Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-11 Thread Markus Armbruster
Avi Kivity a...@redhat.com writes: On 01/07/2010 02:33 PM, Anthony Liguori wrote: There's another option. Make cpuid information part of live migration protocol, and then support something like -cpu Xeon-3550. We would remember the exact cpuid mask we present to the guest and then we

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Dor Laor
On 01/06/2010 05:16 PM, Anthony Liguori wrote: On 01/06/2010 08:48 AM, Dor Laor wrote: On 01/06/2010 04:32 PM, Avi Kivity wrote: On 01/06/2010 04:22 PM, Michael S. Tsirkin wrote: We can probably default -enable-kvm to -cpu host, as long as we explain very carefully that if users wish to

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Avi Kivity
On 01/07/2010 10:03 AM, Dor Laor wrote: We can debate about the exact name/model to represent the Nehalem family, I don't have an issue with that and actually Intel and Amd should define it. AMD and Intel already defined their names (in cat /proc/cpuinfo). They don't define families, the

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Daniel P. Berrange
On Thu, Jan 07, 2010 at 10:03:28AM +0200, Dor Laor wrote: On 01/06/2010 05:16 PM, Anthony Liguori wrote: On 01/06/2010 08:48 AM, Dor Laor wrote: On 01/06/2010 04:32 PM, Avi Kivity wrote: On 01/06/2010 04:22 PM, Michael S. Tsirkin wrote: We can probably default -enable-kvm to -cpu host, as

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Dor Laor
On 01/07/2010 10:18 AM, Avi Kivity wrote: On 01/07/2010 10:03 AM, Dor Laor wrote: We can debate about the exact name/model to represent the Nehalem family, I don't have an issue with that and actually Intel and Amd should define it. AMD and Intel already defined their names (in cat

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Dor Laor
On 01/07/2010 10:24 AM, Daniel P. Berrange wrote: On Thu, Jan 07, 2010 at 10:03:28AM +0200, Dor Laor wrote: On 01/06/2010 05:16 PM, Anthony Liguori wrote: On 01/06/2010 08:48 AM, Dor Laor wrote: On 01/06/2010 04:32 PM, Avi Kivity wrote: On 01/06/2010 04:22 PM, Michael S. Tsirkin wrote: We

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Avi Kivity
On 01/07/2010 11:11 AM, Dor Laor wrote: On 01/07/2010 10:18 AM, Avi Kivity wrote: On 01/07/2010 10:03 AM, Dor Laor wrote: We can debate about the exact name/model to represent the Nehalem family, I don't have an issue with that and actually Intel and Amd should define it. AMD and Intel

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Dor Laor
On 01/07/2010 11:24 AM, Avi Kivity wrote: On 01/07/2010 11:11 AM, Dor Laor wrote: On 01/07/2010 10:18 AM, Avi Kivity wrote: On 01/07/2010 10:03 AM, Dor Laor wrote: We can debate about the exact name/model to represent the Nehalem family, I don't have an issue with that and actually Intel and

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Anthony Liguori
On 01/07/2010 03:40 AM, Dor Laor wrote: There's no simple solution except to restrict features to what was available on the first processors. What's not simple about the above 4 options? What's a better alternative (that insures users understand it and use it and guest msi and even skype

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Dor Laor
On 01/07/2010 01:39 PM, Anthony Liguori wrote: On 01/07/2010 03:40 AM, Dor Laor wrote: There's no simple solution except to restrict features to what was available on the first processors. What's not simple about the above 4 options? What's a better alternative (that insures users understand

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Avi Kivity
On 01/07/2010 11:40 AM, Dor Laor wrote: There's no such thing as Nehalem. Intel were ok with it. Again, you can name is corei7 or xeon34234234234, I don't care, the principle remains the same. There are several processors belonging to the Nehalem family and each have different features.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Avi Kivity
On 01/07/2010 01:44 PM, Dor Laor wrote: So if you had a 2.6.18 kernel and a 2.6.33 kernel, it may be necessary to say: (2.6.33) qemu -cpu Nehalem,-syscall (2.6.18) qemu -cpu Nehalem Or let qemu do it automatically for you. qemu on 2.6.33 doesn't know that you're running qemu on 2.6.18 on

