wr_id_in & RDMA_WRID_TYPE_MASK; + + if (wr_id == RDMA_WRID_NONE) { + break; + } + if (wr_id != wrid_requested) { + trace_qemu_rdma_block_for_wrid_miss(print_wrid(wrid_requested), + wrid_requested, print_wrid(wr_id), wr_id); + } + } + + if (wr_id == wrid_requested) { + return 0; + } + + while (1) { + /* + * Coroutine doesn't start until process_incoming_migration() + * so don't yield unless we know we're running inside of a coroutine. + */ + if (rdma->migration_started_on_destination) { + yield_until_fd_readable(rdma->comp_channel->fd); + } + + if (ibv_get_cq_event(rdma->comp_channel, &cq, &cq_ctx)) { + perror("ibv_get_cq_event"); + goto err_block_for_wrid; + } + + num_cq_events++; + + if (ibv_req_notify_cq(cq, 0)) { + goto err_block_for_wrid; + } + + while (wr_id != wrid_requested) { + ret = qemu_rdma_poll(rdma, &wr_id_in, byte_len); + if (ret < 0) { + goto err_block_for_wrid; + } + + wr_id = wr_id_in & RDMA_WRID_TYPE_MASK; + + if (wr_id == RDMA_WRID_NONE) { + break; + } + if (wr_id != wrid_requested) { + trace_qemu_rdma_block_for_wrid_miss(print_wrid(wrid_requested), + wrid_requested, print_wrid(wr_id), wr_id); + } + } + + if (wr_id == wrid_requested) { + goto success_block_for_wrid; + } + } + +success_block_for_wrid: + if (num_cq_events) { + ibv_ack_cq_events(cq, num_cq_events); + } + return 0; + +err_block_for_wrid: + if (num_cq_events) { + ibv_ack_cq_events(cq, num_cq_events); + } + return ret; +} + +/* + * Post a SEND message work request for the control channel + * containing some data and block until the post completes. + */ +static int qemu_rdma_post_send_control(RDMAContext *rdma, uint8_t *buf, + RDMAControlHeader *head) +{ + int ret = 0; + RDMAWorkRequestData *wr = &rdma->wr_data[RDMA_WRID_CONTROL]; + struct ibv_send_wr *bad_wr; + struct ibv_sge sge = { + .addr = (uintptr_t)(wr->control), + .length = head->len + sizeof(RDMAControlHeader), + .lkey = wr->control_mr->lkey, + }; + struct ibv_send_wr send_wr = { + .wr_id = RDMA_WRID_SEND_CONTROL, + .opcode = IBV_WR_SEND, + .send_flags = IBV_SEND_SIGNALED, + .sg_list = &sge, + .num_sge = 1, + }; + + trace_qemu_rdma_post_send_control(control_desc[head->type]); + + /* + * We don't actually need to do a memcpy() in here if we used + * the "sge" properly, but since we're only sending control messages + * (not RAM in a performance-critical path), then its OK for now. + * + * The copy makes the RDMAControlHeader simpler to manipulate + * for the time being. + */ + assert(head->len <= RDMA_CONTROL_MAX_BUFFER - sizeof(*head)); + memcpy(wr->control, head, sizeof(RDMAControlHeader)); + control_to_network((void *) wr->control); + + if (buf) { + memcpy(wr->control + sizeof(RDMAControlHeader), buf, head->len); + } + + + ret = ibv_post_send(rdma->qp, &send_wr, &bad_wr); + + if (ret > 0) { + error_report("Failed to use post IB SEND for control"); + return -ret; + } + + ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_SEND_CONTROL, NULL); + if (ret < 0) { + error_report("rdma migration: send polling control error"); + } + + return ret; +} + +/* + * Post a RECV work request in anticipation of some future receipt + * of data on the control channel. + */ +static int qemu_rdma_post_recv_control(RDMAContext *rdma, int idx) +{ + struct ibv_recv_wr *bad_wr; + struct ibv_sge sge = { + .addr = (uintptr_t)(rdma->wr_data[idx].control), + .length = RDMA_CONTROL_MAX_BUFFER, + .lkey = rdma->wr_data[idx].control_mr->lkey, + }; + + struct ibv_recv_wr recv_wr = { + .wr_id = RDMA_WRID_RECV_CONTROL + idx, + .sg_list = &sge, + .num_sge = 1, + }; + + + if (ibv_post_recv(rdma->qp, &recv_wr, &bad_wr)) { + return -1; + } + + return 0; +} + +/* + * Block and wait for a RECV control channel message to arrive. + */ +static int qemu_rdma_exchange_get_response(RDMAContext *rdma, + RDMAControlHeader *head, int expecting, int idx) +{ + uint32_t byte_len; + int ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RECV_CONTROL + idx, + &byte_len); + + if (ret < 0) { + error_report("rdma migration: recv polling control error!"); + return ret; + } + + network_to_control((void *) rdma->wr_data[idx].control); + memcpy(head, rdma->wr_data[idx].control, sizeof(RDMAControlHeader)); + + trace_qemu_rdma_exchange_get_response_start(control_desc[expecting]); + + if (expecting == RDMA_CONTROL_NONE) { + trace_qemu_rdma_exchange_get_response_none(control_desc[head->type], + head->type); + } else if (head->type != expecting || head->type == RDMA_CONTROL_ERROR) { + error_report("Was expecting a %s (%d) control message" + ", but got: %s (%d), length: %d", + control_desc[expecting], expecting, + control_desc[head->type], head->type, head->len); + return -EIO; + } + if (head->len > RDMA_CONTROL_MAX_BUFFER - sizeof(*head)) { + error_report("too long length: %d", head->len); + return -EINVAL; + } + if (sizeof(*head) + head->len != byte_len) { + error_report("Malformed length: %d byte_len %d", head->len, byte_len); + return -EINVAL; + } + + return 0; +} + +/* + * When a RECV work request has completed, the work request's + * buffer is pointed at the header. + * + * This will advance the pointer to the data portion + * of the control message of the work request's buffer that + * was populated after the work request finished. + */ +static void qemu_rdma_move_header(RDMAContext *rdma, int idx, + RDMAControlHeader *head) +{ + rdma->wr_data[idx].control_len = head->len; + rdma->wr_data[idx].control_curr = + rdma->wr_data[idx].control + sizeof(RDMAControlHeader); +} + +/* + * This is an 'atomic' high-level operation to deliver a single, unified + * control-channel message. + * + * Additionally, if the user is expecting some kind of reply to this message, + * they can request a 'resp' response message be filled in by posting an + * additional work request on behalf of the user and waiting for an additional + * completion. + * + * The extra (optional) response is used during registration to us from having + * to perform an *additional* exchange of message just to provide a response by + * instead piggy-backing on the acknowledgement. + */ +static int qemu_rdma_exchange_send(RDMAContext *rdma, RDMAControlHeader *head, + uint8_t *data, RDMAControlHeader *resp, + int *resp_idx, + int (*callback)(RDMAContext *rdma)) +{ + int ret = 0; + + /* + * Wait until the dest is ready before attempting to deliver the message + * by waiting for a READY message. + */ + if (rdma->control_ready_expected) { + RDMAControlHeader resp; + ret = qemu_rdma_exchange_get_response(rdma, + &resp, RDMA_CONTROL_READY, RDMA_WRID_READY); + if (ret < 0) { + return ret; + } + } + + /* + * If the user is expecting a response, post a WR in anticipation of it. + */ + if (resp) { + ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_DATA); + if (ret) { + error_report("rdma migration: error posting" + " extra control recv for anticipated result!"); + return ret; + } + } + + /* + * Post a WR to replace the one we just consumed for the READY message. + */ + ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY); + if (ret) { + error_report("rdma migration: error posting first control recv!"); + return ret; + } + + /* + * Deliver the control message that was requested. + */ + ret = qemu_rdma_post_send_control(rdma, data, head); + + if (ret < 0) { + error_report("Failed to send control buffer!"); + return ret; + } + + /* + * If we're expecting a response, block and wait for it. + */ + if (resp) { + if (callback) { + trace_qemu_rdma_exchange_send_issue_callback(); + ret = callback(rdma); + if (ret < 0) { + return ret; + } + } + + trace_qemu_rdma_exchange_send_waiting(control_desc[resp->type]); + ret = qemu_rdma_exchange_get_response(rdma, resp, + resp->type, RDMA_WRID_DATA); + + if (ret < 0) { + return ret; + } + + qemu_rdma_move_header(rdma, RDMA_WRID_DATA, resp); + if (resp_idx) { + *resp_idx = RDMA_WRID_DATA; + } + trace_qemu_rdma_exchange_send_received(control_desc[resp->type]); + } + + rdma->control_ready_expected = 1; + + return 0; +} + +/* + * This is an 'atomic' high-level operation to receive a single, unified + * control-channel message. + */ +static int qemu_rdma_exchange_recv(RDMAContext *rdma, RDMAControlHeader *head, + int expecting) +{ + RDMAControlHeader ready = { + .len = 0, + .type = RDMA_CONTROL_READY, + .repeat = 1, + }; + int ret; + + /* + * Inform the source that we're ready to receive a message. + */ + ret = qemu_rdma_post_send_control(rdma, NULL, &ready); + + if (ret < 0) { + error_report("Failed to send control buffer!"); + return ret; + } + + /* + * Block and wait for the message. + */ + ret = qemu_rdma_exchange_get_response(rdma, head, + expecting, RDMA_WRID_READY); + + if (ret < 0) { + return ret; + } + + qemu_rdma_move_header(rdma, RDMA_WRID_READY, head); + + /* + * Post a new RECV work request to replace the one we just consumed. + */ + ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY); + if (ret) { + error_report("rdma migration: error posting second control recv!"); + return ret; + } + + return 0; +} + +/* + * Write an actual chunk of memory using RDMA. + * + * If we're using dynamic registration on the dest-side, we have to + * send a registration command first. + */ +static int qemu_rdma_write_one(QEMUFile *f, RDMAContext *rdma, + int current_index, uint64_t current_addr, + uint64_t length) +{ + struct ibv_sge sge; + struct ibv_send_wr send_wr = { 0 }; + struct ibv_send_wr *bad_wr; + int reg_result_idx, ret, count = 0; + uint64_t chunk, chunks; + uint8_t *chunk_start, *chunk_end; + RDMALocalBlock *block = &(rdma->local_ram_blocks.block[current_index]); + RDMARegister reg; + RDMARegisterResult *reg_result; + RDMAControlHeader resp = { .type = RDMA_CONTROL_REGISTER_RESULT }; + RDMAControlHeader head = { .len = sizeof(RDMARegister), + .type = RDMA_CONTROL_REGISTER_REQUEST, + .repeat = 1, + }; + +retry: + sge.addr = (uintptr_t)(block->local_host_addr + + (current_addr - block->offset)); + sge.length = length; + + chunk = ram_chunk_index(block->local_host_addr, + (uint8_t *)(uintptr_t)sge.addr); + chunk_start = ram_chunk_start(block, chunk); + + if (block->is_ram_block) { + chunks = length / (1UL << RDMA_REG_CHUNK_SHIFT); + + if (chunks && ((length % (1UL << RDMA_REG_CHUNK_SHIFT)) == 0)) { + chunks--; + } + } else { + chunks = block->length / (1UL << RDMA_REG_CHUNK_SHIFT); + + if (chunks && ((block->length % (1UL << RDMA_REG_CHUNK_SHIFT)) == 0)) { + chunks--; + } + } + + trace_qemu_rdma_write_one_top(chunks + 1, + (chunks + 1) * + (1UL << RDMA_REG_CHUNK_SHIFT) / 1024 / 1024); + + chunk_end = ram_chunk_end(block, chunk + chunks); + + if (!rdma->pin_all) { +#ifdef RDMA_UNREGISTRATION_EXAMPLE + qemu_rdma_unregister_waiting(rdma); +#endif + } + + while (test_bit(chunk, block->transit_bitmap)) { + (void)count; + trace_qemu_rdma_write_one_block(count++, current_index, chunk, + sge.addr, length, rdma->nb_sent, block->nb_chunks); + + ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RDMA_WRITE, NULL); + + if (ret < 0) { + error_report("Failed to Wait for previous write to complete " + "block %d chunk %" PRIu64 + " current %" PRIu64 " len %" PRIu64 " %d", + current_index, chunk, sge.addr, length, rdma->nb_sent); + return ret; + } + } + + if (!rdma->pin_all || !block->is_ram_block) { + if (!block->remote_keys[chunk]) { + /* + * This chunk has not yet been registered, so first check to see + * if the entire chunk is zero. If so, tell the other size to + * memset() + madvise() the entire chunk without RDMA. + */ + + if (can_use_buffer_find_nonzero_offset((void *)(uintptr_t)sge.addr, + length) + && buffer_find_nonzero_offset((void *)(uintptr_t)sge.addr, + length) == length) { + RDMACompress comp = { + .offset = current_addr, + .value = 0, + .block_idx = current_index, + .length = length, + }; + + head.len = sizeof(comp); + head.type = RDMA_CONTROL_COMPRESS; + + trace_qemu_rdma_write_one_zero(chunk, sge.length, + current_index, current_addr); + + compress_to_network(rdma, &comp); + ret = qemu_rdma_exchange_send(rdma, &head, + (uint8_t *) &comp, NULL, NULL, NULL); + + if (ret < 0) { + return -EIO; + } + + acct_update_position(f, sge.length, true); + + return 1; + } + + /* + * Otherwise, tell other side to register. + */ + reg.current_index = current_index; + if (block->is_ram_block) { + reg.key.current_addr = current_addr; + } else { + reg.key.chunk = chunk; + } + reg.chunks = chunks; + + trace_qemu_rdma_write_one_sendreg(chunk, sge.length, current_index, + current_addr); + + register_to_network(rdma, ®); + ret = qemu_rdma_exchange_send(rdma, &head, (uint8_t *) ®, + &resp, ®_result_idx, NULL); + if (ret < 0) { + return ret; + } + + /* try to overlap this single registration with the one we sent. */ + if (qemu_rdma_register_and_get_keys(rdma, block, sge.addr, + &sge.lkey, NULL, chunk, + chunk_start, chunk_end)) { + error_report("cannot get lkey"); + return -EINVAL; + } + + reg_result = (RDMARegisterResult *) + rdma->wr_data[reg_result_idx].control_curr; + + network_to_result(reg_result); + + trace_qemu_rdma_write_one_recvregres(block->remote_keys[chunk], + reg_result->rkey, chunk); + + block->remote_keys[chunk] = reg_result->rkey; + block->remote_host_addr = reg_result->host_addr; + } else { + /* already registered before */ + if (qemu_rdma_register_and_get_keys(rdma, block, sge.addr, + &sge.lkey, NULL, chunk, + chunk_start, chunk_end)) { + error_report("cannot get lkey!"); + return -EINVAL; + } + } + + send_wr.wr.rdma.rkey = block->remote_keys[chunk]; + } else { + send_wr.wr.rdma.rkey = block->remote_rkey; + + if (qemu_rdma_register_and_get_keys(rdma, block, sge.addr, + &sge.lkey, NULL, chunk, + chunk_start, chunk_end)) { + error_report("cannot get lkey!"); + return -EINVAL; + } + } + + /* + * Encode the ram block index and chunk within this wrid. + * We will use this information at the time of completion + * to figure out which bitmap to check against and then which + * chunk in the bitmap to look for. + */ + send_wr.wr_id = qemu_rdma_make_wrid(RDMA_WRID_RDMA_WRITE, + current_index, chunk); + + send_wr.opcode = IBV_WR_RDMA_WRITE; + send_wr.send_flags = IBV_SEND_SIGNALED; + send_wr.sg_list = &sge; + send_wr.num_sge = 1; + send_wr.wr.rdma.remote_addr = block->remote_host_addr + + (current_addr - block->offset); + + trace_qemu_rdma_write_one_post(chunk, sge.addr, send_wr.wr.rdma.remote_addr, + sge.length); + + /* + * ibv_post_send() does not return negative error numbers, + * per the specification they are positive - no idea why. + */ + ret = ibv_post_send(rdma->qp, &send_wr, &bad_wr); + + if (ret == ENOMEM) { + trace_qemu_rdma_write_one_queue_full(); + ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RDMA_WRITE, NULL); + if (ret < 0) { + error_report("rdma migration: failed to make " + "room in full send queue! %d", ret); + return ret; + } + + goto retry; + + } else if (ret > 0) { + perror("rdma migration: post rdma write failed"); + return -ret; + } + + set_bit(chunk, block->transit_bitmap); + acct_update_position(f, sge.length, false); + rdma->total_writes++; + + return 0; +} + +/* + * Push out any unwritten RDMA operations. + * + * We support sending out multiple chunks at the same time. + * Not all of them need to get signaled in the completion queue. + */ +static int qemu_rdma_write_flush(QEMUFile *f, RDMAContext *rdma) +{ + int ret; + + if (!rdma->current_length) { + return 0; + } + + ret = qemu_rdma_write_one(f, rdma, + rdma->current_index, rdma->current_addr, rdma->current_length); + + if (ret < 0) { + return ret; + } + + if (ret == 0) { + rdma->nb_sent++; + trace_qemu_rdma_write_flush(rdma->nb_sent); + } + + rdma->current_length = 0; + rdma->current_addr = 0; + + return 0; +} + +static inline int qemu_rdma_buffer_mergable(RDMAContext *rdma, + uint64_t offset, uint64_t len) +{ + RDMALocalBlock *block; + uint8_t *host_addr; + uint8_t *chunk_end; + + if (rdma->current_index < 0) { + return 0; + } + + if (rdma->current_chunk < 0) { + return 0; + } + + block = &(rdma->local_ram_blocks.block[rdma->current_index]); + host_addr = block->local_host_addr + (offset - block->offset); + chunk_end = ram_chunk_end(block, rdma->current_chunk); + + if (rdma->current_length == 0) { + return 0; + } + + /* + * Only merge into chunk sequentially. + */ + if (offset != (rdma->current_addr + rdma->current_length)) { + return 0; + } + + if (offset < block->offset) { + return 0; + } + + if ((offset + len) > (block->offset + block->length)) { + return 0; + } + + if ((host_addr + len) > chunk_end) { + return 0; + } + + return 1; +} + +/* + * We're not actually writing here, but doing three things: + * + * 1. Identify the chunk the buffer belongs to. + * 2. If the chunk is full or the buffer doesn't belong to the current + * chunk, then start a new chunk and flush() the old chunk. + * 3. To keep the hardware busy, we also group chunks into batches + * and only require that a batch gets acknowledged in the completion + * qeueue instead of each individual chunk. + */ +static int qemu_rdma_write(QEMUFile *f, RDMAContext *rdma, + uint64_t block_offset, uint64_t offset, + uint64_t len) +{ + uint64_t current_addr = block_offset + offset; + uint64_t index = rdma->current_index; + uint64_t chunk = rdma->current_chunk; + int ret; + + /* If we cannot merge it, we flush the current buffer first. */ + if (!qemu_rdma_buffer_mergable(rdma, current_addr, len)) { + ret = qemu_rdma_write_flush(f, rdma); + if (ret) { + return ret; + } + rdma->current_length = 0; + rdma->current_addr = current_addr; + + ret = qemu_rdma_search_ram_block(rdma, block_offset, + offset, len, &index, &chunk); + if (ret) { + error_report("ram block search failed"); + return ret; + } + rdma->current_index = index; + rdma->current_chunk = chunk; + } + + /* merge it */ + rdma->current_length += len; + + /* flush it if buffer is too large */ + if (rdma->current_length >= RDMA_MERGE_MAX) { + return qemu_rdma_write_flush(f, rdma); + } + + return 0; +} + +static void qemu_rdma_cleanup(RDMAContext *rdma) +{ + struct rdma_cm_event *cm_event; + int ret, idx; + + if (rdma->cm_id && rdma->connected) { + if (rdma->error_state) { + RDMAControlHeader head = { .len = 0, + .type = RDMA_CONTROL_ERROR, + .repeat = 1, + }; + error_report("Early error. Sending error."); + qemu_rdma_post_send_control(rdma, NULL, &head); + } + + ret = rdma_disconnect(rdma->cm_id); + if (!ret) { + trace_qemu_rdma_cleanup_waiting_for_disconnect(); + ret = rdma_get_cm_event(rdma->channel, &cm_event); + if (!ret) { + rdma_ack_cm_event(cm_event); + } + } + trace_qemu_rdma_cleanup_disconnect(); + rdma->connected = false; + } + + g_free(rdma->dest_blocks); + rdma->dest_blocks = NULL; + + for (idx = 0; idx < RDMA_WRID_MAX; idx++) { + if (rdma->wr_data[idx].control_mr) { + rdma->total_registrations--; + ibv_dereg_mr(rdma->wr_data[idx].control_mr); + } + rdma->wr_data[idx].control_mr = NULL; + } + + if (rdma->local_ram_blocks.block) { + while (rdma->local_ram_blocks.nb_blocks) { + rdma_delete_block(rdma, &rdma->local_ram_blocks.block[0]); + } + } + + if (rdma->qp) { + rdma_destroy_qp(rdma->cm_id); + rdma->qp = NULL; + } + if (rdma->cq) { + ibv_destroy_cq(rdma->cq); + rdma->cq = NULL; + } + if (rdma->comp_channel) { + ibv_destroy_comp_channel(rdma->comp_channel); + rdma->comp_channel = NULL; + } + if (rdma->pd) { + ibv_dealloc_pd(rdma->pd); + rdma->pd = NULL; + } + if (rdma->cm_id) { + rdma_destroy_id(rdma->cm_id); + rdma->cm_id = NULL; + } + if (rdma->listen_id) { + rdma_destroy_id(rdma->listen_id); + rdma->listen_id = NULL; + } + if (rdma->channel) { + rdma_destroy_event_channel(rdma->channel); + rdma->channel = NULL; + } + g_free(rdma->host); + rdma->host = NULL; +} + + +static int qemu_rdma_source_init(RDMAContext *rdma, Error **errp, bool pin_all) +{ + int ret, idx; + Error *local_err = NULL, **temp = &local_err; + + /* + * Will be validated against destination's actual capabilities + * after the connect() completes. + */ + rdma->pin_all = pin_all; + + ret = qemu_rdma_resolve_host(rdma, temp); + if (ret) { + goto err_rdma_source_init; + } + + ret = qemu_rdma_alloc_pd_cq(rdma); + if (ret) { + ERROR(temp, "rdma migration: error allocating pd and cq! Your mlock()" + " limits may be too low. Please check $ ulimit -a # and " + "search for 'ulimit -l' in the output"); + goto err_rdma_source_init; + } + + ret = qemu_rdma_alloc_qp(rdma); + if (ret) { + ERROR(temp, "rdma migration: error allocating qp!"); + goto err_rdma_source_init; + } + + ret = qemu_rdma_init_ram_blocks(rdma); + if (ret) { + ERROR(temp, "rdma migration: error initializing ram blocks!"); + goto err_rdma_source_init; + } + + /* Build the hash that maps from offset to RAMBlock */ + rdma->blockmap = g_hash_table_new(g_direct_hash, g_direct_equal); + for (idx = 0; idx < rdma->local_ram_blocks.nb_blocks; idx++) { + g_hash_table_insert(rdma->blockmap, + (void *)(uintptr_t)rdma->local_ram_blocks.block[idx].offset, + &rdma->local_ram_blocks.block[idx]); + } + + for (idx = 0; idx < RDMA_WRID_MAX; idx++) { + ret = qemu_rdma_reg_control(rdma, idx); + if (ret) { + ERROR(temp, "rdma migration: error registering %d control!", + idx); + goto err_rdma_source_init; + } + } + + return 0; + +err_rdma_source_init: + error_propagate(errp, local_err); + qemu_rdma_cleanup(rdma); + return -1; +} + +static int qemu_rdma_connect(RDMAContext *rdma, Error **errp) +{ + RDMACapabilities cap = { + .version = RDMA_CONTROL_VERSION_CURRENT, + .flags = 0, + }; + struct rdma_conn_param conn_param = { .initiator_depth = 2, + .retry_count = 5, + .private_data = &cap, + .private_data_len = sizeof(cap), + }; + struct rdma_cm_event *cm_event; + int ret; + + /* + * Only negotiate the capability with destination if the user + * on the source first requested the capability. + */ + if (rdma->pin_all) { + trace_qemu_rdma_connect_pin_all_requested(); + cap.flags |= RDMA_CAPABILITY_PIN_ALL; + } + + caps_to_network(&cap); + + ret = rdma_connect(rdma->cm_id, &conn_param); + if (ret) { + perror("rdma_connect"); + ERROR(errp, "connecting to destination!"); + goto err_rdma_source_connect; + } + + ret = rdma_get_cm_event(rdma->channel, &cm_event); + if (ret) { + perror("rdma_get_cm_event after rdma_connect"); + ERROR(errp, "connecting to destination!"); + rdma_ack_cm_event(cm_event); + goto err_rdma_source_connect; + } + + if (cm_event->event != RDMA_CM_EVENT_ESTABLISHED) { + perror("rdma_get_cm_event != EVENT_ESTABLISHED after rdma_connect"); + ERROR(errp, "connecting to destination!"); + rdma_ack_cm_event(cm_event); + goto err_rdma_source_connect; + } + rdma->connected = true; + + memcpy(&cap, cm_event->param.conn.private_data, sizeof(cap)); + network_to_caps(&cap); + + /* + * Verify that the *requested* capabilities are supported by the destination + * and disable them otherwise. + */ + if (rdma->pin_all && !(cap.flags & RDMA_CAPABILITY_PIN_ALL)) { + ERROR(errp, "Server cannot support pinning all memory. " + "Will register memory dynamically."); + rdma->pin_all = false; + } + + trace_qemu_rdma_connect_pin_all_outcome(rdma->pin_all); + + rdma_ack_cm_event(cm_event); + + ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY); + if (ret) { + ERROR(errp, "posting second control recv!"); + goto err_rdma_source_connect; + } + + rdma->control_ready_expected = 1; + rdma->nb_sent = 0; + return 0; + +err_rdma_source_connect: + qemu_rdma_cleanup(rdma); + return -1; +} + +static int qemu_rdma_dest_init(RDMAContext *rdma, Error **errp) +{ + int ret, idx; + struct rdma_cm_id *listen_id; + char ip[40] = "unknown"; + struct rdma_addrinfo *res, *e; + char port_str[16]; + + for (idx = 0; idx < RDMA_WRID_MAX; idx++) { + rdma->wr_data[idx].control_len = 0; + rdma->wr_data[idx].control_curr = NULL; + } + + if (!rdma->host || !rdma->host[0]) { + ERROR(errp, "RDMA host is not set!"); + rdma->error_state = -EINVAL; + return -1; + } + /* create CM channel */ + rdma->channel = rdma_create_event_channel(); + if (!rdma->channel) { + ERROR(errp, "could not create rdma event channel"); + rdma->error_state = -EINVAL; + return -1; + } + + /* create CM id */ + ret = rdma_create_id(rdma->channel, &listen_id, NULL, RDMA_PS_TCP); + if (ret) { + ERROR(errp, "could not create cm_id!"); + goto err_dest_init_create_listen_id; + } + + snprintf(port_str, 16, "%d", rdma->port); + port_str[15] = '\0'; + + ret = rdma_getaddrinfo(rdma->host, port_str, NULL, &res); + if (ret < 0) { + ERROR(errp, "could not rdma_getaddrinfo address %s", rdma->host); + goto err_dest_init_bind_addr; + } + + for (e = res; e != NULL; e = e->ai_next) { + inet_ntop(e->ai_family, + &((struct sockaddr_in *) e->ai_dst_addr)->sin_addr, ip, sizeof ip); + trace_qemu_rdma_dest_init_trying(rdma->host, ip); + ret = rdma_bind_addr(listen_id, e->ai_dst_addr); + if (ret) { + continue; + } + if (e->ai_family == AF_INET6) { + ret = qemu_rdma_broken_ipv6_kernel(errp, listen_id->verbs); + if (ret) { + continue; + } + } + break; + } + + if (!e) { + ERROR(errp, "Error: could not rdma_bind_addr!"); + goto err_dest_init_bind_addr; + } + + rdma->listen_id = listen_id; + qemu_rdma_dump_gid("dest_init", listen_id); + return 0; + +err_dest_init_bind_addr: + rdma_destroy_id(listen_id); +err_dest_init_create_listen_id: + rdma_destroy_event_channel(rdma->channel); + rdma->channel = NULL; + rdma->error_state = ret; + return ret; + +} + +static void *qemu_rdma_data_init(const char *host_port, Error **errp) +{ + RDMAContext *rdma = NULL; + InetSocketAddress *addr; + + if (host_port) { + rdma = g_new0(RDMAContext, 1); + rdma->current_index = -1; + rdma->current_chunk = -1; + + addr = inet_parse(host_port, NULL); + if (addr != NULL) { + rdma->port = atoi(addr->port); + rdma->host = g_strdup(addr->host); + } else { + ERROR(errp, "bad RDMA migration address '%s'", host_port); + g_free(rdma); + rdma = NULL; + } + + qapi_free_InetSocketAddress(addr); + } + + return rdma; +} + +/* + * QEMUFile interface to the control channel. + * SEND messages for control only. + * VM's ram is handled with