Re: [PATCH 2/2] spapr_iommu: Fix vhost integration regression

[Greg Kurz]

On Tue,  9 Feb 2021 22:32:33 +0100
Eric Auger <eric.auger@redhat.com> wrote:

> Previous work on dev-iotlb message broke spapr_iommu/vhost integration
> as it did for SMMU and virtio-iommu. The spapr_iommu currently
> only sends IOMMU_NOTIFIER_UNMAP notifications. Since commit
> 958ec334bca3 ("vhost: Unbreak SMMU and virtio-iommu on dev-iotlb support"),
> VHOST first tries to register IOMMU_NOTIFIER_DEVIOTLB_UNMAP notifier
> and if it fails, falls back to legacy IOMMU_NOTIFIER_UNMAP. So
> spapr_iommu must fail on the IOMMU_NOTIFIER_DEVIOTLB_UNMAP
> registration.
> 
> Reported-by: Peter Xu <peterx@redhat.com>
> Fixes: b68ba1ca57677acf870d5ab10579e6105c1f5338
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

>  hw/ppc/spapr_iommu.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
> index 30352df00e..24537ffcbd 100644
> --- a/hw/ppc/spapr_iommu.c
> +++ b/hw/ppc/spapr_iommu.c
> @@ -212,6 +212,11 @@ static int 
> spapr_tce_notify_flag_changed(IOMMUMemoryRegion *iommu,
>  {
>      struct SpaprTceTable *tbl = container_of(iommu, SpaprTceTable, iommu);
>  
> +    if (new & IOMMU_NOTIFIER_DEVIOTLB_UNMAP) {
> +        error_setg(errp, "spart_tce does not support dev-iotlb yet");
> +        return -EINVAL;
> +    }
> +
>      if (old == IOMMU_NOTIFIER_NONE && new != IOMMU_NOTIFIER_NONE) {
>          spapr_tce_set_need_vfio(tbl, true);
>      } else if (old != IOMMU_NOTIFIER_NONE && new == IOMMU_NOTIFIER_NONE) {