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Dor Laor
On 01/07/2010 01:59 PM, Avi Kivity wrote: On 01/07/2010 11:40 AM, Dor Laor wrote: There's no such thing as Nehalem. Intel were ok with it. Again, you can name is corei7 or xeon34234234234, I don't care, the principle remains the same. There are several processors belonging to the Nehalem

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Dor Laor
On 01/07/2010 02:00 PM, Avi Kivity wrote: On 01/07/2010 01:44 PM, Dor Laor wrote: So if you had a 2.6.18 kernel and a 2.6.33 kernel, it may be necessary to say: (2.6.33) qemu -cpu Nehalem,-syscall (2.6.18) qemu -cpu Nehalem Or let qemu do it automatically for you. qemu on 2.6.33 doesn't

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Anthony Liguori
On 01/07/2010 06:20 AM, Dor Laor wrote: On 01/07/2010 02:00 PM, Avi Kivity wrote: On 01/07/2010 01:44 PM, Dor Laor wrote: So if you had a 2.6.18 kernel and a 2.6.33 kernel, it may be necessary to say: (2.6.33) qemu -cpu Nehalem,-syscall (2.6.18) qemu -cpu Nehalem Or let qemu do it

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Avi Kivity
On 01/07/2010 02:33 PM, Anthony Liguori wrote: There's another option. Make cpuid information part of live migration protocol, and then support something like -cpu Xeon-3550. We would remember the exact cpuid mask we present to the guest and then we could validate that we can obtain the

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Daniel P. Berrange
On Thu, Jan 07, 2010 at 02:40:34PM +0200, Avi Kivity wrote: On 01/07/2010 02:33 PM, Anthony Liguori wrote: There's another option. Make cpuid information part of live migration protocol, and then support something like -cpu Xeon-3550. We would remember the exact cpuid mask we present

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Avi Kivity
On 01/07/2010 02:47 PM, Daniel P. Berrange wrote: With the introduction of the new -device spport, there's no need to replay hotplug events in order any more. Instead just use static PCI addresses when starting the guest, and the same addresses after migration. You could argue that QEMU should

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Anthony Liguori
On 01/07/2010 06:40 AM, Avi Kivity wrote: On 01/07/2010 02:33 PM, Anthony Liguori wrote: There's another option. Make cpuid information part of live migration protocol, and then support something like -cpu Xeon-3550. We would remember the exact cpuid mask we present to the guest and then

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-07 Thread Dor Laor
On 01/07/2010 03:14 PM, Anthony Liguori wrote: On 01/07/2010 06:40 AM, Avi Kivity wrote: On 01/07/2010 02:33 PM, Anthony Liguori wrote: There's another option. Make cpuid information part of live migration protocol, and then support something like -cpu Xeon-3550. We would remember the exact

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Daniel P. Berrange
On Tue, Jan 05, 2010 at 06:10:10PM -0600, Anthony Liguori wrote: For instance, Xeon-X5570 should be a least common denominator for Nehalem processors. It's probably better for users too. It's easier for them to answer do I have anything older than a Xeon-X5570 than to ask do I have any

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Avi Kivity
On 01/06/2010 11:44 AM, Daniel P. Berrange wrote: This is all a very long way of saying that mgmt apps based on libvirt won't care about model names exposed in /proc/cpuinfo so there's no particular need to have a direct mapping from them to QEMU for libvirt's needs. There is still a need

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Daniel P. Berrange
On Wed, Jan 06, 2010 at 11:54:16AM +0200, Avi Kivity wrote: On 01/06/2010 11:44 AM, Daniel P. Berrange wrote: This is all a very long way of saying that mgmt apps based on libvirt won't care about model names exposed in /proc/cpuinfo so there's no particular need to have a direct mapping

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Avi Kivity
On 01/06/2010 12:21 PM, Daniel P. Berrange wrote: On Wed, Jan 06, 2010 at 11:54:16AM +0200, Avi Kivity wrote: On 01/06/2010 11:44 AM, Daniel P. Berrange wrote: This is all a very long way of saying that mgmt apps based on libvirt won't care about model names exposed in /proc/cpuinfo

