Patch "KVM: arm/arm64: Handle hva aging while destroying the vm" has been added to the 4.12-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

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

to the 4.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     kvm-arm-arm64-handle-hva-aging-while-destroying-the-vm.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 7e5a672289c9754d07e1c3b33649786d3d70f5e4 Mon Sep 17 00:00:00 2001
From: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Date: Wed, 5 Jul 2017 09:57:00 +0100
Subject: KVM: arm/arm64: Handle hva aging while destroying the vm

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

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>

---
 virt/kvm/arm/mmu.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -1665,12 +1665,16 @@ static int kvm_test_age_hva_handler(stru
 
 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);
 }


Patches currently in stable-queue which might be from Suzuki.Poulose@arm.com are

queue-4.12/kvm-arm-arm64-handle-hva-aging-while-destroying-the-vm.patch