Re: [PATCH v4 12/21] IOMMU: fold flush-all hook into "flush one"

[Roger Pau Monné]

On Mon, Apr 25, 2022 at 10:40:06AM +0200, Jan Beulich wrote:
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -772,18 +772,21 @@ static int __must_check cf_check iommu_f
>      struct domain *d, dfn_t dfn, unsigned long page_count,
>      unsigned int flush_flags)
>  {
> -    ASSERT(page_count && !dfn_eq(dfn, INVALID_DFN));
> -    ASSERT(flush_flags);
> +    if ( flush_flags & IOMMU_FLUSHF_all )
> +    {
> +        dfn = INVALID_DFN;
> +        page_count = 0;
> +    }
> +    else
> +    {
> +        ASSERT(page_count && !dfn_eq(dfn, INVALID_DFN));
> +        ASSERT(flush_flags);
> +    }
>  
>      return iommu_flush_iotlb(d, dfn, flush_flags & IOMMU_FLUSHF_modified,
>                               page_count);

In a future patch we could likely move the code in iommu_flush_iotlb
into iommu_flush_iotlb_pages, seeing as iommu_flush_iotlb_pages is the
only caller of iommu_flush_iotlb.

Thanks, Roger.