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From: "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>
To: "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>,
	"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>,
	"Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>
Subject: [PATCH v2 12/15] kvm: i8254: Check LAPIC EOI pending when injecting irq on SVM AVIC
Date: Thu, 15 Aug 2019 16:25:17 +0000
Message-ID: <1565886293-115836-13-git-send-email-suravee.suthikulpanit@amd.com> (raw)
In-Reply-To: <1565886293-115836-1-git-send-email-suravee.suthikulpanit@amd.com>

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);
+	}
+
 	if (atomic_read(&ps->reinject) && !atomic_xchg(&ps->irq_ack, 0))
 		return;
 
@@ -281,12 +306,6 @@ static enum hrtimer_restart pit_timer_fn(struct hrtimer *data)
 		return HRTIMER_NORESTART;
 }
 
-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);
-}
-
 void kvm_pit_set_reinject(struct kvm_pit *pit, bool reinject)
 {
 	struct kvm_kpit_state *ps = &pit->pit_state;
-- 
1.8.3.1


  parent reply index

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 ` Suthikulpanit, Suravee [this message]
2019-08-19 10:42   ` [PATCH v2 12/15] kvm: i8254: Check LAPIC EOI pending when injecting irq on SVM AVIC Alexander Graf
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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