From: Punit Agrawal <punit.agrawal@arm.com>
To: kvmarm@lists.cs.columbia.edu
Cc: Punit Agrawal <punit.agrawal@arm.com>,
linux-kernel@vger.kernel.org,
Christoffer Dall <christoffer.dall@linaro.org>,
Marc Zyngier <marc.zyngier@arm.com>
Subject: [PATCH] KVM: arm/arm64: Check pagesize when allocating a hugepage at Stage 2
Date: Thu, 4 Jan 2018 18:24:33 +0000 [thread overview]
Message-ID: <20180104182433.3790-1-punit.agrawal@arm.com> (raw)
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: ad361f093c1e31d ("KVM: ARM: Support hugetlbfs backed huge pages")
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Marc Zyngier <marc.zyngier@arm.com>
---
virt/kvm/arm/mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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 {
--
2.15.1
next reply other threads:[~2018-01-04 18:24 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-04 18:24 Punit Agrawal [this message]
2018-01-11 12:15 ` [PATCH] KVM: arm/arm64: Check pagesize when allocating a hugepage at Stage 2 Christoffer Dall
2018-01-11 13:01 ` Punit Agrawal
2018-01-11 13:49 ` Christoffer Dall
2018-01-11 14:23 ` Punit Agrawal
2018-01-11 14:25 ` Christoffer Dall
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