Re: x86info: dump kvm cpuid's

[Gleb Natapov <gleb@redhat.com>]

On Sun, Apr 29, 2012 at 01:10:21PM +0300, Michael S. Tsirkin wrote:
> The following makes 'x86info -r' dump kvm cpu ids
> (signature+features) when running in a vm.
> 
> On the guest we see the signature and the features:
> eax in: 0x40000000, eax = 00000000 ebx = 4b4d564b ecx = 564b4d56 edx = 0000004d
> eax in: 0x40000001, eax = 0100007b ebx = 00000000 ecx = 00000000 edx = 00000000
> 
> On the host it just adds a couple of zero lines:
> eax in: 0x40000000, eax = 00000000 ebx = 00000000 ecx = 00000000 edx = 00000000
> eax in: 0x40000001, eax = 00000000 ebx = 00000000 ecx = 00000000 edx = 00000000
> 
This is too KVM specific. Other hypervisors may use more cpuid leafs.
As far as I see Hyper-V uses 5 and use cpuid.0x40000000.eax as max cpuid
leaf available. Haven't checked Xen or VMWare.

> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> 
> ---
> 
> Dave - not sure whether there's a mailing list for x86info.
> The patch is on top of the master branch in
> git://git.codemonkey.org.uk/x86info.git
> 
> Thanks!
> 
> diff --git a/x86info.c b/x86info.c
> index 22c4734..dee5ed1 100644
> --- a/x86info.c
> +++ b/x86info.c
> @@ -44,6 +44,7 @@ static void display_detailed_info(struct cpudata *cpu)
>  
>  		if (cpu->maxei2 >=0xC0000000)
>  			dump_raw_cpuid(cpu->number, 0xC0000000, cpu->maxei2);
> +		dump_raw_cpuid(cpu->number, 0x40000000, 0x40000001);
>  	}
>  
>  	if (show_cacheinfo) {

--
			Gleb.