Messages in this thread | | | From | KY Srinivasan <> | Subject | RE: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency from the hypervisor | Date | Mon, 23 Sep 2013 13:02:42 +0000 |
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> -----Original Message----- > From: Gleb Natapov [mailto:gleb@redhat.com] > Sent: Tuesday, September 17, 2013 10:44 PM > 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 Tue, Sep 17, 2013 at 07:53:36PM +0000, KY Srinivasan wrote: > > > > 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? > > > > If you use the MSR to read the TSC frequency, then indeed when you migrate > then there > > is no guarantee that the TSC frequency won't change when you migrate. The > approach > > described in section 15.4.3 is the preferred approach that can accommodate > migration. > > > Thanks.
Peter, Please let me know if there are other issues I need to address here. Now that Dmitry has queued up the Hyper-V keyboard driver, with this patch we can fully support Linux on our uefi firmware.
Regards,
K. Y
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