RTC: enable lost_tick_policy=slew as default (v2)

PATCH In review Marcelo Tosatti 3 participants 8 messages Dec 12, 2012 – Jul 9, 2013

Share & tools

Marcelo Tosatti

author

2012-12-12 21:37 UTC #0 lore raw

PATCH 1/1 RTC: enable lost_tick_policy=slew as default (v2)

RTC interrupt reinjection has no known negative effect. Lack of RTC interrupt reinjection, though, has negative effects: time drift for Windows guests which use it as a timer source.

Based on that, enable lost_tick_policy=slew option as default.

Signed-off-by Marcelo Tosatti <[email protected]>

v2: do not change default for older machines types (Paolo Bonzini)

hw/mc146818rtc.c +1 -1

index c79fca7..c9e007d 100644
@@ -884,7 +884,7 @@ ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq intercept_irq)
 static Property mc146818rtc_properties[] = {
     DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
-                               lost_tick_policy, LOST_TICK_DISCARD),
+                               lost_tick_policy, LOST_TICK_SLEW),
     DEFINE_PROP_END_OF_LIST(),
 };

hw/pc_piix.c +4 -0

index 19e342a..475bb4c 100644
@@ -295,6 +295,10 @@ static QEMUMachine pc_machine_v1_4 = {
             .driver   = "usb-tablet",\
             .property = "usb_version",\
             .value    = stringify(1),\
+        },{\
+            .driver   = "mc146818rtc",\
+            .property = "lost_tick_policy",\
+            .value    = "discard",\
         }
 
 static QEMUMachine pc_machine_v1_3 = {

Paolo Bonzini

Reviewed-by on v1 1/1

2012-12-13 08:45 UTC #1 lore raw

Il 12/12/2012 22:36, Marcelo Tosatti ha scritto:

Quoted 30 lines

RTC interrupt reinjection has no known negative effect. Lack of RTC interrupt reinjection, though, has negative effects: time drift for Windows guests which use it as a timer source.
Based on that, enable lost_tick_policy=slew option as default.
Signed-off-by Marcelo Tosatti <[email protected]>
v2: do not change default for older machines types (Paolo Bonzini)
hw/mc146818rtc.c +1 -1
index c79fca7..c9e007d 100644
@@ -884,7 +884,7 @@ ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq intercept_irq)
 static Property mc146818rtc_properties[] = {
     DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
-                               lost_tick_policy, LOST_TICK_DISCARD),
+                               lost_tick_policy, LOST_TICK_SLEW),
     DEFINE_PROP_END_OF_LIST(),
 };
 
hw/pc_piix.c +0 -0
index 19e342a..475bb4c 100644

hw/pc_piix.c static QEMUMachine pc_machine_v1_4 = { · line 304

Quoted 10 lines

hw/pc_piix.c +4 -0

@@ -295,6 +295,10 @@ static QEMUMachine pc_machine_v1_4 = {
             .driver   = "usb-tablet",\
             .property = "usb_version",\
             .value    = stringify(1),\
+        },{\
+            .driver   = "mc146818rtc",\
+            .property = "lost_tick_policy",\
+            .value    = "discard",\
         }
 
 static QEMUMachine pc_machine_v1_3 = {

Reviewed-by Paolo Bonzini <[email protected]>

Paolo Bonzini

2013-03-07 08:25 UTC #2 lore raw

In reply to Marcelo Tosatti

Il 12/12/2012 22:36, Marcelo Tosatti ha scritto:

Quoted 31 lines

RTC interrupt reinjection has no known negative effect. Lack of RTC interrupt reinjection, though, has negative effects: time drift for Windows guests which use it as a timer source.
Based on that, enable lost_tick_policy=slew option as default.
Signed-off-by Marcelo Tosatti <[email protected]>
v2: do not change default for older machines types (Paolo Bonzini)
hw/mc146818rtc.c +1 -1
index c79fca7..c9e007d 100644
@@ -884,7 +884,7 @@ ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq intercept_irq)
 static Property mc146818rtc_properties[] = {
     DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
-                               lost_tick_policy, LOST_TICK_DISCARD),
+                               lost_tick_policy, LOST_TICK_SLEW),
     DEFINE_PROP_END_OF_LIST(),
 };
 
hw/pc_piix.c +0 -0
index 19e342a..475bb4c 100644

hw/pc_piix.c static QEMUMachine pc_machine_v1_4 = { · line 304

Quoted 10 lines

hw/pc_piix.c +4 -0

@@ -295,6 +295,10 @@ static QEMUMachine pc_machine_v1_4 = {
             .driver   = "usb-tablet",\
             .property = "usb_version",\
             .value    = stringify(1),\
+        },{\
+            .driver   = "mc146818rtc",\
+            .property = "lost_tick_policy",\
+            .value    = "discard",\
         }
 
 static QEMUMachine pc_machine_v1_3 = {

Looks like this was never applied. Can you redo it for the new 1.5 machine (compatibility defines are now in hw/pc.h)?

