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 easy to include every possible model. It's a >>> hard problem for management tools too. The thing is, I imagine most >>> management tools are going to cat /proc/cpuinfo to get what the >>> processor is and that's going to be a Xeon YYXXXX type name so I >>> really believe that's the thing that makes sense to expose in QEMU. >>> >>> Maybe we could name models like IntelXeonW35xx. >>> >> >> While a W3501 should be similar to a W3599, we don't know if it >> actually will be. You are no longer on a Fully Correct path and >> instead you are wandering in Marketing Land. >> >> Note that the processor type is just part of what determines which >> features are exposed to the guest. Qemu version, kvm version, host >> kernel version, and even kernel command-line parameters all play a >> part, so to really determine migratability the management tool should >> talk to qemu, not /proc/cpuinfo. > > So if I understand correctly, you're advocating to drop the idea of > common model names, and provide a mechanism for a management tool to > query which cpu features are supported both by the processor, but also > filtered by qemu, kvm, etc?
The syscall issue shows there are several other things necessary IMO: - features need to be scoped with Vendor ID as some feature bits might not be 100% compatible. - Some features might be emulated. So it's not yes/no but yes/no/slow and management needs to know IMO. > 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? > >>> Clever use of the preprocessor will make this effort much, much saner. >> >> I cringe whenever I read something like this. > > :-) > > Regards, > > Anthony Liguori
