Commit 27ef63c7 authored by Greg Edwards's avatar Greg Edwards Committed by Gleb Natapov

KVM: IOMMU: hva align mapping page size

When determining the page size we could use to map with the IOMMU, the
page size should also be aligned with the hva, not just the gfn.  The
gfn may not reflect the real alignment within the hugetlbfs file.

Most of the time, this works fine.  However, if the hugetlbfs file is
backed by non-contiguous huge pages, a multi-huge page memslot starts at
an unaligned offset within the hugetlbfs file, and the gfn is aligned
with respect to the huge page size, kvm_host_page_size() will return the
huge page size and we will use that to map with the IOMMU.

When we later unpin that same memslot, the IOMMU returns the unmap size
as the huge page size, and we happily unpin that many pfns in
monotonically increasing order, not realizing we are spanning
non-contiguous huge pages and partially unpin the wrong huge page.

Ensure the IOMMU mapping page size is aligned with the hva corresponding
to the gfn, which does reflect the alignment within the hugetlbfs file.
Reviewed-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarGreg Edwards <gedwards@ddn.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent a9d4e439
...@@ -103,6 +103,10 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot) ...@@ -103,6 +103,10 @@ int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot)
while ((gfn << PAGE_SHIFT) & (page_size - 1)) while ((gfn << PAGE_SHIFT) & (page_size - 1))
page_size >>= 1; page_size >>= 1;
/* Make sure hva is aligned to the page size we want to map */
while (__gfn_to_hva_memslot(slot, gfn) & (page_size - 1))
page_size >>= 1;
/* /*
* Pin all pages we are about to map in memory. This is * Pin all pages we are about to map in memory. This is
* important because we unmap and unpin in 4kb steps later. * important because we unmap and unpin in 4kb steps later.
......
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