On 2020/12/9 20:45, Cornelia Huck wrote: > On Wed, 9 Dec 2020 16:09:18 +0800 > Shenming Lu <lushenm...@huawei.com> wrote: > >> In the VFIO VM state change handler, VFIO devices are transitioned >> in the _SAVING state, which should keep them from sending interrupts. >> Then we can save the pending states of all interrupts in the GIC VM >> state change handler (on ARM). >> >> So we have to set the priority of the VFIO VM state change handler >> explicitly (like virtio devices) to ensure it is called before the >> GIC's in saving. > > What this patch does is to make the priority of the vfio migration > state change handler depending on the position in the qdev tree. As all > state change handlers with no explicit priority are added at priority > 0, this will make sure that this handler runs before (save) resp. after > (restore) nearly all other handlers, which will address your issue here > (and possibly similar ones). > > So, this patch seems fine for now, but I'm wondering whether we need to > think more about priorities for handlers in general, and if there are > more hidden dependencies lurking in there.
As far as I know, as for the migration of interrupt, on x86 the sync from the PIR field to the Virtual-APIC page for posted interrupts (in KVM_GET_LAPIC ioctl) is after the pause of VFIO devices, which is fine. Not sure about others... Thanks, Shenming > >> >> Signed-off-by: Shenming Lu <lushenm...@huawei.com> >> Reviewed-by: Kirti Wankhede <kwankh...@nvidia.com> >> --- >> hw/vfio/migration.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c >> index 3b9de1353a..97ea82b100 100644 >> --- a/hw/vfio/migration.c >> +++ b/hw/vfio/migration.c >> @@ -862,7 +862,8 @@ static int vfio_migration_init(VFIODevice *vbasedev, >> register_savevm_live(id, VMSTATE_INSTANCE_ID_ANY, 1, >> &savevm_vfio_handlers, >> vbasedev); >> >> - migration->vm_state = >> qemu_add_vm_change_state_handler(vfio_vmstate_change, >> + migration->vm_state = qdev_add_vm_change_state_handler(vbasedev->dev, >> + >> vfio_vmstate_change, >> vbasedev); >> migration->migration_state.notify = vfio_migration_state_notifier; >> add_migration_state_change_notifier(&migration->migration_state); > > . >