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Anthony Liguori
On 01/05/2010 09:25 PM, Avi Kivity wrote: Typically, there is at least a little sanity naming for these cases. For instance, any Xeon W35xx should have the same features. A Xeon W55xx may be different. It's not going to be easy to include every possible model. It's a hard problem for

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Michael S. Tsirkin
On Wed, Jan 06, 2010 at 07:25:10AM -0600, Anthony Liguori wrote: On 01/05/2010 09:25 PM, Avi Kivity wrote: Typically, there is at least a little sanity naming for these cases. For instance, any Xeon W35xx should have the same features. A Xeon W55xx may be different. It's not going to be

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Avi Kivity
On 01/06/2010 03:25 PM, Anthony Liguori wrote: On 01/05/2010 09:25 PM, Avi Kivity wrote: Typically, there is at least a little sanity naming for these cases. For instance, any Xeon W35xx should have the same features. A Xeon W55xx may be different. It's not going to be easy to include

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Anthony Liguori
On 01/06/2010 07:47 AM, Avi Kivity wrote: On 01/06/2010 03:25 PM, Anthony Liguori wrote: On 01/05/2010 09:25 PM, Avi Kivity wrote: Typically, there is at least a little sanity naming for these cases. For instance, any Xeon W35xx should have the same features. A Xeon W55xx may be different.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Avi Kivity
On 01/06/2010 03:49 PM, Anthony Liguori wrote: I think that's workable but I think there may be some subtle issues especially across qemu versions. Can you give an example of what you would expect the output to be? - { command: query-cpu-capabalities } - { result: { features: [vm, fpu,

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Alexander Graf
On 06.01.2010, at 14:54, Avi Kivity wrote: On 01/06/2010 03:49 PM, Anthony Liguori wrote: I think that's workable but I think there may be some subtle issues especially across qemu versions. Can you give an example of what you would expect the output to be? - { command:

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Avi Kivity
On 01/06/2010 03:55 PM, Alexander Graf wrote: Well, we can freeze qemu64 if we wish. That's still not 100% accurate since kvm can remove features from qemu64. -cpu none,+flags,vendor=foo,cache=bar,ad=nauseum? I'd rather add a kvm cpu and leave the qemu64 one to qemu tcg features.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Michael S. Tsirkin
On Wed, Jan 06, 2010 at 03:58:01PM +0200, Avi Kivity wrote: On 01/06/2010 03:55 PM, Alexander Graf wrote: Well, we can freeze qemu64 if we wish. That's still not 100% accurate since kvm can remove features from qemu64. -cpu none,+flags,vendor=foo,cache=bar,ad=nauseum? I'd rather

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Avi Kivity
On 01/06/2010 04:22 PM, Michael S. Tsirkin wrote: We can probably default -enable-kvm to -cpu host, as long as we explain very carefully that if users wish to preserve cpu features across upgrades, they can't depend on the default. Hardware upgrades or software upgrades? Yes. --

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Dor Laor
On 01/06/2010 04:32 PM, Avi Kivity wrote: On 01/06/2010 04:22 PM, Michael S. Tsirkin wrote: We can probably default -enable-kvm to -cpu host, as long as we explain very carefully that if users wish to preserve cpu features across upgrades, they can't depend on the default. Hardware upgrades or

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Michael S. Tsirkin
On Wed, Jan 06, 2010 at 04:32:07PM +0200, Avi Kivity wrote: On 01/06/2010 04:22 PM, Michael S. Tsirkin wrote: We can probably default -enable-kvm to -cpu host, as long as we explain very carefully that if users wish to preserve cpu features across upgrades, they can't depend on the default.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Anthony Liguori
On 01/06/2010 07:54 AM, Avi Kivity wrote: On 01/06/2010 03:49 PM, Anthony Liguori wrote: I think that's workable but I think there may be some subtle issues especially across qemu versions. Can you give an example of what you would expect the output to be? - { command:

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Anthony Liguori
On 01/06/2010 08:48 AM, Dor Laor wrote: On 01/06/2010 04:32 PM, Avi Kivity wrote: On 01/06/2010 04:22 PM, Michael S. Tsirkin wrote: We can probably default -enable-kvm to -cpu host, as long as we explain very carefully that if users wish to preserve cpu features across upgrades, they can't

