On Thu, Jun 29, 2017 at 12:26:57PM +0800, Peter Xu wrote:
> Migration is broken after the vfio integration work:
>
> qemu-kvm: AHCI: Failed to start FIS receive engine: bad FIS receive buffer
> address
> qemu-kvm: Failed to load ich9_ahci:ahci
> qemu-kvm: error while loading state for instance 0x0 of device
> '0000:00:1f.2/ich9_ahci'
> qemu-kvm: load of migration failed: Operation not permitted
>
> The problem is that vfio work introduced dynamic memory region
> switching (actually it is also used for future PT mode), and this memory
> region layout is not properly delivered to destination when migration
> happens. Solution is to rebuild the layout in post_load.
>
> Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1459906
> Fixes: 558e0024 ("intel_iommu: allow dynamic switch of IOMMU region")
> Signed-off-by: Peter Xu <pet...@redhat.com>
> ---
> hw/i386/intel_iommu.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index a9b59bd..36b231d 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -2332,11 +2332,28 @@ static void
> vtd_iommu_notify_flag_changed(MemoryRegion *iommu,
> }
> }
>
> +static int vtd_post_load(void *opaque, int version_id)
> +{
> + IntelIOMMUState *iommu = opaque;
> +
> + /*
> + * Since commit 558e00 ("intel_iommu: allow dynamic switch of
> + * IOMMU region"),
I would drop this part of the comment. It isn't of interest
to people reading code directly, while people reading git
history see the commit log.
> memory regions are dynamically turned on/off
> + * depending on context entry configurations from the guest. After
> + * migration, we need to make sure the memory regions are still
> + * correct.
> + */
> + vtd_switch_address_space_all(iommu);
> +
> + return 0;
> +}
> +
> static const VMStateDescription vtd_vmstate = {
> .name = "iommu-intel",
> .version_id = 1,
> .minimum_version_id = 1,
> .priority = MIG_PRI_IOMMU,
> + .post_load = vtd_post_load,
> .fields = (VMStateField[]) {
> VMSTATE_UINT64(root, IntelIOMMUState),
> VMSTATE_UINT64(intr_root, IntelIOMMUState),
> --
> 2.7.4
