Re: [PATCH 07/24] iommu/amd: Add support for AMD vIOMMU VF MMIO region

[Vasant Hegde]

On 7/27/2026 6:58 PM, Suravee Suthikulpanit wrote:
> The AMD vIOMMU virtualizes guest MMIO registers at the 3rd 4K region.
> This is achieved using the iommufd_viommu_alloc_mmap().
> 
> Co-developed-by: Vasant Hegde <Vasant.Hegde@xxxxxxx>
> Signed-off-by: Vasant Hegde <Vasant.Hegde@xxxxxxx>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
> ---
>  drivers/iommu/amd/amd_iommu_types.h |  3 +++
>  drivers/iommu/amd/amd_viommu.h      |  7 +++++++
>  drivers/iommu/amd/iommufd.c         | 17 ++++++++++++++++-
>  drivers/iommu/amd/viommu.c          | 10 ++++++++++
>  4 files changed, 36 insertions(+), 1 deletion(-)
> 

.../...

>  
> diff --git a/drivers/iommu/amd/viommu.c b/drivers/iommu/amd/viommu.c
> index 014ae16bf58b..ee8c09f13035 100644
> --- a/drivers/iommu/amd/viommu.c
> +++ b/drivers/iommu/amd/viommu.c
> @@ -131,6 +131,16 @@ static int __init viommu_vf_vfcntl_init(struct amd_iommu *iommu)
>  	return -ENOMEM;
>  }
>  
> +/*
> + * Returns VF MMIO BAR offset for the give guest ID which will be
> + * mapped to guest vIOMMU 3rd 4K MMIO address
> + */
> +u64 amd_viommu_get_vfmmio_addr(struct amd_iommu *iommu, u16 gid)
> +{
> +	/* TODO: Add check for sVIOMMU and set gid[bit 15] */

We can remove this statement. For secure vIOMMU we should be fixing GID
allocation path.

-Vasant