[PATCH v2 13/15] KVM: x86: Kill cur_tsc_{nsec,offset,write} fields

From: David Woodhouse <dwmw2@infradead.org>
To: kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Sean Christopherson <seanjc@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	Paul Durrant <paul@xen.org>, Shuah Khan <shuah@kernel.org>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org,
	Oliver Upton <oliver.upton@linux.dev>,
	Marcelo Tosatti <mtosatti@redhat.com>,
	jalliste@amazon.co.uk, sveith@amazon.de, zide.chen@intel.com,
	Dongli Zhang <dongli.zhang@oracle.com>
Subject: [PATCH v2 13/15] KVM: x86: Kill cur_tsc_{nsec,offset,write} fields
Date: Sat, 27 Apr 2024 12:05:10 +0100	[thread overview]
Message-ID: <20240427111929.9600-14-dwmw2@infradead.org> (raw)
In-Reply-To: <20240427111929.9600-1-dwmw2@infradead.org>

From: David Woodhouse <dwmw@amazon.co.uk>

These pointlessly duplicate of the last_tsc_{nsec,offset,write} values.

The only place they were used was where the TSC is stable and a new vCPU
is being synchronized to the previous setting, in which case the 'last_'
value is definitely identical.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 arch/x86/include/asm/kvm_host.h | 3 ---
 arch/x86/kvm/x86.c              | 9 ++-------
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index b01c1d000fff..7d06f389a607 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1354,9 +1354,6 @@ struct kvm_arch {
 	u32 last_tsc_khz;
 	u64 last_tsc_offset;
 	u64 last_tsc_scaling_ratio;
-	u64 cur_tsc_nsec;
-	u64 cur_tsc_write;
-	u64 cur_tsc_offset;
 	u64 cur_tsc_generation;
 	int nr_vcpus_matched_tsc;
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6ec43f39bdb0..92e81bfca25a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2737,9 +2737,6 @@ static void __kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 offset, u64 tsc,
 		 * These values are tracked in kvm->arch.cur_xxx variables.
 		 */
 		kvm->arch.cur_tsc_generation++;
-		kvm->arch.cur_tsc_nsec = ns;
-		kvm->arch.cur_tsc_write = tsc;
-		kvm->arch.cur_tsc_offset = offset;
 		kvm->arch.nr_vcpus_matched_tsc = 0;
 	} else if (vcpu->arch.this_tsc_generation != kvm->arch.cur_tsc_generation) {
 		kvm->arch.nr_vcpus_matched_tsc++;
@@ -2747,8 +2744,6 @@ static void __kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 offset, u64 tsc,
 
 	/* Keep track of which generation this VCPU has synchronized to */
 	vcpu->arch.this_tsc_generation = kvm->arch.cur_tsc_generation;
-	vcpu->arch.this_tsc_nsec = kvm->arch.cur_tsc_nsec;
-	vcpu->arch.this_tsc_write = kvm->arch.cur_tsc_write;
 
 	kvm_track_tsc_matching(vcpu);
 }
@@ -2825,8 +2820,8 @@ static void kvm_synchronize_tsc(struct kvm_vcpu *vcpu, u64 *user_value)
 		data = kvm->arch.last_tsc_write;
 
 		if (!kvm_check_tsc_unstable()) {
-			offset = kvm->arch.cur_tsc_offset;
-			ns = kvm->arch.cur_tsc_nsec;
+			offset = kvm->arch.last_tsc_offset;
+			ns = kvm->arch.last_tsc_nsec;
 		} else {
 			/*
 			 * ... unless the TSC is unstable and has to be
-- 
2.44.0

