Re: [PATCH for-5.0 v11 14/20] virtio-iommu: Handle reserved regions in the translation process

[Peter Xu]

On Fri, Nov 22, 2019 at 07:29:37PM +0100, Eric Auger wrote:
> When translating an address we need to check if it belongs to
> a reserved virtual address range. If it does, there are 2 cases:
> 
> - it belongs to a RESERVED region: the guest should neither use
>   this address in a MAP not instruct the end-point to DMA on
>   them. We report an error
> 
> - It belongs to an MSI region: we bypass the translation.
> 
> Signed-off-by: Eric Auger <address@hidden>
> 
> ---
> 
> v10 -> v11:
> - directly use the reserved_regions properties array
> 
> v9 -> v10:
> - in case of MSI region, we immediatly return
> ---
>  hw/virtio/virtio-iommu.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
> index 1ce2218935..c5b202fab7 100644
> --- a/hw/virtio/virtio-iommu.c
> +++ b/hw/virtio/virtio-iommu.c
> @@ -548,6 +548,7 @@ static IOMMUTLBEntry 
> virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
>      uint32_t sid, flags;
>      bool bypass_allowed;
>      bool found;
> +    int i;
>  
>      interval.low = addr;
>      interval.high = addr + 1;
> @@ -580,6 +581,22 @@ static IOMMUTLBEntry 
> virtio_iommu_translate(IOMMUMemoryRegion *mr, hwaddr addr,
>          goto unlock;
>      }
>  
> +    for (i = 0; i < s->nb_reserved_regions; i++) {
> +        if (interval.low >= s->reserved_regions[i].low &&
> +            interval.low <= s->reserved_regions[i].high) {
> +            switch (s->reserved_regions[i].type) {
> +            case VIRTIO_IOMMU_RESV_MEM_T_MSI:
> +                entry.perm = flag;
> +                goto unlock;

Might be a bit clearer to break here instead of goto, then..

> +            case VIRTIO_IOMMU_RESV_MEM_T_RESERVED:

               /* Passthrough */

> +            default:
> +                virtio_iommu_report_fault(s, VIRTIO_IOMMU_FAULT_R_MAPPING,
> +                                          0, sid, addr);
> +            goto unlock;

.. do the same thing here, and...

> +           }

.. goto unlock here..

> +        }
> +    }
> +
>      if (!ep->domain) {
>          if (!bypass_allowed) {
>              qemu_log_mask(LOG_GUEST_ERROR,
> -- 
> 2.20.1
> 

-- 
Peter Xu