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-06 Thread Lennart Sorensen
On Tue, Jan 05, 2010 at 06:10:10PM -0600, Anthony Liguori wrote: Typically, there is at least a little sanity naming for these cases. For instance, any Xeon W35xx should have the same features. A Xeon W55xx may be different. It doesn't work that way for intel. For example: Core 2 Duo

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-05 Thread john cooper
Anthony Liguori wrote: On 12/21/2009 02:28 AM, Dor Laor wrote: John's new cpu definitions are the exact solution for this issue - all users, whether using mgmt app or direct qemu (this is no user, this is a developer/hacker/other, let's do not optimize this case) should use the various 'real'

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-05 Thread Anthony Liguori
On 12/23/2009 04:32 AM, Avi Kivity wrote: On 12/22/2009 06:12 PM, Anthony Liguori wrote: I think the only two Fully Correct approachs are to support a very specific CPU (e.g. Xeon-X5270) or provide the ability to individually tweak cpu flags. Yes. By a curious coincidence these are what

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2010-01-05 Thread Avi Kivity
On 01/06/2010 02:10 AM, Anthony Liguori wrote: On 12/23/2009 04:32 AM, Avi Kivity wrote: On 12/22/2009 06:12 PM, Anthony Liguori wrote: I think the only two Fully Correct approachs are to support a very specific CPU (e.g. Xeon-X5270) or provide the ability to individually tweak cpu flags.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-23 Thread Avi Kivity
On 12/22/2009 06:12 PM, Anthony Liguori wrote: I think the only two Fully Correct approachs are to support a very specific CPU (e.g. Xeon-X5270) or provide the ability to individually tweak cpu flags. Yes. By a curious coincidence these are what the hardware vendors define (unlike compat

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-22 Thread Dor Laor
On 12/22/2009 12:51 AM, john cooper wrote: Dor Laor wrote: Qemu will check the required cpuid of the cpu model on the host and refuse to load otherwise. When moving to this model, migration can be simplified too since there are fewer combination, and one can choose performance over migration

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-22 Thread john cooper
Dor Laor wrote: On 12/22/2009 12:51 AM, john cooper wrote: Dor Laor wrote: Qemu will check the required cpuid of the cpu model on the host and refuse to load otherwise. When moving to this model, migration can be simplified too since there are fewer combination, and one can choose

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-22 Thread Anthony Liguori
On 12/21/2009 02:28 AM, Dor Laor wrote: John's new cpu definitions are the exact solution for this issue - all users, whether using mgmt app or direct qemu (this is no user, this is a developer/hacker/other, let's do not optimize this case) should use the various 'real' cpu definitions like

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-22 Thread Jamie Lokier
Michael S. Tsirkin wrote: Bootup on different machines has some of the same issues as migration. Consider a 64 bit guest as an example, I think it can not boot on a 32 bit host OS with kvm. I think you can use tcg, but it will be slower. Same thing applies to other CPU features. Alas, perhaps

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-22 Thread Jamie Lokier
Anthony Liguori wrote: It would be insane to emulate sse3 too. It doesn't sound too ridiculous if TCG is involved, provided the switching between TCG and KVM isn't too rapid. TCG is slower, but it's not ridiculously slow. Though, I don't expect anyone to volunteer to implement it :-) how

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Dor Laor
On 12/21/2009 09:43 AM, Gleb Natapov wrote: On Sun, Dec 20, 2009 at 11:59:43AM -0600, Anthony Liguori wrote: Gleb Natapov wrote: Windows is a mystery box, so we can speculate as much as we want about it. If you don't like something just say it may break Windows :) Losing activation does sound

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Avi Kivity
On 12/20/2009 07:18 PM, Michael S. Tsirkin wrote: Hmm, then, shouldn't either kvm or qemu mask features that we do not emulate well enough to make windows not crash? -cpu host does that already, no? Alex I expected so, but Avi here seems to say windows will crash if you use a

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Avi Kivity
On 12/20/2009 07:59 PM, Anthony Liguori wrote: Gleb Natapov wrote: Windows is a mystery box, so we can speculate as much as we want about it. If you don't like something just say it may break Windows :) Losing activation does sound like an issue too. Downgrading seems more likely to cause

