From: Toshi Kani <toshi.kani@hpe.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "jgross@suse.com" <jgross@suse.com>,
"boris.ostrovsky@oracle.com" <boris.ostrovsky@oracle.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"paul.gortmaker@windriver.com" <paul.gortmaker@windriver.com>,
"Luis R. Rodriguez" <mcgrof@kernel.org>,
"hpa@zytor.com" <hpa@zytor.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@kernel.org" <mingo@kernel.org>
Subject: Re: [PATCH 1/2] x86/mm/pat: Change pat_disable() to emulate PAT table
Date: Tue, 15 Mar 2016 11:11:23 -0600 [thread overview]
Message-ID: <1458061883.6393.359.camel__4676.88677968017$1458058822$gmane$org@hpe.com> (raw)
In-Reply-To: <20160315154731.GD4559@pd.tnic>
On Tue, 2016-03-15 at 16:47 +0100, Borislav Petkov wrote:
> On Tue, Mar 15, 2016 at 09:43:15AM -0600, Toshi Kani wrote:
> > > Please use on init paths boot_cpu_has(X86_FEATURE_PAT) and on fast
> > > paths static_cpu_has(X86_FEATURE_PAT). No more of that cpu_has_XXX
> > > ugliness.
> >
> > 'cpu_has_pat' is defined as 'boot_cpu_has(X86_FEATURE_PAT)'. Do you
> > mean it should explicitly use 'boot_cpu_has(X86_FEATURE_PAT)'?
>
> No, read what I said.
>
> We use boot_cpu_has(<feature_bit>) on slow paths (i.e., init, bootup,
> etc), where speed is not that important. static_cpu_has(<feature_bit>)
> is an optimized version which should be used in hot paths.
Yes, I understand that part. Let me rephrase my question.
This PAT code is on init paths and speed is not that important. So, it
needs to use 'boot_cpu_has()' here. 'cpu_has_pat' is defined
as boot_cpu_has(X86_FEATURE_PAT), and hence it uses boot_cpu_has() already.
While cpu_has_pat is the same as boot_cpu_has(X86_FEATURE_PAT), cpu_has_XXX
should not be used. So, this code needs to be changed to use
boot_cpu_has(X86_FEATURE_PAT) directly.
Is this right?
Thanks,
-Toshi
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next prev parent reply other threads:[~2016-03-15 16:18 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1457671546-13486-1-git-send-email-toshi.kani@hpe.com>
[not found] ` <1457671546-13486-3-git-send-email-toshi.kani@hpe.com>
[not found] ` <20160311092400.GB4347@pd.tnic>
[not found] ` <1457722632.6393.130.camel@hpe.com>
[not found] ` <20160311221747.GC25147@wotan.suse.de>
[not found] ` <1457740571.6393.236.camel@hpe.com>
[not found] ` <CAB=NE6UE7pKz8bmpRrFmAW=ySY0JnGoRY=MYn2zfOH4g_H81hw@mail.gmail.com>
[not found] ` <1457745396.6393.257.camel@hpe.com>
2016-03-15 0:15 ` [PATCH 2/2] x86/mtrr: Refactor PAT initialization code Luis R. Rodriguez
2016-03-15 23:48 ` Toshi Kani
2016-03-15 23:29 ` Luis R. Rodriguez
2016-03-17 21:56 ` Toshi Kani
2016-03-18 0:06 ` Luis R. Rodriguez
2016-03-18 21:35 ` Toshi Kani
2016-03-29 17:14 ` Luis R. Rodriguez
2016-03-29 21:46 ` Toshi Kani
2016-03-29 22:12 ` Luis R. Rodriguez
2016-03-30 0:16 ` Toshi Kani
2016-03-29 23:43 ` Luis R. Rodriguez
2016-03-30 1:07 ` Toshi Kani
2016-03-30 0:34 ` Luis R. Rodriguez
2016-04-09 2:04 ` Luis R. Rodriguez
2016-04-11 14:30 ` Toshi Kani
[not found] ` <1457671546-13486-2-git-send-email-toshi.kani@hpe.com>
[not found] ` <20160311091229.GA4347@pd.tnic>
[not found] ` <1457713660.6393.55.camel@hpe.com>
[not found] ` <20160311155439.GF4312@pd.tnic>
[not found] ` <1457724504.6393.151.camel@hpe.com>
[not found] ` <20160312115544.GA23410@pd.tnic>
2016-03-15 0:29 ` [PATCH 1/2] x86/mm/pat: Change pat_disable() to emulate PAT table Luis R. Rodriguez
[not found] ` <20160315002921.GG25147@wotan.suse.de>
2016-03-15 3:11 ` Toshi Kani
[not found] ` <1458011476.6393.327.camel@hpe.com>
2016-03-15 11:01 ` Borislav Petkov
[not found] ` <20160315110148.GC4559@pd.tnic>
2016-03-15 15:43 ` Toshi Kani
[not found] ` <1458056595.6393.332.camel@hpe.com>
2016-03-15 15:47 ` Borislav Petkov
[not found] ` <20160315154731.GD4559@pd.tnic>
[not found] ` <1458061883.6393.359.camel@hpe.com>
2016-03-15 16:33 ` Borislav Petkov
2016-03-15 17:11 ` Toshi Kani [this message]
2016-03-15 21:31 ` Luis R. Rodriguez
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