[RFCv2 5/7] vhost/scsi: Enable T10 PI IOV -> SGL memory mapping

From: Nicholas A. Bellinger
Date: Mon Mar 17 2014 - 01:57:00 EST


From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

This patch updates vhost_scsi_handle_vq() to check for the existance
of virtio_scsi_cmd_req_pi comparing vq->iov[0].iov_len in order to
calculate seperate data + protection SGLs from data_num.

Also update tcm_vhost_submission_work() to pass the pre-allocated
cmd->tvc_prot_sgl[] memory into target_submit_cmd_map_sgls(), and
update vhost_scsi_get_tag() parameters to accept scsi_tag, lun, and
task_attr.

v2 changes:
- Use virtio_scsi_cmd_req_pi instead of existing ->prio (Paolo)
- Make protection buffer come before data buffer (Paolo)
- Update vhost_scsi_get_tag() parameter usage

Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/vhost/scsi.c | 164 +++++++++++++++++++++++++++++++++----------------
1 files changed, 110 insertions(+), 54 deletions(-)

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index f720709..00903dc 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -715,11 +715,9 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
}

static struct tcm_vhost_cmd *
-vhost_scsi_get_tag(struct vhost_virtqueue *vq,
- struct tcm_vhost_tpg *tpg,
- struct virtio_scsi_cmd_req *v_req,
- u32 exp_data_len,
- int data_direction)
+vhost_scsi_get_tag(struct vhost_virtqueue *vq, struct tcm_vhost_tpg *tpg,
+ unsigned char *cdb, u64 scsi_tag, u16 lun, u8 task_attr,
+ u32 exp_data_len, int data_direction)
{
struct tcm_vhost_cmd *cmd;
struct tcm_vhost_nexus *tv_nexus;
@@ -751,13 +749,16 @@ vhost_scsi_get_tag(struct vhost_virtqueue *vq,
cmd->tvc_prot_sgl = prot_sg;
cmd->tvc_upages = pages;
cmd->tvc_se_cmd.map_tag = tag;
- cmd->tvc_tag = v_req->tag;
- cmd->tvc_task_attr = v_req->task_attr;
+ cmd->tvc_tag = scsi_tag;
+ cmd->tvc_lun = lun;
+ cmd->tvc_task_attr = task_attr;
cmd->tvc_exp_data_len = exp_data_len;
cmd->tvc_data_direction = data_direction;
cmd->tvc_nexus = tv_nexus;
cmd->inflight = tcm_vhost_get_inflight(vq);

+ memcpy(cmd->tvc_cdb, cdb, TCM_VHOST_MAX_CDB_SIZE);
+
return cmd;
}

@@ -908,18 +909,15 @@ static void tcm_vhost_submission_work(struct work_struct *work)
container_of(work, struct tcm_vhost_cmd, work);
struct tcm_vhost_nexus *tv_nexus;
struct se_cmd *se_cmd = &cmd->tvc_se_cmd;
- struct scatterlist *sg_ptr, *sg_bidi_ptr = NULL;
- int rc, sg_no_bidi = 0;
+ struct scatterlist *sg_ptr, *sg_prot_ptr = NULL;
+ int rc;

