When SCSI passthrough is being used by the guest with virtio-blk, the
guest is not able to detect disk failures. This is because the status
field is expected by the guest driver to include also the msg_status,
host_status and driver_status fields, but the device is only passing
down the SCSI status.
The patch fixes this, and also makes sure that the guest always sees a
CHECK_CONDITION status when there is valid sense data.
---
Sorry for missing the -rc deadline, testing this requires
Fibre Channel stuff so I needed someone to do it for me. :)
hw/virtio-blk.c | 16 +++++++++++++++-
1 files changed, 15 insertions(+), 1 deletions(-)
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index 179747a..8beaa20 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -16,6 +16,7 @@
#include "trace.h"
#include "blockdev.h"
#include "virtio-blk.h"
+#include "scsi-defs.h"
#ifdef __linux__
# include <scsi/sg.h>
#endif
@@ -231,7 +232,20 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
status = VIRTIO_BLK_S_OK;
}
- stl_p(&req->scsi->errors, hdr.status);
+ /*
+ * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)
+ * clear the masked_status field [hence status gets cleared too, see
+ * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED
+ * status has occurred. However they do set DRIVER_SENSE in driver_status
+ * field. Also a (sb_len_wr > 0) indicates there is a sense buffer.
+ */
+ if (hdr.status == 0 && hdr.sb_len_wr > 0) {
+ hdr.status = CHECK_CONDITION;
+ }
+
+ stl_p(&req->scsi->errors,
+ hdr.status | (hdr.msg_status << 8) |
+ (hdr.host_status << 16) | (hdr.driver_status << 24));
stl_p(&req->scsi->residual, hdr.resid);
stl_p(&req->scsi->sense_len, hdr.sb_len_wr);
stl_p(&req->scsi->data_len, hdr.dxfer_len);
--
1.7.6.4
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