From: Roman Kagan <rkagan@virtuozzo.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"rkrcmar@redhat.com" <rkrcmar@redhat.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"vkuznets@redhat.com" <vkuznets@redhat.com>,
"graf@amazon.com" <graf@amazon.com>,
"jschoenh@amazon.de" <jschoenh@amazon.de>,
"karahmed@amazon.de" <karahmed@amazon.de>,
"rimasluk@amazon.com" <rimasluk@amazon.com>,
"Grimm, Jon" <Jon.Grimm@amd.com>
Subject: Re: [PATCH v4 13/17] kvm: i8254: Deactivate APICv when using in-kernel PIT re-injection mode.
Date: Mon, 4 Nov 2019 23:17:16 +0000 [thread overview]
Message-ID: <20191104231712.GD23545@rkaganb.lan> (raw)
In-Reply-To: <70fb2b49-2198-bde4-a38b-f37bc8bc9847@redhat.com>
On Sat, Nov 02, 2019 at 10:57:47AM +0100, Paolo Bonzini wrote:
> On 01/11/19 23:41, Suthikulpanit, Suravee wrote:
> > + /*
> > + * AMD SVM AVIC accelerates EOI write and does not trap.
> > + * This cause in-kernel PIT re-inject mode to fail
> > + * since it checks ps->irq_ack before kvm_set_irq()
> > + * and relies on the ack notifier to timely queue
> > + * the pt->worker work iterm and reinject the missed tick.
> > + * So, deactivate APICv when PIT is in reinject mode.
> > + */
> > if (reinject) {
> > + kvm_request_apicv_update(kvm, false, APICV_DEACT_BIT_PIT_REINJ);
> > /* The initial state is preserved while ps->reinject == 0. */
> > kvm_pit_reset_reinject(pit);
> > kvm_register_irq_ack_notifier(kvm, &ps->irq_ack_notifier);
> > kvm_register_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
> > } else {
> > + kvm_request_apicv_update(kvm, true, APICV_DEACT_BIT_PIT_REINJ);
> > kvm_unregister_irq_ack_notifier(kvm, &ps->irq_ack_notifier);
> > kvm_unregister_irq_mask_notifier(kvm, 0, &pit->mask_notifier);
>
> This is not too nice for Intel which does support (through the EOI exit
> mask) APICv even if PIT reinjection active.
Hmm, it's tempting to just make svm_load_eoi_exitmap() disable AVIC when
given a non-empty eoi_exit_bitmap, and enable it back on a clear
eoi_exit_bitmap. This may remove the need to add special treatment to
PIT etc.
Thanks,
Roman.
next prev parent reply other threads:[~2019-11-04 23:17 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-01 22:41 [PATCH v4 00/17] kvm: x86: Support AMD SVM AVIC w/ in-kernel irqchip mode Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 01/17] kvm: x86: Modify kvm_x86_ops.get_enable_apicv() to use struct kvm parameter Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 02/17] kvm: lapic: Introduce APICv update helper function Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 03/17] kvm: x86: Introduce APICv deactivate bits Suthikulpanit, Suravee
2019-11-02 9:51 ` Paolo Bonzini
2019-11-01 22:41 ` [PATCH v4 04/17] kvm: x86: Add support for activate/de-activate APICv at runtime Suthikulpanit, Suravee
2019-11-02 9:52 ` Paolo Bonzini
2019-11-04 19:22 ` Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 05/17] kvm: x86: Add APICv activate/deactivate request trace points Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 06/17] kvm: x86: svm: Add support to activate/deactivate posted interrupts Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 07/17] svm: Add support for setup/destroy virutal APIC backing page for AVIC Suthikulpanit, Suravee
2019-11-04 21:53 ` Roman Kagan
2019-11-12 0:05 ` Suravee Suthikulpanit
2019-11-01 22:41 ` [PATCH v4 08/17] kvm: x86: Introduce APICv pre-update hook Suthikulpanit, Suravee
2019-11-04 22:05 ` Roman Kagan
2019-11-12 0:08 ` Suravee Suthikulpanit
2019-11-12 11:12 ` Roman Kagan
2019-11-01 22:41 ` [PATCH v4 09/17] svm: Add support for activate/deactivate AVIC at runtime Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 10/17] kvm: x86: hyperv: Use APICv update request interface Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 11/17] svm: Deactivate AVIC when launching guest with nested SVM support Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 12/17] svm: Temporary deactivate AVIC during ExtINT handling Suthikulpanit, Suravee
2019-11-02 10:01 ` Paolo Bonzini
2019-11-01 22:41 ` [PATCH v4 13/17] kvm: i8254: Deactivate APICv when using in-kernel PIT re-injection mode Suthikulpanit, Suravee
2019-11-02 9:57 ` Paolo Bonzini
2019-11-04 18:54 ` Suthikulpanit, Suravee
2019-11-04 21:49 ` Paolo Bonzini
2019-11-05 7:05 ` Graf (AWS), Alexander
2019-11-05 8:40 ` Roman Kagan
2019-11-04 23:17 ` Roman Kagan [this message]
2019-11-05 22:47 ` Paolo Bonzini
2019-11-11 17:37 ` Suravee Suthikulpanit
2019-11-12 12:22 ` Roman Kagan
2019-11-01 22:41 ` [PATCH v4 14/17] kvm: lapic: Clean up APIC predefined macros Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 15/17] kvm: ioapic: Refactor kvm_ioapic_update_eoi() Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 16/17] kvm: ioapic: Lazy update IOAPIC EOI Suthikulpanit, Suravee
2019-11-01 22:41 ` [PATCH v4 17/17] svm: Allow AVIC with in-kernel irqchip mode Suthikulpanit, Suravee
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