From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=44371 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OgWuk-0003uk-Uh for qemu-devel@nongnu.org; Wed, 04 Aug 2010 01:53:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OgWuj-0000Yx-71 for qemu-devel@nongnu.org; Wed, 04 Aug 2010 01:53:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56604) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OgWui-0000Yo-UI for qemu-devel@nongnu.org; Wed, 04 Aug 2010 01:53:17 -0400 Message-ID: <4C590046.2020705@redhat.com> Date: Wed, 04 Aug 2010 08:53:10 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] Anyone seeing huge slowdown launching qemu with Linux 2.6.35? References: <20100803162857.GX13789@amd.home.annexia.org> <4C584781.9040609@redhat.com> <4C5847CD.9080107@codemonkey.ws> <4C5848C7.3090806@redhat.com> <4C584982.5000108@codemonkey.ws> <4C584B66.5070404@redhat.com> <4C5854F1.3000905@codemonkey.ws> <4C5858B2.9090801@redhat.com> <4C585F5B.5070502@codemonkey.ws> <4C58635B.7020407@redhat.com> <20100803190525.GB16570@redhat.com> <4C586AB9.5040302@codemonkey.ws> <4C586CF9.7030206@redhat.com> <4C588804.5060803@redhat.com> In-Reply-To: <4C588804.5060803@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: Gerd Hoffmann Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Gleb Natapov , "Richard W.M. Jones" On 08/04/2010 12:20 AM, Gerd Hoffmann wrote: > Hi, > >>> We're already doing bulk data transfer over fw_cfg as we need to do it >>> to transfer roms and potentially a boot splash. >> >> Why do we need to transfer roms? These are devices on the memory bus or >> pci bus, it just needs to be there at the right address. > > Indeed. We do that in most cases. The exceptions are: > > (1) -M somethingold. PCI devices don't have a pci rom bar then by > default because they didn't not have one in older qemu versions, > so we need some other way to pass the option rom to seabios. What did we do back then? before we had the fwcfg interface? > (2) vgabios.bin. vgabios needs patches to make loading via pci rom > bar work (vgabios-cirrus.bin works fine already). I have patches > in the queue to do that. So not an issue. > (3) roms not associated with a PCI device: multiboot, extboot, > -option-rom command line switch, vgabios for -M isapc. We could lay those out in high memory (4GB-512MB) and have the bios copy them from there. I believe that's what real hardware does - the flash chip is mapped there (the reset vector is at 4GB-16) and shadowed at the end of the 1MB 8086 range. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.