diff options
Diffstat (limited to 'drivers/scsi/virtio_scsi.c')
-rw-r--r-- | drivers/scsi/virtio_scsi.c | 594 |
1 files changed, 594 insertions, 0 deletions
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c new file mode 100644 index 0000000..efccd72 --- /dev/null +++ b/drivers/scsi/virtio_scsi.c @@ -0,0 +1,594 @@ +/* + * Virtio SCSI HBA driver + * + * Copyright IBM Corp. 2010 + * Copyright Red Hat, Inc. 2011 + * + * Authors: + * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> + * Paolo Bonzini <pbonzini@redhat.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 <linux/module.h> +#include <linux/slab.h> +#include <linux/mempool.h> +#include <linux/virtio.h> +#include <linux/virtio_ids.h> +#include <linux/virtio_config.h> +#include <linux/virtio_scsi.h> +#include <scsi/scsi_host.h> +#include <scsi/scsi_device.h> +#include <scsi/scsi_cmnd.h> + +#define VIRTIO_SCSI_MEMPOOL_SZ 64 + +/* Command queue element */ +struct virtio_scsi_cmd { + struct scsi_cmnd *sc; + struct completion *comp; + union { + struct virtio_scsi_cmd_req cmd; + struct virtio_scsi_ctrl_tmf_req tmf; + struct virtio_scsi_ctrl_an_req an; + } req; + union { + struct virtio_scsi_cmd_resp cmd; + struct virtio_scsi_ctrl_tmf_resp tmf; + struct virtio_scsi_ctrl_an_resp an; + struct virtio_scsi_event evt; + } resp; +} ____cacheline_aligned_in_smp; + +/* Driver instance state */ +struct virtio_scsi { + /* Protects ctrl_vq, req_vq and sg[] */ + spinlock_t vq_lock; + + struct virtio_device *vdev; + struct virtqueue *ctrl_vq; + struct virtqueue *event_vq; + struct virtqueue *req_vq; + + /* For sglist construction when adding commands to the virtqueue. */ + struct scatterlist sg[]; +}; + +static struct kmem_cache *virtscsi_cmd_cache; +static mempool_t *virtscsi_cmd_pool; + +static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev) +{ + return vdev->priv; +} + +static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid) +{ + if (!resid) + return; + + if (!scsi_bidi_cmnd(sc)) { + scsi_set_resid(sc, resid); + return; + } + + scsi_in(sc)->resid = min(resid, scsi_in(sc)->length); + scsi_out(sc)->resid = resid - scsi_in(sc)->resid; +} + +/** + * virtscsi_complete_cmd - finish a scsi_cmd and invoke scsi_done + * + * Called with vq_lock held. + */ +static void virtscsi_complete_cmd(void *buf) +{ + struct virtio_scsi_cmd *cmd = buf; + struct scsi_cmnd *sc = cmd->sc; + struct virtio_scsi_cmd_resp *resp = &cmd->resp.cmd; + + dev_dbg(&sc->device->sdev_gendev, + "cmd %p response %u status %#02x sense_len %u\n", + sc, resp->response, resp->status, resp->sense_len); + + sc->result = resp->status; + virtscsi_compute_resid(sc, resp->resid); + switch (resp->response) { + case VIRTIO_SCSI_S_OK: + set_host_byte(sc, DID_OK); + break; + case VIRTIO_SCSI_S_OVERRUN: + set_host_byte(sc, DID_ERROR); + break; + case VIRTIO_SCSI_S_ABORTED: + set_host_byte(sc, DID_ABORT); + break; + case VIRTIO_SCSI_S_BAD_TARGET: + set_host_byte(sc, DID_BAD_TARGET); + break; + case VIRTIO_SCSI_S_RESET: + set_host_byte(sc, DID_RESET); + break; + case VIRTIO_SCSI_S_BUSY: + set_host_byte(sc, DID_BUS_BUSY); + break; + case VIRTIO_SCSI_S_TRANSPORT_FAILURE: + set_host_byte(sc, DID_TRANSPORT_DISRUPTED); + break; + case VIRTIO_SCSI_S_TARGET_FAILURE: + set_host_byte(sc, DID_TARGET_FAILURE); + break; + case VIRTIO_SCSI_S_NEXUS_FAILURE: + set_host_byte(sc, DID_NEXUS_FAILURE); + break; + default: + scmd_printk(KERN_WARNING, sc, "Unknown response %d", + resp->response); + /* fall through */ + case VIRTIO_SCSI_S_FAILURE: + set_host_byte(sc, DID_ERROR); + break; + } + + WARN_ON(resp->sense_len > VIRTIO_SCSI_SENSE_SIZE); + if (sc->sense_buffer) { + memcpy(sc->sense_buffer, resp->sense, + min_t(u32, resp->sense_len, VIRTIO_SCSI_SENSE_SIZE)); + if (resp->sense_len) + set_driver_byte(sc, DRIVER_SENSE); + } + + mempool_free(cmd, virtscsi_cmd_pool); + sc->scsi_done(sc); +} + +static void virtscsi_vq_done(struct virtqueue *vq, void (*fn)(void *buf)) +{ + struct Scsi_Host *sh = virtio_scsi_host(vq->vdev); + struct virtio_scsi *vscsi = shost_priv(sh); + void *buf; + unsigned long flags; + unsigned int len; + + spin_lock_irqsave(&vscsi->vq_lock, flags); + + do { + virtqueue_disable_cb(vq); + while ((buf = virtqueue_get_buf(vq, &len)) != NULL) + fn(buf); + } while (!virtqueue_enable_cb(vq)); + + spin_unlock_irqrestore(&vscsi->vq_lock, flags); +} + +static void virtscsi_req_done(struct virtqueue *vq) +{ + virtscsi_vq_done(vq, virtscsi_complete_cmd); +}; + +static void virtscsi_complete_free(void *buf) +{ + struct virtio_scsi_cmd *cmd = buf; + + if (cmd->comp) + complete_all(cmd->comp); + mempool_free(cmd, virtscsi_cmd_pool); +} + +static void virtscsi_ctrl_done(struct virtqueue *vq) +{ + virtscsi_vq_done(vq, virtscsi_complete_free); +}; + +static void virtscsi_event_done(struct virtqueue *vq) +{ + virtscsi_vq_done(vq, virtscsi_complete_free); +}; + +static void virtscsi_map_sgl(struct scatterlist *sg, unsigned int *p_idx, + struct scsi_data_buffer *sdb) +{ + struct sg_table *table = &sdb->table; + struct scatterlist *sg_elem; + unsigned int idx = *p_idx; + int i; + + for_each_sg(table->sgl, sg_elem, table->nents, i) + sg_set_buf(&sg[idx++], sg_virt(sg_elem), sg_elem->length); + + *p_idx = idx; +} + +/** + * virtscsi_map_cmd - map a scsi_cmd to a virtqueue scatterlist + * @vscsi : virtio_scsi state + * @cmd : command structure + * @out_num : number of read-only elements + * @in_num : number of write-only elements + * @req_size : size of the request buffer + * @resp_size : size of the response buffer + * + * Called with vq_lock held. + */ +static void virtscsi_map_cmd(struct virtio_scsi *vscsi, + struct virtio_scsi_cmd *cmd, + unsigned *out_num, unsigned *in_num, + size_t req_size, size_t resp_size) +{ + struct scsi_cmnd *sc = cmd->sc; + struct scatterlist *sg = vscsi->sg; + unsigned int idx = 0; + + if (sc) { + struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev); + BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize); + + /* TODO: check feature bit and fail if