Paolo

Marcelo Tosatti

author

2013-03-08 17:12 UTC #3 lore raw

Quoted 39 lines · Paolo Bonzini

Il 12/12/2012 22:36, Marcelo Tosatti ha scritto:
Quoted 38 lines
RTC interrupt reinjection has no known negative effect. Lack of RTC interrupt reinjection, though, has negative effects: time drift for Windows guests which use it as a timer source.
Based on that, enable lost_tick_policy=slew option as default.
Signed-off-by Marcelo Tosatti <[email protected]>
v2: do not change default for older machines types (Paolo Bonzini)
hw/mc146818rtc.c +1 -1
index c79fca7..c9e007d 100644
@@ -884,7 +884,7 @@ ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq intercept_irq)
 static Property mc146818rtc_properties[] = {
     DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
-                               lost_tick_policy, LOST_TICK_DISCARD),
+                               lost_tick_policy, LOST_TICK_SLEW),
     DEFINE_PROP_END_OF_LIST(),
 };
 
hw/pc_piix.c +4 -0
index 19e342a..475bb4c 100644
@@ -295,6 +295,10 @@ static QEMUMachine pc_machine_v1_4 = {
             .driver   = "usb-tablet",\
             .property = "usb_version",\
             .value    = stringify(1),\
+        },{\
+            .driver   = "mc146818rtc",\
+            .property = "lost_tick_policy",\
+            .value    = "discard",\
         }
 

Quoted 8 lines

hw/pc_piix.c static QEMUMachine pc_machine_v1_4 = { · line 304
Quoted 3 lines
hw/pc_piix.c +0 -0
 static QEMUMachine pc_machine_v1_3 = {
Looks like this was never applied. Can you redo it for the new 1.5 machine (compatibility defines are now in hw/pc.h)?
Paolo

Anthony mentioned that this

http://article.gmane.org/gmane.comp.emulators.qemu/160699

Is the proper way to do it.

Anthony Liguori

2013-03-08 17:54 UTC #4 lore raw

Quoted 47 lines · Marcelo Tosatti

Quoted 46 lines · Paolo Bonzini
Il 12/12/2012 22:36, Marcelo Tosatti ha scritto:
Quoted 31 lines
RTC interrupt reinjection has no known negative effect. Lack of RTC interrupt reinjection, though, has negative effects: time drift for Windows guests which use it as a timer source.
Based on that, enable lost_tick_policy=slew option as default.
Signed-off-by Marcelo Tosatti <[email protected]>
v2: do not change default for older machines types (Paolo Bonzini)
hw/mc146818rtc.c +1 -1
index c79fca7..c9e007d 100644
@@ -884,7 +884,7 @@ ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq intercept_irq)
 static Property mc146818rtc_properties[] = {
     DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
-                               lost_tick_policy, LOST_TICK_DISCARD),
+                               lost_tick_policy, LOST_TICK_SLEW),
     DEFINE_PROP_END_OF_LIST(),
 };
 
hw/pc_piix.c +0 -0
index 19e342a..475bb4c 100644
hw/pc_piix.c static QEMUMachine pc_machine_v1_4 = { · line 304
Quoted 10 lines
hw/pc_piix.c +4 -0
@@ -295,6 +295,10 @@ static QEMUMachine pc_machine_v1_4 = {
             .driver   = "usb-tablet",\
             .property = "usb_version",\
             .value    = stringify(1),\
+        },{\
+            .driver   = "mc146818rtc",\
+            .property = "lost_tick_policy",\
+            .value    = "discard",\
         }
 
 static QEMUMachine pc_machine_v1_3 = {
Looks like this was never applied. Can you redo it for the new 1.5 machine (compatibility defines are now in hw/pc.h)?

Quoted 7 lines

Quoted 1 line
Paolo
Anthony mentioned that this
http://article.gmane.org/gmane.comp.emulators.qemu/160699
Is the proper way to do it.

That breaks too. I don't have a solution but I also don't remember what the exact failures are.

I'm planning on running this patch through testing again so I can provide better feedback.

Regards,

Anthony Liguori

Paolo Bonzini

2013-03-09 05:44 UTC #5 lore raw

Il 08/03/2013 18:53, Anthony Liguori ha scritto:

Quoted 8 lines

Quoted 5 lines
Anthony mentioned that this
http://article.gmane.org/gmane.comp.emulators.qemu/160699
Is the proper way to do it.
That breaks too. I don't have a solution but I also don't remember what the exact failures are.

What about a more generic version of that? Adding a priority field to global properties, so that -global can have a higher priority than the default (used by machine types)?

Paolo

Marcelo Tosatti

author

2013-07-09 21:24 UTC #6 lore raw

Quoted 7 lines · Paolo Bonzini

Il 08/03/2013 18:53, Anthony Liguori ha scritto:
Quoted 6 lines
Quoted 5 lines
Anthony mentioned that this
http://article.gmane.org/gmane.comp.emulators.qemu/160699
Is the proper way to do it.

Quoted 8 lines

Quoted 2 lines
That breaks too. I don't have a solution but I also don't remember what the exact failures are.
What about a more generic version of that? Adding a priority field to global properties, so that -global can have a higher priority than the default (used by machine types)?
Paolo

What exactly is the problem with

http://lists.gnu.org/archive/html/qemu-devel/2012-12/msg01733.html

Again? Should it just be resubmitted ?

Anthony Liguori

2013-07-09 22:06 UTC #7 lore raw

Quoted 15 lines · Marcelo Tosatti

Quoted 14 lines · Paolo Bonzini
Il 08/03/2013 18:53, Anthony Liguori ha scritto:
Quoted 8 lines
Quoted 5 lines
Anthony mentioned that this
http://article.gmane.org/gmane.comp.emulators.qemu/160699
Is the proper way to do it.
That breaks too. I don't have a solution but I also don't remember what the exact failures are.
What about a more generic version of that? Adding a priority field to global properties, so that -global can have a higher priority than the default (used by machine types)?

Quoted 7 lines

Quoted 1 line
Paolo
What exactly is the problem with
http://lists.gnu.org/archive/html/qemu-devel/2012-12/msg01733.html
Again? Should it just be resubmitted ?

Breaks the -rtc option which also uses globals.

Try qemu -M pc-1.4 -rtc driftfix=slew

Or qemu -M pc-1.4 -rtc-td-hack

Regards,

Anthony Liguori