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 Cc: Christoffer Dall christoffer.dall@arm.com Cc: Marc Zyngier marc.zyngier@arm.com Cc: Suzuki Poulose suzuki.poulose@arm.com Cc: stable@vger.kernel.org # v4.13+ --- virt/kvm/arm/mmu.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 7e477b3cae5b..c23a1b323aad 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -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