unsupported? */ + BUG_ON(sc->sc_data_direction == DMA_BIDIRECTIONAL); + } + + /* Request header. */ + sg_set_buf(&sg[idx++], &cmd->req, req_size); + + /* Data-out buffer. */ + if (sc && sc->sc_data_direction != DMA_FROM_DEVICE) + virtscsi_map_sgl(sg, &idx, scsi_out(sc)); + + *out_num = idx; + + /* Response header. */ + sg_set_buf(&sg[idx++], &cmd->resp, resp_size); + + /* Data-in buffer */ + if (sc && sc->sc_data_direction != DMA_TO_DEVICE) + virtscsi_map_sgl(sg, &idx, scsi_in(sc)); + + *in_num = idx - *out_num; +} + +static int virtscsi_kick_cmd(struct virtio_scsi *vscsi, struct virtqueue *vq, + struct virtio_scsi_cmd *cmd, + size_t req_size, size_t resp_size, gfp_t gfp) +{ + unsigned int out_num, in_num; + unsigned long flags; + int ret; + + spin_lock_irqsave(&vscsi->vq_lock, flags); + + virtscsi_map_cmd(vscsi, cmd, &out_num, &in_num, req_size, resp_size); + + ret = virtqueue_add_buf(vq, vscsi->sg, out_num, in_num, cmd, gfp); + if (ret >= 0) + virtqueue_kick(vq); + + spin_unlock_irqrestore(&vscsi->vq_lock, flags); + return ret; +} + +static int virtscsi_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc) +{ + struct virtio_scsi *vscsi = shost_priv(sh); + struct virtio_scsi_cmd *cmd; + int ret; + + dev_dbg(&sc->device->sdev_gendev, + "cmd %p CDB: %#02x\n", sc, sc->cmnd[0]); + + ret = SCSI_MLQUEUE_HOST_BUSY; + cmd = mempool_alloc(virtscsi_cmd_pool, GFP_ATOMIC); + if (!cmd) + goto out; + + memset(cmd, 0, sizeof(*cmd)); + cmd->sc = sc; + cmd->req.cmd = (struct virtio_scsi_cmd_req){ + .lun[0] = 1, + .lun[1] = sc->device->id, + .lun[2] = (sc->device->lun >> 8) | 0x40, + .lun[3] = sc->device->lun & 0xff, + .tag = (unsigned long)sc, + .task_attr = VIRTIO_SCSI_S_SIMPLE, + .prio = 0, + .crn = 0, + }; + + BUG_ON(sc->cmd_len > VIRTIO_SCSI_CDB_SIZE); + memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len); + + if (virtscsi_kick_cmd(vscsi, vscsi->req_vq, cmd, + sizeof cmd->req.cmd, sizeof cmd->resp.cmd, + GFP_ATOMIC) >= 0) + ret = 0; + +out: + return ret; +} + +static int virtscsi_tmf(struct virtio_scsi *vscsi, struct virtio_scsi_cmd *cmd) +{ + DECLARE_COMPLETION_ONSTACK(comp); + int ret; + + cmd->comp = ∁ + ret = virtscsi_kick_cmd(vscsi, vscsi->ctrl_vq, cmd, + sizeof cmd->req.tmf, sizeof cmd->resp.tmf, + GFP_NOIO); + if (ret < 0) + return FAILED; + + wait_for_completion(&comp); + if (cmd->resp.tmf.response != VIRTIO_SCSI_S_OK && + cmd->resp.tmf.response != VIRTIO_SCSI_S_FUNCTION_SUCCEEDED) + return FAILED; + + return SUCCESS; +} + +static int virtscsi_device_reset(struct scsi_cmnd *sc) +{ + struct virtio_scsi *vscsi = shost_priv(sc->device->host); + struct virtio_scsi_cmd *cmd; + + sdev_printk(KERN_INFO, sc->device, "device reset\n"); + cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); + if (!cmd) + return FAILED; + + memset(cmd, 0, sizeof(*cmd)); + cmd->sc = sc; + cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ + .type = VIRTIO_SCSI_T_TMF, + .subtype = VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET, + .lun[0] = 