From b3646477d458fbe7694a15b9c78fbe2fa426b703 Mon Sep 17 00:00:00 2001
From: Jason Baron <jbaron@akamai.com>
Date: Thu, 14 Jan 2021 22:27:56 -0500
Subject: KVM: x86: use static calls to reduce kvm_x86_ops overhead
Convert kvm_x86_ops to use static calls. Note that all kvm_x86_ops are
covered here except for 'pmu_ops and 'nested ops'.
Here are some numbers running cpuid in a loop of 1 million calls averaged
over 5 runs, measured in the vm (lower is better).
Intel Xeon 3000MHz:
|default |mitigations=off
-------------------------------------
vanilla |.671s |.486s
static call|.573s(-15%)|.458s(-6%)
AMD EPYC 2500MHz:
|default |mitigations=off
-------------------------------------
vanilla |.710s |.609s
static call|.664s(-6%) |.609s(0%)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jason Baron <jbaron@akamai.com>
Message-Id: <e057bf1b8a7ad15652df6eeba3f907ae758d3399.1610680941.git.jbaron@akamai.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/trace.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
(limited to 'arch/x86/kvm/trace.h')
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 2de30c20bc26..5ef238621881 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -256,7 +256,7 @@ TRACE_EVENT(name, \
__entry->guest_rip = kvm_rip_read(vcpu); \
__entry->isa = isa; \
__entry->vcpu_id = vcpu->vcpu_id; \
- kvm_x86_ops.get_exit_info(vcpu, &__entry->info1, \
+ static_call(kvm_x86_get_exit_info)(vcpu, &__entry->info1, \
&__entry->info2, \
&__entry->intr_info, \
&__entry->error_code); \
@@ -738,7 +738,7 @@ TRACE_EVENT(kvm_emulate_insn,
),
TP_fast_assign(
- __entry->csbase = kvm_x86_ops.get_segment_base(vcpu, VCPU_SREG_CS);
+ __entry->csbase = static_call(kvm_x86_get_segment_base)(vcpu, VCPU_SREG_CS);
__entry->len = vcpu->arch.emulate_ctxt->fetch.ptr
- vcpu->arch.emulate_ctxt->fetch.data;
__entry->rip = vcpu->arch.emulate_ctxt->_eip - __entry->len;
--
cgit v1.2.3-70-g09d2