+ /* FIXME: BIDI operation */
if (cmd->tvc_sgl_count) {
sg_ptr = cmd->tvc_sgl;
-/* FIXME: Fix BIDI operation in tcm_vhost_submission_work() */
-#if 0
- if (se_cmd->se_cmd_flags & SCF_BIDI) {
- sg_bidi_ptr = NULL;
- sg_no_bidi = 0;
- }
-#endif
+
+ if (cmd->tvc_prot_sgl_count)
+ sg_prot_ptr = cmd->tvc_prot_sgl;
} else {
sg_ptr = NULL;
}
@@ -930,7 +928,7 @@ static void tcm_vhost_submission_work(struct work_struct *work)
cmd->tvc_lun, cmd->tvc_exp_data_len,
cmd->tvc_task_attr, cmd->tvc_data_direction,
TARGET_SCF_ACK_KREF, sg_ptr, cmd->tvc_sgl_count,
- sg_bidi_ptr, sg_no_bidi, NULL, 0);
+ NULL, 0, sg_prot_ptr, cmd->tvc_prot_sgl_count);
if (rc < 0) {
transport_send_check_condition_and_sense(se_cmd,
TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
@@ -962,12 +960,18 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
{
struct tcm_vhost_tpg **vs_tpg;
struct virtio_scsi_cmd_req v_req;
+ struct virtio_scsi_cmd_req_pi v_req_pi;
struct tcm_vhost_tpg *tpg;
struct tcm_vhost_cmd *cmd;
- u32 exp_data_len, data_first, data_num, data_direction;
+ u64 tag;
+ u32 exp_data_len, data_first, data_num, data_direction, prot_first;
unsigned out, in, i;
- int head, ret;
- u8 target;
+ int head, ret, data_niov, prot_niov;
+ size_t req_size;
+ u16 lun;
+ u8 *target, task_attr;
+ bool hdr_pi;
+ unsigned char *req, *cdb;

mutex_lock(&vq->mutex);
/*
@@ -998,7 +1002,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
break;
}

-/* FIXME: BIDI operation */
+ /* FIXME: BIDI operation */
if (out == 1 && in == 1) {
data_direction = DMA_NONE;
data_first = 0;
@@ -1028,23 +1032,31 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
break;
}

- if (unlikely(vq->iov[0].iov_len != sizeof(v_req))) {
- vq_err(vq, "Expecting virtio_scsi_cmd_req, got %zu"
+ if (vq->iov[0].iov_len == sizeof(v_req_pi)) {
+ req = (unsigned char *)&v_req_pi;
+ target = &v_req_pi.lun[1];
+ req_size = sizeof(v_req_pi);
+ hdr_pi = true;
+ } else if (vq->iov[0].iov_len == sizeof(v_req)) {
+ req = (unsigned char *)&v_req;
+ target = &v_req.lun[1];
+ req_size = sizeof(v_req);
+ hdr_pi = false;
+ } else {
+ vq_err(vq, "Expecting virtio_scsi_cmd_req*, got %zu"
" bytes\n", vq->iov[0].iov_len);
break;
}
+
pr_debug("Calling __copy_from_user: vq->iov[0].iov_base: %p,"
- " len: %zu\n", vq->iov[0].iov_base, sizeof(v_req));
- ret = __copy_from_user(&v_req, vq->iov[0].iov_base,
- sizeof(v_req));
+ " len: %zu\n", vq->iov[0].iov_base, req_size);
+ ret = __copy_from_user(req, vq->iov[0].iov_base, req_size);
if (unlikely(ret)) {
vq_err(vq, "Faulted on virtio_scsi_cmd_req\n");
break;
}

- /* Extract the tpgt */
- target = v_req.lun[1];
- tpg = ACCESS_ONCE(vs_tpg[target]);
+ tpg = ACCESS_ONCE(vs_tpg[*target]);

/* Target does not exist, fail the request */
if (unlikely(!tpg)) {
@@ -1052,17 +1064,73 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
continue;
}

