From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: c/s 19576 vs. AMD systems Date: Thu, 30 Apr 2009 07:58:27 +0100 Message-ID: <49F96833.76EA.0078.0@novell.com> References: <49F8318D.76EA.0078.0@novell.com> <1241025791.3003.133.camel@mendozza.osrc.amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <1241025791.3003.133.camel@mendozza.osrc.amd.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: Frank Arnold , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Keir, these log fragments point out another issue: Only RAM regions should be removed, but all other regions should remain. This is not the least becau= se Linux checks the E820 table to have e.g. the MCFG area covered as reserved. Jan >>> Frank Arnold 29.04.09 19:23 >>> Am Mittwoch, den 29.04.2009, 09:53 +0100 schrieb Jan Beulich: > Keir, >=20 > I'm afraid this change is going to hurt on AMD systems where memory ext= ends > beyond the 4Gb boundary: Both such systems that I have direct access to > have their Intel MTRRs only defined up to the 4Gb boundary, yet through > the use of AMD specific MSRs (SYS_CFG.Tom2ForceMemTypeWB and TOM2) > the default memory type for everything beyond the 4Gb boundary is WB. > On these systems there shouldn't be any clipping. I certainly can put t= ogether > a patch for this, but it'll take me a couple of days until I'd get to i= t. We can confirm this to be a very real issue. At least on 4 of our test boxes the memory gets truncated after these changes. One example: Mainboard: ASUSTeK Computer INC. M2N-MX SE Plus CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 5000+ Family: 15, Model: 107, Stepping: 1 BIOS Information: Vendor: American Megatrends Inc. Version: 0302 Release Date: 12/04/2007 Memory: 4 GB With changeset 19575:dc5bd14a4675: # xm info ... total_memory : 3967 ... # xm dmesg ... (XEN) Xen-e820 RAM map: (XEN) 0000000000000000 - 000000000009fc00 (usable) (XEN) 000000000009fc00 - 00000000000a0000 (reserved) (XEN) 00000000000e4000 - 0000000000100000 (reserved) (XEN) 0000000000100000 - 00000000b7fb0000 (usable) (XEN) 00000000b7fb0000 - 00000000b7fbe000 (ACPI data) (XEN) 00000000b7fbe000 - 00000000b7fe0000 (ACPI NVS) (XEN) 00000000b7fe0000 - 00000000b7fee000 (reserved) (XEN) 00000000b7ff0000 - 00000000b8000000 (reserved) (XEN) 00000000fec00000 - 00000000fec01000 (reserved) (XEN) 00000000fee00000 - 00000000fef00000 (reserved) (XEN) 00000000fff00000 - 0000000100000000 (reserved) (XEN) 0000000100000000 - 0000000140000000 (usable) (XEN) System RAM: 3967MB (4062524kB) ... Same box with changeset 19582:648d7de355dd: # xm info ... total_memory : 2943 ... # xm dmesg ... (XEN) WARNING: MTRRs do not cover all of memory. (XEN) Truncating memory map to 3145728kB (XEN) Xen-e820 RAM map: (XEN) 0000000000000000 - 000000000009fc00 (usable) (XEN) 000000000009fc00 - 00000000000a0000 (reserved) (XEN) 00000000000e4000 - 0000000000100000 (reserved) (XEN) 0000000000100000 - 00000000b7fb0000 (usable) (XEN) 00000000b7fb0000 - 00000000b7fbe000 (ACPI data) (XEN) 00000000b7fbe000 - 00000000b7fe0000 (ACPI NVS) (XEN) 00000000b7fe0000 - 00000000b7fee000 (reserved) (XEN) 00000000b7ff0000 - 00000000b8000000 (reserved) (XEN) System RAM: 2943MB (3013948kB) ... --=20 Frank Arnold System Design Technician, Software Test AMD Operating System Research Center Dresden, Germany Tel: +49 351 448 356702 Legal Information: Advanced Micro Devices GmbH Karl-Hammerschmidt-Str. 34 85609 Dornach b. M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Jochen Polster; Thomas M. McCoy; Giuliano Mero= ni Sitz: Dornach, Gemeinde Aschheim, Landkreis M=C3=BCnchen Registergericht M=C3=BCnchen, HRB Nr. 43632