linux-kernel - [PATCH stable-5.2 2/3] KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12

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Message-Id: <20190725120436.5432-3-vkuznets@redhat.com>
Date:   Thu, 25 Jul 2019 14:04:35 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     stable@...r.kernel.org
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Subject: [PATCH stable-5.2 2/3] KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested

From: Jan Kiszka <jan.kiszka@...mens.com>

[ Upstream commit cf64527bb33f6cec2ed50f89182fc4688d0056b6 ]

Letting this pend may cause nested_get_vmcs12_pages to run against an
invalid state, corrupting the effective vmcs of L1.

This was triggerable in QEMU after a guest corruption in L2, followed by
a L1 reset.

Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
Reviewed-by: Liran Alon <liran.alon@...cle.com>
Cc: stable@...r.kernel.org
Fixes: 7f7f1ba33cf2 ("KVM: x86: do not load vmcs12 pages while still in SMM")
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/vmx/nested.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index b72d6aec4e90..df6e26894e25 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -210,6 +210,8 @@ static void free_nested(struct kvm_vcpu *vcpu)
 	if (!vmx->nested.vmxon && !vmx->nested.smm.vmxon)
 		return;
 
+	kvm_clear_request(KVM_REQ_GET_VMCS12_PAGES, vcpu);
+
 	vmx->nested.vmxon = false;
 	vmx->nested.smm.vmxon = false;
 	free_vpid(vmx->nested.vpid02);
-- 
2.20.1