From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NHeqi-000454-JD for qemu-devel@nongnu.org; Mon, 07 Dec 2009 09:46:04 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NHeqd-0003yO-GZ for qemu-devel@nongnu.org; Mon, 07 Dec 2009 09:46:03 -0500 Received: from [199.232.76.173] (port=37826 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NHeqd-0003xv-7W for qemu-devel@nongnu.org; Mon, 07 Dec 2009 09:45:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:49684) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NHeqc-0004mB-Ux for qemu-devel@nongnu.org; Mon, 07 Dec 2009 09:45:59 -0500 Date: Mon, 7 Dec 2009 16:43:14 +0200 From: "Michael S. Tsirkin" Message-ID: <20091207144314.GA5734@redhat.com> References: <1259137008-9669-1-git-send-email-kraxel@redhat.com> <1259137008-9669-2-git-send-email-kraxel@redhat.com> <20091207093716.GA31370@redhat.com> <4B1CD9C4.4020509@redhat.com> <20091207105950.GA3376@redhat.com> <4B1CE5D2.5080205@redhat.com> <20091207130329.GA3937@redhat.com> <4B1D0031.20705@redhat.com> <20091207141339.GC5328@redhat.com> <4B1D1171.1000701@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B1D1171.1000701@redhat.com> Subject: [Qemu-devel] Re: [PATCH 2/2] virtio: enable msi-x for console+balloon List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: qemu-devel@nongnu.org On Mon, Dec 07, 2009 at 03:30:09PM +0100, Gerd Hoffmann wrote: > On 12/07/09 15:13, Michael S. Tsirkin wrote: >> Gerd, any idea whether "one MSI-X vector" feature is worth pursuing? > > I'd rate it low priority. First because virtio-enabled guests can use > virtio-net+blk. Also because with the upcoming p35 support we'll get a > more modern pc emulation including a ioapic with all 24 IRQ lines being > wired up, which will help reducing IRQ sharing too. > > MSI support (no -X) could be more intresting (for emulated devices) as > it is older and thus support is more common. My T60 for example has no > device with MSI-X support but 9 with MSI support. Linux turns on MSI > for 7 of them (4 PCIe ports, e1000, ahci, iwl3945). > > cheers, > Gerd Yes, but what matters is guest support I think. On windows it seems that both msix and msi support were added simulataneously. It won't be hard to add MSI support, but let's determine when is it needed. -- MST