From: Borislav Petkov <bp@alien8.de>
To: Jan Beulich <jbeulich@suse.com>
Cc: Andrew Lutomirski <luto@kernel.org>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
lkml <linux-kernel@vger.kernel.org>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH] x86/PAT: have pat_enabled() properly reflect state when running on e.g. Xen
Date: Mon, 11 Jul 2022 12:40:26 +0200 [thread overview]
Message-ID: <Ysv+Gh0Gk4+uGwrb@zn.tnic> (raw)
In-Reply-To: <bc13c66d-a885-e405-7b53-8cd7afdbecff@suse.com>
On Thu, Jul 07, 2022 at 08:38:44AM +0200, Jan Beulich wrote:
> Well, right now the pvops hook for Xen swallows #GP anyway (wrongly
> so imo, but any of my earlier pointing out of that has been left
> unheard, despite even the code comments there saying "It may be worth
> changing that").
Oh great. ;-\
> The point is therefore that after writing PAT, it would need reading
> back. In which case it feels (slightly) more clean to me to avoid the
> write attempt in the first place, when we know it's not going to work.
X86_FEATURE_XENPV check then.
> If I may ask - doesn't this mean this patch, in its current shape, is
> already a (small) step in that direction? In any event what you say
> doesn't sound to me like a viable (backportable) route to addressing
> the regression at hand.
Backportable to where? To whatever tree has
bdd8b6c98239 ("drm/i915: replace X86_FEATURE_PAT with pat_enabled()")
? If it is that, then 5.17 and newer.
Anyway, I don't mind it as long as you put the proper splitting out
ontop and it all goes as a single patchset, with the minimal fix
CC:stable and queued first.
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2022-07-11 11:18 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-28 14:50 [PATCH] x86/PAT: have pat_enabled() properly reflect state when running on e.g. Xen Jan Beulich
2022-05-03 12:54 ` Juergen Gross
2022-05-11 13:32 ` Juergen Gross
2022-05-21 13:56 ` Chuck Zmudzinski
2022-05-25 8:55 ` Ping: " Jan Beulich
2022-07-04 11:58 ` Thorsten Leemhuis
2022-07-04 12:26 ` Jan Beulich
2022-07-05 10:57 ` Thorsten Leemhuis
2022-07-05 11:02 ` Jan Beulich
2022-07-05 13:36 ` Borislav Petkov
2022-07-05 13:38 ` Juergen Gross
2022-07-14 17:17 ` Chuck Zmudzinski
2022-07-14 22:33 ` Chuck Zmudzinski
2022-07-14 22:45 ` Chuck Zmudzinski
2022-07-19 14:26 ` Chuck Zmudzinski
2022-07-05 15:04 ` Borislav Petkov
2022-07-05 15:56 ` Jan Beulich
2022-07-05 16:14 ` Borislav Petkov
2022-07-06 6:17 ` Jan Beulich
2022-07-06 17:01 ` Borislav Petkov
2022-07-07 6:38 ` Jan Beulich
2022-07-11 10:40 ` Borislav Petkov [this message]
2022-07-11 11:38 ` Chuck Zmudzinski
2022-07-11 12:28 ` [PATCH] x86/PAT: have pat_enabled() properly reflect state when running on e.g. Xen, with corrected patch Chuck Zmudzinski
2022-07-11 14:18 ` [PATCH] x86/PAT: have pat_enabled() properly reflect state when running on e.g. Xen Chuck Zmudzinski
2022-07-11 14:31 ` Juergen Gross
2022-07-11 17:41 ` Chuck Zmudzinski
2022-07-12 5:49 ` Juergen Gross
2022-07-12 6:04 ` Jan Beulich
2022-07-12 13:22 ` Chuck Zmudzinski
2022-07-12 13:32 ` Juergen Gross
2022-07-12 15:09 ` Chuck Zmudzinski
2022-07-12 15:30 ` Juergen Gross
2022-07-12 16:34 ` Chuck Zmudzinski
2022-08-15 10:20 ` [tip: x86/urgent] x86/PAT: Have pat_enabled() properly reflect state when running on Xen tip-bot2 for Jan Beulich
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