[PATCH stable-4.19 2/2] KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested

From: Vitaly Kuznetsov
Date: Thu Jul 25 2019 - 14:05:25 EST

From: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>

[ 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@xxxxxxxxxxx>
Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 7f7f1ba33cf2 ("KVM: x86: do not load vmcs12 pages while still in SMM")
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
arch/x86/kvm/vmx.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 880bc36a0d5d..4cf16378dffe 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8490,6 +8490,8 @@ static void free_nested(struct vcpu_vmx *vmx)
if (!vmx->nested.vmxon && !vmx->nested.smm.vmxon)

+ kvm_clear_request(KVM_REQ_GET_VMCS12_PAGES, &vmx->vcpu);
vmx->nested.vmxon = false;
vmx->nested.smm.vmxon = false;