From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Joerg Roedel <joro@8bytes.org>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
kvm@vger.kernel.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH v3 24/26] KVM: x86: Skip APICv update if APICv is disable at the module level
Date: Wed, 8 Dec 2021 01:52:34 +0000 [thread overview]
Message-ID: <20211208015236.1616697-25-seanjc@google.com> (raw)
In-Reply-To: <20211208015236.1616697-1-seanjc@google.com>
Bail from the APICv update paths _before_ taking apicv_update_lock if
APICv is disabled at the module level. kvm_request_apicv_update() in
particular is invoked from multiple paths that can be reached without
APICv being enabled, e.g. svm_enable_irq_window(), and taking the
rw_sem for write when APICv is disabled may introduce unnecessary
contention and stalls.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/hyperv.c | 3 +++
arch/x86/kvm/x86.c | 3 +++
2 files changed, 6 insertions(+)
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 7179fa645eda..175c1bace091 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -112,6 +112,9 @@ static void synic_update_vector(struct kvm_vcpu_hv_synic *synic,
if (!!auto_eoi_old == !!auto_eoi_new)
return;
+ if (!enable_apicv)
+ return;
+
down_write(&vcpu->kvm->arch.apicv_update_lock);
if (auto_eoi_new)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index abf99b77883e..c804cc39c90d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9602,6 +9602,9 @@ EXPORT_SYMBOL_GPL(__kvm_request_apicv_update);
void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit)
{
+ if (!enable_apicv)
+ return;
+
down_write(&kvm->arch.apicv_update_lock);
__kvm_request_apicv_update(kvm, activate, bit);
up_write(&kvm->arch.apicv_update_lock);
--
2.34.1.400.ga245620fadb-goog
next prev parent reply other threads:[~2021-12-08 1:56 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-08 1:52 [PATCH v3 00/26] KVM: x86: Halt and APICv overhaul Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 01/26] KVM: fix avic_set_running for preemptable kernels Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 02/26] KVM: nVMX: Ensure vCPU honors event request if posting nested IRQ fails Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 03/26] KVM: VMX: Clean up PI pre/post-block WARNs Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 04/26] KVM: VMX: Handle PI wakeup shenanigans during vcpu_put/load Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 05/26] KVM: Drop unused kvm_vcpu.pre_pcpu field Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 06/26] KVM: Move x86 VMX's posted interrupt list_head to vcpu_vmx Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 07/26] KVM: VMX: Move preemption timer <=> hrtimer dance to common x86 Sean Christopherson
2023-03-29 12:34 ` Tudor Ambarus
2023-03-29 13:47 ` Paolo Bonzini
2023-03-29 15:22 ` Tudor Ambarus
2023-03-30 7:12 ` Tudor Ambarus
2021-12-08 1:52 ` [PATCH v3 08/26] KVM: x86: Unexport LAPIC's switch_to_{hv,sw}_timer() helpers Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 09/26] KVM: x86: Remove defunct pre_block/post_block kvm_x86_ops hooks Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 10/26] KVM: SVM: Signal AVIC doorbell iff vCPU is in guest mode Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 11/26] KVM: SVM: Don't bother checking for "running" AVIC when kicking for IPIs Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 12/26] KVM: SVM: Remove unnecessary APICv/AVIC update in vCPU unblocking path Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 13/26] KVM: SVM: Use kvm_vcpu_is_blocking() in AVIC load to handle preemption Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 14/26] KVM: SVM: Skip AVIC and IRTE updates when loading blocking vCPU Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 15/26] iommu/amd: KVM: SVM: Use pCPU to infer IsRun state for IRTE Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 16/26] KVM: VMX: Don't do full kick when triggering posted interrupt "fails" Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 17/26] KVM: VMX: Wake vCPU when delivering posted IRQ even if vCPU == this vCPU Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 18/26] KVM: VMX: Pass desired vector instead of bool for triggering posted IRQ Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 19/26] KVM: VMX: Fold fallback path into triggering posted IRQ helper Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 20/26] KVM: VMX: Don't do full kick when handling posted interrupt wakeup Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 21/26] KVM: SVM: Drop AVIC's intermediate avic_set_running() helper Sean Christopherson
2021-12-08 14:43 ` Paolo Bonzini
2021-12-08 15:03 ` Maxim Levitsky
2021-12-08 15:43 ` Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 22/26] KVM: SVM: Move svm_hardware_setup() and its helpers below svm_x86_ops Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 23/26] KVM: SVM: Nullify vcpu_(un)blocking() hooks if AVIC is disabled Sean Christopherson
2021-12-08 1:52 ` Sean Christopherson [this message]
2021-12-08 1:52 ` [PATCH v3 25/26] KVM: x86: Drop NULL check on kvm_x86_ops.check_apicv_inhibit_reasons Sean Christopherson
2021-12-08 1:52 ` [PATCH v3 26/26] KVM: x86: Unexport __kvm_request_apicv_update() Sean Christopherson
2021-12-08 9:04 ` [PATCH v3 00/26] KVM: x86: Halt and APICv overhaul Paolo Bonzini
2021-12-08 14:51 ` Paolo Bonzini
2021-12-08 23:00 ` Maxim Levitsky
2021-12-08 23:16 ` Maxim Levitsky
2021-12-08 23:34 ` Maxim Levitsky
2021-12-09 0:04 ` Sean Christopherson
2021-12-09 6:36 ` Maxim Levitsky
2021-12-09 0:02 ` Sean Christopherson
2021-12-09 14:29 ` Paolo Bonzini
2021-12-09 14:48 ` Maxim Levitsky
2021-12-09 15:45 ` Sean Christopherson
2021-12-09 16:03 ` Maxim Levitsky
2021-12-09 1:37 ` Sean Christopherson
2021-12-09 6:31 ` Maxim Levitsky
2021-12-08 23:43 ` Sean Christopherson
2021-12-09 6:34 ` Maxim Levitsky
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