Re: [PATCH v3 5/6] vfio/migration: Block VFIO migration with postcopy migration

[Peter Xu]

On Wed, Sep 06, 2023 at 06:08:52PM +0300, Avihai Horon wrote:
> VFIO migration is not compatible with postcopy migration. A VFIO device
> in the destination can't handle page faults for pages that have not been
> sent yet.
> 
> Doing such migration will cause the VM to crash in the destination:
> 
> qemu-system-x86_64: VFIO_MAP_DMA failed: Bad address
> qemu-system-x86_64: vfio_dma_map(0x55a28c7659d0, 0xc0000, 0xb000, 
> 0x7f1b11a00000) = -14 (Bad address)
> qemu: hardware error: vfio: DMA mapping failed, unable to continue
> 
> To prevent this, block VFIO migration with postcopy migration.
> 
> Reported-by: Yanghang Liu <yanghliu@redhat.com>
> Signed-off-by: Avihai Horon <avihaih@nvidia.com>
> Tested-by: Yanghang Liu <yanghliu@redhat.com>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu