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From: Jeremy Fitzhardinge <jeremy@goop.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Linux Virtualization"
	<virtualization@lists.linux-foundation.org>,
	"Glauber Costa" <glommer@redhat.com>,
	"Avi Kivity" <avi@redhat.com>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	"Linux Virtualization"
	<virtualization@lists.linux-foundation.org>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Xen-devel@lists.xensource.com" <Xen-devel@lists.xensource.com>,
	kvm-devel <kvm@vger.kernel.org>,
	"Cédric Schieli" <cschieli@gmail.com>,
	"Eelco Dolstra" <e.dolstra@tudelft.nl>,
	"Olivier Hanesse" <olivier.hanesse@gmail.com>
Subject: [PATCH] x86/pvclock-xen: zero last_value on resume
Date: Tue, 26 Oct 2010 09:59:10 -0700	[thread overview]
Message-ID: <4CC708DE.1070000@goop.org> (raw)

[-- Attachment #1: Type: text/plain, Size: 1899 bytes --]



If the guest domain has been suspend/resumed or migrated, then the
system clock backing the pvclock clocksource may revert to a smaller
value (ie, can be non-monotonic across the migration/save-restore).
Make sure we zero last_value in that case so that the domain
continues to see clock updates.

[ I don't know if kvm needs an analogous fix or not. ]

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Reported-by: Eelco Dolstra <e.dolstra@tudelft.nl>
Reported-by: Olivier Hanesse <olivier.hanesse@gmail.com>
Bisected-by: Cédric Schieli <cschieli@gmail.com>
Tested-by: Cédric Schieli <cschieli@gmail.com>

diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index cd02f32..6226870 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -11,5 +11,6 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
 			    struct pvclock_vcpu_time_info *vcpu,
 			    struct timespec *ts);
+void pvclock_resume(void);
 
 #endif /* _ASM_X86_PVCLOCK_H */
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 239427c..a4f07c1 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -120,6 +120,11 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
 
 static atomic64_t last_value = ATOMIC64_INIT(0);
 
+void pvclock_resume(void)
+{
+	atomic64_set(&last_value, 0);
+}
+
 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
 {
 	struct pvclock_shadow_time shadow;
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index b2bb5aa..5da5e53 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -426,6 +426,8 @@ void xen_timer_resume(void)
 {
 	int cpu;
 
+	pvclock_resume();
+
 	if (xen_clockevent != &xen_vcpuop_clockevent)
 		return;
 



[-- Attachment #2: x86-pvclock-resume.patch --]
[-- Type: text/plain, Size: 2064 bytes --]

From 29acbb4e1d93e719250648db1ce8c7a24144fd86 Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Date: Mon, 25 Oct 2010 16:53:46 -0700
Subject: [PATCH] x86/pvclock: zero last_value on resume

If the guest domain has been suspend/resumed or migrated, then the
system clock backing the pvclock clocksource may revert to a smaller
value (ie, can be non-monotonic across the migration/save-restore).
Make sure we zero last_value in that case so that the domain
continues to see clock updates.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Reported-by: Eelco Dolstra <e.dolstra@tudelft.nl>
Reported-by: Olivier Hanesse <olivier.hanesse@gmail.com>
Bisected-by: Cédric Schieli <cschieli@gmail.com>
Tested-by: Cédric Schieli <cschieli@gmail.com>

diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index cd02f32..6226870 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -11,5 +11,6 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
 			    struct pvclock_vcpu_time_info *vcpu,
 			    struct timespec *ts);
+void pvclock_resume(void);
 
 #endif /* _ASM_X86_PVCLOCK_H */
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 239427c..a4f07c1 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -120,6 +120,11 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
 
 static atomic64_t last_value = ATOMIC64_INIT(0);
 
+void pvclock_resume(void)
+{
+	atomic64_set(&last_value, 0);
+}
+
 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
 {
 	struct pvclock_shadow_time shadow;
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index b2bb5aa..5da5e53 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -426,6 +426,8 @@ void xen_timer_resume(void)
 {
 	int cpu;
 
+	pvclock_resume();
+
 	if (xen_clockevent != &xen_vcpuop_clockevent)
 		return;
 

WARNING: multiple messages have this Message-ID (diff)
From: Jeremy Fitzhardinge <jeremy@goop.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Linux Virtualization"
	<virtualization@lists.linux-foundation.org>,
	"Glauber Costa" <glommer@redhat.com>,
	"Avi Kivity" <avi@redhat.com>,
	"the arch/x86 maintainers" <x86@kernel.org>
Subject: [PATCH] x86/pvclock-xen: zero last_value on resume
Date: Tue, 26 Oct 2010 09:59:10 -0700	[thread overview]
Message-ID: <4CC708DE.1070000@goop.org> (raw)

[-- Attachment #1: Type: text/plain, Size: 1899 bytes --]



If the guest domain has been suspend/resumed or migrated, then the
system clock backing the pvclock clocksource may revert to a smaller
value (ie, can be non-monotonic across the migration/save-restore).
Make sure we zero last_value in that case so that the domain
continues to see clock updates.

[ I don't know if kvm needs an analogous fix or not. ]

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Reported-by: Eelco Dolstra <e.dolstra@tudelft.nl>
Reported-by: Olivier Hanesse <olivier.hanesse@gmail.com>
Bisected-by: Cédric Schieli <cschieli@gmail.com>
Tested-by: Cédric Schieli <cschieli@gmail.com>

diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index cd02f32..6226870 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -11,5 +11,6 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
 			    struct pvclock_vcpu_time_info *vcpu,
 			    struct timespec *ts);
+void pvclock_resume(void);
 
 #endif /* _ASM_X86_PVCLOCK_H */
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 239427c..a4f07c1 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -120,6 +120,11 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
 
 static atomic64_t last_value = ATOMIC64_INIT(0);
 
+void pvclock_resume(void)
+{
+	atomic64_set(&last_value, 0);
+}
+
 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
 {
 	struct pvclock_shadow_time shadow;
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index b2bb5aa..5da5e53 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -426,6 +426,8 @@ void xen_timer_resume(void)
 {
 	int cpu;
 
+	pvclock_resume();
+
 	if (xen_clockevent != &xen_vcpuop_clockevent)
 		return;
 



[-- Attachment #2: x86-pvclock-resume.patch --]
[-- Type: text/plain, Size: 2064 bytes --]

From 29acbb4e1d93e719250648db1ce8c7a24144fd86 Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Date: Mon, 25 Oct 2010 16:53:46 -0700
Subject: [PATCH] x86/pvclock: zero last_value on resume

If the guest domain has been suspend/resumed or migrated, then the
system clock backing the pvclock clocksource may revert to a smaller
value (ie, can be non-monotonic across the migration/save-restore).
Make sure we zero last_value in that case so that the domain
continues to see clock updates.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Reported-by: Eelco Dolstra <e.dolstra@tudelft.nl>
Reported-by: Olivier Hanesse <olivier.hanesse@gmail.com>
Bisected-by: Cédric Schieli <cschieli@gmail.com>
Tested-by: Cédric Schieli <cschieli@gmail.com>

diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index cd02f32..6226870 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -11,5 +11,6 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);
 void pvclock_read_wallclock(struct pvclock_wall_clock *wall,
 			    struct pvclock_vcpu_time_info *vcpu,
 			    struct timespec *ts);
+void pvclock_resume(void);
 
 #endif /* _ASM_X86_PVCLOCK_H */
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 239427c..a4f07c1 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -120,6 +120,11 @@ unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src)
 
 static atomic64_t last_value = ATOMIC64_INIT(0);
 
+void pvclock_resume(void)
+{
+	atomic64_set(&last_value, 0);
+}
+
 cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src)
 {
 	struct pvclock_shadow_time shadow;
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index b2bb5aa..5da5e53 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -426,6 +426,8 @@ void xen_timer_resume(void)
 {
 	int cpu;
 
+	pvclock_resume();
+
 	if (xen_clockevent != &xen_vcpuop_clockevent)
 		return;
 

             reply	other threads:[~2010-10-26 16:59 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-26 16:59 Jeremy Fitzhardinge [this message]
2010-10-26 16:59 ` [PATCH] x86/pvclock-xen: zero last_value on resume Jeremy Fitzhardinge
2010-10-26 17:48 ` Glauber Costa
2010-10-26 17:48   ` Glauber Costa
2010-10-27 18:53   ` [Xen-devel] " Jeremy Fitzhardinge
2010-10-27 18:53   ` Jeremy Fitzhardinge
2010-10-27 20:59     ` H. Peter Anvin
2010-10-27 20:59     ` H. Peter Anvin
2010-11-03 12:46       ` Ian Campbell
2010-11-03 12:46       ` Ian Campbell
2010-11-03 12:46         ` Ian Campbell
2010-11-03 12:46         ` Ian Campbell
2010-10-26 17:48 ` Glauber Costa
2010-11-22 20:16 ` Jeremy Fitzhardinge
2010-11-22 20:16 ` Jeremy Fitzhardinge
2010-11-26 10:40   ` Ingo Molnar
2010-11-26 10:40   ` Ingo Molnar
2010-11-26 10:40     ` Ingo Molnar
2010-11-26 22:29     ` Jeremy Fitzhardinge
2010-11-26 22:29     ` Jeremy Fitzhardinge
2010-11-26 22:29       ` Jeremy Fitzhardinge
  -- strict thread matches above, loose matches on Subject: below --
2010-10-26 16:59 Jeremy Fitzhardinge

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