diff options
Diffstat (limited to 'src/hw/block/xen_disk.c')
| -rw-r--r-- | src/hw/block/xen_disk.c | 1122 |
1 files changed, 1122 insertions, 0 deletions
diff --git a/src/hw/block/xen_disk.c b/src/hw/block/xen_disk.c new file mode 100644 index 0000000..8146650 --- /dev/null +++ b/src/hw/block/xen_disk.c @@ -0,0 +1,1122 @@ +/* + * xen paravirt block device backend + * + * (c) Gerd Hoffmann <kraxel@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; under version 2 of the License. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, see <http://www.gnu.org/licenses/>. + * + * Contributions after 2012-01-13 are licensed under the terms of the + * GNU GPL, version 2 or (at your option) any later version. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <stdarg.h> +#include <string.h> +#include <unistd.h> +#include <inttypes.h> +#include <time.h> +#include <fcntl.h> +#include <errno.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/mman.h> +#include <sys/uio.h> + +#include "hw/hw.h" +#include "hw/xen/xen_backend.h" +#include "xen_blkif.h" +#include "sysemu/blockdev.h" +#include "sysemu/block-backend.h" +#include "qapi/qmp/qdict.h" +#include "qapi/qmp/qstring.h" + +/* ------------------------------------------------------------- */ + +static int batch_maps = 0; + +static int max_requests = 32; + +/* ------------------------------------------------------------- */ + +#define BLOCK_SIZE 512 +#define IOCB_COUNT (BLKIF_MAX_SEGMENTS_PER_REQUEST + 2) + +struct PersistentGrant { + void *page; + struct XenBlkDev *blkdev; +}; + +typedef struct PersistentGrant PersistentGrant; + +struct PersistentRegion { + void *addr; + int num; +}; + +typedef struct PersistentRegion PersistentRegion; + +struct ioreq { + blkif_request_t req; + int16_t status; + + /* parsed request */ + off_t start; + QEMUIOVector v; + int presync; + uint8_t mapped; + + /* grant mapping */ + uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + int prot; + void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + void *pages; + int num_unmap; + + /* aio status */ + int aio_inflight; + int aio_errors; + + struct XenBlkDev *blkdev; + QLIST_ENTRY(ioreq) list; + BlockAcctCookie acct; +}; + +struct XenBlkDev { + struct XenDevice xendev; /* must be first */ + char *params; + char *mode; + char *type; + char *dev; + char *devtype; + bool directiosafe; + const char *fileproto; + const char *filename; + int ring_ref; + void *sring; + int64_t file_blk; + int64_t file_size; + int protocol; + blkif_back_rings_t rings; + int more_work; + int cnt_map; + + /* request lists */ + QLIST_HEAD(inflight_head, ioreq) inflight; + QLIST_HEAD(finished_head, ioreq) finished; + QLIST_HEAD(freelist_head, ioreq) freelist; + int requests_total; + int requests_inflight; + int requests_finished; + + /* Persistent grants extension */ + gboolean feature_discard; + gboolean feature_persistent; + GTree *persistent_gnts; + GSList *persistent_regions; + unsigned int persistent_gnt_count; + unsigned int max_grants; + + /* qemu block driver */ + DriveInfo *dinfo; + BlockBackend *blk; + QEMUBH *bh; +}; + +/* ------------------------------------------------------------- */ + +static void ioreq_reset(struct ioreq *ioreq) +{ + memset(&ioreq->req, 0, sizeof(ioreq->req)); + ioreq->status = 0; + ioreq->start = 0; + ioreq->presync = 0; + ioreq->mapped = 0; + + memset(ioreq->domids, 0, sizeof(ioreq->domids)); + memset(ioreq->refs, 0, sizeof(ioreq->refs)); + ioreq->prot = 0; + memset(ioreq->page, 0, sizeof(ioreq->page)); + ioreq->pages = NULL; + + ioreq->aio_inflight = 0; + ioreq->aio_errors = 0; + + ioreq->blkdev = NULL; + memset(&ioreq->list, 0, sizeof(ioreq->list)); + memset(&ioreq->acct, 0, sizeof(ioreq->acct)); + + qemu_iovec_reset(&ioreq->v); +} + +static