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Michael S. Tsirkin
On Mon, Dec 21, 2009 at 01:12:26PM +0200, Avi Kivity wrote: On 12/20/2009 07:18 PM, Michael S. Tsirkin wrote: Hmm, then, shouldn't either kvm or qemu mask features that we do not emulate well enough to make windows not crash? -cpu host does that already, no? Alex I expected

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Alexander Graf
On 21.12.2009, at 12:18, Michael S. Tsirkin wrote: On Mon, Dec 21, 2009 at 01:12:26PM +0200, Avi Kivity wrote: On 12/20/2009 07:18 PM, Michael S. Tsirkin wrote: Hmm, then, shouldn't either kvm or qemu mask features that we do not emulate well enough to make windows not crash? -cpu host

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Yaniv Kaul
On 12/21/2009 1:12 PM, Avi Kivity wrote: On 12/20/2009 07:18 PM, Michael S. Tsirkin wrote: Hmm, then, shouldn't either kvm or qemu mask features that we do not emulate well enough to make windows not crash? -cpu host does that already, no? Alex I expected so, but Avi here seems to say

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Alexander Graf
On 21.12.2009, at 12:38, Michael S. Tsirkin wrote: On Mon, Dec 21, 2009 at 12:22:53PM +0100, Alexander Graf wrote: On 21.12.2009, at 12:18, Michael S. Tsirkin wrote: On Mon, Dec 21, 2009 at 01:12:26PM +0200, Avi Kivity wrote: On 12/20/2009 07:18 PM, Michael S. Tsirkin wrote: Hmm,

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Avi Kivity
On 12/21/2009 01:18 PM, Michael S. Tsirkin wrote: No, Windows tries to detect changes in your hardware and assumes that if too many things change, you might be a pirate and requires you to phone their offices to re-authenticate. How often does a casual user upgrade his host CPU? I

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Michael S. Tsirkin
On Mon, Dec 21, 2009 at 12:45:26PM +0100, Alexander Graf wrote: On 21.12.2009, at 12:38, Michael S. Tsirkin wrote: On Mon, Dec 21, 2009 at 12:22:53PM +0100, Alexander Graf wrote: On 21.12.2009, at 12:18, Michael S. Tsirkin wrote: On Mon, Dec 21, 2009 at 01:12:26PM +0200, Avi

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Avi Kivity
On 12/21/2009 01:45 PM, Alexander Graf wrote: Well, we have two groups: 1) Casual user w/o management app 2) Enterprise user w/ management app So I clearly belong to the first group. 3) Developer/power user who knows what he's about. You could simply add -cpu qemu64 for those guests

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Michael S. Tsirkin
On Mon, Dec 21, 2009 at 02:04:47PM +0200, Avi Kivity wrote: On 12/21/2009 01:18 PM, Michael S. Tsirkin wrote: No, Windows tries to detect changes in your hardware and assumes that if too many things change, you might be a pirate and requires you to phone their offices to re-authenticate.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Avi Kivity
On 12/21/2009 02:04 PM, Michael S. Tsirkin wrote: I think so - if this does not happen a lot, it's not a problem to phone home, right? I'm sure it's very annoying when it happens. -- error compiling committee.c: too many arguments to function

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Michael S. Tsirkin
On Mon, Dec 21, 2009 at 02:09:31PM +0200, Avi Kivity wrote: On 12/21/2009 02:04 PM, Michael S. Tsirkin wrote: I think so - if this does not happen a lot, it's not a problem to phone home, right? I'm sure it's very annoying when it happens. It could well be less annoying than having

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Andre Przywara
Avi Kivity wrote: On 12/20/2009 07:59 PM, Anthony Liguori wrote: Gleb Natapov wrote: Windows is a mystery box, so we can speculate as much as we want about it. If you don't like something just say it may break Windows :) Losing activation does sound like an issue too. Downgrading seems more

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread David S. Ahern
On 12/21/2009 05:05 AM, Avi Kivity wrote: On 12/21/2009 01:45 PM, Alexander Graf wrote: Well, we have two groups: 1) Casual user w/o management app 2) Enterprise user w/ management app So I clearly belong to the first group. 3) Developer/power user who knows what he's about.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Michael S. Tsirkin
On Mon, Dec 21, 2009 at 06:45:22AM -0700, David S. Ahern wrote: On 12/21/2009 05:05 AM, Avi Kivity wrote: On 12/21/2009 01:45 PM, Alexander Graf wrote: Well, we have two groups: 1) Casual user w/o management app 2) Enterprise user w/ management app So I clearly belong to the

