From: Suzuki K Poulose <suzuki.poulose@arm.com>
Date: Tue, 16 May 2017 09:34:54 +0000 (+0100)
Subject: kvm: arm/arm64: Force reading uncached stage2 PGD
X-Git-Tag: v4.11.3~30
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=90c676ffabd45acaa931b36415cb600e90054ae1;p=thirdparty%2Fkernel%2Fstable.git

kvm: arm/arm64: Force reading uncached stage2 PGD

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 9624b193ce1e4..3837b096e1a66 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -844,7 +844,7 @@ 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);
 		kvm->arch.pgd = NULL;
 	}
 	spin_unlock(&kvm->mmu_lock);