[RFC PATCH-for-5.1 v2] hw/ide: Cancel pending DMA requests before setting as inactive

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

libFuzzer found a case where requests are queued for later in the
AIO context, but a command set the bus inactive, then when finally
the requests are processed by the DMA it aborts because it is
inactive:

 include/hw/ide/pci.h:59: IDEState *bmdma_active_if(BMDMAState *): Assertion `bmdma->bus->retry_unit != (uint8_t)-1' failed.

Reproducer available on the BugLink.

Fix by draining the pending DMA requests before inactivating the bus.

BugLink: https://bugs.launchpad.net/qemu/+bug/1887303
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
RFC because I don't have much clue about block drive and IDE,
so block-team please be very careful while reviewing this bug.
---
 hw/ide/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index d997a78e47..f7affafb0c 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -804,7 +804,7 @@ void dma_buf_commit(IDEState *s, uint32_t tx_bytes)
 
 void ide_set_inactive(IDEState *s, bool more)
 {
-    s->bus->dma->aiocb = NULL;
+    ide_cancel_dma_sync(s);
     ide_clear_retry(s);
     if (s->bus->dma->ops->set_inactive) {
         s->bus->dma->ops->set_inactive(s->bus->dma, more);
-- 
2.21.3