[PULL 1/6] ide: Fix potential assertion failure on VM stop for PIO read error

[Kevin Wolf <kwolf@redhat.com>]

ide_sector_read() as well as its callers neglect to call ide_set_retry()
before starting I/O. If the I/O fails, this means that the retry
information is stale. In particular, ide_handle_rw_error() has an
assertion that s->bus->retry_unit == s->unit, which can fail if either
there was no previous request or it came from another device on the bus.
If the assertion weren't there, a wrong request would be retried after
resuming the VM.

Fix this by adding a ide_set_retry() call to ide_sector_read().

This affects only reads because ide_transfer_start() does call
ide_set_retry(). For writes, the data transfer comes first and the I/O
is only started when the data has been read into s->io_buffer, so by
that time, ide_set_retry() has been called. For reads, however, the I/O
comes first and only then the data is transferred to the guest, so the
call in ide_transfer_start() is too late.

Buglink: https://redhat.atlassian.net/browse/RHEL-153537
Reported-by: Tingting Mao <timao@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20260326165124.138593-1-kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/ide/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index d6719dbf31d..7a15d6cac9b 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -799,6 +799,7 @@ static void ide_sector_read(IDEState *s)
     s->error = 0; /* not needed by IDE spec, but needed by Windows */
     sector_num = ide_get_sector(s);
     n = s->nsector;
+    ide_set_retry(s);
 
     if (n == 0) {
         ide_transfer_stop(s);
-- 
2.53.0