regular RDMA messages. + */ +static ssize_t qemu_rdma_put_buffer(void *opaque, const uint8_t *buf, + int64_t pos, size_t size) +{ + QEMUFileRDMA *r = opaque; + QEMUFile *f = r->file; + RDMAContext *rdma = r->rdma; + size_t remaining = size; + uint8_t * data = (void *) buf; + int ret; + + CHECK_ERROR_STATE(); + + /* + * Push out any writes that + * we're queued up for VM's ram. + */ + ret = qemu_rdma_write_flush(f, rdma); + if (ret < 0) { + rdma->error_state = ret; + return ret; + } + + while (remaining) { + RDMAControlHeader head; + + r->len = MIN(remaining, RDMA_SEND_INCREMENT); + remaining -= r->len; + + /* Guaranteed to fit due to RDMA_SEND_INCREMENT MIN above */ + head.len = (uint32_t)r->len; + head.type = RDMA_CONTROL_QEMU_FILE; + + ret = qemu_rdma_exchange_send(rdma, &head, data, NULL, NULL, NULL); + + if (ret < 0) { + rdma->error_state = ret; + return ret; + } + + data += r->len; + } + + return size; +} + +static size_t qemu_rdma_fill(RDMAContext *rdma, uint8_t *buf, + size_t size, int idx) +{ + size_t len = 0; + + if (rdma->wr_data[idx].control_len) { + trace_qemu_rdma_fill(rdma->wr_data[idx].control_len, size); + + len = MIN(size, rdma->wr_data[idx].control_len); + memcpy(buf, rdma->wr_data[idx].control_curr, len); + rdma->wr_data[idx].control_curr += len; + rdma->wr_data[idx].control_len -= len; + } + + return len; +} + +/* + * QEMUFile interface to the control channel. + * RDMA links don't use bytestreams, so we have to + * return bytes to QEMUFile opportunistically. + */ +static ssize_t qemu_rdma_get_buffer(void *opaque, uint8_t *buf, + int64_t pos, size_t size) +{ + QEMUFileRDMA *r = opaque; + RDMAContext *rdma = r->rdma; + RDMAControlHeader head; + int ret = 0; + + CHECK_ERROR_STATE(); + + /* + * First, we hold on to the last SEND message we + * were given and dish out the bytes until we run + * out of bytes. + */ + r->len = qemu_rdma_fill(r->rdma, buf, size, 0); + if (r->len) { + return r->len; + } + + /* + * Once we run out, we block and wait for another + * SEND message to arrive. + */ + ret = qemu_rdma_exchange_recv(rdma, &head, RDMA_CONTROL_QEMU_FILE); + + if (ret < 0) { + rdma->error_state = ret; + return ret; + } + + /* + * SEND was received with new bytes, now try again. + */ + return qemu_rdma_fill(r->rdma, buf, size, 0); +} + +/* + * Block until all the outstanding chunks have been delivered by the hardware. + */ +static int qemu_rdma_drain_cq(QEMUFile *f, RDMAContext *rdma) +{ + int ret; + + if (qemu_rdma_write_flush(f, rdma) < 0) { + return -EIO; + } + + while (rdma->nb_sent) { + ret = qemu_rdma_block_for_wrid(rdma, RDMA_WRID_RDMA_WRITE, NULL); + if (ret < 0) { + error_report("rdma migration: complete polling error!"); + return -EIO; + } + } + + qemu_rdma_unregister_waiting(rdma); + + return 0; +} + +static int qemu_rdma_close(void *opaque) +{ + trace_qemu_rdma_close(); + QEMUFileRDMA *r = opaque; + if (r->rdma) { + qemu_rdma_cleanup(r->rdma); + g_free(r->rdma); + } + g_free(r); + return 0; +} + +/* + * Parameters: + * @offset == 0 : + * This means that 'block_offset' is a full virtual address that does not + * belong to a RAMBlock of the virtual machine and instead + * represents a private malloc'd memory area that the caller wishes to + * transfer. + * + * @offset != 0 : + * Offset is an offset to be added to block_offset and used + * to also lookup the corresponding RAMBlock. + * + * @size > 0 : + * Initiate an transfer this size. + * + * @size == 0 : + * A 'hint' or 'advice' that means that we wish to speculatively + * and asynchronously unregister this memory. In this case, there is no + * guarantee that the unregister will actually happen, for example, + * if the memory is being actively transmitted. Additionally, the memory + * may be re-registered at any future time if a write within the same + * chunk was requested again, even if you attempted to unregister it + * here. + * + * @size < 0 : TODO, not yet supported + * Unregister the memory NOW. This means that the caller does not + * expect there to be any future RDMA transfers and we just want to clean + * things up. This is used in case the upper layer owns the memory and + * cannot wait for qemu_fclose() to occur. + * + * @bytes_sent : User-specificed pointer to indicate how many bytes were + * sent. Usually, this will not be more than a few bytes of + * the protocol because most transfers are sent asynchronously. + */ +static size_t qemu_rdma_save_page(QEMUFile *f, void *opaque, + ram_addr_t block_offset, ram_addr_t offset, + size_t size, uint64_t *bytes_sent) +{ + QEMUFileRDMA *rfile = opaque; + RDMAContext *rdma = rfile->rdma; + int ret; + + CHECK_ERROR_STATE(); + + qemu_fflush(f); + + if (size > 0) { + /* + * Add this page to the current 'chunk'. If the chunk + * is full, or the page doen't belong to the current chunk, + * an actual RDMA write will occur and a new chunk will be formed. + */ + ret = qemu_rdma_write(f, rdma, block_offset, offset, size); + if (ret < 0) { + error_report("rdma migration: write error! %d", ret); + goto err; + } + + /* + * We always return 1 bytes because the RDMA + * protocol is completely asynchronous. We do not yet know + * whether an identified chunk is zero or not because we're + * waiting for other pages to potentially be merged with + * the current chunk. So, we have to call qemu_update_position() + * later on when the actual write occurs. + */ + if (bytes_sent) { + *bytes_sent = 1; + } + } else { + uint64_t index, chunk; + + /* TODO: Change QEMUFileOps prototype to be signed: size_t => long + if (size < 0) { + ret = qemu_rdma_drain_cq(f, rdma); + if (ret < 0) { + fprintf(stderr, "rdma: failed to synchronously drain" + " completion queue before unregistration.