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread David S. Ahern
On 12/21/2009 06:51 AM, Michael S. Tsirkin wrote: On Mon, Dec 21, 2009 at 06:45:22AM -0700, David S. Ahern wrote: On 12/21/2009 05:05 AM, Avi Kivity wrote: On 12/21/2009 01:45 PM, Alexander Graf wrote: Well, we have two groups: 1) Casual user w/o management app 2) Enterprise user w/

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Avi Kivity
On 12/21/2009 03:45 PM, David S. Ahern wrote: On 12/21/2009 05:05 AM, Avi Kivity wrote: On 12/21/2009 01:45 PM, Alexander Graf wrote: Well, we have two groups: 1) Casual user w/o management app 2) Enterprise user w/ management app So I clearly belong to the first group.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread Avi Kivity
On 12/21/2009 02:59 PM, Andre Przywara wrote: KVM's cpuid filter doesn't help here because it won't attempt to mask things like sse3. It would be insane to emulate sse3 too. It does expose sse3 support (called pni in Linux IIRC). Not sure if qemu masks it, but the information is there.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-21 Thread john cooper
Dor Laor wrote: Qemu will check the required cpuid of the cpu model on the host and refuse to load otherwise. When moving to this model, migration can be simplified too since there are fewer combination, and one can choose performance over migration flexibility and wise versa. Due to the

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Avi Kivity
On 12/15/2009 07:56 PM, Michael S. Tsirkin wrote: I see. But unfortunately this bit has multiple meanings for 64/32 bit, kvm does not know whether you will run a 32 bit or a 64 bit program. This is a cpu architecture bug. Correct. One bit is used for two separate features (syscall-32

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Avi Kivity
On 12/14/2009 10:18 PM, Anthony Liguori wrote: Michael S. Tsirkin wrote: This might help 32 bit guests, but not guests with 64 bit kernel and 32 bit userspace (my case) because all 64 bit CPUs advertise syscall bit in cpuid. Thus 64 bit guests do not seem to even bother checking this bit: AMD +

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Anthony Liguori
Avi Kivity wrote: Maybe we should make -cpu host the default. That will give the best performance for casual users, more testing for newer features, and will force management apps to treat migration much more seriously. The downside is that casual users upgrading their machines might

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Avi Kivity
On 12/20/2009 04:48 PM, Anthony Liguori wrote: Avi Kivity wrote: Maybe we should make -cpu host the default. That will give the best performance for casual users, more testing for newer features, and will force management apps to treat migration much more seriously. The downside is that

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Anthony Liguori
Avi Kivity wrote: On 12/20/2009 04:48 PM, Anthony Liguori wrote: Avi Kivity wrote: Maybe we should make -cpu host the default. That will give the best performance for casual users, more testing for newer features, and will force management apps to treat migration much more seriously. The

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Avi Kivity
On 12/20/2009 05:33 PM, Anthony Liguori wrote: - casual (non-management-app-using) users will start seeing problems with Windows guests unless they change their command lines Assuming their migrating across different CPU types. I was thinking about upgrading their host cpu. I doubt you'd

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Gleb Natapov
On Sun, Dec 20, 2009 at 05:36:57PM +0200, Avi Kivity wrote: On 12/20/2009 05:33 PM, Anthony Liguori wrote: - casual (non-management-app-using) users will start seeing problems with Windows guests unless they change their command lines Assuming their migrating across different CPU types.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Avi Kivity
On 12/20/2009 05:38 PM, Gleb Natapov wrote: I was thinking about upgrading their host cpu. I doubt you'd live migrate without a management app. And what about VM on disk-on-key or VM image on NFS that can be started from different locations? That needs a config file anyway to

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Michael S. Tsirkin
On Sun, Dec 20, 2009 at 05:40:53PM +0200, Avi Kivity wrote: On 12/20/2009 05:38 PM, Gleb Natapov wrote: I was thinking about upgrading their host cpu. I doubt you'd live migrate without a management app. And what about VM on disk-on-key or VM image on NFS that can be started from

