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

[Cédric Le Goater]

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