From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:51403) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RDcKP-0006cI-CG for qemu-devel@nongnu.org; Tue, 11 Oct 2011 09:25:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RDcKK-0006dv-Qo for qemu-devel@nongnu.org; Tue, 11 Oct 2011 09:25:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:12765) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RDcKK-0006dZ-1u for qemu-devel@nongnu.org; Tue, 11 Oct 2011 09:25:00 -0400 Date: Tue, 11 Oct 2011 15:24:56 +0200 From: Gleb Natapov Message-ID: <20111011132456.GA30105@redhat.com> References: <20111011082315.GI14627@redhat.com> <4E940919.7010901@redhat.com> <5C80782F-C30A-4F35-93FD-0397A1040AFF@suse.de> <4E940BB6.2000400@redhat.com> <050FFBD4-BF45-4425-865B-24E7C228B592@suse.de> <4E9440B6.3060201@codemonkey.ws> <2DB3FD25-4BF7-4F82-9A62-49A6891316B3@suse.de> <4E944252.7020508@codemonkey.ws> <4E944358.6030304@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E944358.6030304@redhat.com> Subject: Re: [Qemu-devel] Slow kernel/initrd loading via fw_cfg; Was Re: Hack integrating SeaBios / LinuxBoot option rom with QEMU trace backends List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: qemu-devel , Alexander Graf , "Richard W.M. Jones" On Tue, Oct 11, 2011 at 03:23:36PM +0200, Avi Kivity wrote: > On 10/11/2011 03:19 PM, Anthony Liguori wrote: > >> No, DMA has a lot bigger granularities in kvm/user interaction. We > >> can easily DMA a 50MB region with a single kvm/user exit. For PIO we > >> can at most do page granularity. > > > > > > So make a proper PCI device for kernel loading. It's a much more > > natural approach and let's use alias -kernel/-initrd/-append to > > -device kernel-pci,kernel=PATH,initrd=PATH > > This is overkill. First let's optimize rep/movs before introducing any > more interfaces. If that doesn't work, then we can have a dma interface > for fwcfg. But a new pci device? > We can hot unplug it right after the boot :) -- Gleb.