From: Gleb Natapov <gleb@redhat.com>
To: KY Srinivasan <kys@microsoft.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
"x86@kernel.org" <x86@kernel.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
"olaf@aepfle.de" <olaf@aepfle.de>,
"apw@canonical.com" <apw@canonical.com>,
"jasowang@redhat.com" <jasowang@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"JBeulich@suse.com" <JBeulich@suse.com>,
"bp@alien8.de" <bp@alien8.de>
Subject: Re: [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency from the hypervisor
Date: Wed, 18 Sep 2013 08:43:35 +0300 [thread overview]
Message-ID: <20130918054335.GE5657@redhat.com> (raw)
In-Reply-To: <2b4a9a0cff5143c59a0802a2e425c4db@SN2PR03MB061.namprd03.prod.outlook.com>
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.
--
Gleb.
next prev parent reply other threads:[~2013-09-18 5:44 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-03 18:30 [PATCH V2 1/1] X86: Hyper-V: Get the local APIC timer frequency from the hypervisor K. Y. Srinivasan
2013-09-04 7:17 ` Jan Beulich
2013-09-04 15:03 ` KY Srinivasan
2013-09-04 9:40 ` Gleb Natapov
2013-09-04 15:16 ` KY Srinivasan
2013-09-05 14:16 ` Gleb Natapov
2013-09-13 0:06 ` KY Srinivasan
2013-09-13 0:28 ` H. Peter Anvin
2013-09-13 1:43 ` KY Srinivasan
2013-09-13 6:39 ` Jan Beulich
2013-09-13 14:28 ` KY Srinivasan
2013-09-13 9:55 ` Gleb Natapov
2013-09-13 14:28 ` KY Srinivasan
2013-09-17 13:59 ` Gleb Natapov
2013-09-17 19:53 ` KY Srinivasan
2013-09-18 5:43 ` Gleb Natapov [this message]
2013-09-23 13:02 ` KY Srinivasan
2013-09-23 15:50 ` H. Peter Anvin
2013-09-23 19:23 ` KY Srinivasan
2013-10-02 23:11 ` KY Srinivasan
2013-09-27 15:10 ` Olaf Hering
2013-09-27 15:23 ` KY Srinivasan
2013-09-27 15:32 ` Olaf Hering
2013-09-27 15:35 ` KY Srinivasan
2013-10-09 22:50 ` H. Peter Anvin
2013-10-10 0:04 ` KY Srinivasan
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