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From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Brijesh Singh <brijesh.singh@amd.com>,
	Tom Lendacky <thomas.lendacky@amd.com>
Subject: [PATCH 2/3] KVM: x86: Revert "KVM: x86: Mark GPRs dirty when written"
Date: Fri, 22 Jan 2021 15:50:48 -0800	[thread overview]
Message-ID: <20210122235049.3107620-3-seanjc@google.com> (raw)
In-Reply-To: <20210122235049.3107620-1-seanjc@google.com>

Revert the dirty/available tracking of GPRs now that KVM copies the GPRs
to the GHCB on any post-VMGEXIT VMRUN, even if a GPR is not dirty.  Per
commit de3cd117ed2f ("KVM: x86: Omit caching logic for always-available
GPRs"), tracking for GPRs noticeably impacts KVM's code footprint.

This reverts commit 1c04d8c986567c27c56c05205dceadc92efb14ff.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/kvm_cache_regs.h | 51 +++++++++++++++++------------------
 1 file changed, 25 insertions(+), 26 deletions(-)

diff --git a/arch/x86/kvm/kvm_cache_regs.h b/arch/x86/kvm/kvm_cache_regs.h
index f15bc16de07c..a889563ad02d 100644
--- a/arch/x86/kvm/kvm_cache_regs.h
+++ b/arch/x86/kvm/kvm_cache_regs.h
@@ -9,31 +9,6 @@
 	(X86_CR4_PVI | X86_CR4_DE | X86_CR4_PCE | X86_CR4_OSFXSR  \
 	 | X86_CR4_OSXMMEXCPT | X86_CR4_PGE | X86_CR4_TSD | X86_CR4_FSGSBASE)
 
-static inline bool kvm_register_is_available(struct kvm_vcpu *vcpu,
-					     enum kvm_reg reg)
-{
-	return test_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
-}
-
-static inline bool kvm_register_is_dirty(struct kvm_vcpu *vcpu,
-					 enum kvm_reg reg)
-{
-	return test_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
-}
-
-static inline void kvm_register_mark_available(struct kvm_vcpu *vcpu,
-					       enum kvm_reg reg)
-{
-	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
-}
-
-static inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu,
-					   enum kvm_reg reg)
-{
-	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
-	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
-}
-
 #define BUILD_KVM_GPR_ACCESSORS(lname, uname)				      \
 static __always_inline unsigned long kvm_##lname##_read(struct kvm_vcpu *vcpu)\
 {									      \
@@ -43,7 +18,6 @@ static __always_inline void kvm_##lname##_write(struct kvm_vcpu *vcpu,	      \
 						unsigned long val)	      \
 {									      \
 	vcpu->arch.regs[VCPU_REGS_##uname] = val;			      \
-	kvm_register_mark_dirty(vcpu, VCPU_REGS_##uname);		      \
 }
 BUILD_KVM_GPR_ACCESSORS(rax, RAX)
 BUILD_KVM_GPR_ACCESSORS(rbx, RBX)
@@ -63,6 +37,31 @@ BUILD_KVM_GPR_ACCESSORS(r14, R14)
 BUILD_KVM_GPR_ACCESSORS(r15, R15)
 #endif
 
+static inline bool kvm_register_is_available(struct kvm_vcpu *vcpu,
+					     enum kvm_reg reg)
+{
+	return test_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
+}
+
+static inline bool kvm_register_is_dirty(struct kvm_vcpu *vcpu,
+					 enum kvm_reg reg)
+{
+	return test_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
+}
+
+static inline void kvm_register_mark_available(struct kvm_vcpu *vcpu,
+					       enum kvm_reg reg)
+{
+	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
+}
+
+static inline void kvm_register_mark_dirty(struct kvm_vcpu *vcpu,
+					   enum kvm_reg reg)
+{
+	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_avail);
+	__set_bit(reg, (unsigned long *)&vcpu->arch.regs_dirty);
+}
+
 static inline unsigned long kvm_register_read(struct kvm_vcpu *vcpu, int reg)
 {
 	if (WARN_ON_ONCE((unsigned int)reg >= NR_VCPU_REGS))
-- 
2.30.0.280.ga3ce27912f-goog


  parent reply	other threads:[~2021-01-22 23:54 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-22 23:50 [PATCH 0/3] KVM: x86: Revert dirty tracking for GPRs Sean Christopherson
2021-01-22 23:50 ` [PATCH 1/3] KVM: SVM: Unconditionally sync GPRs to GHCB on VMRUN of SEV-ES guest Sean Christopherson
2021-01-25 15:05   ` Tom Lendacky
2021-01-22 23:50 ` Sean Christopherson [this message]
2021-01-22 23:50 ` [PATCH 3/3] KVM: SVM: Sync GPRs to the GHCB only after VMGEXIT Sean Christopherson
2021-01-23  0:09   ` Tom Lendacky
2021-01-23  0:29     ` Sean Christopherson
2021-01-25 17:22 ` [PATCH 0/3] KVM: x86: Revert dirty tracking for GPRs Paolo Bonzini

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