Commit fd2ef358 authored Oct 01, 2018 by Punit Agrawal Committed by Marc Zyngier Oct 03, 2018

KVM: arm/arm64: Ensure only THP is candidate for adjustment



PageTransCompoundMap() returns true for hugetlbfs and THP
hugepages. This behaviour incorrectly leads to stage 2 faults for
unsupported hugepage sizes (e.g., 64K hugepage with 4K pages) to be
treated as THP faults.

Tighten the check to filter out hugetlbfs pages. This also leads to
consistently mapping all unsupported hugepage sizes as PTE level
entries at stage 2.

Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: Christoffer Dall <christoffer.dall@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: stable@vger.kernel.org # v4.13+
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

parent f0725345

virt/kvm/arm/mmu.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -1231,8 +1231,14 @@ static bool transparent_hugepage_adjust(kvm_pfn_t pfnp, phys_addr_t ipap)
		{
		kvm_pfn_t pfn = *pfnp;
		gfn_t gfn = *ipap >> PAGE_SHIFT;
		struct page *page = pfn_to_page(pfn);

		if (PageTransCompoundMap(pfn_to_page(pfn))) {
		/*
		* PageTransCompoungMap() returns true for THP and
		* hugetlbfs. Make sure the adjustment is done only for THP
		* pages.
		*/
		if (!PageHuge(page) && PageTransCompoundMap(page)) {
		unsigned long mask;
		/*
		* The address we faulted on is backed by a transparent huge

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