gint int_cmp(gconstpointer a, gconstpointer b, gpointer user_data) +{ + uint ua = GPOINTER_TO_UINT(a); + uint ub = GPOINTER_TO_UINT(b); + return (ua > ub) - (ua < ub); +} + +static void destroy_grant(gpointer pgnt) +{ + PersistentGrant *grant = pgnt; + XenGnttab gnt = grant->blkdev->xendev.gnttabdev; + + if (xc_gnttab_munmap(gnt, grant->page, 1) != 0) { + xen_be_printf(&grant->blkdev->xendev, 0, + "xc_gnttab_munmap failed: %s\n", + strerror(errno)); + } + grant->blkdev->persistent_gnt_count--; + xen_be_printf(&grant->blkdev->xendev, 3, + "unmapped grant %p\n", grant->page); + g_free(grant); +} + +static void remove_persistent_region(gpointer data, gpointer dev) +{ + PersistentRegion *region = data; + struct XenBlkDev *blkdev = dev; + XenGnttab gnt = blkdev->xendev.gnttabdev; + + if (xc_gnttab_munmap(gnt, region->addr, region->num) != 0) { + xen_be_printf(&blkdev->xendev, 0, + "xc_gnttab_munmap region %p failed: %s\n", + region->addr, strerror(errno)); + } + xen_be_printf(&blkdev->xendev, 3, + "unmapped grant region %p with %d pages\n", + region->addr, region->num); + g_free(region); +} + +static struct ioreq *ioreq_start(struct XenBlkDev *blkdev) +{ + struct ioreq *ioreq = NULL; + + if (QLIST_EMPTY(&blkdev->freelist)) { + if (blkdev->requests_total >= max_requests) { + goto out; + } + /* allocate new struct */ + ioreq = g_malloc0(sizeof(*ioreq)); + ioreq->blkdev = blkdev; + blkdev->requests_total++; + qemu_iovec_init(&ioreq->v, BLKIF_MAX_SEGMENTS_PER_REQUEST); + } else { + /* get one from freelist */ + ioreq = QLIST_FIRST(&blkdev->freelist); + QLIST_REMOVE(ioreq, list); + } + QLIST_INSERT_HEAD(&blkdev->inflight, ioreq, list); + blkdev->requests_inflight++; + +out: + return ioreq; +} + +static void ioreq_finish(struct ioreq *ioreq) +{ + struct XenBlkDev *blkdev = ioreq->blkdev; + + QLIST_REMOVE(ioreq, list); + QLIST_INSERT_HEAD(&blkdev->finished, ioreq, list); + blkdev->requests_inflight--; + blkdev->requests_finished++; +} + +static void ioreq_release(struct ioreq *ioreq, bool finish) +{ + struct XenBlkDev *blkdev = ioreq->blkdev; + + QLIST_REMOVE(ioreq, list); + ioreq_reset(ioreq); + ioreq->blkdev = blkdev; + QLIST_INSERT_HEAD(&blkdev->freelist, ioreq, list); + if (finish) { + blkdev->requests_finished--; + } else { + blkdev->requests_inflight--; + } +} + +/* + * translate request into iovec + start offset + * do sanity checks along the way + */ +static int ioreq_parse(struct ioreq *ioreq) +{ + struct XenBlkDev *blkdev = ioreq->blkdev; + uintptr_t mem; + size_t len; + int i; + + xen_be_printf(&blkdev->xendev, 3, + "op %d, nr %d, handle %d, id %" PRId64 ", sector %" PRId64 "\n", + ioreq->req.operation, ioreq->req.nr_segments, + ioreq->req.handle, ioreq->req.id, ioreq->req.sector_number); + switch (ioreq->req.operation) { + case BLKIF_OP_READ: + ioreq->prot = PROT_WRITE; /* to memory */ + break; + case BLKIF_OP_FLUSH_DISKCACHE: + ioreq->presync = 1; + if (!ioreq->req.nr_segments) { + return 0; + } + /* fall through */ + case BLKIF_OP_WRITE: + ioreq->prot = PROT_READ; /* from memory */ + break; + case BLKIF_OP_DISCARD: + return 0; + default: + xen_be_printf(&blkdev->xendev, 0, "error: unknown operation (%d)\n", + ioreq->req.operation); + goto err; + }; + + if (ioreq->req.operation != BLKIF_OP_READ && blkdev->mode[0] != 'w') { + xen_be_printf(&blkdev->xendev, 0, "error: write req for ro device\n"); + goto err; + } + + ioreq->start = ioreq->req.sector_number * blkdev->file_blk; + for (i = 0; i < ioreq->req.nr_segments; i++) { + if (i == BLKIF_MAX_SEGMENTS_PER_REQUEST) { + xen_be_printf(&blkdev->xendev, 0, "error: nr_segments too big\n"); + goto err; + } + if (ioreq->req.seg[i].first_sect > ioreq->req.seg[i].last_sect) { + xen_be_printf(&blkdev->xendev, 0, "error: first > last