Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Marcelo Tosatti
On Wed, Aug 29, 2012 at 01:21:13AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 07:02:42PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 12:35:28AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 04:13:38PM -0300, Eduardo Habkost wrote: On Tue, Aug 28, 2012

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Marcelo Tosatti
On Wed, Aug 29, 2012 at 06:59:03AM -0300, Marcelo Tosatti wrote: I don't understand. What is the problem with the proposal? What will not work with our protocol? Can you give an example please? Too late for 1.2? Absolutely (in my opinion). My concern here is that you are

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Michael S. Tsirkin
On Tue, Aug 28, 2012 at 08:50:09PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 01:25:35AM +0300, Michael S. Tsirkin wrote: On Wed, Aug 29, 2012 at 01:21:13AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 07:02:42PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Michael S. Tsirkin
On Wed, Aug 29, 2012 at 06:59:03AM -0300, Marcelo Tosatti wrote: On Wed, Aug 29, 2012 at 01:21:13AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 07:02:42PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 12:35:28AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Michael S. Tsirkin
On Wed, Aug 29, 2012 at 01:23:24PM +0300, Michael S. Tsirkin wrote: Michael, not migrating the PVEOI MSR actually crashes the guest? Not at all. migration currently simply disables PV EOI, so each EOI triggers exits after migration. I would like to add: without this patch guest will

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Michael S. Tsirkin
On Wed, Aug 29, 2012 at 07:03:34AM -0300, Marcelo Tosatti wrote: On Wed, Aug 29, 2012 at 06:59:03AM -0300, Marcelo Tosatti wrote: I don't understand. What is the problem with the proposal? What will not work with our protocol? Can you give an example please? Too late for

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Eduardo Habkost
On Wed, Aug 29, 2012 at 01:06:32PM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 08:50:09PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 01:25:35AM +0300, Michael S. Tsirkin wrote: On Wed, Aug 29, 2012 at 01:21:13AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28,

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Michael S. Tsirkin
On Wed, Aug 29, 2012 at 09:56:12AM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 01:06:32PM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 08:50:09PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 01:25:35AM +0300, Michael S. Tsirkin wrote: On Wed, Aug 29, 2012

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Eduardo Habkost
On Wed, Aug 29, 2012 at 04:18:12PM +0300, Michael S. Tsirkin wrote: On Wed, Aug 29, 2012 at 09:56:12AM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 01:06:32PM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 08:50:09PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Eduardo Habkost
On Wed, Aug 29, 2012 at 08:36:30AM -0500, Anthony Liguori wrote: Michael S. Tsirkin m...@redhat.com writes: In preparation for adding PV EOI support, disable PV EOI by default for 1.1 and older machine types, to avoid CPUID changing during migration. PV EOI can still be enabled/disabled

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Michael S. Tsirkin
On Wed, Aug 29, 2012 at 10:49:04AM -0300, Eduardo Habkost wrote: Normally CPUID will tell you if such important MSR is available. So we can check that at destination. How can qemu check it, if when the qemu code was written when the MSR didn't even exist yet? (You could add an interface

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Eduardo Habkost
On Wed, Aug 29, 2012 at 05:11:12PM +0300, Michael S. Tsirkin wrote: On Wed, Aug 29, 2012 at 10:49:04AM -0300, Eduardo Habkost wrote: Normally CPUID will tell you if such important MSR is available. So we can check that at destination. How can qemu check it, if when the qemu code was

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-29 Thread Eduardo Habkost
On Wed, Aug 29, 2012 at 09:09:16AM -0500, Anthony Liguori wrote: Gleb Natapov g...@redhat.com writes: On Wed, Aug 29, 2012 at 08:36:30AM -0500, Anthony Liguori wrote: Michael S. Tsirkin m...@redhat.com writes: In preparation for adding PV EOI support, disable PV EOI by default for

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-28 Thread Eduardo Habkost
On Tue, Aug 28, 2012 at 08:43:52PM +0300, Michael S. Tsirkin wrote: In preparation for adding PV EOI support, disable PV EOI by default for 1.1 and older machine types, to avoid CPUID changing during migration. PV EOI can still be enabled/disabled by specifying it explicitly. Enable for

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-28 Thread Michael S. Tsirkin
On Tue, Aug 28, 2012 at 04:13:38PM -0300, Eduardo Habkost wrote: On Tue, Aug 28, 2012 at 08:43:52PM +0300, Michael S. Tsirkin wrote: In preparation for adding PV EOI support, disable PV EOI by default for 1.1 and older machine types, to avoid CPUID changing during migration. PV EOI can

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-28 Thread Eduardo Habkost
On Wed, Aug 29, 2012 at 12:35:28AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 04:13:38PM -0300, Eduardo Habkost wrote: On Tue, Aug 28, 2012 at 08:43:52PM +0300, Michael S. Tsirkin wrote: In preparation for adding PV EOI support, disable PV EOI by default for 1.1 and older

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-28 Thread Michael S. Tsirkin
On Tue, Aug 28, 2012 at 07:02:42PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 12:35:28AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 04:13:38PM -0300, Eduardo Habkost wrote: On Tue, Aug 28, 2012 at 08:43:52PM +0300, Michael S. Tsirkin wrote: In preparation for

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-28 Thread Michael S. Tsirkin
On Wed, Aug 29, 2012 at 01:21:13AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 07:02:42PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 12:35:28AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 04:13:38PM -0300, Eduardo Habkost wrote: On Tue, Aug 28, 2012

Re: [Qemu-devel] [PATCHv4 3/4] cpuid: disable pv eoi for 1.1 and older compat types

2012-08-28 Thread Eduardo Habkost
On Wed, Aug 29, 2012 at 01:25:35AM +0300, Michael S. Tsirkin wrote: On Wed, Aug 29, 2012 at 01:21:13AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28, 2012 at 07:02:42PM -0300, Eduardo Habkost wrote: On Wed, Aug 29, 2012 at 12:35:28AM +0300, Michael S. Tsirkin wrote: On Tue, Aug 28,