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Avi Kivity
On 12/20/2009 05:49 PM, Michael S. Tsirkin wrote: That needs a config file anyway to let the host qemu know which machine level (e.g. -M pc-0.11) to use. Hmm, yes, but will qemu ship config files which configure host cpu as well? If it doesn't, the management app will have to to

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Michael S. Tsirkin
On Sun, Dec 20, 2009 at 11:49:40AM +0200, Avi Kivity wrote: On 12/14/2009 10:18 PM, Anthony Liguori wrote: Michael S. Tsirkin wrote: This might help 32 bit guests, but not guests with 64 bit kernel and 32 bit userspace (my case) because all 64 bit CPUs advertise syscall bit in cpuid. Thus 64

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Avi Kivity
On 12/20/2009 05:51 PM, Michael S. Tsirkin wrote: Maybe we should make -cpu host the default. That will give the best performance for casual users, more testing for newer features, and will force management apps to treat migration much more seriously. The downside is that casual users

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Michael S. Tsirkin
On Sun, Dec 20, 2009 at 05:59:33PM +0200, Avi Kivity wrote: On 12/20/2009 05:51 PM, Michael S. Tsirkin wrote: Maybe we should make -cpu host the default. That will give the best performance for casual users, more testing for newer features, and will force management apps to treat migration

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Alexander Graf
On 20.12.2009, at 17:56, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 05:59:33PM +0200, Avi Kivity wrote: On 12/20/2009 05:51 PM, Michael S. Tsirkin wrote: Maybe we should make -cpu host the default. That will give the best performance for casual users, more testing for newer

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Michael S. Tsirkin
On Sun, Dec 20, 2009 at 06:17:02PM +0100, Alexander Graf wrote: On 20.12.2009, at 17:56, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 05:59:33PM +0200, Avi Kivity wrote: On 12/20/2009 05:51 PM, Michael S. Tsirkin wrote: Maybe we should make -cpu host the default. That will give

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Alexander Graf
On 20.12.2009, at 18:18, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 06:17:02PM +0100, Alexander Graf wrote: On 20.12.2009, at 17:56, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 05:59:33PM +0200, Avi Kivity wrote: On 12/20/2009 05:51 PM, Michael S. Tsirkin wrote: Maybe we

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Gleb Natapov
On Sun, Dec 20, 2009 at 07:18:22PM +0200, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 06:17:02PM +0100, Alexander Graf wrote: On 20.12.2009, at 17:56, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 05:59:33PM +0200, Avi Kivity wrote: On 12/20/2009 05:51 PM, Michael S.

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Alexander Graf
On 20.12.2009, at 18:23, Gleb Natapov wrote: On Sun, Dec 20, 2009 at 07:18:22PM +0200, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 06:17:02PM +0100, Alexander Graf wrote: On 20.12.2009, at 17:56, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 05:59:33PM +0200, Avi Kivity wrote:

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Gleb Natapov
On Sun, Dec 20, 2009 at 06:29:11PM +0100, Alexander Graf wrote: On 20.12.2009, at 18:23, Gleb Natapov wrote: On Sun, Dec 20, 2009 at 07:18:22PM +0200, Michael S. Tsirkin wrote: On Sun, Dec 20, 2009 at 06:17:02PM +0100, Alexander Graf wrote: On 20.12.2009, at 17:56, Michael S. Tsirkin

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Anthony Liguori
Gleb Natapov wrote: Windows is a mystery box, so we can speculate as much as we want about it. If you don't like something just say it may break Windows :) Losing activation does sound like an issue too. Downgrading seems more likely to cause problems. Considering running mplayer in a

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Alexander Graf
On 20.12.2009, at 18:59, Anthony Liguori wrote: Gleb Natapov wrote: Windows is a mystery box, so we can speculate as much as we want about it. If you don't like something just say it may break Windows :) Losing activation does sound like an issue too. Downgrading seems more likely to

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Michael S. Tsirkin
On Sun, Dec 20, 2009 at 11:59:43AM -0600, Anthony Liguori wrote: Gleb Natapov wrote: Windows is a mystery box, so we can speculate as much as we want about it. If you don't like something just say it may break Windows :) Losing activation does sound like an issue too. Downgrading seems