sector\n"); + goto err; + } + if (ioreq->req.seg[i].last_sect * BLOCK_SIZE >= XC_PAGE_SIZE) { + xen_be_printf(&blkdev->xendev, 0, "error: page crossing\n"); + goto err; + } + + ioreq->domids[i] = blkdev->xendev.dom; + ioreq->refs[i] = ioreq->req.seg[i].gref; + + mem = ioreq->req.seg[i].first_sect * blkdev->file_blk; + len = (ioreq->req.seg[i].last_sect - ioreq->req.seg[i].first_sect + 1) * blkdev->file_blk; + qemu_iovec_add(&ioreq->v, (void*)mem, len); + } + if (ioreq->start + ioreq->v.size > blkdev->file_size) { + xen_be_printf(&blkdev->xendev, 0, "error: access beyond end of file\n"); + goto err; + } + return 0; + +err: + ioreq->status = BLKIF_RSP_ERROR; + return -1; +} + +static void ioreq_unmap(struct ioreq *ioreq) +{ + XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev; + int i; + + if (ioreq->num_unmap == 0 || ioreq->mapped == 0) { + return; + } + if (batch_maps) { + if (!ioreq->pages) { + return; + } + if (xc_gnttab_munmap(gnt, ioreq->pages, ioreq->num_unmap) != 0) { + xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n", + strerror(errno)); + } + ioreq->blkdev->cnt_map -= ioreq->num_unmap; + ioreq->pages = NULL; + } else { + for (i = 0; i < ioreq->num_unmap; i++) { + if (!ioreq->page[i]) { + continue; + } + if (xc_gnttab_munmap(gnt, ioreq->page[i], 1) != 0) { + xen_be_printf(&ioreq->blkdev->xendev, 0, "xc_gnttab_munmap failed: %s\n", + strerror(errno)); + } + ioreq->blkdev->cnt_map--; + ioreq->page[i] = NULL; + } + } + ioreq->mapped = 0; +} + +static int ioreq_map(struct ioreq *ioreq) +{ + XenGnttab gnt = ioreq->blkdev->xendev.gnttabdev; + uint32_t domids[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + uint32_t refs[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + void *page[BLKIF_MAX_SEGMENTS_PER_REQUEST]; + int i, j, new_maps = 0; + PersistentGrant *grant; + PersistentRegion *region; + /* domids and refs variables will contain the information necessary + * to map the grants that are needed to fulfill this request. + * + * After mapping the needed grants, the page array will contain the + * memory address of each granted page in the order specified in ioreq + * (disregarding if it's a persistent grant or not). + */ + + if (ioreq->v.niov == 0 || ioreq->mapped == 1) { + return 0; + } + if (ioreq->blkdev->feature_persistent) { + for (i = 0; i < ioreq->v.niov; i++) { + grant = g_tree_lookup(ioreq->blkdev->persistent_gnts, + GUINT_TO_POINTER(ioreq->refs[i])); + + if (grant != NULL) { + page[i] = grant->page; + xen_be_printf(&ioreq->blkdev->xendev, 3, + "using persistent-grant %" PRIu32 "\n", + ioreq->refs[i]); + } else { + /* Add the grant to the list of grants that + * should be mapped + */ + domids[new_maps] = ioreq->domids[i]; + refs[new_maps] = ioreq->refs[i]; + page[i] = NULL; + new_maps++; + } + } + /* Set the protection to RW, since grants may be reused later + * with a different protection than the one needed for this request + */ + ioreq->prot = PROT_WRITE | PROT_READ; + } else { + /* All grants in the request should be mapped */ + memcpy(refs, ioreq->refs, sizeof(refs)); + memcpy(domids, ioreq->domids, sizeof(domids)); + memset(page, 0, sizeof(page)); + new_maps = ioreq->v.niov; + } + + if (batch_maps && new_maps) { + ioreq->pages = xc_gnttab_map_grant_refs + (gnt, new_maps, domids, refs, ioreq->prot); + if (ioreq->pages == NULL) { + xen_be_printf(&ioreq->blkdev->xendev, 0, + "can't map %d grant refs (%s, %d maps)\n", + new_maps, strerror(errno), ioreq->blkdev->cnt_map); + return -1; + } + for (i = 0, j = 0; i < ioreq->v.niov; i++) { + if (page[i] == NULL) { + page[i] = ioreq->pages + (j++) * XC_PAGE_SIZE; + } + } + ioreq->blkdev->cnt_map += new_maps; + } else if (new_maps) { + for (i = 0; i < new_maps; i++) { + ioreq->page[i] = xc_gnttab_map_grant_ref + (gnt, domids[i], refs[i], ioreq->prot); + if (ioreq->page[i] == NULL) { + xen_be_printf(&ioreq->blkdev->xendev, 0, + "can't map grant ref %d (%s, %d maps)\n", + refs[i], strerror(errno), ioreq->blkdev->cnt_map); + ioreq->mapped = 1; + ioreq_unmap(ioreq); + return -1; + } + ioreq->blkdev->cnt_map++; + } + for (i = 0, j = 0; i < ioreq->v.niov; i++) { + if (page[i] == NULL) { + page[i] = ioreq->page[j++]; + } + } + } + if (ioreq->blkdev->feature_persistent && new_maps != 0 && + (!batch_maps || (ioreq->blkdev->persistent_gnt_count + new_maps <= + ioreq->blkdev->max_grants))) { + /* + * If we are using persistent grants and batch mappings only + * add the new maps to the list of persistent grants if the whole + * area can be persistently mapped. + */ + if (batch_maps) { + region = g_malloc0(sizeof(*region)); + region->addr = ioreq->pages; + region->num = new_maps; + ioreq->blkdev->persistent_regions = g_slist_append( + ioreq->blkdev->persistent_regions, + region); + } + while ((ioreq->blkdev->persistent_gnt_count < ioreq->blkdev->max_grants) + && new_maps) { + /* Go through the list of newly mapped grants and add as many + * as possible to the list of persistently mapped grants. + * + * Since we start at the end of ioreq->page(s), we only need + * to decrease new_maps to prevent this granted pages from + * being unmapped in ioreq_unmap. + */ + grant = g_malloc0(sizeof(*grant)); + new_maps--; + if (batch_maps) { + grant->page = ioreq->pages + (new_maps) * XC_PAGE_SIZE; + } else { + grant->page = ioreq->page[new_maps]; + } + grant->blkdev = ioreq->blkdev; + xen_be_printf(&ioreq->blkdev->xendev, 3, + "adding grant %" PRIu32 " page: %p\n", + refs[new_maps], grant->page); + g_tree_insert(ioreq->blkdev->persistent_gnts, + GUINT_TO_POINTER(refs[new_maps]), + grant); + ioreq->blkdev->persistent_gnt_count++; + } + assert(!batch_maps || new_maps == 0); + } + for (i = 0; i < ioreq->v.niov; i++) { + ioreq->v.iov[i].iov_base += (uintptr_t)page[i]; + } + ioreq->mapped = 1; + ioreq->num_unmap = new_maps; + return 0; +} + +static int ioreq_runio_qemu_aio(struct ioreq *ioreq); + +static void qemu_aio_complete(void *opaque, int ret) +{ + struct ioreq *ioreq = opaque; + + if (ret != 0) { + xen_be_printf(&ioreq->blkdev->xendev, 0, "%s I/O error\n", + ioreq->req.operation == BLKIF_OP_READ ? "read" : "write"); + ioreq->aio_errors++; + } + + ioreq->aio_inflight--; + if (ioreq->presync) { + ioreq->presync = 0; + ioreq_runio_qemu_aio(ioreq); + return; + } + if (ioreq->aio_inflight > 0) { + return; + } + + ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY; + ioreq_unmap(ioreq); + ioreq_finish(ioreq); + switch (ioreq->req.operation) { + case BLKIF_OP_WRITE: + case BLKIF_OP_FLUSH_DISKCACHE: + if (!ioreq->req.nr_segments) { + break; + } + case BLKIF_OP_READ: + if (ioreq->status == BLKIF_RSP_OKAY) { + block_acct_done(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct); + } else { + block_acct_failed(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct); + } + break; + case BLKIF_OP_DISCARD: + default: + break; + } + qemu_bh_schedule(ioreq->blkdev->bh); +} + +static int ioreq_runio_qemu_aio(struct ioreq *ioreq) +{ + struct XenBlkDev *blkdev = ioreq->blkdev; + + if (ioreq->req.nr_segments && ioreq_map(ioreq) == -1) { + goto err_no_map; + } + + ioreq->aio_inflight++; + if (ioreq->presync) { + blk_aio_flush(ioreq->blkdev->blk, qemu_aio_complete, ioreq); + return 0; + } + + switch (ioreq->req.operation) { + case BLKIF_OP_READ: + block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct, + ioreq->v.size, BLOCK_ACCT_READ); + ioreq->aio_inflight++; + blk_aio_readv(blkdev->blk, ioreq->start / BLOCK_SIZE, + &ioreq->v, ioreq->v.size / BLOCK_SIZE, + qemu_aio_complete, ioreq); + break; + case