Messages in this thread | | | Date | Tue, 18 Feb 2020 20:42:35 -0800 | From | Moritz Fischer <> | Subject | Re: [PATCH] iommu/vt-d: Fix a bug in intel_iommu_iova_to_phys() for huge page |
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Hi Baolu, Yonghyun
On Wed, Feb 19, 2020 at 11:15:36AM +0800, Lu Baolu wrote: > Hi Yonghyun, > > Thanks for the patch. > > On 2020/2/19 6:23, Yonghyun Hwang wrote: > > intel_iommu_iova_to_phys() has a bug when it translates an IOVA for a huge > > page onto its corresponding physical address. This commit fixes the bug by > > accomodating the level of page entry for the IOVA and adds IOVA's lower > > address to the physical address. > > > Signed-off-by: Yonghyun Hwang <yonghyun@google.com> > > --- > > drivers/iommu/intel-iommu.c | 11 +++++++++-- > > 1 file changed, 9 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > > index 0c8d81f56a30..ed6e69adb578 100644 > > --- a/drivers/iommu/intel-iommu.c > > +++ b/drivers/iommu/intel-iommu.c > > @@ -5555,13 +5555,20 @@ static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain, > > struct dma_pte *pte; > > int level = 0; > > u64 phys = 0; > > + const unsigned long pfn = iova >> VTD_PAGE_SHIFT; > > Why do you need a "const unsigned long" here? > > > if (dmar_domain->flags & DOMAIN_FLAG_LOSE_CHILDREN) > > return 0; > > - pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level); > > - if (pte) > > + pte = pfn_to_dma_pte(dmar_domain, pfn, &level); > > + if (pte) { > > phys = dma_pte_addr(pte); > > + if (level > 1) > > + phys += (pfn & > > + ((1UL << level_to_offset_bits(level)) - 1)) > > + << VTD_PAGE_SHIFT; > > + phys += iova & (VTD_PAGE_SIZE - 1); > > How about
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c > index 9dc37672bf89..bd17c2510bb2 100644 > --- a/drivers/iommu/intel-iommu.c > +++ b/drivers/iommu/intel-iommu.c > @@ -5693,8 +5693,14 @@ static phys_addr_t intel_iommu_iova_to_phys(struct > iommu_domain *domain, > u64 phys = 0; > > pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level); > - if (pte) > + if (pte) { > + unsigned long offset_mask; > + > + offset_mask = BIT_MASK(level_to_offset_bits(level) + > + VTD_PAGE_SHIFT) - 1; > phys = dma_pte_addr(pte); > + phys += iova & (bitmask - 1); Did you mean:
phys += iova & (offset_mask - 1);
> + }
At that point why not define a helper:
static inline unsigned long offset_mask(int level) { return BIT_MASK(level_to_offset_bits(level) + VTD_PAGE_SHIFT) - 1; }
At which point the above would reduce to:
if (pte) phys = dma_pte_addr(pte) + iova & offset_mask(level) - 1;
I might've fatfingered something here, but you get the idea :)
Cheers, Moritz
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