linux-kernel - [PATCH 20/28] KVM: SVM: preserve VGIF across VMCB switch

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Message-Id: <20200526172308.111575-21-pbonzini@redhat.com>
Date:   Tue, 26 May 2020 13:23:00 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     vkuznets@...hat.com, mlevitsk@...hat.com,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Jim Mattson <jmattson@...gle.com>
Subject: [PATCH 20/28] KVM: SVM: preserve VGIF across VMCB switch

There is only one GIF flag for the whole processor, so make sure it is
not clobbered when switching to L2 (in which case we also have to include
the V_GIF_ENABLE_MASK, lest we confuse enable_gif/disable_gif/gif_set).

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm/nested.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index f5956ecfeeac..607531db8a94 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -293,6 +293,7 @@ static void nested_prepare_vmcb_save(struct vcpu_svm *svm, struct vmcb *nested_v
 
 static void nested_prepare_vmcb_control(struct vcpu_svm *svm)
 {
+	const u32 mask = V_INTR_MASKING_MASK | V_GIF_ENABLE_MASK | V_GIF_MASK;
 	if (svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE)
 		nested_svm_init_mmu_context(&svm->vcpu);
 
@@ -308,7 +309,10 @@ static void nested_prepare_vmcb_control(struct vcpu_svm *svm)
 	svm->vmcb->control.tsc_offset = svm->vcpu.arch.tsc_offset =
 		svm->vcpu.arch.l1_tsc_offset + svm->nested.ctl.tsc_offset;
 
-	svm->vmcb->control.int_ctl             = svm->nested.ctl.int_ctl | V_INTR_MASKING_MASK;
+	svm->vmcb->control.int_ctl             =
+		(svm->nested.ctl.int_ctl & ~mask) |
+		(svm->nested.hsave->control.int_ctl & mask);
+
 	svm->vmcb->control.virt_ext            = svm->nested.ctl.virt_ext;
 	svm->vmcb->control.int_vector          = svm->nested.ctl.int_vector;
 	svm->vmcb->control.int_state           = svm->nested.ctl.int_state;
-- 
2.26.2