| Message ID | 601a7b61-d7b8-57b2-af41-c7c6d89bcef1@redhat.com |
|---|---|
| State | New |
| Headers | show |
At 2017-01-03 17:38:49, Paolo Bonzini <pbonzini@redhat.com> wrote: > > >On 03/01/2017 09:12, Zhang Qian wrote: >> yes, you are right. >> The scenarios of problem is >> a scsi-disk object receives VERIFY command with BYTCHK bit being zero, >> scsi_block_is_passthrough returns false and finally scsi-block uses >> scsi_disk_dma_command for >> VERIFY. So the mode is set to SCSI_XFER_NONE. >> In scsi_req_continue, scsi_read_data function is called. > >Uhm, is the fix simply > >diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c >index bdd1e5f..c080888 100644 >--- a/hw/scsi/scsi-disk.c >+++ b/hw/scsi/scsi-disk.c >@@ -2701,7 +2701,7 @@ static bool scsi_block_is_passthrough(SCSIDiskState *s, uint8_t *buf) > * for the number of logical blocks specified in the length > * field). For other modes, do not use scatter/gather operation. > */ >- if ((buf[1] & 6) != 2) { >+ if ((buf[1] & 6) == 2) { > return false; > } > break; > >then? I verified your patch, it is ok. but why not use (buf[1] & 2) == 2 ? >Thanks, > >Paolo
On 03/01/2017 10:58, Zhang Qian wrote: > > At 2017-01-03 17:38:49, Paolo Bonzini <pbonzini@redhat.com> wrote: >> >> >>On 03/01/2017 09:12, Zhang Qian wrote: >>> yes, you are right. >>> The scenarios of problem is >>> a scsi-disk object receives VERIFY command with BYTCHK bit being zero, >>> scsi_block_is_passthrough returns false and finally scsi-block uses >>> scsi_disk_dma_command for >>> VERIFY. So the mode is set to SCSI_XFER_NONE. >>> In scsi_req_continue, scsi_read_data function is called. >> >>Uhm, is the fix simply >> >>diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c >>index bdd1e5f..c080888 100644 >>--- a/hw/scsi/scsi-disk.c >>+++ b/hw/scsi/scsi-disk.c >>@@ -2701,7 +2701,7 @@ static bool scsi_block_is_passthrough(SCSIDiskState *s, uint8_t *buf) >> * for the number of logical blocks specified in the length >> * field). For other modes, do not use scatter/gather operation. >> */ >>- if ((buf[1] & 6) != 2) { >>+ if ((buf[1] & 6) == 2) { >> return false; >> } >> break; >> >>then? > I verified your patch, it is ok. > > but why not use (buf[1] & 2) == 2 ? Isn't BYTCHK bits 1 and 2? Paolo
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c index bdd1e5f..c080888 100644 --- a/hw/scsi/scsi-disk.c +++ b/hw/scsi/scsi-disk.c @@ -2701,7 +2701,7 @@ static bool scsi_block_is_passthrough(SCSIDiskState *s, uint8_t *buf) * for the number of logical blocks specified in the length * field). For other modes, do not use scatter/gather operation. */ - if ((buf[1] & 6) != 2) { + if ((buf[1] & 6) == 2) { return false; } break;