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* [PATCH] KVM: nVMX: Allow restore nested-state to enable eVMCS when vCPU in SMM
@ 2019-06-25 11:26 Liran Alon
  2019-06-25 13:11 ` Vitaly Kuznetsov
  0 siblings, 1 reply; 3+ messages in thread
From: Liran Alon @ 2019-06-25 11:26 UTC (permalink / raw)
  To: pbonzini, rkrcmar, kvm; +Cc: vkuznets, Liran Alon, Joao Martins

As comment in code specifies, SMM temporarily disables VMX so we cannot
be in guest mode, nor can VMLAUNCH/VMRESUME be pending.

However, code currently assumes that these are the only flags that can be
set on kvm_state->flags. This is not true as KVM_STATE_NESTED_EVMCS
can also be set on this field to signal that eVMCS should be enabled.

Therefore, fix code to check for guest-mode and pending VMLAUNCH/VMRESUME
explicitly.

Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
---
 arch/x86/kvm/vmx/nested.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 5c470db311f7..27ff04874f67 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5373,7 +5373,10 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu,
 	 * nor can VMLAUNCH/VMRESUME be pending.  Outside SMM, SMM flags
 	 * must be zero.
 	 */
-	if (is_smm(vcpu) ? kvm_state->flags : kvm_state->hdr.vmx.smm.flags)
+	if (is_smm(vcpu) ?
+		(kvm_state->flags &
+		 (KVM_STATE_NESTED_GUEST_MODE | KVM_STATE_NESTED_RUN_PENDING))
+		: kvm_state->hdr.vmx.smm.flags)
 		return -EINVAL;
 
 	if ((kvm_state->hdr.vmx.smm.flags & KVM_STATE_NESTED_SMM_GUEST_MODE) &&
-- 
2.20.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2019-07-01 23:17 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2019-06-25 11:26 [PATCH] KVM: nVMX: Allow restore nested-state to enable eVMCS when vCPU in SMM Liran Alon
2019-06-25 13:11 ` Vitaly Kuznetsov
2019-07-01 23:16   ` Liran Alon

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