linux-kernel - [PATCH 10/15] KVM: X86: Mark CR3 dirty when vcpu->arch.cr3 is changed

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Message-Id: <20211108124407.12187-11-jiangshanlai@gmail.com>
Date:   Mon,  8 Nov 2021 20:44:02 +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 10/15] KVM: X86: Mark CR3 dirty when vcpu->arch.cr3 is changed

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

When vcpu->arch.cr3 is changed, it should be marked dirty unless it
is being updated to the value of the architecture guest CR3 (i.e.
VMX.GUEST_CR3 or vmcb->save.cr3 when tdp is enabled).

This patch has no functionality changed because
kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3) is superset of
kvm_register_mark_available(vcpu, VCPU_EXREG_CR3) with additional
change to vcpu->arch.regs_dirty, but no code uses regs_dirty for
VCPU_EXREG_CR3.  (vmx_load_mmu_pgd() uses vcpu->arch.regs_avail instead
to test if VCPU_EXREG_CR3 dirty which means current code (ab)uses
regs_avail for VCPU_EXREG_CR3 dirty information.)

Signed-off-by: Lai Jiangshan <laijs@...ux.alibaba.com>
---
 arch/x86/kvm/vmx/nested.c | 2 +-
 arch/x86/kvm/x86.c        | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index dc0e5f80715d..ee5a68c2ea3a 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1134,7 +1134,7 @@ static int nested_vmx_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
 		kvm_mmu_new_pgd(vcpu, cr3);
 
 	vcpu->arch.cr3 = cr3;
-	kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
+	kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
 
 	/* Re-initialize the MMU, e.g. to pick up CR4 MMU role changes. */
 	kvm_init_mmu(vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e5f5042d4842..6ca19cac4aff 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1159,7 +1159,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
 		kvm_mmu_new_pgd(vcpu, cr3);
 
 	vcpu->arch.cr3 = cr3;
-	kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
+	kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
 
 handle_tlb_flush:
 	/*
@@ -10591,7 +10591,7 @@ static int __set_sregs_common(struct kvm_vcpu *vcpu, struct kvm_sregs *sregs,
 	vcpu->arch.cr2 = sregs->cr2;
 	*mmu_reset_needed |= kvm_read_cr3(vcpu) != sregs->cr3;
 	vcpu->arch.cr3 = sregs->cr3;
-	kvm_register_mark_available(vcpu, VCPU_EXREG_CR3);
+	kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
 
 	kvm_set_cr8(vcpu, sregs->cr8);
 
-- 
2.19.1.6.gb485710b