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Date: Mon, 14 Dec 2020 17:04:59 -0700 From: Alex Williamson <alex.williamson@...hat.com> To: Keqian Zhu <zhukeqian1@...wei.com> Cc: <linux-kernel@...r.kernel.org>, <linux-arm-kernel@...ts.infradead.org>, <iommu@...ts.linux-foundation.org>, <kvm@...r.kernel.org>, <kvmarm@...ts.cs.columbia.edu>, Cornelia Huck <cohuck@...hat.com>, Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>, Joerg Roedel <joro@...tes.org>, Catalin Marinas <catalin.marinas@....com>, James Morse <james.morse@....com>, Suzuki K Poulose <suzuki.poulose@....com>, Sean Christopherson <sean.j.christopherson@...el.com>, Julien Thierry <julien.thierry.kdev@...il.com>, Mark Brown <broonie@...nel.org>, "Thomas Gleixner" <tglx@...utronix.de>, Andrew Morton <akpm@...ux-foundation.org>, Alexios Zavras <alexios.zavras@...el.com>, <wanghaibin.wang@...wei.com>, <jiangkunkun@...wei.com> Subject: Re: [PATCH 4/7] vfio: iommu_type1: Fix missing dirty page when promote pinned_scope On Thu, 10 Dec 2020 15:34:22 +0800 Keqian Zhu <zhukeqian1@...wei.com> wrote: > When we pin or detach a group which is not dirty tracking capable, > we will try to promote pinned_scope of vfio_iommu. > > If we succeed to do so, vfio only report pinned_scope as dirty to > userspace next time, but these memory written before pin or detach > is missed. > > The solution is that we must populate all dma range as dirty before > promoting pinned_scope of vfio_iommu. Please don't bury fixes patches into a series with other optimizations and semantic changes. Send it separately. > > Signed-off-by: Keqian Zhu <zhukeqian1@...wei.com> > --- > drivers/vfio/vfio_iommu_type1.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index bd9a94590ebc..00684597b098 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -1633,6 +1633,20 @@ static struct vfio_group *vfio_iommu_find_iommu_group(struct vfio_iommu *iommu, > return group; > } > > +static void vfio_populate_bitmap_all(struct vfio_iommu *iommu) > +{ > + struct rb_node *n; > + unsigned long pgshift = __ffs(iommu->pgsize_bitmap); > + > + for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) { > + struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node); > + unsigned long nbits = dma->size >> pgshift; > + > + if (dma->iommu_mapped) > + bitmap_set(dma->bitmap, 0, nbits); > + } > +} If we detach a group which results in only non-IOMMU backed mdevs, don't we also clear dma->iommu_mapped as part of vfio_unmap_unpin() such that this test is invalid? Thanks, Alex > + > static void promote_pinned_page_dirty_scope(struct vfio_iommu *iommu) > { > struct vfio_domain *domain; > @@ -1657,6 +1671,10 @@ static void promote_pinned_page_dirty_scope(struct vfio_iommu *iommu) > } > > iommu->pinned_page_dirty_scope = true; > + > + /* Set all bitmap to avoid missing dirty page */ > + if (iommu->dirty_page_tracking) > + vfio_populate_bitmap_all(iommu); > } > > static bool vfio_iommu_has_sw_msi(struct list_head *group_resv_regions,
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