From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@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 v2 5/9] KVM: LAPIC: Narrow down the kick target vCPU
Date: Thu, 10 Sep 2020 17:50:40 +0800 [thread overview]
Message-ID: <1599731444-3525-6-git-send-email-wanpengli@tencent.com> (raw)
In-Reply-To: <1599731444-3525-1-git-send-email-wanpengli@tencent.com>
From: Wanpeng Li <wanpengli@tencent.com>
The kick after setting KVM_REQ_PENDING_TIMER is used to handle the timer
fires on a different pCPU which vCPU is running on, this kick is expensive
since memory barrier, rcu, preemption disable/enable operations. We don't
need this kick when injecting already-expired timer, we also should call
out the VMX preemption timer case, which also passes from_timer_fn=false
but doesn't need a kick because kvm_lapic_expired_hv_timer() is called
from the target vCPU.
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
arch/x86/kvm/lapic.c | 4 +++-
arch/x86/kvm/x86.c | 6 ------
arch/x86/kvm/x86.h | 1 -
3 files changed, 3 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e446bdf..3b32d3b 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1642,7 +1642,9 @@ static void apic_timer_expired(struct kvm_lapic *apic, bool from_timer_fn)
}
atomic_inc(&apic->lapic_timer.pending);
- kvm_set_pending_timer(vcpu);
+ kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
+ if (from_timer_fn)
+ kvm_vcpu_kick(vcpu);
}
static void start_sw_tscdeadline(struct kvm_lapic *apic)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d39d6cf..dcf4494 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1774,12 +1774,6 @@ static s64 get_kvmclock_base_ns(void)
}
#endif
-void kvm_set_pending_timer(struct kvm_vcpu *vcpu)
-{
- kvm_make_request(KVM_REQ_PENDING_TIMER, vcpu);
- kvm_vcpu_kick(vcpu);
-}
-
static void kvm_write_wall_clock(struct kvm *kvm, gpa_t wall_clock)
{
int version;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 995ab69..ea20b8b 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -246,7 +246,6 @@ static inline bool kvm_vcpu_latch_init(struct kvm_vcpu *vcpu)
return is_smm(vcpu) || kvm_x86_ops.apic_init_signal_blocked(vcpu);
}
-void kvm_set_pending_timer(struct kvm_vcpu *vcpu);
void kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
void kvm_write_tsc(struct kvm_vcpu *vcpu, struct msr_data *msr);
--
2.7.4
next prev parent reply other threads:[~2020-09-10 9:54 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-10 9:50 [PATCH v2 0/9] KVM: collect sporadic patches Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 1/9] KVM: LAPIC: Return 0 when getting the tscdeadline timer if the lapic is hw disabled Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 2/9] KVM: LAPIC: Guarantee the timer is in tsc-deadline mode when setting Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 3/9] KVM: LAPIC: Fix updating DFR missing apic map recalculation Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 4/9] KVM: VMX: Don't freeze guest when event delivery causes an APIC-access exit Wanpeng Li
2020-09-29 21:42 ` Jim Mattson
2020-09-10 9:50 ` Wanpeng Li [this message]
2020-09-12 6:46 ` [PATCH v2 5/9] KVM: LAPIC: Narrow down the kick target vCPU Paolo Bonzini
2020-09-10 9:50 ` [PATCH v2 6/9] KVM: LAPIC: Reduce world switch latency caused by timer_advance_ns Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 7/9] KVM: SVM: Get rid of handle_fastpath_set_msr_irqoff() Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 8/9] KVM: SVM: Move svm_complete_interrupts() into svm_vcpu_run() Wanpeng Li
2020-09-10 9:50 ` [PATCH v2 9/9] KVM: SVM: Reenable handle_fastpath_set_msr_irqoff() after complete_interrupts() Wanpeng Li
2020-09-12 6:47 ` [PATCH v2 0/9] KVM: collect sporadic patches Paolo Bonzini
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