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From: Maxim Levitsky <mlevitsk@redhat.com>
To: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT
	AND 64-BIT)), Jim Mattson <jmattson@google.com>,
	Joerg Roedel <joro@8bytes.org>, Borislav Petkov <bp@alien8.de>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	Sean Christopherson <seanjc@google.com>,
	Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH v2 4/8] KVM: x86: APICv: drop immediate APICv disablement on current vCPU
Date: Tue, 13 Jul 2021 17:20:19 +0300	[thread overview]
Message-ID: <20210713142023.106183-5-mlevitsk@redhat.com> (raw)
In-Reply-To: <20210713142023.106183-1-mlevitsk@redhat.com>

Special case of disabling the APICv on the current vCPU right away in
kvm_request_apicv_update doesn't bring much benefit vs raising
KVM_REQ_APICV_UPDATE on it instead, since this request will be processed
on the next entry to the guest.
(the comment about having another #VMEXIT is wrong).

It also hides various assumptions that APIVc enable state matches
the APICv inhibit state, as this special case only makes those states
match on the current vCPU.

Previous patches fixed few such assumptions so now it should be safe
to drop this special case.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/x86.c | 12 +-----------
 1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76dae88cf524..29b92f6cbad4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9204,7 +9204,6 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_update_apicv);
  */
 void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit)
 {
-	struct kvm_vcpu *except;
 	unsigned long old, new, expected;
 
 	if (!kvm_x86_ops.check_apicv_inhibit_reasons ||
@@ -9230,16 +9229,7 @@ void kvm_request_apicv_update(struct kvm *kvm, bool activate, ulong bit)
 	if (kvm_x86_ops.pre_update_apicv_exec_ctrl)
 		static_call(kvm_x86_pre_update_apicv_exec_ctrl)(kvm, activate);
 
-	/*
-	 * Sending request to update APICV for all other vcpus,
-	 * while update the calling vcpu immediately instead of
-	 * waiting for another #VMEXIT to handle the request.
-	 */
-	except = kvm_get_running_vcpu();
-	kvm_make_all_cpus_request_except(kvm, KVM_REQ_APICV_UPDATE,
-					 except);
-	if (except)
-		kvm_vcpu_update_apicv(except);
+	kvm_make_all_cpus_request(kvm, KVM_REQ_APICV_UPDATE);
 }
 EXPORT_SYMBOL_GPL(kvm_request_apicv_update);
 
-- 
2.26.3


  parent reply	other threads:[~2021-07-13 14:20 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-13 14:20 [PATCH v2 0/8] My AVIC patch queue Maxim Levitsky
2021-07-13 14:20 ` [PATCH v2 1/8] KVM: SVM: svm_set_vintr don't warn if AVIC is active but is about to be deactivated Maxim Levitsky
2021-07-13 14:20 ` [PATCH v2 2/8] KVM: SVM: tweak warning about enabled AVIC on nested entry Maxim Levitsky
2021-07-13 14:20 ` [PATCH v2 3/8] KVM: SVM: use vmcb01 in svm_refresh_apicv_exec_ctrl Maxim Levitsky
2021-07-13 14:20 ` Maxim Levitsky [this message]
2021-07-13 14:20 ` [PATCH v2 5/8] KVM: x86: APICv: fix race in kvm_request_apicv_update on SVM Maxim Levitsky
2021-07-26 22:34   ` Paolo Bonzini
2021-07-27 13:22     ` Maxim Levitsky
2021-07-13 14:20 ` [PATCH v2 6/8] KVM: SVM: add warning for mistmatch between AVIC state and AVIC access page state Maxim Levitsky
2021-07-13 14:20 ` [PATCH v2 7/8] KVM: SVM: call avic_vcpu_load/avic_vcpu_put when enabling/disabling AVIC Maxim Levitsky
2021-07-13 14:20 ` [PATCH v2 8/8] KVM: x86: hyper-v: Deactivate APICv only when AutoEOI feature is in use Maxim Levitsky
2021-07-18 12:13   ` Maxim Levitsky
2021-07-19  7:47     ` Vitaly Kuznetsov
2021-07-19  9:00       ` Maxim Levitsky
2021-07-19  9:23         ` Vitaly Kuznetsov
2021-07-19  9:58           ` Maxim Levitsky
2021-07-19 18:49     ` Sean Christopherson
2021-07-20  9:40       ` Maxim Levitsky
2021-07-22  9:12       ` KVM's support for non default APIC base Maxim Levitsky
2021-08-02  9:20         ` Maxim Levitsky
2021-08-06 21:55         ` Sean Christopherson
2021-08-09  9:40           ` Maxim Levitsky
2021-08-09 15:57             ` Sean Christopherson
2021-08-09 16:47             ` Jim Mattson
2021-08-10 20:42               ` Maxim Levitsky
2021-07-22 17:35       ` [PATCH v2 8/8] KVM: x86: hyper-v: Deactivate APICv only when AutoEOI feature is in use Maxim Levitsky
2021-07-22 19:06         ` Sean Christopherson
2021-07-27 13:05           ` Maxim Levitsky
2021-07-27 17:48             ` Ben Gardon
2021-07-27 18:17               ` Sean Christopherson
2021-07-29 14:10                 ` Maxim Levitsky
2021-07-26 17:24 ` [PATCH v2 0/8] My AVIC patch queue Paolo Bonzini

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