[PATCH 3/5] KVM: nSVM: leave the guest mode prior to loading a nested state

From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: Wanpeng Li <wanpengli@tencent.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT
	AND 64-BIT)), Jim Mattson <jmattson@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
	Joerg Roedel <joro@8bytes.org>, Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	Sean Christopherson <seanjc@google.com>,
	Cathy Avery <cavery@redhat.com>,
	Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH 3/5] KVM: nSVM: leave the guest mode prior to loading a nested state
Date: Mon,  3 May 2021 15:54:44 +0300	[thread overview]
Message-ID: <20210503125446.1353307-4-mlevitsk@redhat.com> (raw)
In-Reply-To: <20210503125446.1353307-1-mlevitsk@redhat.com>

This allows the KVM to load the nested state more than
once without warnings.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/svm/nested.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index a88c64e004c3..32400cba608d 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1309,12 +1309,15 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
 	 * L2 registers if needed are moved from the current VMCB to VMCB02.
 	 */
 
+	if (is_guest_mode(vcpu))
+		svm_leave_nested(svm);
+	else
+		svm->nested.vmcb02.ptr->save = svm->vmcb01.ptr->save;
+
 	svm->nested.nested_run_pending =
 		!!(kvm_state->flags & KVM_STATE_NESTED_RUN_PENDING);
 
 	svm->nested.vmcb12_gpa = kvm_state->hdr.svm.vmcb_pa;
-	if (svm->current_vmcb == &svm->vmcb01)
-		svm->nested.vmcb02.ptr->save = svm->vmcb01.ptr->save;
 
 	svm->vmcb01.ptr->save.es = save->es;
 	svm->vmcb01.ptr->save.cs = save->cs;
-- 
2.26.2

