linux-kernel - [PATCH 03/15] KVM: SVM: Always clear available of VCPU_EXREG_PDPTR in svm_vcpu

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Date:   Mon,  8 Nov 2021 20:43:55 +0800
From:   Lai Jiangshan <jiangshanlai@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Lai Jiangshan <laijs@...ux.alibaba.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>
Subject: [PATCH 03/15] KVM: SVM: Always clear available of VCPU_EXREG_PDPTR in svm_vcpu_run()

From: Lai Jiangshan <laijs@...ux.alibaba.com>

Make it the same logic to handle the availability of VCPU_EXREG_PDPTR
as VMX and also remove a branch in svm_vcpu_run().

Signed-off-by: Lai Jiangshan <laijs@...ux.alibaba.com>
---
 arch/x86/kvm/svm/svm.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 88a730ad47a1..3e7043173668 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1583,10 +1583,16 @@ static void svm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
 
 static void svm_cache_reg(struct kvm_vcpu *vcpu, enum kvm_reg reg)
 {
+	kvm_register_mark_available(vcpu, reg);
+
 	switch (reg) {
 	case VCPU_EXREG_PDPTR:
-		BUG_ON(!npt_enabled);
-		load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
+		/*
+		 * When !npt_enabled, mmu->pdptrs[] is already available since
+		 * it is always updated per SDM when moving to CRs.
+		 */
+		if (npt_enabled)
+			load_pdptrs(vcpu, vcpu->arch.walk_mmu, kvm_read_cr3(vcpu));
 		break;
 	default:
 		KVM_BUG_ON(1, vcpu->kvm);
@@ -3964,8 +3970,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
 	svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING;
 	vmcb_mark_all_clean(svm->vmcb);
 
-	if (npt_enabled)
-		kvm_register_clear_available(vcpu, VCPU_EXREG_PDPTR);
+	kvm_register_clear_available(vcpu, VCPU_EXREG_PDPTR);
 
 	/*
 	 * We need to handle MC intercepts here before the vcpu has a chance to
-- 
2.19.1.6.gb485710b