BLKIF_OP_WRITE: + case BLKIF_OP_FLUSH_DISKCACHE: + if (!ioreq->req.nr_segments) { + break; + } + + block_acct_start(blk_get_stats(blkdev->blk), &ioreq->acct, + ioreq->v.size, + ioreq->req.operation == BLKIF_OP_WRITE ? + BLOCK_ACCT_WRITE : BLOCK_ACCT_FLUSH); + ioreq->aio_inflight++; + blk_aio_writev(blkdev->blk, ioreq->start / BLOCK_SIZE, + &ioreq->v, ioreq->v.size / BLOCK_SIZE, + qemu_aio_complete, ioreq); + break; + case BLKIF_OP_DISCARD: + { + struct blkif_request_discard *discard_req = (void *)&ioreq->req; + ioreq->aio_inflight++; + blk_aio_discard(blkdev->blk, + discard_req->sector_number, discard_req->nr_sectors, + qemu_aio_complete, ioreq); + break; + } + default: + /* unknown operation (shouldn't happen -- parse catches this) */ + goto err; + } + + qemu_aio_complete(ioreq, 0); + + return 0; + +err: + ioreq_unmap(ioreq); +err_no_map: + ioreq_finish(ioreq); + ioreq->status = BLKIF_RSP_ERROR; + return -1; +} + +static int blk_send_response_one(struct ioreq *ioreq) +{ + struct XenBlkDev *blkdev = ioreq->blkdev; + int send_notify = 0; + int have_requests = 0; + blkif_response_t resp; + void *dst; + + resp.id = ioreq->req.id; + resp.operation = ioreq->req.operation; + resp.status = ioreq->status; + + /* Place on the response ring for the relevant domain. */ + switch (blkdev->protocol) { + case BLKIF_PROTOCOL_NATIVE: + dst = RING_GET_RESPONSE(&blkdev->rings.native, blkdev->rings.native.rsp_prod_pvt); + break; + case BLKIF_PROTOCOL_X86_32: + dst = RING_GET_RESPONSE(&blkdev->rings.x86_32_part, + blkdev->rings.x86_32_part.rsp_prod_pvt); + break; + case BLKIF_PROTOCOL_X86_64: + dst = RING_GET_RESPONSE(&blkdev->rings.x86_64_part, + blkdev->rings.x86_64_part.rsp_prod_pvt); + break; + default: + dst = NULL; + return 0; + } + memcpy(dst, &resp, sizeof(resp)); + blkdev->rings.common.rsp_prod_pvt++; + + RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blkdev->rings.common, send_notify); + if (blkdev->rings.common.rsp_prod_pvt == blkdev->rings.common.req_cons) { + /* + * Tail check for pending requests. Allows frontend to avoid + * notifications if requests are already in flight (lower + * overheads and promotes batching). + */ + RING_FINAL_CHECK_FOR_REQUESTS(&blkdev->rings.common, have_requests); + } else if (RING_HAS_UNCONSUMED_REQUESTS(&blkdev->rings.common)) { + have_requests = 1; + } + + if (have_requests) { + blkdev->more_work++; + } + return send_notify; +} + +/* walk finished list, send outstanding responses, free requests */ +static void blk_send_response_all(struct XenBlkDev *blkdev) +{ + struct ioreq *ioreq; + int send_notify = 0; + + while (!QLIST_EMPTY(&blkdev->finished)) { + ioreq = QLIST_FIRST(&blkdev->finished); + send_notify += blk_send_response_one(ioreq); + ioreq_release(ioreq, true); + } + if (send_notify) { + xen_be_send_notify(&blkdev->xendev); + } +} + +static int blk_get_request(struct XenBlkDev *blkdev, struct ioreq *ioreq, RING_IDX rc) +{ + switch (blkdev->protocol) { + case BLKIF_PROTOCOL_NATIVE: + memcpy(&ioreq->req, RING_GET_REQUEST(&blkdev->rings.native, rc), + sizeof(ioreq->req)); + break; + case BLKIF_PROTOCOL_X86_32: + blkif_get_x86_32_req(&ioreq->req, + RING_GET_REQUEST(&blkdev->rings.x86_32_part, rc)); + break; + case BLKIF_PROTOCOL_X86_64: + blkif_get_x86_64_req(&ioreq->req, + RING_GET_REQUEST(&blkdev->rings.x86_64_part, rc)); + break; + } + return 0; +} + +static void blk_handle_requests(struct XenBlkDev *blkdev) +{ + RING_IDX rc, rp; + struct ioreq *ioreq; + + blkdev->more_work = 0; + + rc = blkdev->rings.common.req_cons; + rp = blkdev->rings.common.sring->req_prod; + xen_rmb(); /* Ensure we see queued requests up to 'rp'. */ + + blk_send_response_all(blkdev); + while (rc != rp) { + /* pull request from ring */ + if (RING_REQUEST_CONS_OVERFLOW(&blkdev->rings.common, rc)) { + break; + } + ioreq = ioreq_start(blkdev); + if (ioreq == NULL) { + blkdev->more_work++; + break; + } + blk_get_request(blkdev, ioreq, rc); + blkdev->rings.common.req_cons = ++rc; + + /* parse them */ + if (ioreq_parse(ioreq) != 0) { + + switch (ioreq->req.operation) { + case BLKIF_OP_READ: + block_acct_invalid(blk_get_stats(blkdev->blk), + BLOCK_ACCT_READ); + break; + case BLKIF_OP_WRITE: + block_acct_invalid(blk_get_stats(blkdev->blk), + BLOCK_ACCT_WRITE); + break; + case BLKIF_OP_FLUSH_DISKCACHE: + block_acct_invalid(blk_get_stats(blkdev->blk), + BLOCK_ACCT_FLUSH); + default: + break; + }; + + if (blk_send_response_one(ioreq)) { + xen_be_send_notify(&blkdev->xendev); + } + ioreq_release(ioreq, false); + continue; + } + + ioreq_runio_qemu_aio(ioreq); + } + + if (blkdev->more_work && blkdev->requests_inflight < max_requests) { + qemu_bh_schedule(blkdev->bh); + } +} + +/* ------------------------------------------------------------- */ + +static void blk_bh(void *opaque) +{ + struct XenBlkDev *blkdev = opaque; + blk_handle_requests(blkdev); +} + +/* + * We need to account for the grant allocations requiring contiguous + * chunks; the worst case number would be + * max_req * max_seg + (max_req - 1) * (max_seg - 1) + 1, + * but in order to keep things simple just use + * 2 * max_req * max_seg. + */ +#define MAX_GRANTS(max_req, max_seg) (2 * (max_req) * (max_seg)) + +static void blk_alloc(struct XenDevice *xendev) +{ + struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); + + QLIST_INIT(&blkdev->inflight); + QLIST_INIT(&blkdev->finished); + QLIST_INIT(&blkdev->freelist); + blkdev->bh = qemu_bh_new(blk_bh, blkdev); + if (xen_mode != XEN_EMULATE) { + batch_maps = 1; + } + if (xc_gnttab_set_max_grants(xendev->gnttabdev, + MAX_GRANTS(max_requests, BLKIF_MAX_SEGMENTS_PER_REQUEST)) < 0) { + xen_be_printf(xendev, 0, "xc_gnttab_set_max_grants failed: %s\n", + strerror(errno)); + } +} + +static void blk_parse_discard(struct XenBlkDev *blkdev) +{ + int enable; + + blkdev->feature_discard = true; + + if (xenstore_read_be_int(&blkdev->xendev, "discard-enable", &enable) == 0) { + blkdev->feature_discard = !!enable; + } + + if (blkdev->feature_discard) { + xenstore_write_be_int(&blkdev->xendev, "feature-discard", 1); + } +} + +static int blk_init(struct XenDevice *xendev) +{ + struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); + int info = 0; + char *directiosafe = NULL; + + /* read xenstore entries */ + if (blkdev->params == NULL) { + char *h = NULL; + blkdev->params = xenstore_read_be_str(&blkdev->xendev, "params"); + if (blkdev->params != NULL) { + h = strchr(blkdev->params, ':'); + } + if (h != NULL) { + blkdev->fileproto = blkdev->params; + blkdev->filename = h+1; + *h = 0; + } else { + blkdev->fileproto = "<unset>"; + blkdev->filename = blkdev->params; + } + } + if (!strcmp("aio", blkdev->fileproto)) { + blkdev->fileproto = "raw"; + } + if (blkdev->mode == NULL) { + blkdev->mode = xenstore_read_be_str(&blkdev->xendev, "mode"); + } + if (blkdev->type == NULL) { + blkdev->type = xenstore_read_be_str(&blkdev->xendev, "type"); + } + if (blkdev->dev == NULL) { + blkdev->dev = xenstore_read_be_str(&blkdev->xendev, "dev"); + } + if (blkdev->devtype == NULL) { + blkdev->devtype = xenstore_read_be_str(&blkdev->xendev, "device-type"); + } + directiosafe = xenstore_read_be_str(&blkdev->xendev, "direct-io-safe"); + blkdev->directiosafe = (directiosafe && atoi(directiosafe)); + + /* do we have all we need? */ + if (blkdev->params == NULL || + blkdev->mode == NULL || + blkdev->type == NULL || + blkdev->dev == NULL) { + goto out_error; + } + + /* read-only ? */ + if (strcmp(blkdev->mode, "w")) { + info |= VDISK_READONLY; + } + + /* cdrom ? */ + if (blkdev->devtype && !strcmp(blkdev->devtype, "cdrom")) { + info |= VDISK_CDROM; + } + + blkdev->file_blk = BLOCK_SIZE; + + /* fill info + * blk_connect supplies sector-size and sectors + */ + xenstore_write_be_int(&blkdev->xendev, "feature-flush-cache", 1); + xenstore_write_be_int(&blkdev->xendev, "feature-persistent", 1); + xenstore_write_be_int(&blkdev->xendev, "info", info); + + blk_parse_discard(blkdev); + + g_free(directiosafe); + return 0; + +out_error: + g_free(blkdev->params); + blkdev->params = NULL; + g_free(blkdev->mode); + blkdev->mode = NULL; + g_free(blkdev->type); + blkdev->type = NULL; + g_free(blkdev->dev); + blkdev->dev = NULL; + g_free(blkdev->devtype); + blkdev->devtype = NULL; + g_free(directiosafe); + blkdev->directiosafe = false; + return -1; +} + +static int blk_connect(struct XenDevice *xendev) +{ + struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); + int pers, index, qflags; + bool readonly = true; + + /* read-only ? */ + if (blkdev->directiosafe) { + qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO; + } else { + qflags = BDRV_O_CACHE_WB; + } + if (strcmp(blkdev->mode, "w") == 0) { + qflags |= BDRV_O_RDWR; + readonly = false; + } + if (blkdev->feature_discard) { + qflags |= BDRV_O_UNMAP; + } + + /* init qemu block driver */ + index = (blkdev->xendev.dev - 202 * 256) / 16; + blkdev->dinfo = drive_get(IF_XEN, 0, index); + if (!blkdev->dinfo) { + Error *local_err = NULL; + QDict *options = NULL; + + if (strcmp(blkdev->fileproto, "<unset>")) { + options = qdict_new(); + qdict_put(options, "driver", qstring_from_str(blkdev->fileproto)); + } + + /* setup via xenbus -> create new block driver instance */ + xen_be_printf(&blkdev->xendev, 2, "create new bdrv (xenbus setup)\n"); + blkdev->blk = blk_new_open(blkdev->dev, blkdev->filename, NULL, options, + qflags, &local_err); + if (!blkdev->blk) { + xen_be_printf(&blkdev->xendev, 0, "error: %s\n", + error_get_pretty(local_err)); + error_free(local_err); + return -1; + } + } else { + /* setup via qemu cmdline -> already setup for us */ + xen_be_printf(&blkdev->xendev, 2, "get configured bdrv (cmdline setup)\n"); + blkdev->blk = blk_by_legacy_dinfo(blkdev->dinfo); + if (blk_is_read_only(blkdev->blk) && !readonly) { + xen_be_printf(&blkdev->xendev, 0, "Unexpected read-only drive"); + blkdev->blk = NULL; + return -1; + } + /* blkdev->blk is not create by us, we get a reference + * so we can blk_unref() unconditionally */ + blk_ref(blkdev->blk); + } + blk_attach_dev_nofail(blkdev->blk, blkdev); + blkdev->file_size = blk_getlength(blkdev->blk); + if (blkdev->file_size < 0) { + BlockDriverState *bs = blk_bs(blkdev->blk); + const char *drv_name = bs ? bdrv_get_format_name(bs) : NULL; + xen_be_printf(&blkdev->xendev, 1, "blk_getlength: %d (%s) | drv %s\n", + (int)blkdev->file_size, strerror(-blkdev->file_size), + drv_name ?: "-"); + blkdev->file_size = 0; + } + + xen_be_printf(xendev, 1, "type \"%s\", fileproto \"%s\", filename \"%s\"," + " size %" PRId64 " (%" PRId64 " MB)\n", + blkdev->type, blkdev->fileproto, blkdev->filename, + blkdev->file_size, blkdev->file_size >> 20); + + /* Fill in number of sector size and number of sectors */ + xenstore_write_be_int(&blkdev->xendev, "sector-size", blkdev->file_blk); + xenstore_write_be_int64(&blkdev->xendev, "sectors", + blkdev->file_size / blkdev->file_blk); + + if (xenstore_read_fe_int(&blkdev->xendev, "ring-ref", &blkdev->ring_ref) == -1) { + return -1; + } + if (xenstore_read_fe_int(&blkdev->xendev, "event-channel", + &blkdev->xendev.remote_port) == -1) { + return -1; + } + if (xenstore_read_fe_int(&blkdev->xendev, "feature-persistent", &pers)) { + blkdev->feature_persistent = FALSE; + } else { + blkdev->feature_persistent = !!pers; + } + + blkdev->protocol = BLKIF_PROTOCOL_NATIVE; + if (blkdev->xendev.protocol) { + if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_32) == 0) { + blkdev->protocol = BLKIF_PROTOCOL_X86_32; + } + if (strcmp(blkdev->xendev.protocol, XEN_IO_PROTO_ABI_X86_64) == 0) { + blkdev->protocol = BLKIF_PROTOCOL_X86_64; + } + } + + blkdev->sring = xc_gnttab_map_grant_ref(blkdev->xendev.gnttabdev, + blkdev->xendev.dom, + blkdev->ring_ref, + PROT_READ | PROT_WRITE); + if (!blkdev->sring) { + return -1; + } + blkdev->cnt_map++; + + switch (blkdev->protocol) { + case BLKIF_PROTOCOL_NATIVE: + { + blkif_sring_t *sring_native = blkdev->sring; + BACK_RING_INIT(&blkdev->rings.native, sring_native, XC_PAGE_SIZE); + break; + } + case BLKIF_PROTOCOL_X86_32: + { + blkif_x86_32_sring_t *sring_x86_32 = blkdev->sring; + + BACK_RING_INIT(&blkdev->rings.x86_32_part, sring_x86_32, XC_PAGE_SIZE); + break; + } + case BLKIF_PROTOCOL_X86_64: + { + blkif_x86_64_sring_t *sring_x86_64 = blkdev->sring; + + BACK_RING_INIT(&blkdev->rings.x86_64_part, sring_x86_64, XC_PAGE_SIZE); + break; + } + } + + if (blkdev->feature_persistent) { + /* Init persistent grants */ + blkdev->max_grants = max_requests * BLKIF_MAX_SEGMENTS_PER_REQUEST; + blkdev->persistent_gnts = g_tree_new_full((GCompareDataFunc)int_cmp, + NULL, NULL, + batch_maps ? + (GDestroyNotify)g_free : + (GDestroyNotify)destroy_grant); + blkdev->persistent_regions = NULL; + blkdev->persistent_gnt_count = 0; + } + + xen_be_bind_evtchn(&blkdev->xendev); + + xen_be_printf(&blkdev->xendev, 1, "ok: proto %s, ring-ref %d, " + "remote port %d, local port %d\n", + blkdev->xendev.protocol, blkdev->ring_ref, + blkdev->xendev.remote_port, blkdev->xendev.local_port); + return 0; +} + +static void blk_disconnect(struct XenDevice *xendev) +{ + struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); + + if (blkdev->blk) { + blk_detach_dev(blkdev->blk, blkdev); + blk_unref(blkdev->blk); + blkdev->blk = NULL; + } + xen_be_unbind_evtchn(&blkdev->xendev); + + if (blkdev->sring) { + xc_gnttab_munmap(blkdev->xendev.gnttabdev, blkdev->sring, 1); + blkdev->cnt_map--; + blkdev->sring = NULL; + } + + /* + * Unmap persistent grants before switching to the closed state + * so the frontend can free them. + * + * In the !batch_maps case g_tree_destroy will take care of unmapping + * the grant, but in the batch_maps case we need to iterate over every + * region in persistent_regions and unmap it. + */ + if (blkdev->feature_persistent) { + g_tree_destroy(blkdev->persistent_gnts); + assert(batch_maps || blkdev->persistent_gnt_count == 0); + if (batch_maps) { + blkdev->persistent_gnt_count = 0; + g_slist_foreach(blkdev->persistent_regions, + (GFunc)remove_persistent_region, blkdev); + g_slist_free(blkdev->persistent_regions); + } + blkdev->feature_persistent = false; + } +} + +static int blk_free(struct XenDevice *xendev) +{ + struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); + struct ioreq *ioreq; + + if (blkdev->blk || blkdev->sring) { + blk_disconnect(xendev); + } + + while (!QLIST_EMPTY(&blkdev->freelist)) { + ioreq = QLIST_FIRST(&blkdev->freelist); + QLIST_REMOVE(ioreq, list); + qemu_iovec_destroy(&ioreq->v); + g_free(ioreq); + } + + g_free(blkdev->params); + g_free(blkdev->mode); + g_free(blkdev->type); + g_free(blkdev->dev); + g_free(blkdev->devtype); + qemu_bh_delete(blkdev->bh); + return 0; +} + +static void blk_event(struct XenDevice *xendev) +{ + struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); + + qemu_bh_schedule(blkdev->bh); +} + +struct XenDevOps xen_blkdev_ops = { + .size = sizeof(struct XenBlkDev), + .flags = DEVOPS_FLAG_NEED_GNTDEV, + .alloc = blk_alloc, + .init = blk_init, + .initialise = blk_connect, + .disconnect = blk_disconnect, + .event = blk_event, + .free = blk_free, +}; |
