From: Sean Christopherson <seanjc@google.com>
To: "Suthikulpanit, Suravee" <suravee.suthikulpanit@amd.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Maxim Levitsky <mlevitsk@redhat.com>,
Li RongQing <lirongqing@baidu.com>
Subject: Re: [PATCH v2 04/23] KVM: x86: Inhibit AVIC SPTEs if any vCPU enables x2APIC
Date: Fri, 16 Sep 2022 19:10:06 +0000 [thread overview]
Message-ID: <YyTKDl04BQviLGW6@google.com> (raw)
In-Reply-To: <b6fcb487-56fc-12ea-6f67-b14b0b156ee0@amd.com>
On Tue, Sep 13, 2022, Suthikulpanit, Suravee wrote:
> > @@ -10122,7 +10136,15 @@ void __kvm_set_or_clear_apicv_inhibit(struct kvm *kvm,
> > set_or_clear_apicv_inhibit(&new, reason, set);
> > - if (!!old != !!new) {
> > + /*
> > + * If the overall "is APICv activated" status is unchanged, simply add
> > + * or remove the inihbit from the pile. x2APIC is an exception, as it
> > + * is a partial inhibit (only blocks SPTEs for the APIC access page).
> > + * If x2APIC is the only inhibit in either the old or the new set, then
> > + * vCPUs need to be kicked to transition between partially-inhibited
> > + * and fully-inhibited.
> > + */
> > + if ((!!old != !!new) || old == X2APIC_ENABLE || new == X2APIC_ENABLE) {
>
> Why are we comparing APICV inhibit reasons (old, new) with X2APIC_ENABLE
> here? Do you mean to compare with APICV_INHIBIT_REASON_X2APIC?
Heh, the truly hilarious part about this is that the code actually works, because
by pure coincidence, X2APIC_ENABLE == BIT(APICV_INHIBIT_REASON_X2APIC). Obviously
still needs to be changed, just found it amusing.
next prev parent reply other threads:[~2022-09-16 19:10 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-03 0:22 [PATCH v2 00/23] KVM: x86: AVIC and local APIC fixes+cleanups Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 01/23] KVM: x86: Purge "highest ISR" cache when updating APICv state Sean Christopherson
2022-09-05 21:58 ` Paolo Bonzini
2022-09-03 0:22 ` [PATCH v2 02/23] KVM: SVM: Flush the "current" TLB when activating AVIC Sean Christopherson
2022-09-05 21:58 ` Paolo Bonzini
2022-09-03 0:22 ` [PATCH v2 03/23] KVM: SVM: Process ICR on AVIC IPI delivery failure due to invalid target Sean Christopherson
2022-09-05 21:59 ` Paolo Bonzini
2022-09-03 0:22 ` [PATCH v2 04/23] KVM: x86: Inhibit AVIC SPTEs if any vCPU enables x2APIC Sean Christopherson
2022-09-05 22:02 ` Paolo Bonzini
2022-09-13 19:52 ` Suthikulpanit, Suravee
2022-09-14 7:39 ` Sean Christopherson
2022-09-14 17:41 ` Suthikulpanit, Suravee
2022-09-16 17:47 ` Sean Christopherson
2022-09-16 19:10 ` Sean Christopherson [this message]
2022-09-20 13:07 ` Maxim Levitsky
2022-09-20 15:46 ` Sean Christopherson
2022-09-20 16:50 ` Sean Christopherson
2022-09-23 10:18 ` Maxim Levitsky
2022-09-23 10:19 ` Maxim Levitsky
2022-09-03 0:22 ` [PATCH v2 05/23] KVM: SVM: Don't put/load AVIC when setting virtual APIC mode Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 06/23] KVM: SVM: Replace "avic_mode" enum with "x2avic_enabled" boolean Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 07/23] KVM: SVM: Compute dest based on sender's x2APIC status for AVIC kick Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 08/23] KVM: SVM: Fix x2APIC Logical ID calculation for avic_kick_target_vcpus_fast Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 09/23] Revert "KVM: SVM: Use target APIC ID to complete x2AVIC IRQs when possible" Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 10/23] KVM: SVM: Document that vCPU ID == APIC ID in AVIC kick fastpatch Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 11/23] KVM: SVM: Add helper to perform final AVIC "kick" of single vCPU Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 12/23] KVM: x86: Disable APIC logical map if logical ID covers multiple MDAs Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 13/23] KVM: x86: Disable APIC logical map if vCPUs are aliased in logical mode Sean Christopherson
2022-09-13 23:32 ` Suthikulpanit, Suravee
2022-09-14 7:42 ` Sean Christopherson
2022-09-15 2:11 ` Suthikulpanit, Suravee
2022-09-16 18:52 ` Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 14/23] KVM: x86: Honor architectural behavior for aliased 8-bit APIC IDs Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 15/23] KVM: x86: Explicitly skip adding vCPU to optimized logical map if LDR==0 Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 16/23] KVM: x86: Explicitly track all possibilities for APIC map's logical modes Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 17/23] KVM: SVM: Inhibit AVIC if vCPUs are aliased in logical mode Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 18/23] KVM: SVM: Always update local APIC on writes to logical dest register Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 19/23] KVM: SVM: Update svm->ldr_reg cache even if LDR is "bad" Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 20/23] KVM: SVM: Require logical ID to be power-of-2 for AVIC entry Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 21/23] KVM: SVM: Handle multiple logical targets in AVIC kick fastpath Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 22/23] KVM: SVM: Ignore writes to Remote Read Data on AVIC write traps Sean Christopherson
2022-09-03 0:22 ` [PATCH v2 23/23] Revert "KVM: SVM: Do not throw warning when calling avic_vcpu_load on a running vcpu" Sean Christopherson
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