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: v4.12-rc2~17^2~6^2~3
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=2952a6070e07ebdd5896f1f5b861acad677caded;p=linux.git

kvm: arm/arm64: Force reading uncached stage2 PGD

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>
Cc: stable@vger.kernel.org
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>
---

diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 909a1a793b31..704e35f312a4 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -837,7 +837,7 @@ 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);