[Qemu-devel] [PULL 27/31] scsi-generic: Merge block max xfer len in INQUIRY response

[Paolo Bonzini <pbonzini@redhat.com>]

From: Fam Zheng <famz@redhat.com>

The rationale is similar to the above mode sense response interception:
this is practically the only channel to communicate restraints from
elsewhere such as host and block driver.

The scsi bus we attach onto can have a larger max xfer len than what is
accepted by the host file system (guarding between the host scsi LUN and
QEMU), in which case the SG_IO we generate would get -EINVAL.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <1464243305-10661-3-git-send-email-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/scsi/scsi-generic.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 7459465..71372a8 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -222,6 +222,18 @@ static void scsi_read_complete(void * opaque, int ret)
             r->buf[3] |= 0x80;
         }
     }
+    if (s->type == TYPE_DISK &&
+        r->req.cmd.buf[0] == INQUIRY &&
+        r->req.cmd.buf[2] == 0xb0) {
+        uint32_t max_xfer_len = blk_get_max_transfer_length(s->conf.blk);
+        if (max_xfer_len) {
+            stl_be_p(&r->buf[8], max_xfer_len);
+            /* Also take care of the opt xfer len. */
+            if (ldl_be_p(&r->buf[12]) > max_xfer_len) {
+                stl_be_p(&r->buf[12], max_xfer_len);
+            }
+        }
+    }
     scsi_req_data(&r->req, len);
     scsi_req_unref(&r->req);
 }
-- 
2.5.5