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/qemu/hw/scsi/
H A Dtrace-events389e18eb9aa4877f33326afa426643769185d014 Wed Jun 22 10:53:09 UTC 2022 Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> scsi-disk: add SCSI_DISK_QUIRK_MODE_PAGE_TRUNCATED quirk for Macintosh

When A/UX configures the CDROM device it sends a truncated MODE SELECT request
for page 1 (MODE_PAGE_R_W_ERROR) which is only 6 bytes in length rather than
10. This seems to be due to bug in Apple's code which calculates the CDB message
length incorrectly.

The work at [1] suggests that this truncated request is accepted on real
hardware whereas in QEMU it generates an INVALID_PARAM_LEN sense code which
causes A/UX to get stuck in a loop retrying the command in an attempt to succeed.

Alter the mode page request length check so that truncated requests are allowed
if the SCSI_DISK_QUIRK_MODE_PAGE_TRUNCATED quirk is enabled, whilst also adding a
trace event to enable the condition to be detected.

[1] https://68kmla.org/bb/index.php?threads/scsi2sd-project-anyone-interested.29040/page-7#post-316444

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20220622105314.802852-10-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
H A Dscsi-disk.c389e18eb9aa4877f33326afa426643769185d014 Wed Jun 22 10:53:09 UTC 2022 Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> scsi-disk: add SCSI_DISK_QUIRK_MODE_PAGE_TRUNCATED quirk for Macintosh

When A/UX configures the CDROM device it sends a truncated MODE SELECT request
for page 1 (MODE_PAGE_R_W_ERROR) which is only 6 bytes in length rather than
10. This seems to be due to bug in Apple's code which calculates the CDB message
length incorrectly.

The work at [1] suggests that this truncated request is accepted on real
hardware whereas in QEMU it generates an INVALID_PARAM_LEN sense code which
causes A/UX to get stuck in a loop retrying the command in an attempt to succeed.

Alter the mode page request length check so that truncated requests are allowed
if the SCSI_DISK_QUIRK_MODE_PAGE_TRUNCATED quirk is enabled, whilst also adding a
trace event to enable the condition to be detected.

[1] https://68kmla.org/bb/index.php?threads/scsi2sd-project-anyone-interested.29040/page-7#post-316444

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20220622105314.802852-10-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
/qemu/include/hw/scsi/
H A Dscsi.h389e18eb9aa4877f33326afa426643769185d014 Wed Jun 22 10:53:09 UTC 2022 Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> scsi-disk: add SCSI_DISK_QUIRK_MODE_PAGE_TRUNCATED quirk for Macintosh

When A/UX configures the CDROM device it sends a truncated MODE SELECT request
for page 1 (MODE_PAGE_R_W_ERROR) which is only 6 bytes in length rather than
10. This seems to be due to bug in Apple's code which calculates the CDB message
length incorrectly.

The work at [1] suggests that this truncated request is accepted on real
hardware whereas in QEMU it generates an INVALID_PARAM_LEN sense code which
causes A/UX to get stuck in a loop retrying the command in an attempt to succeed.

Alter the mode page request length check so that truncated requests are allowed
if the SCSI_DISK_QUIRK_MODE_PAGE_TRUNCATED quirk is enabled, whilst also adding a
trace event to enable the condition to be detected.

[1] https://68kmla.org/bb/index.php?threads/scsi2sd-project-anyone-interested.29040/page-7#post-316444

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20220622105314.802852-10-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>