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Subject[RFCv2 7/7] virtio-scsi: Enable DIF/DIX modes in SCSI host LLD
Date
From: Nicholas Bellinger <nab@linux-iscsi.org>

This patch updates virtscsi_probe() to setup necessary Scsi_Host
level protection resources. (currently hardcoded to 1)

It changes virtscsi_add_cmd() to attach outgoing / incoming
protection SGLs preceeding the data payload, and is using the
new virtio_scsi_cmd_req_pi->d[oi],pi_niv field to signal
to signal to vhost/scsi how many prot_sgs to expect.

v2 changes:
- Make protection buffer come before data buffer (Paolo)
- Enable virtio_scsi_cmd_req_pi usage (Paolo)

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@dev.mellanox.co.il>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/scsi/virtio_scsi.c | 79 ++++++++++++++++++++++++++++++++++----------
1 files changed, 61 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 16bfd50..4cccfed 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -37,6 +37,7 @@ struct virtio_scsi_cmd {
struct completion *comp;
union {
struct virtio_scsi_cmd_req cmd;
+ struct virtio_scsi_cmd_req_pi cmd_pi;
struct virtio_scsi_ctrl_tmf_req tmf;
struct virtio_scsi_ctrl_an_req an;
} req;
@@ -440,7 +441,7 @@ static int virtscsi_add_cmd(struct virtqueue *vq,
size_t req_size, size_t resp_size, gfp_t gfp)
{
struct scsi_cmnd *sc = cmd->sc;
- struct scatterlist *sgs[4], req, resp;
+ struct scatterlist *sgs[6], req, resp;
struct sg_table *out, *in;
unsigned out_num = 0, in_num = 0;

@@ -458,16 +459,24 @@ static int virtscsi_add_cmd(struct virtqueue *vq,
sgs[out_num++] = &req;

/* Data-out buffer. */
- if (out)
+ if (out) {
+ /* Place WRITE protection SGLs before Data OUT payload */
+ if (scsi_prot_sg_count(sc))
+ sgs[out_num++] = scsi_prot_sglist(sc);
sgs[out_num++] = out->sgl;
+ }

/* Response header. */
sg_init_one(&resp, &cmd->resp, resp_size);
sgs[out_num + in_num++] = &resp;

/* Data-in buffer */
- if (in)
+ if (in) {
+ /* Place READ protection SGLs before Data IN payload */
+ if (scsi_prot_sg_count(sc))
+ sgs[out_num + in_num++] = scsi_prot_sglist(sc);
sgs[out_num + in_num++] = in->sgl;
+ }

return virtqueue_add_sgs(vq, sgs, out_num, in_num, cmd, gfp);
}
@@ -492,12 +501,36 @@ static int virtscsi_kick_cmd(struct virtio_scsi_vq *vq,
return err;
}

+static void virtio_scsi_init_hdr(struct virtio_scsi_cmd_req *cmd,
+ struct scsi_cmnd *sc)
+{
+ cmd->lun[0] = 1;
+ cmd->lun[1] = sc->device->id;
+ cmd->lun[2] = (sc->device->lun >> 8) | 0x40;
+ cmd->lun[3] = sc->device->lun & 0xff;
+ cmd->tag = (unsigned long)sc;
+ cmd->task_attr = VIRTIO_SCSI_S_SIMPLE;
+ cmd->prio = 0;
+ cmd->crn = 0;
+}
+
+static void virtio_scsi_init_hdr_pi(struct virtio_scsi_cmd_req_pi *cmd_pi,
+ struct scsi_cmnd *sc)
+{
+ virtio_scsi_init_hdr((struct virtio_scsi_cmd_req *)cmd_pi, sc);
+
+ if (sc->sc_data_direction == DMA_TO_DEVICE)
+ cmd_pi->do_pi_niov = scsi_prot_sg_count(sc);
+ else if (sc->sc_data_direction == DMA_FROM_DEVICE)
+ cmd_pi->di_pi_niov = scsi_prot_sg_count(sc);
+}
+
static int virtscsi_queuecommand(struct virtio_scsi *vscsi,
struct virtio_scsi_vq *req_vq,
struct scsi_cmnd *sc)
{
struct virtio_scsi_cmd *cmd;
- int ret;
+ int ret, req_size;

struct Scsi_Host *shost = virtio_scsi_host(vscsi->vdev);
BUG_ON(scsi_sg_count(sc) > shost->sg_tablesize);
@@ -515,22 +548,20 @@ static int virtscsi_queuecommand(struct virtio_scsi *vscsi,

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(req_vq, cmd,
- sizeof cmd->req.cmd, sizeof cmd->resp.cmd,
+ if (scsi_prot_sg_count(sc)) {
+ virtio_scsi_init_hdr_pi(&cmd->req.cmd_pi, sc);
+ memcpy(cmd->req.cmd_pi.cdb, sc->cmnd, sc->cmd_len);
+ req_size = sizeof(cmd->req.cmd_pi);
+ } else {
+ virtio_scsi_init_hdr(&cmd->req.cmd, sc);
+ memcpy(cmd->req.cmd.cdb, sc->cmnd, sc->cmd_len);
+ req_size = sizeof(cmd->req.cmd);
+ }
+
+ if (virtscsi_kick_cmd(req_vq, cmd, req_size, sizeof(cmd->resp.cmd),
GFP_ATOMIC) == 0)
ret = 0;
else
@@ -871,7 +902,7 @@ static int virtscsi_probe(struct virtio_device *vdev)
{
struct Scsi_Host *shost;
struct virtio_scsi *vscsi;
- int err;
+ int err, host_prot;
u32 sg_elems, num_targets;
u32 cmd_per_lun;
u32 num_queues;
@@ -921,6 +952,17 @@ static int virtscsi_probe(struct virtio_device *vdev)
shost->max_id = num_targets;
shost->max_channel = 0;
shost->max_cmd_len = VIRTIO_SCSI_CDB_SIZE;
+
+ /* FIXME: Figure out why this is broken.. */
+ if (1 || virtio_has_feature(vdev, VIRTIO_SCSI_F_T10_PI)) {
+ host_prot = SHOST_DIF_TYPE1_PROTECTION | SHOST_DIF_TYPE2_PROTECTION |
+ SHOST_DIF_TYPE3_PROTECTION | SHOST_DIX_TYPE1_PROTECTION |
+ SHOST_DIX_TYPE2_PROTECTION | SHOST_DIX_TYPE3_PROTECTION;
+
+ scsi_host_set_prot(shost, host_prot);
+ scsi_host_set_guard(shost, SHOST_DIX_GUARD_CRC);
+ }
+
err = scsi_add_host(shost, &vdev->dev);
if (err)
goto scsi_add_host_failed;
@@ -990,6 +1032,7 @@ static struct virtio_device_id id_table[] = {
static unsigned int features[] = {
VIRTIO_SCSI_F_HOTPLUG,
VIRTIO_SCSI_F_CHANGE,
+ VIRTIO_SCSI_F_T10_PI,
};

static struct virtio_driver virtio_scsi_driver = {
--
1.7.2.5


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