From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Mfv2j-00071n-Gm for qemu-devel@nongnu.org; Tue, 25 Aug 2009 08:22:29 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Mfv2e-0006uJ-3Y for qemu-devel@nongnu.org; Tue, 25 Aug 2009 08:22:28 -0400 Received: from [199.232.76.173] (port=43078 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Mfv2d-0006u2-Qh for qemu-devel@nongnu.org; Tue, 25 Aug 2009 08:22:23 -0400 Received: from tx2ehsobe001.messaging.microsoft.com ([65.55.88.11]:28364 helo=TX2EHSOBE001.bigfish.com) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_ARCFOUR_MD5:16) (Exim 4.60) (envelope-from ) id 1Mfv2c-0007ay-PV for qemu-devel@nongnu.org; Tue, 25 Aug 2009 08:22:23 -0400 Message-ID: <4A93D760.4060707@amd.com> Date: Tue, 25 Aug 2009 14:21:52 +0200 From: Andre Przywara MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 2/3] push CPUID level to 4 to allow Intel multicore decoding References: <1250689362-11067-1-git-send-email-andre.przywara@amd.com> <1250689362-11067-3-git-send-email-andre.przywara@amd.com> <4A8D2037.4000002@redhat.com> <4A8D2722.2000905@amd.com> <4A8D2E1E.2040608@redhat.com> In-Reply-To: <4A8D2E1E.2040608@redhat.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: qemu-devel@nongnu.org Avi Kivity wrote: > Andre Przywara wrote: >> The only problem I can think of is that the advertised cache topology >> is somehow bogus and could confuse OSes. > > So long as it's smaller than contemporary caches we should be fine. Oh, I see now that Alex' Core2Duo (on which QEMU's leaf 4 values are based on) has 4 MB of L2-Cache. Although that is not gigantic for Intel CPUs, it's certainly too high for many host CPUs. I will lower this value to say 1MB or 512K to better match the majority of host. I will send a patch together with some more CPUID reworks I am working on. > > btw, does -cpu host use the host cpu cache information? Good point. It does not, it only deals with leaves 0, 1, 8000_0000 and 8000_0001. I have created a white list of further CPUID leaves which are safe to propagate to the guest and will also send this in a while. Thanks for these hints, Andre. -- Andre Przywara AMD-Operating System Research Center (OSRC), Dresden, Germany Tel: +49 351 448 3567 12 ----to satisfy European Law for business letters: Advanced Micro Devices GmbH Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen Geschaeftsfuehrer: Thomas M. McCoy; Giuliano Meroni Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632