From: Jan Beulich <jbeulich@suse.com>
To: Jason Andryuk <jandryuk@gmail.com>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Ian Jackson" <iwj@xenproject.org>,
"Julien Grall" <julien@xen.org>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH 04/13] cpufreq: Add Hardware P-State (HWP) driver
Date: Thu, 27 May 2021 09:45:04 +0200 [thread overview]
Message-ID: <7fde649c-5271-72a9-5af8-b6323725d49d@suse.com> (raw)
In-Reply-To: <20210503192810.36084-5-jandryuk@gmail.com>
On 03.05.2021 21:28, Jason Andryuk wrote:
> If HWP Energy_Performance_Preference isn't supported, the code falls
> back to IA32_ENERGY_PERF_BIAS. Right now, we don't check
> CPUID.06H:ECX.SETBH[bit 3] before using that MSR. The SDM reads like
> it'll be available, and I assume it was available by the time Skylake
> introduced HWP.
Upon more detailed reading of the respective SDM sections, I only
see two options: Either you fail driver initialization if the bit
is clear, or you correctly deal with the bit being clear. If Xen
runs virtualized itself, the combination of CPUID bits set may
not match that of any bare metal hardware that exists.
Jan
next prev parent reply other threads:[~2021-05-27 7:45 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-03 19:27 [PATCH 00/13] Intel Hardware P-States (HWP) support Jason Andryuk
2021-05-03 19:27 ` [PATCH 01/13] cpufreq: Allow restricting to internal governors only Jason Andryuk
2021-05-26 13:18 ` Jan Beulich
2021-05-26 14:12 ` Jason Andryuk
2021-05-26 15:09 ` Jan Beulich
2021-05-26 16:44 ` Jason Andryuk
2021-05-03 19:27 ` [PATCH 02/13] cpufreq: Add perf_freq to cpuinfo Jason Andryuk
2021-05-26 13:24 ` Jan Beulich
2021-05-26 14:19 ` Jason Andryuk
2021-05-03 19:28 ` [PATCH 03/13] cpufreq: Export intel_feature_detect Jason Andryuk
2021-05-26 13:27 ` Jan Beulich
2021-05-26 14:44 ` Jason Andryuk
2021-05-26 15:11 ` Jan Beulich
2021-05-03 19:28 ` [PATCH 04/13] cpufreq: Add Hardware P-State (HWP) driver Jason Andryuk
2021-05-26 14:59 ` Jan Beulich
2021-05-27 7:23 ` Jan Beulich
2021-05-27 18:50 ` Jason Andryuk
2021-05-28 6:35 ` Jan Beulich
2021-06-03 11:55 ` Jason Andryuk
2021-06-04 6:39 ` Jan Beulich
2021-05-27 7:45 ` Jan Beulich [this message]
2021-05-03 19:28 ` [PATCH 05/13] xenpm: Change get-cpufreq-para output for internal Jason Andryuk
2021-05-26 15:21 ` Jan Beulich
2021-05-27 5:54 ` Jan Beulich
2021-05-03 19:28 ` [PATCH 06/13] cpufreq: Export HWP parameters to userspace Jason Andryuk
2021-05-27 7:55 ` Jan Beulich
2021-05-28 13:19 ` Jason Andryuk
2021-05-28 13:39 ` Jan Beulich
2021-05-03 19:28 ` [PATCH 07/13] libxc: Include hwp_para in definitions Jason Andryuk
2021-05-03 19:28 ` [PATCH 08/13] xenpm: Print HWP parameters Jason Andryuk
2021-05-27 8:02 ` Jan Beulich
2021-05-03 19:28 ` [PATCH 09/13] xen: Add SET_CPUFREQ_HWP xen_sysctl_pm_op Jason Andryuk
2021-05-27 8:33 ` Jan Beulich
2021-05-03 19:28 ` [PATCH 10/13] libxc: Add xc_set_cpufreq_hwp Jason Andryuk
2021-05-04 8:03 ` Jan Beulich
2021-05-04 11:31 ` Jason Andryuk
2021-05-27 9:45 ` Jan Beulich
2021-05-03 19:28 ` [PATCH 11/13] xenpm: Factor out a non-fatal cpuid_parse variant Jason Andryuk
2021-05-27 8:41 ` Jan Beulich
2021-05-03 19:28 ` [PATCH 12/13] xenpm: Add set-cpufreq-hwp subcommand Jason Andryuk
2021-05-27 9:46 ` Jan Beulich
2021-05-03 19:28 ` [PATCH 13/13] CHANGELOG: Add Intel HWP entry Jason Andryuk
2021-05-27 9:48 ` Jan Beulich
2021-05-20 14:57 ` [PATCH 00/13] Intel Hardware P-States (HWP) support Jan Beulich
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7fde649c-5271-72a9-5af8-b6323725d49d@suse.com \
--to=jbeulich@suse.com \
--cc=andrew.cooper3@citrix.com \
--cc=george.dunlap@citrix.com \
--cc=iwj@xenproject.org \
--cc=jandryuk@gmail.com \
--cc=julien@xen.org \
--cc=roger.pau@citrix.com \
--cc=sstabellini@kernel.org \
--cc=wl@xen.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).