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From: Ulrich Obergfell <uobergfe@redhat.com>
To: qemu-devel@nongnu.org
Cc: kvm@vger.kernel.org, uobergfe@redhat.com, gcosta@redhat.com,
	avi@redhat.com, mtosatti@redhat.com, zamsden@redhat.com,
	aliguori@us.ibm.com, jan.kiszka@siemens.com
Subject: [PATCH v5 4/5] hpet 'driftfix': add code in update_irq() to detect coalesced interrupts (x86 apic only)
Date: Fri, 20 May 2011 09:13:22 +0200	[thread overview]
Message-ID: <1305875603-3104-5-git-send-email-uobergfe@redhat.com> (raw)
In-Reply-To: <1305875603-3104-1-git-send-email-uobergfe@redhat.com>

update_irq() uses a similar method as in 'rtc_td_hack' to detect
coalesced interrupts. The function entry addresses are retrieved
from 'target_get_irq_delivered' and 'target_reset_irq_delivered'.

This change can be replaced if a generic feedback infrastructure to
track coalesced IRQs for periodic, clock providing devices becomes
available.

Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
---
 hw/hpet.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/hpet.c b/hw/hpet.c
index dba9370..0428290 100644
--- a/hw/hpet.c
+++ b/hw/hpet.c
@@ -184,11 +184,12 @@ static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
     }
 }
 
-static void update_irq(struct HPETTimer *timer, int set)
+static int update_irq(struct HPETTimer *timer, int set)
 {
     uint64_t mask;
     HPETState *s;
     int route;
+    int irq_delivered = 1;
 
     if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
         /* if LegacyReplacementRoute bit is set, HPET specification requires
@@ -213,8 +214,16 @@ static void update_irq(struct HPETTimer *timer, int set)
         qemu_irq_raise(s->irqs[route]);
     } else {
         s->isr &= ~mask;
-        qemu_irq_pulse(s->irqs[route]);
+        if (s->driftfix) {
+            target_reset_irq_delivered();
+            qemu_irq_raise(s->irqs[route]);
+            irq_delivered = target_get_irq_delivered();
+            qemu_irq_lower(s->irqs[route]);
+        } else {
+            qemu_irq_pulse(s->irqs[route]);
+        }
     }
+    return irq_delivered;
 }
 
 static void hpet_pre_save(void *opaque)
-- 
1.6.2.5


WARNING: multiple messages have this Message-ID
From: Ulrich Obergfell <uobergfe@redhat.com>
To: qemu-devel@nongnu.org
Cc: aliguori@us.ibm.com, mtosatti@redhat.com, kvm@vger.kernel.org,
	jan.kiszka@siemens.com, zamsden@redhat.com, uobergfe@redhat.com,
	gcosta@redhat.com, avi@redhat.com
Subject: [Qemu-devel] [PATCH v5 4/5] hpet 'driftfix': add code in update_irq() to detect coalesced interrupts (x86 apic only)
Date: Fri, 20 May 2011 09:13:22 +0200	[thread overview]
Message-ID: <1305875603-3104-5-git-send-email-uobergfe@redhat.com> (raw)
In-Reply-To: <1305875603-3104-1-git-send-email-uobergfe@redhat.com>

update_irq() uses a similar method as in 'rtc_td_hack' to detect
coalesced interrupts. The function entry addresses are retrieved
from 'target_get_irq_delivered' and 'target_reset_irq_delivered'.

This change can be replaced if a generic feedback infrastructure to
track coalesced IRQs for periodic, clock providing devices becomes
available.

Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
---
 hw/hpet.c |   13 +++++++++++--
 1 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/hpet.c b/hw/hpet.c
index dba9370..0428290 100644
--- a/hw/hpet.c
+++ b/hw/hpet.c
@@ -184,11 +184,12 @@ static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)
     }
 }
 
-static void update_irq(struct HPETTimer *timer, int set)
+static int update_irq(struct HPETTimer *timer, int set)
 {
     uint64_t mask;
     HPETState *s;
     int route;
+    int irq_delivered = 1;
 
     if (timer->tn <= 1 && hpet_in_legacy_mode(timer->state)) {
         /* if LegacyReplacementRoute bit is set, HPET specification requires
@@ -213,8 +214,16 @@ static void update_irq(struct HPETTimer *timer, int set)
         qemu_irq_raise(s->irqs[route]);
     } else {
         s->isr &= ~mask;
-        qemu_irq_pulse(s->irqs[route]);
+        if (s->driftfix) {
+            target_reset_irq_delivered();
+            qemu_irq_raise(s->irqs[route]);
+            irq_delivered = target_get_irq_delivered();
+            qemu_irq_lower(s->irqs[route]);
+        } else {
+            qemu_irq_pulse(s->irqs[route]);
+        }
     }
+    return irq_delivered;
 }
 
 static void hpet_pre_save(void *opaque)
-- 
1.6.2.5

  parent reply	other threads:[~2011-05-20  7:13 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-20  7:13 [PATCH v5 0/5] hpet 'driftfix': alleviate time drift with HPET periodic timers Ulrich Obergfell
2011-05-20  7:13 ` [Qemu-devel] " Ulrich Obergfell
2011-05-20  7:13 ` [PATCH v5 1/5] hpet 'driftfix': add hooks required to detect coalesced interrupts (x86 apic only) Ulrich Obergfell
2011-05-20  7:13   ` [Qemu-devel] " Ulrich Obergfell
2011-05-20  7:13 ` [PATCH v5 2/5] hpet 'driftfix': add driftfix property to HPETState and DeviceInfo Ulrich Obergfell
2011-05-20  7:13   ` [Qemu-devel] " Ulrich Obergfell
2011-05-20  7:13 ` [PATCH v5 3/5] hpet 'driftfix': add fields to HPETTimer and VMStateDescription Ulrich Obergfell
2011-05-20  7:13   ` [Qemu-devel] " Ulrich Obergfell
2011-05-20  7:13 ` Ulrich Obergfell [this message]
2011-05-20  7:13   ` [Qemu-devel] [PATCH v5 4/5] hpet 'driftfix': add code in update_irq() to detect coalesced interrupts (x86 apic only) Ulrich Obergfell
2011-05-20  7:13 ` [PATCH v5 5/5] hpet 'driftfix': add code in hpet_timer() to compensate delayed callbacks and coalesced interrupts Ulrich Obergfell
2011-05-20  7:13   ` [Qemu-devel] " Ulrich Obergfell

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