From: Andrew Cooper <andrew.cooper3@citrix.com>
To: pgnet.dev@gmail.com, Randy Dunlap <rdunlap@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Clemens Ladisch <clemens@ladisch.de>,
xen-devel@lists.xenproject.org
Subject: Re: [Xen-devel] HPET enabled in BIOS, not presented as available_clocksource -- config, kernel code, &/or BIOS?
Date: Sat, 13 May 2017 20:59:37 +0100 [thread overview]
Message-ID: <be4448d3-7661-8653-c65f-2a023292b842@citrix.com> (raw)
In-Reply-To: <34c505d9-9dc6-8982-4875-74dedfc5e0d1@gmail.com>
On 13/05/2017 20:49, PGNet Dev wrote:
> On 5/13/17 12:38 PM, Andrew Cooper wrote:
>> What is the issue here?
>>
>> Xen owns (and may use) any HPETs in the system. They are purposefully
>> unavailable to even dom0.
> The issue is that, when booting to Xen, hpet is not advertised as an available clocksource, AND reports the hpet boot error pointed out by Randy.
>
> Following
>
> https://wiki.xen.org/wiki/Xen_power_management#HPET_as_broadcast_timer_source_.28clocksource.29_.3D
>
> there's discussion there re: 'if HPET is available / not missing'.
>
> It appears to be available only booting to non-Xen.
>
> What specific indication does one look for that Xen's using available hpet?
>
Ok. Lack of a clocksource is to be expected.
The reason why the HPETs are unavailable is that dom0 is not a position
to program them; dom0 doesn't know what Xen has set up in the IDT.
Use `xl dmesg` to get to the hypervisor dmesg log. You should see
mention of the HPET in there if Xen has found it.
~Andrew
next prev parent reply other threads:[~2017-05-13 19:59 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-13 2:30 PGNet Dev
2017-05-13 17:41 ` Randy Dunlap
2017-05-13 18:26 ` PGNet Dev
2017-05-13 19:28 ` Randy Dunlap
2017-05-13 19:38 ` [Xen-devel] " Andrew Cooper
2017-05-13 19:49 ` PGNet Dev
2017-05-13 19:59 ` Andrew Cooper [this message]
2017-05-13 20:05 ` PGNet Dev
2017-05-13 20:16 ` Andrew Cooper
2017-05-13 21:07 ` PGNet Dev
2017-05-14 17:13 ` Juergen Gross
2017-05-13 20:28 ` Valentin Vidic
2017-05-13 21:06 ` PGNet Dev
2017-05-13 21:32 ` Valentin Vidic
2017-05-13 21:58 ` PGNet Dev
2017-05-13 22:15 ` Valentin Vidic
2017-05-13 23:17 ` PGNet Dev
2017-05-14 15:39 ` Andrew Cooper
2017-05-14 17:41 ` Randy Dunlap
2017-05-15 18:06 ` Austin S. Hemmelgarn
2017-05-17 0:12 ` PGNet Dev
2017-05-17 0:15 ` PGNet Dev
2017-05-13 19:45 ` Clemens Ladisch
2017-05-13 19:52 ` PGNet Dev
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