On Fri, Sep 24, 2021 at 11:53:59AM +0200, Jan Beulich wrote:
> Having a separate flush-all hook has always been puzzling me some. We
> will want to be able to force a full flush via accumulated flush flags
> from the map/unmap functions. Introduce a respective new flag and fold
> all flush handling to use the single remaining hook.
>
> Note that because of the respective comments in SMMU and IPMMU-VMSA
> code, I've folded the two prior hook functions into one. For SMMU-v3,
> which lacks a comment towards incapable hardware, I've left both
> functions in place on the assumption that selective and full flushes
> will eventually want separating.
>
> Signed-off-by: Jan Beulich <[email protected]>
Just one nit I think.
> --- a/xen/drivers/passthrough/vtd/iommu.c
> +++ b/xen/drivers/passthrough/vtd/iommu.c
> @@ -731,18 +731,21 @@ static int __must_check iommu_flush_iotl
> 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;
Don't we expect callers to already pass an invalid dfn and a 0 page
count when doing a full flush?
In the equivalent AMD code you didn't set those for the FLUSHF_all
case.
Thanks, Roger.
