From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41688) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zhyoi-0006Or-4A for qemu-devel@nongnu.org; Fri, 02 Oct 2015 07:48:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zhyoe-0004ml-UK for qemu-devel@nongnu.org; Fri, 02 Oct 2015 07:48:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39054) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zhyoe-0004mS-P2 for qemu-devel@nongnu.org; Fri, 02 Oct 2015 07:47:56 -0400 References: <1443701677-13629-1-git-send-email-markmb@redhat.com> <1443701819-13855-1-git-send-email-markmb@redhat.com> <1443701819-13855-7-git-send-email-markmb@redhat.com> <560D5057.6010308@redhat.com> <20151001160242.GA7766@morn.lan> <1443773786.14636.12.camel@redhat.com> <20151002102408.23266dc0@markmb_rh> <1443776468.14636.20.camel@redhat.com> From: Laszlo Ersek Message-ID: <560E6EE9.3090502@redhat.com> Date: Fri, 2 Oct 2015 13:47:53 +0200 MIME-Version: 1.0 In-Reply-To: <1443776468.14636.20.camel@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4 6/7] Make the kernel image in the fw_cfg DMA interface bootable List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann , =?UTF-8?Q?Marc_Mar=c3=ad?= Cc: Stefan Hajnoczi , Drew , Kevin O'Connor , "Gabriel L. Somlo" , qemu-devel@nongnu.org On 10/02/15 11:01, Gerd Hoffmann wrote: > Hi, > >> A solution that I can see is adding DMA boot capabilities to the >> linuxboot.S optionrom. I was trying to avoid this, but it looks like >> not doing so creates lots of problems. It may be better than adding a >> "nice" shortcut somewhere in QEMU or SeaBIOS. >> >> Who uses this optionrom (and will benefit from this change)? > > Any -kernel boot on x86 will use either linuxboot.bin or multiboot.bin. (Except when your firmware is OVMF -- OVMF has its own LoadLinuxLib. So, if you decide to extend linuxboot.bin / multiboot.bin with the DMA capability, that can't regress OVMF by definition, and you certainly won't hear me complain.) Thanks Laszlo > From a compatibility point of view implementing it in the option rom > certainly has its advantages. And as the option roms are shipped with > and loaded by qemu you don't even have to do runtime detection if that > simplifies things. We can just build two versions of the roms and qemu > can use the one or the other depending on whenever the machine type in > question has fw_cfg dma enabled or not. > > cheers, > Gerd > > > >