hw/i386/intel-iommu: Migrate to 3-phase reset

hw/i386/intel-iommu: Migrate to 3-phase reset

Currently the IOMMU may be reset before the devices
it protects. For example this happens with virtio devices
but also with VFIO devices. In this latter case this
produces spurious translation faults on host.

Let's use 3-phase reset mechanism and reset the IOMMU on
exit phase after all DMA capable devices have been reset
on 'enter' or 'hold' phase.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Zhenzhong Duan <zhenzhong.duan@intel.com>

Message-Id: <20250218182737.76722-3-eric.auger@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>