From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: x86info: dump kvm cpuid's Date: Mon, 30 Apr 2012 12:38:13 +0300 Message-ID: <20120430093811.GC5414@redhat.com> References: <20120429101019.GA21165@redhat.com> <20120430084319.GE15413@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20120430084319.GE15413@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Gleb Natapov Cc: xen-devel@lists.xensource.com, kvm@vger.kernel.org, pv-drivers@vmware.com, virtualization@lists.linux-foundation.org, devel@linuxdriverproject.org, davej@redhat.com List-Id: xen-devel@lists.xenproject.org On Mon, Apr 30, 2012 at 11:43:19AM +0300, Gleb Natapov wrote: > 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. That's what I have. I scratch my own itch. > Other hypervisors may use more cpuid leafs. But not less so no harm's done. > 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. I don't think guessing at the CPU behaviour from linux source is the right thing to do. I Cc'd some addresses found in MAINTAINERS in the linux kernel. This will give more people the opportunity to ask for their stuff to be added, if they care. > > Signed-off-by: Michael S. Tsirkin > > > > --- > > > > 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.