From ea3bd56f56822350bbb91518b3d786948f573359 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Thu, 16 Dec 2010 19:36:43 +0100
Subject: scsi-disk: support WRITE SAME (16) with unmap bit

Support discards via the WRITE SAME command with the unmap bit set, and
tell the initiator about the support for it via the block limit and the
new thin provisioning EVPD pages.  Also fix the comment which incorrectly
describedthe block limits EVPD page.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/scsi-disk.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 51 insertions(+), 2 deletions(-)

(limited to 'hw/scsi-disk.c')

diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index 87f9e86..6cb317c 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -424,7 +424,8 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req, uint8_t *outbuf)
             outbuf[buflen++] = 0x80; // unit serial number
             outbuf[buflen++] = 0x83; // device identification
             if (bdrv_get_type_hint(s->bs) != BDRV_TYPE_CDROM) {
-                outbuf[buflen++] = 0xb0; // block device characteristics
+                outbuf[buflen++] = 0xb0; // block limits
+                outbuf[buflen++] = 0xb2; // thin provisioning
             }
             outbuf[pages] = buflen - pages - 1; // number of pages
             break;
@@ -466,8 +467,10 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req, uint8_t *outbuf)
             buflen += id_len;
             break;
         }
-        case 0xb0: /* block device characteristics */
+        case 0xb0: /* block limits */
         {
+            unsigned int unmap_sectors =
+                    s->qdev.conf.discard_granularity / s->qdev.blocksize;
             unsigned int min_io_size =
                     s->qdev.conf.min_io_size / s->qdev.blocksize;
             unsigned int opt_io_size =
@@ -492,6 +495,21 @@ static int scsi_disk_emulate_inquiry(SCSIRequest *req, uint8_t *outbuf)
             outbuf[13] = (opt_io_size >> 16) & 0xff;
             outbuf[14] = (opt_io_size >> 8) & 0xff;
             outbuf[15] = opt_io_size & 0xff;
+
+            /* optimal unmap granularity */
+            outbuf[28] = (unmap_sectors >> 24) & 0xff;
+            outbuf[29] = (unmap_sectors >> 16) & 0xff;
+            outbuf[30] = (unmap_sectors >> 8) & 0xff;
+            outbuf[31] = unmap_sectors & 0xff;
+            break;
+        }
+        case 0xb2: /* thin provisioning */
+        {
+            outbuf[3] = buflen = 8;
+            outbuf[4] = 0;
+            outbuf[5] = 0x40; /* write same with unmap supported */
+            outbuf[6] = 0;
+            outbuf[7] = 0;
             break;
         }
         default:
@@ -959,6 +977,12 @@ static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf)
             outbuf[11] = 0;
             outbuf[12] = 0;
             outbuf[13] = get_physical_block_exp(&s->qdev.conf);
+
+            /* set TPE bit if the format supports discard */
+            if (s->qdev.conf.discard_granularity) {
+                outbuf[14] = 0x80;
+            }
+
             /* Protection, exponent and lowest lba field left blank. */
             buflen = req->cmd.xfer;
             break;
@@ -1123,6 +1147,31 @@ static int32_t scsi_send_command(SCSIDevice *d, uint32_t tag,
             goto illegal_lba;
         }
         break;
+    case WRITE_SAME_16:
+        len = r->req.cmd.xfer / d->blocksize;
+
+        DPRINTF("WRITE SAME(16) (sector %" PRId64 ", count %d)\n",
+                r->req.cmd.lba, len);
+
+        if (r->req.cmd.lba > s->max_lba) {
+            goto illegal_lba;
+        }
+
+        /*
+         * We only support WRITE SAME with the unmap bit set for now.
+         */
+        if (!(buf[1] & 0x8)) {
+            goto fail;
+        }
+
+        rc = bdrv_discard(s->bs, r->req.cmd.lba * s->cluster_size,
+                          len * s->cluster_size);
+        if (rc < 0) {
+            /* XXX: better error code ?*/
+            goto fail;
+        }
+
+        break;
     default:
         DPRINTF("Unknown SCSI command (%2.2x)\n", buf[0]);
     fail:
-- 
cgit v1.1