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From: "Roedel, Joerg" <Joerg.Roedel@amd.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"x86@kernel.org" <x86@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"stable@kernel.org" <stable@kernel.org>
Subject: Re: [PATCH 4/4] x86, gart: Make sure GART does not map physmem above 1TB
Date: Mon, 18 Apr 2011 16:52:30 +0200	[thread overview]
Message-ID: <20110418145230.GH2192@amd.com> (raw)
In-Reply-To: <4DAC4EC0.80008@zytor.com>

On Mon, Apr 18, 2011 at 10:46:24AM -0400, H. Peter Anvin wrote:
> On 04/18/2011 06:45 AM, Joerg Roedel wrote:
> > The GART can only map physical memory below 1TB. Make sure
> > the gart driver in the kernel does not try to map memory
> > above 1TB.
> 
> Where does this limit come from?

>From the hardware. A GART PTE is only 32 bits in size so that it cannot
be expanded. The physical address bits 32-39 are mapped 11:4 in the PTE.
This can not be architecturally expanded to more than 40 physical bits.

Regards,

	Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632


  reply	other threads:[~2011-04-18 14:52 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-18 13:45 [PATCH 0/4] gart cleanups and fixes Joerg Roedel
2011-04-18 13:45 ` [PATCH 1/4] x86, gart: Don't enforce GART aperture lower-bound by alignment Joerg Roedel
2011-04-18 14:45   ` H. Peter Anvin
2011-04-18 14:56     ` Roedel, Joerg
2011-04-18 15:51       ` H. Peter Anvin
2011-04-18 17:36         ` Joerg Roedel
2011-04-18 17:39           ` H. Peter Anvin
2011-04-18 17:50             ` Joerg Roedel
2011-04-18 19:06             ` Joerg Roedel
2011-04-18 19:40               ` H. Peter Anvin
2011-04-18 18:29   ` Yinghai Lu
2011-04-18 18:39   ` [tip:x86/gart] " tip-bot for Joerg Roedel
2011-04-18 13:45 ` [PATCH 2/4] x86, gart: Convert spaces to tabs in enable_gart_translation Joerg Roedel
2011-04-18 16:39   ` [tip:x86/urgent] " tip-bot for Joerg Roedel
2011-04-18 13:45 ` [PATCH 3/4] x86, gart: Set DISTLBWALKPRB bit always Joerg Roedel
2011-04-18 16:40   ` [tip:x86/urgent] " tip-bot for Joerg Roedel
2011-04-18 13:45 ` [PATCH 4/4] x86, gart: Make sure GART does not map physmem above 1TB Joerg Roedel
2011-04-18 14:46   ` H. Peter Anvin
2011-04-18 14:52     ` Roedel, Joerg [this message]
2011-04-18 15:53       ` H. Peter Anvin
2011-04-18 14:54     ` H. Peter Anvin
2011-04-18 14:59       ` Roedel, Joerg
2011-04-18 15:50         ` Ingo Molnar
2011-04-19  6:12           ` Roedel, Joerg
2011-04-19  7:25             ` Ingo Molnar
2011-04-19  9:15               ` [PATCH] x86, gart: Rename pci-gart_64.c to amd64_gart.c Roedel, Joerg
2011-04-19 13:43               ` [PATCH 4/4] x86, gart: Make sure GART does not map physmem above 1TB H. Peter Anvin
2011-04-19 14:29                 ` Roedel, Joerg
2011-04-20 17:38                   ` H. Peter Anvin
2011-05-10 15:32                     ` [PATCH] x86, gart: Rename pci-gart_64.c to amd_gart_64.c 1TB Roedel, Joerg
2011-04-18 16:40   ` [tip:x86/urgent] x86, gart: Make sure GART does not map physmem above 1TB tip-bot for Joerg Roedel

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