[Xen-changelog] [qemu-upstream-unstable] virtio-scsi: Fix some endian bugs with virtio-scsi

[patchbot@xxxxxxx]

commit 474ee55a18765e7de8f0b2cc00db5d26286bb24d
Author: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Date:   Fri Nov 23 16:08:44 2012 +1100

    virtio-scsi: Fix some endian bugs with virtio-scsi
    
    The virtio-scsi specification does not specify the correct endianness for
    fields in the request structure.  It's therefore best to assume that it is
    "guest native" endian since that's the (stupid and poorly defined) norm in
    virtio.
    
    However, the qemu device for virtio-scsi has no byteswaps at all, and so
    will break if the guest has different endianness from the host.  This patch
    fixes it by adding tswap() calls for the sense_len and resid fields in
    the request structure.  In theory status_qualifier needs swaps as well,
    but that field is never actually touched.  The tag field is a uint64_t, but
    since its value is completely arbitrary, it might as well be uint8_t[8]
    and so it does not need swapping.
    
    Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
    Cc: Paul 'Rusty' Russell <rusty@xxxxxxxxxxxxxxx>
    Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
 hw/virtio-scsi.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/hw/virtio-scsi.c b/hw/virtio-scsi.c
index 7d546f6..924fc69 100644
--- a/hw/virtio-scsi.c
+++ b/hw/virtio-scsi.c
@@ -424,15 +424,17 @@ static void virtio_scsi_command_complete(SCSIRequest *r, 
uint32_t status,
                                          size_t resid)
 {
     VirtIOSCSIReq *req = r->hba_private;
+    uint32_t sense_len;
 
     req->resp.cmd->response = VIRTIO_SCSI_S_OK;
     req->resp.cmd->status = status;
     if (req->resp.cmd->status == GOOD) {
-        req->resp.cmd->resid = resid;
+        req->resp.cmd->resid = tswap32(resid);
     } else {
         req->resp.cmd->resid = 0;
-        req->resp.cmd->sense_len =
-            scsi_req_get_sense(r, req->resp.cmd->sense, 
VIRTIO_SCSI_SENSE_SIZE);
+        sense_len = scsi_req_get_sense(r, req->resp.cmd->sense,
+                                       VIRTIO_SCSI_SENSE_SIZE);
+        req->resp.cmd->sense_len = tswap32(sense_len);
     }
     virtio_scsi_complete_req(req);
 }
--
generated by git-patchbot for /home/xen/git/qemu-upstream-unstable.git

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