Re: [PATCH] hw/vfio: fix iteration over global VFIODevice list

["Cédric Le Goater" <clg@redhat.com>]

On 1/2/24 05:27, Duan, Zhenzhong wrote:
> 
> 
>> -----Original Message-----
>> From: Volker Rümelin <vr_qemu@t-online.de>
>> Subject: [PATCH] hw/vfio: fix iteration over global VFIODevice list
>>
>> Commit 3d779abafe ("vfio/common: Introduce a global VFIODevice list")
>> introduced a global VFIODevice list, but forgot to update the list
>> element field name when iterating over the new list. Change the code
>> to use the correct list element field.
>>
>> Fixes: 3d779abafe ("vfio/common: Introduce a global VFIODevice list")
>> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2061
>> Signed-off-by: Volker Rümelin <vr_qemu@t-online.de>
> 
> Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> 
> My fault, thanks for fixing!
> 
> I also digged into why I didn't reproduce this issue with two vfio devices before.
> This issue only reproduce with two vfio devices in one reset group(same slot or bus)
> plus a third vfio device in a different reset group. Then the two vfio devices will
> miss reset due to this bug.

Thanks for digging.

C.



> BRs.
> Zhenzhong
> 
>> ---
>> hw/vfio/common.c | 8 ++++----
>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/vfio/common.c b/hw/vfio/common.c
>> index 08a3e57672..3ba892d7d3 100644
>> --- a/hw/vfio/common.c
>> +++ b/hw/vfio/common.c
>> @@ -74,7 +74,7 @@ bool vfio_mig_active(void)
>>          return false;
>>      }
>>
>> -    QLIST_FOREACH(vbasedev, &vfio_device_list, next) {
>> +    QLIST_FOREACH(vbasedev, &vfio_device_list, global_next) {
>>          if (vbasedev->migration_blocker) {
>>              return false;
>>          }
>> @@ -95,7 +95,7 @@ static bool
>> vfio_multiple_devices_migration_is_supported(void)
>>      unsigned int device_num = 0;
>>      bool all_support_p2p = true;
>>
>> -    QLIST_FOREACH(vbasedev, &vfio_device_list, next) {
>> +    QLIST_FOREACH(vbasedev, &vfio_device_list, global_next) {
>>          if (vbasedev->migration) {
>>              device_num++;
>>
>> @@ -1367,13 +1367,13 @@ void vfio_reset_handler(void *opaque)
>> {
>>      VFIODevice *vbasedev;
>>
>> -    QLIST_FOREACH(vbasedev, &vfio_device_list, next) {
>> +    QLIST_FOREACH(vbasedev, &vfio_device_list, global_next) {
>>          if (vbasedev->dev->realized) {
>>              vbasedev->ops->vfio_compute_needs_reset(vbasedev);
>>          }
>>      }
>>
>> -    QLIST_FOREACH(vbasedev, &vfio_device_list, next) {
>> +    QLIST_FOREACH(vbasedev, &vfio_device_list, global_next) {
>>          if (vbasedev->dev->realized && vbasedev->needs_reset) {
>>              vbasedev->ops->vfio_hot_reset_multi(vbasedev);
>>          }
>> --
>> 2.35.3
>