\n"); + goto err; + } + } + */ + + ret = qemu_rdma_search_ram_block(rdma, block_offset, + offset, size, &index, &chunk); + + if (ret) { + error_report("ram block search failed"); + goto err; + } + + qemu_rdma_signal_unregister(rdma, index, chunk, 0); + + /* + * TODO: Synchronous, guaranteed unregistration (should not occur during + * fast-path). Otherwise, unregisters will process on the next call to + * qemu_rdma_drain_cq() + if (size < 0) { + qemu_rdma_unregister_waiting(rdma); + } + */ + } + + /* + * Drain the Completion Queue if possible, but do not block, + * just poll. + * + * If nothing to poll, the end of the iteration will do this + * again to make sure we don't overflow the request queue. + */ + while (1) { + uint64_t wr_id, wr_id_in; + int ret = qemu_rdma_poll(rdma, &wr_id_in, NULL); + if (ret < 0) { + error_report("rdma migration: polling error! %d", ret); + goto err; + } + + wr_id = wr_id_in & RDMA_WRID_TYPE_MASK; + + if (wr_id == RDMA_WRID_NONE) { + break; + } + } + + return RAM_SAVE_CONTROL_DELAYED; +err: + rdma->error_state = ret; + return ret; +} + +static int qemu_rdma_accept(RDMAContext *rdma) +{ + RDMACapabilities cap; + struct rdma_conn_param conn_param = { + .responder_resources = 2, + .private_data = &cap, + .private_data_len = sizeof(cap), + }; + struct rdma_cm_event *cm_event; + struct ibv_context *verbs; + int ret = -EINVAL; + int idx; + + ret = rdma_get_cm_event(rdma->channel, &cm_event); + if (ret) { + goto err_rdma_dest_wait; + } + + if (cm_event->event != RDMA_CM_EVENT_CONNECT_REQUEST) { + rdma_ack_cm_event(cm_event); + goto err_rdma_dest_wait; + } + + memcpy(&cap, cm_event->param.conn.private_data, sizeof(cap)); + + network_to_caps(&cap); + + if (cap.version < 1 || cap.version > RDMA_CONTROL_VERSION_CURRENT) { + error_report("Unknown source RDMA version: %d, bailing...", + cap.version); + rdma_ack_cm_event(cm_event); + goto err_rdma_dest_wait; + } + + /* + * Respond with only the capabilities this version of QEMU knows about. + */ + cap.flags &= known_capabilities; + + /* + * Enable the ones that we do know about. + * Add other checks here as new ones are introduced. + */ + if (cap.flags & RDMA_CAPABILITY_PIN_ALL) { + rdma->pin_all = true; + } + + rdma->cm_id = cm_event->id; + verbs = cm_event->id->verbs; + + rdma_ack_cm_event(cm_event); + + trace_qemu_rdma_accept_pin_state(rdma->pin_all); + + caps_to_network(&cap); + + trace_qemu_rdma_accept_pin_verbsc(verbs); + + if (!rdma->verbs) { + rdma->verbs = verbs; + } else if (rdma->verbs != verbs) { + error_report("ibv context not matching %p, %p!", rdma->verbs, + verbs); + goto err_rdma_dest_wait; + } + + qemu_rdma_dump_id("dest_init", verbs); + + ret = qemu_rdma_alloc_pd_cq(rdma); + if (ret) { + error_report("rdma migration: error allocating pd and cq!"); + goto err_rdma_dest_wait; + } + + ret = qemu_rdma_alloc_qp(rdma); + if (ret) { + error_report("rdma migration: error allocating qp!"); + goto err_rdma_dest_wait; + } + + ret = qemu_rdma_init_ram_blocks(rdma); + if (ret) { + error_report("rdma migration: error initializing ram blocks!"); + goto err_rdma_dest_wait; + } + + for (idx = 0; idx < RDMA_WRID_MAX; idx++) { + ret = qemu_rdma_reg_control(rdma, idx); + if (ret) { + error_report("rdma: error registering %d control", idx); + goto err_rdma_dest_wait; + } + } + + qemu_set_fd_handler(rdma->channel->fd, NULL, NULL, NULL); + + ret = rdma_accept(rdma->cm_id, &conn_param); + if (ret) { + error_report("rdma_accept returns %d", ret); + goto err_rdma_dest_wait; + } + + ret = rdma_get_cm_event(rdma->channel, &cm_event); + if (ret) { + error_report("rdma_accept get_cm_event failed %d", ret); + goto err_rdma_dest_wait; + } + + if (cm_event->event != RDMA_CM_EVENT_ESTABLISHED) { + error_report("rdma_accept not event established"); + rdma_ack_cm_event(cm_event); + goto err_rdma_dest_wait; + } + + rdma_ack_cm_event(cm_event); + rdma->connected = true; + + ret = qemu_rdma_post_recv_control(rdma, RDMA_WRID_READY); + if (ret) { + error_report("rdma migration: error posting second control recv"); + goto err_rdma_dest_wait; + } + + qemu_rdma_dump_gid("dest_connect", rdma->cm_id); + + return 0; + +err_rdma_dest_wait: + rdma->error_state = ret; + qemu_rdma_cleanup(rdma); + return ret; +} + +static int dest_ram_sort_func(const void *a, const void *b) +{ + unsigned int a_index = ((const RDMALocalBlock *)a)->src_index; + unsigned int b_index = ((const RDMALocalBlock *)b)->src_index; + + return (a_index < b_index) ? -1 : (a_index != b_index); +} + +/* + * During each iteration of the migration, we listen for instructions + * by the source VM to perform dynamic page registrations before they + * can perform RDMA operations. + * + * We respond with the 'rkey'. + * + * Keep doing this until the source tells us to stop. + */ +static int qemu_rdma_registration_handle(QEMUFile *f, void *opaque) +{ + RDMAControlHeader reg_resp = { .len = sizeof(RDMARegisterResult), + .type = RDMA_CONTROL_REGISTER_RESULT, + .repeat = 0, + }; + RDMAControlHeader unreg_resp = { .len = 0, + .type = RDMA_CONTROL_UNREGISTER_FINISHED, + .repeat = 0, + }; + RDMAControlHeader blocks = { .type = RDMA_CONTROL_RAM_BLOCKS_RESULT, + .repeat = 1 }; + QEMUFileRDMA *rfile = opaque; + RDMAContext *rdma = rfile->rdma; + RDMALocalBlocks *local = &rdma->local_ram_blocks; + RDMAControlHeader head; + RDMARegister *reg, *registers; + RDMACompress *comp; + RDMARegisterResult *reg_result; + static RDMARegisterResult results[RDMA_CONTROL_MAX_COMMANDS_PER_MESSAGE]; + RDMALocalBlock *block; + void *host_addr; + int ret = 0; + int idx = 0; + int count = 0; + int i = 0; + + CHECK_ERROR_STATE(); + + do { + trace_qemu_rdma_registration_handle_wait(); + + ret = qemu_rdma_exchange_recv(rdma, &head, RDMA_CONTROL_NONE); + + if (ret < 0) { + break; + } + + if (head.repeat > RDMA_CONTROL_MAX_COMMANDS_PER_MESSAGE) { + error_report("rdma: Too many requests in this message (%d)." + "Bailing.", head.repeat); + ret = -EIO; + break; + } + + switch (head.type) { + case RDMA_CONTROL_COMPRESS: + comp = (RDMACompress *) rdma->wr_data[idx].control_curr; + network_to_compress(comp); + + trace_qemu_rdma_registration_handle_compress(comp->length, + comp->block_idx, + comp->offset); + if (comp->block_idx >= rdma->local_ram_blocks.nb_blocks) { + error_report("rdma: 'compress' bad block index %u (vs %d)", + (unsigned int)comp->block_idx, + rdma->local_ram_blocks.nb_blocks); + ret = -EIO; + goto out; + } + block = &(rdma->local_ram_blocks.block[comp->block_idx]); + + host_addr = block->local_host_addr + + (comp->offset - block->offset); + + ram_handle_compressed(host_addr, comp->value, comp->length); + break; + + case RDMA_CONTROL_REGISTER_FINISHED: + trace_qemu_rdma_registration_handle_finished(); + goto out; + + case RDMA_CONTROL_RAM_BLOCKS_REQUEST: + trace_qemu_rdma_registration_handle_ram_blocks(); + + /* Sort our local RAM Block list so it's the same as the source, + * we can do this since we've filled in a src_index in the list + * as we received the RAMBlock list earlier. + */ + qsort(rdma->local_ram_blocks.block, + rdma->local_ram_blocks.nb_blocks, + sizeof(RDMALocalBlock), dest_ram_sort_func); + if (rdma->pin_all) { + ret = qemu_rdma_reg_whole_ram_blocks(rdma); + if (ret) { + error_report("rdma migration: error dest " + "registering ram blocks"); + goto out; + } + } + + /* + * Dest uses this to prepare to transmit the RAMBlock descriptions + * to the source VM after connection setup. + * Both sides use the "remote" structure to communicate and update + * their "local" descriptions with what was sent. + */ + for (i = 0; i < local->nb_blocks; i++) { + rdma->dest_blocks[i].remote_host_addr = + (uintptr_t)(local->block[i].local_host_addr); + + if (rdma->pin_all) { + rdma->dest_blocks[i].remote_rkey = local->block[i].mr->rkey; + } + + rdma->dest_blocks[i].offset = local->block[i].offset; + rdma->dest_blocks[i].length = local->block[i].length; + + dest_block_to_network(&rdma->dest_blocks[i]); + trace_qemu_rdma_registration_handle_ram_blocks_loop( + local->block[i].block_name, + local->block[i].offset, + local->block[i].length, + local->block[i].local_host_addr, + local->block[i].src_index); + } + + blocks.len = rdma->local_ram_blocks.nb_blocks + * sizeof(RDMADestBlock); + + + ret = qemu_rdma_post_send_control(rdma, + (uint8_t *) rdma->dest_blocks, &blocks); + + if (ret < 0) { + error_report("rdma migration: error sending remote info"); + goto out; + } + + break; + case RDMA_CONTROL_REGISTER_REQUEST: + trace_qemu_rdma_registration_handle_register(head.repeat); + + reg_resp.repeat = head.repeat; + registers = (RDMARegister *) rdma->wr_data[idx].control_curr; + + for (count = 0; count < head.repeat; count++) { + uint64_t chunk; + uint8_t *chunk_start, *chunk_end; + + reg = ®isters[count]; + network_to_register(reg); + + reg_result = &results[count]; + + trace_qemu_rdma_registration_handle_register_loop(count, + reg->current_index, reg->key.current_addr, reg->chunks); + + if (reg->current_index >= rdma->local_ram_blocks.nb_blocks) { + error_report("rdma: 'register' bad block index %u (vs %d)", + (unsigned int)reg->current_index, + rdma->local_ram_blocks.nb_blocks); + ret = -ENOENT; + goto out; + } + block = &(rdma->local_ram_blocks.block[reg->current_index]); + if (block->is_ram_block) { + if (block->offset > reg->key.current_addr) { + error_report("rdma: bad register address for block %s" + " offset: %" PRIx64 " current_addr: %" PRIx64, + block->block_name, block->offset, + reg->key.current_addr); + ret = -ERANGE; + goto out; + } + host_addr = (block->local_host_addr + + (reg->key.current_addr - block->offset)); + chunk = ram_chunk_index(block->local_host_addr, + (uint8_t *) host_addr); + } else { + chunk = reg->key.chunk; + host_addr = block->local_host_addr + + (reg->key.chunk * (1UL << RDMA_REG_CHUNK_SHIFT)); + /* Check for particularly bad chunk value */ + if (host_addr < (void *)block->local_host_addr) { + error_report("rdma: bad chunk for block %s" + " chunk: %" PRIx64, + block->block_name, reg->key.chunk); + ret = -ERANGE; + goto out; + } + } + chunk_start = ram_chunk_start(block, chunk); + chunk_end = ram_chunk_end(block, chunk + reg->chunks); + if (qemu_rdma_register_and_get_keys(rdma, block, + (uintptr_t)host_addr, NULL, ®_result->rkey, + chunk, chunk_start, chunk_end)) { + error_report("cannot get rkey"); + ret = -EINVAL; + goto out; + } + + reg_result->host_addr = (uintptr_t)block->local_host_addr; + + trace_qemu_rdma_registration_handle_register_rkey( + reg_result->rkey); + + result_to_network(reg_result); + } + + ret = qemu_rdma_post_send_control(rdma, + (uint8_t *) results, ®_resp); + + if (ret < 0) { + error_report("Failed to send control buffer"); + goto out; + } + break; + case RDMA_CONTROL_UNREGISTER_REQUEST: + trace_qemu_rdma_registration_handle_unregister(head.repeat); + unreg_resp.repeat = head.repeat; + registers = (RDMARegister *) rdma->wr_data[idx].control_curr; + + for (count = 0; count < head.repeat; count++) { + reg = ®isters[count]; + network_to_register(reg); + + trace_qemu_rdma_registration_handle_unregister_loop(count, + reg->current_index, reg->key.chunk); + + block = &(rdma->local_ram_blocks.block[reg->current_index]); + + ret = ibv_dereg_mr(block->pmr[reg->key.chunk]); + block->pmr[reg->key.chunk] = NULL; + + if (ret != 0) { + perror("rdma unregistration chunk failed"); + ret = -ret; + goto out; + } + + rdma->total_registrations--; + + trace_qemu_rdma_registration_handle_unregister_success( + reg->key.chunk); + } + + ret = qemu_rdma_post_send_control(rdma, NULL, &unreg_resp); + + if (ret < 0) { + error_report("Failed to send control buffer"); + goto out; + } + break; + case RDMA_CONTROL_REGISTER_RESULT: + error_report("Invalid RESULT message at dest."); + ret = -EIO; + goto out; + default: + error_report("Unknown control message %s", control_desc[head.type]); + ret = -EIO; + goto out; + } + } while (1); +out: + if (ret < 0) { + rdma->error_state = ret; + } + return ret; +} + +/* Destination: + * Called via a ram_control_load_hook during the initial RAM load section which + * lists the RAMBlocks by name. This lets us know the order of the RAMBlocks + * on the source. + * We've already built our local RAMBlock list, but not yet sent the list to + * the source. + */ +static int rdma_block_notification_handle(QEMUFileRDMA *rfile, const char *name) +{ + RDMAContext *rdma = rfile->rdma; + int curr; + int found = -1; + + /* Find the matching RAMBlock in our local list */ + for (curr = 0; curr < rdma->local_ram_blocks.nb_blocks; curr++) { + if (!strcmp(rdma->local_ram_blocks.block[curr].block_name, name)) { + found = curr; + break; + } + } + + if (found == -1) { + error_report("RAMBlock '%s' not found on destination", name); + return -ENOENT; + } + + rdma->local_ram_blocks.block[curr].src_index = rdma->next_src_index; + trace_rdma_block_notification_handle(name, rdma->next_src_index); + rdma->next_src_index++; + + return 0; +} + +static int rdma_load_hook(QEMUFile *f, void *opaque, uint64_t flags, void *data) +{ + switch (flags) { + case RAM_CONTROL_BLOCK_REG: + return rdma_block_notification_handle(opaque, data); + + case RAM_CONTROL_HOOK: + return qemu_rdma_registration_handle(f, opaque); + + default: + /* Shouldn't be called with any other values */ + abort(); + } +} + +static int qemu_rdma_registration_start(QEMUFile *f, void *opaque, + uint64_t flags, void *data) +{ + QEMUFileRDMA *rfile = opaque; + RDMAContext *rdma = rfile->rdma; + + CHECK_ERROR_STATE(); + + trace_qemu_rdma_registration_start(flags); + qemu_put_be64(f, RAM_SAVE_FLAG_HOOK); + qemu_fflush(f); + + return 0; +} + +/* + * Inform dest that dynamic registrations are done for now. + * First, flush