From: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Date: Wed, 5 Jul 2017 08:57:00 +0000 (+0100)
Subject: KVM: arm/arm64: Handle hva aging while destroying the vm
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=7e86f2d55f66e0026aa70ea268021df6bf294c5b;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git

KVM: arm/arm64: Handle hva aging while destroying the vm

commit 7e5a672289c9754d07e1c3b33649786d3d70f5e4 upstream.

The mmu_notifier_release() callback of KVM triggers cleaning up
the stage2 page table on kvm-arm. However there could be other
notifier callbacks in parallel with the mmu_notifier_release(),
which could cause the call backs ending up in an empty stage2
page table. Make sure we check it for all the notifier callbacks.

Fixes: commit 293f29363 ("kvm-arm: Unmap shadow pagetables properly")
Reported-by: Alex Graf <agraf@suse.de>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c
index 1f1ff7e7b9cf..ba079e279b58 100644
--- a/arch/arm/kvm/mmu.c
+++ b/arch/arm/kvm/mmu.c
@@ -1629,12 +1629,16 @@ static int kvm_test_age_hva_handler(struct kvm *kvm, gpa_t gpa, void *data)
 
 int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
 {
+	if (!kvm->arch.pgd)
+		return 0;
 	trace_kvm_age_hva(start, end);
 	return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
 }
 
 int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
 {
+	if (!kvm->arch.pgd)
+		return 0;
 	trace_kvm_test_age_hva(hva);
 	return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
 }