linux-kernel - [PATCH 4.19 49/50] KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12

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Message-Id: <20190726152305.944211946@linuxfoundation.org>
Date:   Fri, 26 Jul 2019 17:25:24 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jan Kiszka <jan.kiszka@...mens.com>,
        Liran Alon <liran.alon@...cle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 4.19 49/50] KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested

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

commit cf64527bb33f6cec2ed50f89182fc4688d0056b6 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/kvm/vmx.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8490,6 +8490,8 @@ static void free_nested(struct vcpu_vmx
 	if (!vmx->nested.vmxon && !vmx->nested.smm.vmxon)
 		return;
 
+	kvm_clear_request(KVM_REQ_GET_VMCS12_PAGES, &vmx->vcpu);
+
 	hrtimer_cancel(&vmx->nested.preemption_timer);
 	vmx->nested.vmxon = false;
 	vmx->nested.smm.vmxon = false;