The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
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: [PATCH] KVM: arm/arm64: Check pagesize when allocating a hugepage at Stage 2
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 Cc: stable@vger.kernel.org # v4.5+ Reviewed-by: Christoffer Dall christoffer.dall@linaro.org Signed-off-by: Christoffer Dall christoffer.dall@linaro.org
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index b4b69c2d1012..9dea96380339 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -1310,7 +1310,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, 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 {