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Gleb Natapov
On Sun, Dec 20, 2009 at 11:59:43AM -0600, Anthony Liguori wrote: Gleb Natapov wrote: Windows is a mystery box, so we can speculate as much as we want about it. If you don't like something just say it may break Windows :) Losing activation does sound like an issue too. Downgrading seems more

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-20 Thread Gleb Natapov
On Sun, Dec 20, 2009 at 07:06:03PM +0100, Alexander Graf wrote: On 20.12.2009, at 18:59, Anthony Liguori wrote: Gleb Natapov wrote: Windows is a mystery box, so we can speculate as much as we want about it. If you don't like something just say it may break Windows :) Losing activation

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-16 Thread Andre Przywara
Anthony Liguori wrote: Gleb Natapov wrote: I thought KVM emulates the syscall instruction? I swear I've seen patches for that. It is. Starting from 2.6.32. Okay, so this is a performance vs. migration compatibility issue then? BTW, couldn't we just not advertise syscall in cpuid?

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-15 Thread Michael S. Tsirkin
On Mon, Dec 14, 2009 at 03:49:39PM -0600, Anthony Liguori wrote: Michael S. Tsirkin wrote: On Mon, Dec 14, 2009 at 02:54:49PM -0600, Anthony Liguori wrote: Michael S. Tsirkin wrote: On Mon, Dec 14, 2009 at 02:18:33PM -0600, Anthony Liguori wrote: Michael S. Tsirkin wrote:

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-15 Thread Michael S. Tsirkin
On Tue, Dec 15, 2009 at 11:37:34AM -0600, Anthony Liguori wrote: Michael S. Tsirkin wrote: I don't think it does: cpuid is an unpriveledged operation, is it not? We (qemu) ask the kernel (kvm.ko) to filter out the features bits from the cpuid we expose to the guest in order to remove

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-14 Thread Anthony Liguori
Michael S. Tsirkin wrote: Hi! I have a linux guest where init crashes during boot with invalid opcode error with kernel 2.6.31, but works fine with kernel 2.6.32. It also works fine even with 2.6.31 with qemu-kvm. With Gleb's help, we figured out that the opcode in question is syscall, which is

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-14 Thread Michael S. Tsirkin
On Mon, Dec 14, 2009 at 01:44:22PM -0600, Anthony Liguori wrote: Michael S. Tsirkin wrote: Hi! I have a linux guest where init crashes during boot with invalid opcode error with kernel 2.6.31, but works fine with kernel 2.6.32. It also works fine even with 2.6.31 with qemu-kvm. With Gleb's

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-14 Thread Anthony Liguori
Michael S. Tsirkin wrote: On Mon, Dec 14, 2009 at 01:44:22PM -0600, Anthony Liguori wrote: Michael S. Tsirkin wrote: Hi! I have a linux guest where init crashes during boot with invalid opcode error with kernel 2.6.31, but works fine with kernel 2.6.32. It also works fine even with

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-14 Thread Gleb Natapov
On Mon, Dec 14, 2009 at 01:57:29PM -0600, Anthony Liguori wrote: Michael S. Tsirkin wrote: On Mon, Dec 14, 2009 at 01:44:22PM -0600, Anthony Liguori wrote: Michael S. Tsirkin wrote: Hi! I have a linux guest where init crashes during boot with invalid opcode error with kernel 2.6.31, but

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-14 Thread Anthony Liguori
Gleb Natapov wrote: I thought KVM emulates the syscall instruction? I swear I've seen patches for that. It is. Starting from 2.6.32. Okay, so this is a performance vs. migration compatibility issue then? BTW, couldn't we just not advertise syscall in cpuid? That should fix it too

Re: [Qemu-devel] cpuid problem in upstream qemu with kvm

2009-12-14 Thread Gleb Natapov
On Mon, Dec 14, 2009 at 02:02:03PM -0600, Anthony Liguori wrote: Gleb Natapov wrote: I thought KVM emulates the syscall instruction? I swear I've seen patches for that. It is. Starting from 2.6.32. Okay, so this is a performance vs. migration compatibility issue then? BTW, couldn't we

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