writes, if any. + */ +static int qemu_rdma_registration_stop(QEMUFile *f, void *opaque, + uint64_t flags, void *data) +{ + Error *local_err = NULL, **errp = &local_err; + QEMUFileRDMA *rfile = opaque; + RDMAContext *rdma = rfile->rdma; + RDMAControlHeader head = { .len = 0, .repeat = 1 }; + int ret = 0; + + CHECK_ERROR_STATE(); + + qemu_fflush(f); + ret = qemu_rdma_drain_cq(f, rdma); + + if (ret < 0) { + goto err; + } + + if (flags == RAM_CONTROL_SETUP) { + RDMAControlHeader resp = {.type = RDMA_CONTROL_RAM_BLOCKS_RESULT }; + RDMALocalBlocks *local = &rdma->local_ram_blocks; + int reg_result_idx, i, nb_dest_blocks; + + head.type = RDMA_CONTROL_RAM_BLOCKS_REQUEST; + trace_qemu_rdma_registration_stop_ram(); + + /* + * Make sure that we parallelize the pinning on both sides. + * For very large guests, doing this serially takes a really + * long time, so we have to 'interleave' the pinning locally + * with the control messages by performing the pinning on this + * side before we receive the control response from the other + * side that the pinning has completed. + */ + ret = qemu_rdma_exchange_send(rdma, &head, NULL, &resp, + ®_result_idx, rdma->pin_all ? + qemu_rdma_reg_whole_ram_blocks : NULL); + if (ret < 0) { + ERROR(errp, "receiving remote info!"); + return ret; + } + + nb_dest_blocks = resp.len / sizeof(RDMADestBlock); + + /* + * The protocol uses two different sets of rkeys (mutually exclusive): + * 1. One key to represent the virtual address of the entire ram block. + * (dynamic chunk registration disabled - pin everything with one rkey.) + * 2. One to represent individual chunks within a ram block. + * (dynamic chunk registration enabled - pin individual chunks.) + * + * Once the capability is successfully negotiated, the destination transmits + * the keys to use (or sends them later) including the virtual addresses + * and then propagates the remote ram block descriptions to his local copy. + */ + + if (local->nb_blocks != nb_dest_blocks) { + ERROR(errp, "ram blocks mismatch (Number of blocks %d vs %d) " + "Your QEMU command line parameters are probably " + "not identical on both the source and destination.", + local->nb_blocks, nb_dest_blocks); + rdma->error_state = -EINVAL; + return -EINVAL; + } + + qemu_rdma_move_header(rdma, reg_result_idx, &resp); + memcpy(rdma->dest_blocks, + rdma->wr_data[reg_result_idx].control_curr, resp.len); + for (i = 0; i < nb_dest_blocks; i++) { + network_to_dest_block(&rdma->dest_blocks[i]); + + /* We require that the blocks are in the same order */ + if (rdma->dest_blocks[i].length != local->block[i].length) { + ERROR(errp, "Block %s/%d has a different length %" PRIu64 + "vs %" PRIu64, local->block[i].block_name, i, + local->block[i].length, + rdma->dest_blocks[i].length); + rdma->error_state = -EINVAL; + return -EINVAL; + } + local->block[i].remote_host_addr = + rdma->dest_blocks[i].remote_host_addr; + local->block[i].remote_rkey = rdma->dest_blocks[i].remote_rkey; + } + } + + trace_qemu_rdma_registration_stop(flags); + + head.type = RDMA_CONTROL_REGISTER_FINISHED; + ret = qemu_rdma_exchange_send(rdma, &head, NULL, NULL, NULL, NULL); + + if (ret < 0) { + goto err; + } + + return 0; +err: + rdma->error_state = ret; + return ret; +} + +static int qemu_rdma_get_fd(void *opaque) +{ + QEMUFileRDMA *rfile = opaque; + RDMAContext *rdma = rfile->rdma; + + return rdma->comp_channel->fd; +} + +static const QEMUFileOps rdma_read_ops = { + .get_buffer = qemu_rdma_get_buffer, + .get_fd = qemu_rdma_get_fd, + .close = qemu_rdma_close, + .hook_ram_load = rdma_load_hook, +}; + +static const QEMUFileOps rdma_write_ops = { + .put_buffer = qemu_rdma_put_buffer, + .close = qemu_rdma_close, + .before_ram_iterate = qemu_rdma_registration_start, + .after_ram_iterate = qemu_rdma_registration_stop, + .save_page = qemu_rdma_save_page, +}; + +static void *qemu_fopen_rdma(RDMAContext *rdma, const char *mode) +{ + QEMUFileRDMA *r; + + if (qemu_file_mode_is_not_valid(mode)) { + return NULL; + } + + r = g_new0(QEMUFileRDMA, 1); + r->rdma = rdma; + + if (mode[0] == 'w') { + r->file = qemu_fopen_ops(r, &rdma_write_ops); + } else { + r->file = qemu_fopen_ops(r, &rdma_read_ops); + } + + return r->file; +} + +static void rdma_accept_incoming_migration(void *opaque) +{ + RDMAContext *rdma = opaque; + int ret; + QEMUFile *f; + Error *local_err = NULL, **errp = &local_err; + + trace_qemu_rdma_accept_incoming_migration(); + ret = qemu_rdma_accept(rdma); + + if (ret) { + ERROR(errp, "RDMA Migration initialization failed!"); + return; + } + + trace_qemu_rdma_accept_incoming_migration_accepted(); + + f = qemu_fopen_rdma(rdma, "rb"); + if (f == NULL) { + ERROR(errp, "could not qemu_fopen_rdma!"); + qemu_rdma_cleanup(rdma); + return; + } + + rdma->migration_started_on_destination = 1; + process_incoming_migration(f); +} + +void rdma_start_incoming_migration(const char *host_port, Error **errp) +{ + int ret; + RDMAContext *rdma; + Error *local_err = NULL; + + trace_rdma_start_incoming_migration(); + rdma = qemu_rdma_data_init(host_port, &local_err); + + if (rdma == NULL) { + goto err; + } + + ret = qemu_rdma_dest_init(rdma, &local_err); + + if (ret) { + goto err; + } + + trace_rdma_start_incoming_migration_after_dest_init(); + + ret = rdma_listen(rdma->listen_id, 5); + + if (ret) { + ERROR(errp, "listening on socket!"); + goto err; + } + + trace_rdma_start_incoming_migration_after_rdma_listen(); + + qemu_set_fd_handler(rdma->channel->fd, rdma_accept_incoming_migration, + NULL, (void *)(intptr_t)rdma); + return; +err: + error_propagate(errp, local_err); + g_free(rdma); +} + +void rdma_start_outgoing_migration(void *opaque, + const char *host_port, Error **errp) +{ + MigrationState *s = opaque; + Error *local_err = NULL, **temp = &local_err; + RDMAContext *rdma = qemu_rdma_data_init(host_port, &local_err); + int ret = 0; + + if (rdma == NULL) { + ERROR(temp, "Failed to initialize RDMA data structures! %d", ret); + goto err; + } + + ret = qemu_rdma_source_init(rdma, &local_err, + s->enabled_capabilities[MIGRATION_CAPABILITY_RDMA_PIN_ALL]); + + if (ret) { + goto err; + } + + trace_rdma_start_outgoing_migration_after_rdma_source_init(); + ret = qemu_rdma_connect(rdma, &local_err); + + if (ret) { + goto err; + } + + trace_rdma_start_outgoing_migration_after_rdma_connect(); + + s->file = qemu_fopen_rdma(rdma, "wb"); + migrate_fd_connect(s); + return; +err: + error_propagate(errp, local_err); + g_free(rdma); + migrate_fd_error(s); +} |