1, + .lun[1] = sc->device->id, + .lun[2] = (sc->device->lun >> 8) | 0x40, + .lun[3] = sc->device->lun & 0xff, + }; + return virtscsi_tmf(vscsi, cmd); +} + +static int virtscsi_abort(struct scsi_cmnd *sc) +{ + struct virtio_scsi *vscsi = shost_priv(sc->device->host); + struct virtio_scsi_cmd *cmd; + + scmd_printk(KERN_INFO, sc, "abort\n"); + cmd = mempool_alloc(virtscsi_cmd_pool, GFP_NOIO); + if (!cmd) + return FAILED; + + memset(cmd, 0, sizeof(*cmd)); + cmd->sc = sc; + cmd->req.tmf = (struct virtio_scsi_ctrl_tmf_req){ + .type = VIRTIO_SCSI_T_TMF, + .subtype = VIRTIO_SCSI_T_TMF_ABORT_TASK, + .lun[0] = 1, + .lun[1] = sc->device->id, + .lun[2] = (sc->device->lun >> 8) | 0x40, + .lun[3] = sc->device->lun & 0xff, + .tag = (unsigned long)sc, + }; + return virtscsi_tmf(vscsi, cmd); +} + +static struct scsi_host_template virtscsi_host_template = { + .module = THIS_MODULE, + .name = "Virtio SCSI HBA", + .proc_name = "virtio_scsi", + .queuecommand = virtscsi_queuecommand, + .this_id = -1, + .eh_abort_handler = virtscsi_abort, + .eh_device_reset_handler = virtscsi_device_reset, + + .can_queue = 1024, + .dma_boundary = UINT_MAX, + .use_clustering = ENABLE_CLUSTERING, +}; + +#define virtscsi_config_get(vdev, fld) \ + ({ \ + typeof(((struct virtio_scsi_config *)0)->fld) __val; \ + vdev->config->get(vdev, \ + offsetof(struct virtio_scsi_config, fld), \ + &__val, sizeof(__val)); \ + __val; \ + }) + +#define virtscsi_config_set(vdev, fld, val) \ + (void)({ \ + typeof(((struct virtio_scsi_config *)0)->fld) __val = (val); \ + vdev->config->set(vdev, \ + offsetof(struct virtio_scsi_config, fld), \ + &__val, sizeof(__val)); \ + }) + +static int virtscsi_init(struct virtio_device *vdev, + struct virtio_scsi *vscsi) +{ + int err; + struct virtqueue *vqs[3]; + vq_callback_t *callbacks[] = { + virtscsi_ctrl_done, + virtscsi_event_done, + virtscsi_req_done + }; + const char *names[] = { + "control", + "event", + "request" + }; + + /* Discover virtqueues and write information to configuration. */ + err = vdev->config->find_vqs(vdev, 3, vqs, callbacks, names); + if (err) + return err; + + vscsi->ctrl_vq = vqs[0]; + vscsi->event_vq = vqs[1]; + vscsi->req_vq = vqs[2]; + + virtscsi_config_set(vdev, cdb_size, VIRTIO_SCSI_CDB_SIZE); + virtscsi_config_set(vdev, sense_size, VIRTIO_SCSI_SENSE_SIZE); + return 0; +} + +static int __devinit virtscsi_probe(struct virtio_device *vdev) +{ + struct Scsi_Host *shost; + struct virtio_scsi *vscsi; + int err; + u32 sg_elems; + u32 cmd_per_lun; + + /* We need to know how many segments before we allocate. + * We need an extra sg elements at head and tail. + */ + sg_elems = virtscsi_config_get(vdev, seg_max) ?: 1; + + /* Allocate memory and link the structs together. */ + shost = scsi_host_alloc(&virtscsi_host_template, + sizeof(*vscsi) + sizeof(vscsi->sg[0]) * (sg_elems + 2)); + + if (!shost) + return -ENOMEM; + + shost->sg_tablesize = sg_elems; + vscsi = shost_priv(shost); + vscsi->vdev = vdev; + vdev->priv = shost; + + /* Random initializations. */ + spin_lock_init(&vscsi->vq_lock); + sg_init_table(vscsi->sg, sg_elems + 2); + + err = virtscsi_init(vdev, vscsi); + if (err) + goto virtscsi_init_failed; + + cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1; + shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue); + shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF; + shost->max_lun = virtscsi_config_get(vdev, max_lun) + 1; + shost->max_id = virtscsi_config_get(vdev, max_target) + 1; + shost->max_channel = 0; + shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE; + err = scsi_add_host(shost, &vdev->dev); + if (err) + goto scsi_add_host_failed; + + scsi_scan_host(shost); + + return 0; + +scsi_add_host_failed: + vdev->config->del_vqs(vdev); +virtscsi_init_failed: + scsi_host_put(shost); + return err; +} + +static void virtscsi_remove_vqs(struct virtio_device *vdev) +{ + /* Stop all the virtqueues. */ + vdev->config->reset(vdev); + + vdev->config->del_vqs(vdev); +} + +static void __devexit virtscsi_remove(struct virtio_device *vdev) +{ + struct Scsi_Host *shost = virtio_scsi_host(vdev); + + scsi_remove_host(shost); + + virtscsi_remove_vqs(vdev); + scsi_host_put(shost); +} + +#ifdef CONFIG_PM +static int virtscsi_freeze(struct virtio_device *vdev) +{ + virtscsi_remove_vqs(vdev); + return 0; +} + +static int virtscsi_restore(struct virtio_device *vdev) +{ + struct Scsi_Host *sh = virtio_scsi_host(vdev); + struct virtio_scsi *vscsi = shost_priv(sh); + + return virtscsi_init(vdev, vscsi); +} +#endif + +static struct virtio_device_id id_table[] = { + { VIRTIO_ID_SCSI, VIRTIO_DEV_ANY_ID }, + { 0 }, +}; + +static struct virtio_driver virtio_scsi_driver = { + .driver.name = KBUILD_MODNAME, + .driver.owner = THIS_MODULE, + .id_table = id_table, + .probe = virtscsi_probe, +#ifdef CONFIG_PM + .freeze = virtscsi_freeze, + .restore = virtscsi_restore, +#endif + .remove = __devexit_p(virtscsi_remove), +}; + +static int __init init(void) +{ + int ret = -ENOMEM; + + virtscsi_cmd_cache = KMEM_CACHE(virtio_scsi_cmd, 0); + if (!virtscsi_cmd_cache) { + printk(KERN_ERR "kmem_cache_create() for " + "virtscsi_cmd_cache failed\n"); + goto error; + } + + + virtscsi_cmd_pool = + mempool_create_slab_pool(VIRTIO_SCSI_MEMPOOL_SZ, + virtscsi_cmd_cache); + if (!virtscsi_cmd_pool) { + printk(KERN_ERR "mempool_create() for" + "virtscsi_cmd_pool failed\n"); + goto error; + } + ret = register_virtio_driver(&virtio_scsi_driver); + if (ret < 0) + goto error; + + return 0; + +error: + if (virtscsi_cmd_pool) { + mempool_destroy(virtscsi_cmd_pool); + virtscsi_cmd_pool = NULL; + } + if (virtscsi_cmd_cache) { + kmem_cache_destroy(virtscsi_cmd_cache); + virtscsi_cmd_cache = NULL; + } + return ret; +} + +static void __exit fini(void) +{ + unregister_virtio_driver(&virtio_scsi_driver); + mempool_destroy(virtscsi_cmd_pool); + kmem_cache_destroy(virtscsi_cmd_cache); +} +module_init(init); +module_exit(fini); + +MODULE_DEVICE_TABLE(virtio, id_table); +MODULE_DESCRIPTION("Virtio SCSI HBA driver"); +MODULE_LICENSE("GPL"); |