Re: [PATCH v2 2/2] vfio/type1: Set IOMMU_MMIO in dma->prot for MMIO-backed addresses

[Wei Wang]

On Friday, November 7, 2025 11:57 PM, Jason Gunthorpe wrote:
On Fri, Nov 07, 2025 at 03:49:17PM +0000, Wei Wang wrote:
>    > (are you aware of any real examples in use?)
>    > VM_IO should indicate MMIO, yes, but we don't actually check that in
>    > this type 1 path..

>    Is it because VFIO type1 didn’t need to check for MMIO before?
>    (not sure how this impacts this patch adding the VM_IO check for MMIO
>    :) )

> Okay, but it still doesn't mean it has to be decrypted..

I think "decrypted or not" is the job of the 1st patch. For now, MMIO cannot be encrypted, particularly not via sme_set(). If MMIO encryption is ever introduced in the future, a new flag (probably different from sme_me_mask) would need to be added.