RE: [PATCH v7 9/9] iommu/vt-d: Add iotlb flush for nested domain

From: Tian, Kevin
Date: Fri Dec 22 2023 - 02:12:50 EST


> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Friday, December 22, 2023 3:02 PM
>
>
> > On Dec 22, 2023, at 14:47, Tian, Kevin <kevin.tian@xxxxxxxxx> wrote:
> >
> >
> >>
> >> From: Yang, Weijiang <weijiang.yang@xxxxxxxxx>
> >> Sent: Friday, December 22, 2023 11:56 AM
> >>> +
> >>> + xa_for_each(&domain->iommu_array, i, info) {
> >>> + nested_flush_pasid_iotlb(info->iommu, domain, addr,
> >> npages, 0);
> >>> +
> >>> + if (domain->has_iotlb_device)
> >>> + continue;
> >>
> >> Shouldn't this be if (!domain->has_iotlb_device)?
> >
> > yes that is wrong.
> >
> > actually it's weird to put domain check in a loop of domain->iommu_array.
> >
> > that check along with devtlb flush should be done out of that loop.
>
> Maybe adding a bool, set it out of the loop, check the bool in the loop.

the point is that dev iotlb doesn't rely on info->iommu:

nested_flush_dev_iotlb(domain, addr, mask, &fault);

then why do it in the loop of info->iommu?