Re: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency from the hypervisor

[Gleb Natapov <gleb@redhat.com>]

On Fri, Sep 13, 2013 at 02:28:35PM +0000, KY Srinivasan wrote:
> 
> 
> > -----Original Message-----
> > From: Gleb Natapov [mailto:gleb@redhat.com]
> > Sent: Friday, September 13, 2013 2:55 AM
> > To: KY Srinivasan
> > Cc: H. Peter Anvin; x86@kernel.org; gregkh@linuxfoundation.org; linux-
> > kernel@vger.kernel.org; devel@linuxdriverproject.org; olaf@aepfle.de;
> > apw@canonical.com; jasowang@redhat.com; tglx@linutronix.de;
> > JBeulich@suse.com; bp@alien8.de
> > Subject: Re: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency
> > from the hypervisor
> > 
> > On Fri, Sep 13, 2013 at 01:43:09AM +0000, KY Srinivasan wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: H. Peter Anvin [mailto:hpa@zytor.com]
> > > > Sent: Thursday, September 12, 2013 5:28 PM
> > > > To: KY Srinivasan
> > > > Cc: x86@kernel.org; gregkh@linuxfoundation.org; linux-
> > kernel@vger.kernel.org;
> > > > devel@linuxdriverproject.org; olaf@aepfle.de; apw@canonical.com;
> > > > jasowang@redhat.com; tglx@linutronix.de; JBeulich@suse.com;
> > bp@alien8.de
> > > > Subject: Re: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency
> > > > from the hypervisor
> > > >
> > > > On 09/12/2013 05:06 PM, KY Srinivasan wrote:
> > > > >
> > > > > Peter,
> > > > >
> > > > > Let me know if you want me to address any additional issues in this patch.
> > > > >
> > > >
> > > > Please address Jan and Gleb's feedback.
> > >
> > > Gleb's feedback was a question and I answered that as I did Jan's feedback as
> > well.
> > > Gleb, Jan, please let me know if there is something else you want addressed
> > here.
> > >
> > No, I am just interesting to know some details about the interface since
> > I cannot find it documented in Hyper-V spec.
> 
> Thanks Gleb. Here is the link for the latest Hyper-V specification:
> http://www.microsoft.com/en-us/download/details.aspx?id=39289
> 
> This spec talks about how migration is handled with regards to TSC.
> 
All I can see is "15.4.3 Partition Reference TSC Mechanism". I see
nothing about HV_X64_MSR_TSC_FREQUENCY specifically. To access this MSR
a partition needs AccessFrequencyMsrs privilege, may be partition that
cab be migrated does not have this privilege?

--
			Gleb.