[PATCH 4.4 14/16] kvm: arm/arm64: Force reading uncached stage2 PGD

Greg Kroah-Hartman
2017-09-05T07:10:32Z

From: Suzuki K Poulose <suzuki.poulose@arm.com>

commit 2952a6070e07ebdd5896f1f5b861acad677caded upstream.

Make sure we don't use a cached value of the KVM stage2 PGD while
resetting the PGD.

Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -833,7 +833,7 @@ void kvm_free_stage2_pgd(struct kvm *kvm
spin_lock(&kvm->mmu_lock);
if (kvm->arch.pgd) {
unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);
- pgd = kvm->arch.pgd;
+ pgd = READ_ONCE(kvm->arch.pgd);
hwpgd = kvm_get_hwpgd(kvm);
kvm->arch.pgd = NULL;
}