linux-kernel - [PATCH 17/24] KVM: nSVM: do all MMU switch work in init/uninit functions

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Date:   Wed, 20 May 2020 13:21:38 -0400
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     vkuznets@...hat.com, Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 17/24] KVM: nSVM: do all MMU switch work in init/uninit functions

Move the kvm_mmu_reset_context calls to nested_svm_init_mmu_context and
nested_svm_uninit_mmu_context, so that the state of the MMU is consistent
with the vcpu->arch.mmu and vcpu->arch.walk_mmu state.  Remove an
unnecessary kvm_mmu_load, which can wait until the first vcpu_run.

Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
---
 arch/x86/kvm/svm/nested.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 024e27bebba3..54a3384a60f8 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -90,12 +90,17 @@ static void nested_svm_init_mmu_context(struct kvm_vcpu *vcpu)
 	vcpu->arch.mmu->shadow_root_level = vcpu->arch.tdp_level;
 	reset_shadow_zero_bits_mask(vcpu, vcpu->arch.mmu);
 	vcpu->arch.walk_mmu              = &vcpu->arch.nested_mmu;
+
+	/* Guest paging mode is active - reset mmu */
+	kvm_mmu_reset_context(vcpu);
 }
 
 static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
 {
 	vcpu->arch.mmu = &vcpu->arch.root_mmu;
 	vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
+
+	kvm_mmu_reset_context(vcpu);
 }
 
 void recalc_intercepts(struct vcpu_svm *svm)
@@ -277,9 +282,6 @@ static void nested_prepare_vmcb_control(struct vcpu_svm *svm)
 	if (svm->nested.ctl.nested_ctl & SVM_NESTED_CTL_NP_ENABLE)
 		nested_svm_init_mmu_context(&svm->vcpu);
 
-	/* Guest paging mode is active - reset mmu */
-	kvm_mmu_reset_context(&svm->vcpu);
-
 	svm_flush_tlb(&svm->vcpu);
 
 	svm->vmcb->control.tsc_offset = svm->vcpu.arch.tsc_offset =
@@ -573,8 +575,6 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 	kvm_vcpu_unmap(&svm->vcpu, &map, true);
 
 	nested_svm_uninit_mmu_context(&svm->vcpu);
-	kvm_mmu_reset_context(&svm->vcpu);
-	kvm_mmu_load(&svm->vcpu);
 
 	/*
 	 * Drop what we picked up for L2 via svm_complete_interrupts() so it
-- 
2.18.2