diff options
| author | Wanpeng Li <wanpengli@tencent.com> | 2020-03-26 10:20:02 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-03-26 05:58:26 -0400 |
| commit | d5361678e63c8a5e72d75cee6d15b840c44306f2 (patch) | |
| tree | f7ff872c969cbe77c3c7e324302781097c0e3d5e /arch/x86/kvm/lapic.c | |
| parent | 8a1038de11a5536c76054061837b11648bec5b46 (diff) | |
KVM: X86: Micro-optimize IPI fastpath delay
This patch optimizes the virtual IPI fastpath emulation sequence:
write ICR2 send virtual IPI
read ICR2 write ICR2
send virtual IPI ==> write ICR
write ICR
We can observe ~0.67% performance improvement for IPI microbenchmark
(https://lore.kernel.org/kvm/20171219085010.4081-1-ynorov@caviumnetworks.com/)
on Skylake server.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1585189202-1708-4-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/lapic.c')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 41bd49ebe355..b754e49adbc5 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1241,7 +1241,7 @@ void kvm_apic_set_eoi_accelerated(struct kvm_vcpu *vcpu, int vector) } EXPORT_SYMBOL_GPL(kvm_apic_set_eoi_accelerated); -static void apic_send_ipi(struct kvm_lapic *apic, u32 icr_low, u32 icr_high) +void kvm_apic_send_ipi(struct kvm_lapic *apic, u32 icr_low, u32 icr_high) { struct kvm_lapic_irq irq; @@ -1955,7 +1955,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val) case APIC_ICR: /* No delay here, so we always clear the pending bit */ val &= ~(1 << 12); - apic_send_ipi(apic, val, kvm_lapic_get_reg(apic, APIC_ICR2)); + kvm_apic_send_ipi(apic, val, kvm_lapic_get_reg(apic, APIC_ICR2)); kvm_lapic_set_reg(apic, APIC_ICR, val); break; |