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authorMark Cave-Ayland <mark.cave-ayland@ilande.co.uk>2022-06-22 11:53:09 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2022-07-13 16:58:58 +0200
commit389e18eb9aa4877f33326afa426643769185d014 (patch)
treec8b70a86fd03e750b58a3c1d02eb98a8316a764e /hw/scsi/scsi-disk.c
parent6ab717610fe7ef791454df6c61e2b5736d26c8bf (diff)
downloadfocaccia-qemu-389e18eb9aa4877f33326afa426643769185d014.tar.gz
focaccia-qemu-389e18eb9aa4877f33326afa426643769185d014.zip
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>
Diffstat (limited to 'hw/scsi/scsi-disk.c')
-rw-r--r--hw/scsi/scsi-disk.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index 9413b33bac..2b2e496ebd 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -1552,7 +1552,10 @@ static int mode_select_pages(SCSIDiskReq *r, uint8_t *p, int len, bool change)
             goto invalid_param;
         }
         if (page_len > len) {
-            goto invalid_param_len;
+            if (!(s->quirks & SCSI_DISK_QUIRK_MODE_PAGE_TRUNCATED)) {
+                goto invalid_param_len;
+            }
+            trace_scsi_disk_mode_select_page_truncated(page, page_len, len);
         }
 
         if (!change) {
@@ -3151,6 +3154,8 @@ static Property scsi_cd_properties[] = {
     DEFINE_PROP_BIT("quirk_mode_page_vendor_specific_apple", SCSIDiskState,
                     quirks, SCSI_DISK_QUIRK_MODE_PAGE_VENDOR_SPECIFIC_APPLE,
                     0),
+    DEFINE_PROP_BIT("quirk_mode_page_truncated", SCSIDiskState, quirks,
+                    SCSI_DISK_QUIRK_MODE_PAGE_TRUNCATED, 0),
     DEFINE_PROP_END_OF_LIST(),
 };