Re: [PATCH 2/3] intel-iommu: fail DEVIOTLB_UNMAP without dt mode

[Peter Xu <peterx@redhat.com>]

On Tue, Nov 29, 2022 at 04:10:36PM +0800, Jason Wang wrote:
> Without dt mode, device IOTLB notifier won't work since guest won't
> send device IOTLB invalidation descriptor in this case. Let's fail
> early instead of misbehaving silently.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  hw/i386/intel_iommu.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 9143376677..d025ef2873 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -3179,6 +3179,7 @@ static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
>  {
>      VTDAddressSpace *vtd_as = container_of(iommu, VTDAddressSpace, iommu);
>      IntelIOMMUState *s = vtd_as->iommu_state;
> +    X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);
>  
>      /* TODO: add support for VFIO and vhost users */
>      if (s->snoop_control) {
> @@ -3193,6 +3194,13 @@ static int vtd_iommu_notify_flag_changed(IOMMUMemoryRegion *iommu,
>                           PCI_FUNC(vtd_as->devfn));
>          return -ENOTSUP;
>      }
> +    if (!x86_iommu->dt_supported && (new & IOMMU_NOTIFIER_DEVIOTLB_UNMAP)) {
> +        error_setg_errno(errp, ENOTSUP,
> +                         "device %02x.%02x.%x requires device IOTLB mode",
> +                         pci_bus_num(vtd_as->bus), PCI_SLOT(vtd_as->devfn),
> +                         PCI_FUNC(vtd_as->devfn));
> +        return -ENOTSUP;
> +    }

Hmm I thought we have had this already, so we don't?... :-(

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

-- 
Peter Xu