+ data_niov = data_num;
+ prot_niov = prot_first = 0;
+ /*
+ * Determine if any proteciton information iovecs are preceeding
+ * the actual data payload, and adjust data_niov + data_first
+ *
+ * Also extract virtio_scsi header bits for vhost_scsi_get_tag()
+ */
+ if (data_num && hdr_pi) {
+ if (v_req_pi.do_pi_niov) {
+ if (data_direction != DMA_TO_DEVICE) {
+ vq_err(vq, "Received non zero do_pi_niov"
+ ", but wrong data_direction\n");
+ goto err_cmd;
+ }
+ prot_niov = v_req_pi.do_pi_niov;
+ } else if (v_req_pi.di_pi_niov) {
+ if (data_direction != DMA_FROM_DEVICE) {
+ vq_err(vq, "Received non zero di_pi_niov"
+ ", but wrong data_direction\n");
+ goto err_cmd;
+ }
+ prot_niov = v_req_pi.di_pi_niov;
+ } else {
+ vq_err(vq, "Received zero do_pi_niov + di_pi_niov"
+ ", but still using hdr_pi\n");
+ goto err_cmd;
+ }
+
+ data_niov = data_num - prot_niov;
+ prot_first = data_first;
+ data_first += prot_niov;
+
+ tag = v_req_pi.tag;
+ task_attr = v_req_pi.task_attr;
+ cdb = &v_req_pi.cdb[0];
+ lun = ((v_req_pi.lun[2] << 8) | v_req_pi.lun[3]) & 0x3FFF;
+ } else {
+ tag = v_req.tag;
+ task_attr = v_req.task_attr;
+ cdb = &v_req.cdb[0];
+ lun = ((v_req.lun[2] << 8) | v_req.lun[3]) & 0x3FFF;
+ }
exp_data_len = 0;
- for (i = 0; i < data_num; i++)
+ for (i = 0; i < data_niov; i++)
exp_data_len += vq->iov[data_first + i].iov_len;
+ /*
+ * Check that the recieved CDB size does not exceeded our
+ * hardcoded max for vhost-scsi
+ *
+ * TODO what if cdb was too small for varlen cdb header?
+ */
+ if (unlikely(scsi_command_size(cdb) > TCM_VHOST_MAX_CDB_SIZE)) {
+ vq_err(vq, "Received SCSI CDB with command_size: %d that"
+ " exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
+ scsi_command_size(cdb), TCM_VHOST_MAX_CDB_SIZE);
+ goto err_cmd;
+ }

- cmd = vhost_scsi_get_tag(vq, tpg, &v_req,
+ cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
exp_data_len, data_direction);
if (IS_ERR(cmd)) {
vq_err(vq, "vhost_scsi_get_tag failed %ld\n",
PTR_ERR(cmd));
goto err_cmd;
}
+
pr_debug("Allocated tv_cmd: %p exp_data_len: %d, data_direction"
": %d\n", cmd, exp_data_len, data_direction);

@@ -1070,40 +1138,28 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
cmd->tvc_vq = vq;
cmd->tvc_resp = vq->iov[out].iov_base;

- /*
- * Copy in the recieved CDB descriptor into cmd->tvc_cdb
- * that will be used by tcm_vhost_new_cmd_map() and down into
- * target_setup_cmd_from_cdb()
- */
- memcpy(cmd->tvc_cdb, v_req.cdb, TCM_VHOST_MAX_CDB_SIZE);
- /*
- * Check that the recieved CDB size does not exceeded our
- * hardcoded max for tcm_vhost
- */
- /* TODO what if cdb was too small for varlen cdb header? */
- if (unlikely(scsi_command_size(cmd->tvc_cdb) >
- TCM_VHOST_MAX_CDB_SIZE)) {
- vq_err(vq, "Received SCSI CDB with command_size: %d that"
- " exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
- scsi_command_size(cmd->tvc_cdb),
- TCM_VHOST_MAX_CDB_SIZE);
- goto err_free;
- }
- cmd->tvc_lun = ((v_req.lun[2] << 8) | v_req.lun[3]) & 0x3FFF;
-
pr_debug("vhost_scsi got command opcode: %#02x, lun: %d\n",
cmd->tvc_cdb[0], cmd->tvc_lun);

+ if (prot_niov) {
+ ret = vhost_scsi_map_iov_to_prot(cmd,
+ &vq->iov[prot_first], prot_niov,
+ data_direction == DMA_FROM_DEVICE);
+ if (unlikely(ret)) {
+ vq_err(vq, "Failed to map iov to"
+ " prot_sgl\n");
+ goto err_free;
+ }
+ }
if (data_direction != DMA_NONE) {
ret = vhost_scsi_map_iov_to_sgl(cmd,
- &vq->iov[data_first], data_num,
+ &vq->iov[data_first], data_niov,
data_direction == DMA_FROM_DEVICE);
if (unlikely(ret)) {
vq_err(vq, "Failed to map iov to sgl\n");
goto err_free;
}
}
-
/*
* Save the descriptor from vhost_get_vq_desc() to be used to
* complete the virtio-scsi request in TCM callback context via
--
1.7.2.5

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