This is a note to let you know that I've just added the patch titled

KVM: arm/arm64: Check pagesize when allocating a hugepage at Stage 2

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: kvm-arm-arm64-check-pagesize-when-allocating-a-hugepage-at-stage-2.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From c507babf10ead4d5c8cca704539b170752a8ac84 Mon Sep 17 00:00:00 2001

From: Punit Agrawal punit.agrawal@arm.com Date: Thu, 4 Jan 2018 18:24:33 +0000 Subject: KVM: arm/arm64: Check pagesize when allocating a hugepage at Stage 2

From: Punit Agrawal punit.agrawal@arm.com

commit c507babf10ead4d5c8cca704539b170752a8ac84 upstream.

KVM only supports PMD hugepages at stage 2 but doesn't actually check that the provided hugepage memory pagesize is PMD_SIZE before populating stage 2 entries.

In cases where the backing hugepage size is smaller than PMD_SIZE (such as when using contiguous hugepages), KVM can end up creating stage 2 mappings that extend beyond the supplied memory.

Fix this by checking for the pagesize of userspace vma before creating PMD hugepage at stage 2.

Fixes: 66b3923a1a0f77a ("arm64: hugetlb: add support for PTE contiguous bit") Signed-off-by: Punit Agrawal punit.agrawal@arm.com Cc: Marc Zyngier marc.zyngier@arm.com Reviewed-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- virt/kvm/arm/mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1310,7 +1310,7 @@ static int user_mem_abort(struct kvm_vcp return -EFAULT; }

- if (is_vm_hugetlb_page(vma) && !logging_active) { + if (vma_kernel_pagesize(vma) == PMD_SIZE && !logging_active) { hugetlb = true; gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT; } else {

Patches currently in stable-queue which might be from punit.agrawal@arm.com are

queue-4.14/kvm-arm-arm64-check-pagesize-when-allocating-a-hugepage-at-stage-2.patch