From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: "Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Sean Christopherson" <sean.j.christopherson@intel.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Wanpeng Li" <wanpengli@tencent.com>,
"Jim Mattson" <jmattson@google.com>,
"Joerg Roedel" <joro@8bytes.org>
Subject: [PATCH 2/2] KVM: LAPIC: micro-optimize fixed mode ipi delivery
Date: Sat, 9 Nov 2019 15:05:35 +0800 [thread overview]
Message-ID: <1573283135-5502-2-git-send-email-wanpengli@tencent.com> (raw)
In-Reply-To: <1573283135-5502-1-git-send-email-wanpengli@tencent.com>
From: Wanpeng Li <wanpengli@tencent.com>
After disabling mwait/halt/pause vmexits, RESCHEDULE_VECTOR and
CALL_FUNCTION_SINGLE_VECTOR etc IPI is one of the main remaining
cause of vmexits observed in product environment which can't be
optimized by PV IPIs. This patch is the follow-up on commit
0e6d242eccdb (KVM: LAPIC: Micro optimize IPI latency), to optimize
redundancy logic before fixed mode ipi is delivered in the fast
path.
- broadcast handling needs to go slow path, so the delivery mode repair
can be delayed to before slow path.
- self-IPI will not be intervened by hypervisor any more after APICv is
introduced and the boxes support APICv are popular now. In addition,
kvm_apic_map_get_dest_lapic() can handle the self-IPI, so there is no
need a shortcut for the non-APICv case.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/irq_comm.c | 6 +++---
arch/x86/kvm/lapic.c | 5 -----
2 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 8ecd48d..aa88156 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -52,15 +52,15 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)];
unsigned int dest_vcpus = 0;
+ if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r, dest_map))
+ return r;
+
if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
kvm_lowest_prio_delivery(irq)) {
printk(KERN_INFO "kvm: apic: phys broadcast and lowest prio\n");
irq->delivery_mode = APIC_DM_FIXED;
}
- if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r, dest_map))
- return r;
-
memset(dest_vcpu_bitmap, 0, sizeof(dest_vcpu_bitmap));
kvm_for_each_vcpu(i, vcpu, kvm) {
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b29d00b..ea936fa 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -951,11 +951,6 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
*r = -1;
- if (irq->shorthand == APIC_DEST_SELF) {
- *r = kvm_apic_set_irq(src->vcpu, irq, dest_map);
- return true;
- }
-
rcu_read_lock();
map = rcu_dereference(kvm->arch.apic_map);
--
2.7.4
next prev parent reply other threads:[~2019-11-09 7:05 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-09 7:05 [PATCH 1/2] KVM: X86: Single target IPI fastpath Wanpeng Li
2019-11-09 7:05 ` Wanpeng Li [this message]
2019-11-11 21:59 ` [PATCH 2/2] KVM: LAPIC: micro-optimize fixed mode ipi delivery Paolo Bonzini
2019-11-12 1:34 ` Wanpeng Li
2019-11-10 1:59 ` [PATCH 1/2] KVM: X86: Single target IPI fastpath kbuild test robot
2019-11-10 1:59 ` [PATCH] KVM: X86: fix semicolon.cocci warnings kbuild test robot
2019-11-11 13:06 ` [PATCH 1/2] KVM: X86: Single target IPI fastpath Vitaly Kuznetsov
2019-11-12 1:18 ` Wanpeng Li
2019-11-11 21:59 ` Paolo Bonzini
2019-11-12 1:33 ` Wanpeng Li
2019-11-13 6:05 ` Wanpeng Li
2019-11-14 3:12 ` Wanpeng Li
2019-11-14 11:58 ` Paolo Bonzini
2019-11-14 15:22 ` Sean Christopherson
2019-11-14 15:44 ` Paolo Bonzini
2019-11-14 16:34 ` Sean Christopherson
2019-11-15 5:56 ` Wanpeng Li
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