diff mbox series

[Stable-8.0.5,37/43] hw/ide/ahci: fix broken SError handling

Message ID 20230909130020.352951-37-mjt@tls.msk.ru
State New
Headers show
Series Patch Round-up for stable 8.0.5, freeze on 2023-09-19 | expand

Commit Message

Michael Tokarev Sept. 9, 2023, 1 p.m. UTC 
From: Niklas Cassel <niklas.cassel@wdc.com>

When encountering an NCQ error, you should not write the NCQ tag to the
SError register. This is completely wrong.

The SError register has a clear definition, where each bit represents a
different error, see PxSERR definition in AHCI 1.3.1.

If we write a random value (like the NCQ tag) in SError, e.g. Linux will
read SError, and will trigger arbitrary error handling depending on the
NCQ tag that happened to be executing.

In case of success, ncq_cb() will call ncq_finish().
In case of error, ncq_cb() will call ncq_err() (which will clear
ncq_tfs->used), and then call ncq_finish(), thus using ncq_tfs->used is
sufficient to tell if finished should get set or not.

Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20230609140844.202795-9-nks@flawful.org
Signed-off-by: John Snow <jsnow@redhat.com>
(cherry picked from commit 9f89423537653de07ca40c18b5ff5b70b104cc93)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
diff mbox series

Patch

diff --git a/hw/ide/ahci.c b/hw/ide/ahci.c
index 28a6f59c95..123816c348 100644
--- a/hw/ide/ahci.c
+++ b/hw/ide/ahci.c
@@ -1012,7 +1012,6 @@  static void ncq_err(NCQTransferState *ncq_tfs)
 
     ide_state->error = ABRT_ERR;
     ide_state->status = READY_STAT | ERR_STAT;
-    ncq_tfs->drive->port_regs.scr_err |= (1 << ncq_tfs->tag);
     qemu_sglist_destroy(&ncq_tfs->sglist);
     ncq_tfs->used = 0;
 }
@@ -1022,7 +1021,7 @@  static void ncq_finish(NCQTransferState *ncq_tfs)
     /* If we didn't error out, set our finished bit. Errored commands
      * do not get a bit set for the SDB FIS ACT register, nor do they
      * clear the outstanding bit in scr_act (PxSACT). */
-    if (!(ncq_tfs->drive->port_regs.scr_err & (1 << ncq_tfs->tag))) {
+    if (ncq_tfs->used) {
         ncq_tfs->drive->finished |= (1 << ncq_tfs->tag);
     }