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From: Toshi Kani <toshi.kani@hp.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	akpm@linuxfoundation.org, Arnd Bergmann <arnd@arndb.de>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Juergen Gross <jgross@suse.com>,
	Stefan Bader <stefan.bader@canonical.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH 1/5] x86, mm, pat: Set WT to PA4 slot of PAT MSR
Date: Fri, 05 Sep 2014 09:22:54 -0600	[thread overview]
Message-ID: <1409930574.28990.192.camel@misato.fc.hp.com> (raw)
In-Reply-To: <5409D197.2060900@zytor.com>

On Fri, 2014-09-05 at 08:07 -0700, H. Peter Anvin wrote:
> On 09/05/2014 07:00 AM, Toshi Kani wrote:
> > 
> > That's a fine idea, but as Ingo also suggested, I am going to disable
> > this feature on all Pentium 4 models.  That should give us a safety
> > margin.  Using slot 4 has a benefit that it keeps the PAT setup
> > consistent with Xen.      
> > 
> 
> Slot 4 is also the maximally problematic one, because it is the one that
> might be incorrectly invoked for the page tables themselves.

Good point.  I wonder if Xen folks feel strongly about keeping the PAT
setup consistent with the kernel.  If not, we may choose to use slot 6
(or 7).

Thanks,
-Toshi

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WARNING: multiple messages have this Message-ID (diff)
From: Toshi Kani <toshi.kani@hp.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	akpm@linuxfoundation.org, Arnd Bergmann <arnd@arndb.de>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Juergen Gross <jgross@suse.com>,
	Stefan Bader <stefan.bader@canonical.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH 1/5] x86, mm, pat: Set WT to PA4 slot of PAT MSR
Date: Fri, 05 Sep 2014 09:22:54 -0600	[thread overview]
Message-ID: <1409930574.28990.192.camel@misato.fc.hp.com> (raw)
In-Reply-To: <5409D197.2060900@zytor.com>

On Fri, 2014-09-05 at 08:07 -0700, H. Peter Anvin wrote:
> On 09/05/2014 07:00 AM, Toshi Kani wrote:
> > 
> > That's a fine idea, but as Ingo also suggested, I am going to disable
> > this feature on all Pentium 4 models.  That should give us a safety
> > margin.  Using slot 4 has a benefit that it keeps the PAT setup
> > consistent with Xen.      
> > 
> 
> Slot 4 is also the maximally problematic one, because it is the one that
> might be incorrectly invoked for the page tables themselves.

Good point.  I wonder if Xen folks feel strongly about keeping the PAT
setup consistent with the kernel.  If not, we may choose to use slot 6
(or 7).

Thanks,
-Toshi


  reply	other threads:[~2014-09-05 15:33 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-04 18:35 [PATCH 0/5] Support Write-Through mapping on x86 Toshi Kani
2014-09-04 18:35 ` Toshi Kani
2014-09-04 18:35 ` [PATCH 1/5] x86, mm, pat: Set WT to PA4 slot of PAT MSR Toshi Kani
2014-09-04 18:35   ` Toshi Kani
2014-09-04 20:11   ` Henrique de Moraes Holschuh
2014-09-04 20:11     ` Henrique de Moraes Holschuh
2014-09-04 20:21     ` H. Peter Anvin
2014-09-04 20:21       ` H. Peter Anvin
2014-09-04 23:19       ` Henrique de Moraes Holschuh
2014-09-04 23:19         ` Henrique de Moraes Holschuh
2014-09-04 23:34         ` Andy Lutomirski
2014-09-04 23:34           ` Andy Lutomirski
2014-09-05  0:29           ` Toshi Kani
2014-09-05  0:29             ` Toshi Kani
2014-09-05  0:51             ` Andy Lutomirski
2014-09-05  0:51               ` Andy Lutomirski
2014-09-05 14:00               ` Toshi Kani
2014-09-05 14:00                 ` Toshi Kani
2014-09-05 15:07                 ` H. Peter Anvin
2014-09-05 15:07                   ` H. Peter Anvin
2014-09-05 15:22                   ` Toshi Kani [this message]
2014-09-05 15:22                     ` Toshi Kani
2014-09-05 15:41                     ` H. Peter Anvin
2014-09-05 15:41                       ` H. Peter Anvin
2014-09-05 15:42                       ` Toshi Kani
2014-09-05 15:42                         ` Toshi Kani
2014-09-12 19:25           ` Konrad Rzeszutek Wilk
2014-09-12 19:25             ` Konrad Rzeszutek Wilk
2014-09-12 20:03             ` Andy Lutomirski
2014-09-12 20:03               ` Andy Lutomirski
2014-09-12 20:21               ` Konrad Rzeszutek Wilk
2014-09-12 20:21                 ` Konrad Rzeszutek Wilk
2014-09-04 20:31     ` Toshi Kani
2014-09-04 20:31       ` Toshi Kani
2014-09-04 20:50       ` Andy Lutomirski
2014-09-04 20:50         ` Andy Lutomirski
2014-09-04 23:27       ` Toshi Kani
2014-09-04 23:27         ` Toshi Kani
2014-09-05 10:23         ` Ingo Molnar
2014-09-05 10:23           ` Ingo Molnar
2014-09-05 13:50           ` Toshi Kani
2014-09-05 13:50             ` Toshi Kani
2014-09-07 13:58             ` Henrique de Moraes Holschuh
2014-09-07 13:58               ` Henrique de Moraes Holschuh
2014-09-04 18:35 ` [PATCH 2/5] x86, mm, pat: Change reserve_memtype() to handle WT Toshi Kani
2014-09-04 18:35   ` Toshi Kani
2014-09-04 18:35 ` [PATCH 3/5] x86, mm, asm-gen: Add ioremap_wt() for WT Toshi Kani
2014-09-04 18:35   ` Toshi Kani
2014-09-04 18:35 ` [PATCH 4/5] x86, mm: Add set_memory_wt() " Toshi Kani
2014-09-04 18:35   ` Toshi Kani
2014-09-04 18:57   ` Andy Lutomirski
2014-09-04 18:57     ` Andy Lutomirski
2014-09-04 18:57     ` Toshi Kani
2014-09-04 18:57       ` Toshi Kani
2014-09-04 19:14       ` Andy Lutomirski
2014-09-04 19:14         ` Andy Lutomirski
2014-09-04 19:30         ` Toshi Kani
2014-09-07  8:49       ` Yigal Korman
2014-09-07  8:49         ` Yigal Korman
2014-09-07 16:49         ` Andy Lutomirski
2014-09-07 16:49           ` Andy Lutomirski
2014-09-08 15:07           ` Toshi Kani
2014-09-08 15:07             ` Toshi Kani
2014-09-08 17:23             ` Andy Lutomirski
2014-09-08 17:23               ` Andy Lutomirski
2014-09-08 18:42               ` Toshi Kani
2014-09-08 18:42                 ` Toshi Kani
2014-09-04 18:35 ` [PATCH 5/5] x86, mm, pat: Add pgprot_writethrough() " Toshi Kani
2014-09-04 18:35   ` Toshi Kani

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