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authorWanpeng Li <wanpengli@tencent.com>2020-03-26 10:20:01 +0800
committerPaolo Bonzini <pbonzini@redhat.com>2020-03-26 05:44:21 -0400
commite1be9ac8e6014a9b0a216aebae7250f9863e9fc3 (patch)
treec14008c823087424a16f2885cab2a7cba3633655 /arch/x86/kvm
parent94be4b85d89520329f766c7d69a4d74bcc87f5b5 (diff)
KVM: X86: Narrow down the IPI fastpath to single target IPI
The original single target IPI fastpath patch forgot to filter the ICR destination shorthand field. Multicast IPI is not suitable for this feature since wakeup the multiple sleeping vCPUs will extend the interrupt disabled time, it especially worse in the over-subscribe and VM has a little bit more vCPUs scenario. Let's narrow it down to single target IPI. Two VMs, each is 76 vCPUs, one running 'ebizzy -M', the other running cyclictest on all vCPUs, w/ this patch, the avg score of cyclictest can improve more than 5%. (pv tlb, pv ipi, pv sched yield are disabled during testing to avoid the disturb). Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Message-Id: <1585189202-1708-3-git-send-email-wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r--arch/x86/kvm/x86.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d65ff2008cf1..cf95c36cb4f4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1554,7 +1554,10 @@ EXPORT_SYMBOL_GPL(kvm_emulate_wrmsr);
*/
static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data)
{
- if (lapic_in_kernel(vcpu) && apic_x2apic_mode(vcpu->arch.apic) &&
+ if (!lapic_in_kernel(vcpu) || !apic_x2apic_mode(vcpu->arch.apic))
+ return 1;
+
+ if (((data & APIC_SHORT_MASK) == APIC_DEST_NOSHORT) &&
((data & APIC_DEST_MASK) == APIC_DEST_PHYSICAL) &&
((data & APIC_MODE_MASK) == APIC_DM_FIXED)) {