From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LjCm5-0001Zz-LU for qemu-devel@nongnu.org; Mon, 16 Mar 2009 09:22:37 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LjCm0-0001ZG-AV for qemu-devel@nongnu.org; Mon, 16 Mar 2009 09:22:36 -0400 Received: from [199.232.76.173] (port=35555 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LjCm0-0001Z9-3E for qemu-devel@nongnu.org; Mon, 16 Mar 2009 09:22:32 -0400 Received: from mx2.redhat.com ([66.187.237.31]:50301) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1LjClz-0003gN-K3 for qemu-devel@nongnu.org; Mon, 16 Mar 2009 09:22:31 -0400 Message-ID: <49BE5290.6060401@redhat.com> Date: Mon, 16 Mar 2009 15:22:24 +0200 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] virtio-blk issues References: <20090303125411.GA16099@lst.de> <200903031422.44151.paul@codesourcery.com> In-Reply-To: <200903031422.44151.paul@codesourcery.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Christoph Hellwig Paul Brook wrote: > On Tuesday 03 March 2009, Christoph Hellwig wrote: > >> I've been trying to move setup from kvm 72 in debian testing to the current >> qemu CVS. The setup is using 7 virtio_blk disks and used to work on the >> old setup, but with current qemu the kernel (current Linus' HEAD from a few >> days ago) hangs when trying to setup the irq routing for the virtio_pci >> devices: >> >> virtio pci 0000:00:06.0: can't derive routing for PCI INT A >> virtio pci 0000:00:06.0: PCI INT A: no GSI - using IRQ 9 >> > > IIRC this is partly a bios issue. Real PIIX3 based systems never have more > than ~5 PCI slots, so it doesn't have interrupt routing for more devices. > > There are two solutions: Fix the bios to handle machines with large numbers of > PCI slots, or have create multifunction PCI devices so lots of virtio > instances don't use so many virtual PCI slots. > > The kvm bios supports 32 slots; I don't know if upstream bochs picked up these changes. In any case I'd like to see a virtio-blk controller which can support an arbitrary number of disks, much like a SCSI controller. A pci slot or function per disk is wasteful. -- error compiling committee.c: too many arguments to function