linux-kernel - [PATCH 13/15] KVM: SVM: Add and use svm_register_cache

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Message-Id: <20211108124407.12187-14-jiangshanlai@gmail.com>
Date:   Mon,  8 Nov 2021 20:44:05 +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 13/15] KVM: SVM: Add and use svm_register_cache_reset()

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

It resets all the appropriate bits like vmx.

Signed-off-by: Lai Jiangshan <laijs@...ux.alibaba.com>
---
 arch/x86/kvm/svm/svm.c |  3 +--
 arch/x86/kvm/svm/svm.h | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b7da66935e72..ba9cfddd2875 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3969,8 +3969,7 @@ 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);
-
-	kvm_register_clear_available(vcpu, VCPU_EXREG_PDPTR);
+	svm_register_cache_reset(vcpu);
 
 	/*
 	 * We need to handle MC intercepts here before the vcpu has a chance to
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 0d7bbe548ac3..1cf5d5e2d0cd 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -274,6 +274,32 @@ static inline bool vmcb_is_dirty(struct vmcb *vmcb, int bit)
         return !test_bit(bit, (unsigned long *)&vmcb->control.clean);
 }
 
+static inline void svm_register_cache_reset(struct kvm_vcpu *vcpu)
+{
+/*
+ * SVM_REGS_AVAIL_SET - The set of registers that will be updated in cache on
+ *			demand.  Other registers not listed here are synced to
+ *			the cache immediately after VM-Exit.
+ *
+ * SVM_REGS_DIRTY_SET - The set of registers that might be outdated in
+ *			architecture. Other registers not listed here are synced
+ *			to the architecture immediately when modifying.
+ *
+ *			Special case: VCPU_EXREG_CR3 should be in this set due
+ *			to the fact.  But KVM_REQ_LOAD_MMU_PGD is always
+ *			requested when the cache vcpu->arch.cr3 is changed and
+ *			svm_load_mmu_pgd() always syncs the new CR3 value into
+ *			the architecture.  So the dirty information of
+ *			VCPU_EXREG_CR3 is not used which means VCPU_EXREG_CR3
+ *			isn't required to be put in this set.
+ */
+#define SVM_REGS_AVAIL_SET	(1 << VCPU_EXREG_PDPTR)
+#define SVM_REGS_DIRTY_SET	(0)
+
+	vcpu->arch.regs_avail &= ~SVM_REGS_AVAIL_SET;
+	vcpu->arch.regs_dirty &= ~SVM_REGS_DIRTY_SET;
+}
+
 static inline struct vcpu_svm *to_svm(struct kvm_vcpu *vcpu)
 {
 	return container_of(vcpu, struct vcpu_svm, vcpu);
-- 
2.19.1.6.gb485710b