From: Alexander Graf <graf@amazon.com>
To: "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Cc: "pbonzini@redhat.com" <pbonzini@redhat.com>,
"rkrcmar@redhat.com" <rkrcmar@redhat.com>,
"joro@8bytes.org" <joro@8bytes.org>,
"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 v2 12/15] kvm: i8254: Check LAPIC EOI pending when injecting irq on SVM AVIC
Date: Mon, 19 Aug 2019 12:42:31 +0200 [thread overview]
Message-ID: <ac9fa8d4-2c25-52a5-3938-3ce373b3c3e0@amazon.com> (raw)
In-Reply-To: <1565886293-115836-13-git-send-email-suravee.suthikulpanit@amd.com>
On 15.08.19 18:25, Suthikulpanit, Suravee wrote:
> ACK notifiers don't work with AMD SVM w/ AVIC when the PIT interrupt
> is delivered as edge-triggered fixed interrupt since AMD processors
> cannot exit on EOI for these interrupts.
>
> Add code to check LAPIC pending EOI before injecting any pending PIT
> interrupt on AMD SVM when AVIC is activated.
>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
> arch/x86/kvm/i8254.c | 31 +++++++++++++++++++++++++------
> 1 file changed, 25 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
> index 4a6dc54..31c4a9b 100644
> --- a/arch/x86/kvm/i8254.c
> +++ b/arch/x86/kvm/i8254.c
> @@ -34,10 +34,12 @@
>
> #include <linux/kvm_host.h>
> #include <linux/slab.h>
> +#include <asm/virtext.h>
>
> #include "ioapic.h"
> #include "irq.h"
> #include "i8254.h"
> +#include "lapic.h"
> #include "x86.h"
>
> #ifndef CONFIG_X86_64
> @@ -236,6 +238,12 @@ static void destroy_pit_timer(struct kvm_pit *pit)
> kthread_flush_work(&pit->expired);
> }
>
> +static inline void kvm_pit_reset_reinject(struct kvm_pit *pit)
> +{
> + atomic_set(&pit->pit_state.pending, 0);
> + atomic_set(&pit->pit_state.irq_ack, 1);
> +}
> +
> static void pit_do_work(struct kthread_work *work)
> {
> struct kvm_pit *pit = container_of(work, struct kvm_pit, expired);
> @@ -244,6 +252,23 @@ static void pit_do_work(struct kthread_work *work)
> int i;
> struct kvm_kpit_state *ps = &pit->pit_state;
>
> + /*
> + * Since, AMD SVM AVIC accelerates write access to APIC EOI
> + * register for edge-trigger interrupts. PIT will not be able
> + * to receive the IRQ ACK notifier and will always be zero.
> + * Therefore, we check if any LAPIC EOI pending for vector 0
> + * and reset irq_ack if no pending.
> + */
> + if (cpu_has_svm(NULL) && kvm->arch.apicv_state == APICV_ACTIVATED) {
> + int eoi = 0;
> +
> + kvm_for_each_vcpu(i, vcpu, kvm)
> + if (kvm_apic_pending_eoi(vcpu, 0))
> + eoi++;
> + if (!eoi)
> + kvm_pit_reset_reinject(pit);
In which case would eoi be != 0 when APIC-V is active?
Alex
next prev parent reply other threads:[~2019-08-19 10:42 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-15 16:25 [PATCH v2 00/15] kvm: x86: Support AMD SVM AVIC w/ in-kernel irqchip mode Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 01/15] kvm: x86: Modify kvm_x86_ops.get_enable_apicv() to use struct kvm parameter Suthikulpanit, Suravee
2019-08-27 7:15 ` Vitaly Kuznetsov
2019-08-15 16:25 ` [PATCH v2 02/15] kvm: x86: Introduce KVM APICv state Suthikulpanit, Suravee
2019-08-19 9:49 ` Alexander Graf
2019-08-26 19:06 ` Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 03/15] kvm: Add arch-specific per-VM debugfs support Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 04/15] kvm: x86: Add per-VM APICv state debugfs Suthikulpanit, Suravee
2019-08-19 9:57 ` Alexander Graf
2019-08-26 19:41 ` Suthikulpanit, Suravee
2019-08-27 8:20 ` Alexander Graf
2019-08-28 18:39 ` Suthikulpanit, Suravee
2019-08-28 19:36 ` Graf (AWS), Alexander
2019-08-15 16:25 ` [PATCH v2 05/15] kvm: lapic: Introduce APICv update helper function Suthikulpanit, Suravee
2019-08-27 7:22 ` Vitaly Kuznetsov
2019-08-15 16:25 ` [PATCH v2 06/15] kvm: x86: Add support for activate/de-activate APICv at runtime Suthikulpanit, Suravee
2019-08-27 7:29 ` Vitaly Kuznetsov
2019-08-27 8:05 ` Alexander Graf
2019-08-15 16:25 ` [PATCH v2 07/15] kvm: x86: svm: Add support to activate/deactivate posted interrupts Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 08/15] svm: Add support for setup/destroy virutal APIC backing page for AVIC Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 09/15] svm: Add support for activate/deactivate AVIC at runtime Suthikulpanit, Suravee
2019-08-19 10:28 ` Alexander Graf
2019-08-15 16:25 ` [PATCH v2 10/15] kvm: x86: hyperv: Use APICv deactivate request interface Suthikulpanit, Suravee
2019-08-19 10:31 ` Alexander Graf
2019-08-15 16:25 ` [PATCH v2 11/15] svm: Temporary deactivate AVIC during ExtINT handling Suthikulpanit, Suravee
2019-08-19 10:35 ` Alexander Graf
2019-08-28 15:17 ` Suthikulpanit, Suravee
2019-08-28 19:37 ` Graf (AWS), Alexander
2019-09-10 15:46 ` Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 12/15] kvm: i8254: Check LAPIC EOI pending when injecting irq on SVM AVIC Suthikulpanit, Suravee
2019-08-19 10:42 ` Alexander Graf [this message]
2019-08-26 20:46 ` Suthikulpanit, Suravee
2019-08-27 9:10 ` Alexander Graf
2019-09-13 14:50 ` Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 13/15] kvm: lapic: Clean up APIC predefined macros Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 14/15] kvm: ioapic: Delay update IOAPIC EOI for RTC Suthikulpanit, Suravee
2019-08-19 11:00 ` Alexander Graf
2019-09-04 2:06 ` Suthikulpanit, Suravee
2019-08-15 16:25 ` [PATCH v2 15/15] svm: Allow AVIC with in-kernel irqchip mode Suthikulpanit, Suravee
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