From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33778) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VK2Rw-0007xq-Ii for qemu-devel@nongnu.org; Thu, 12 Sep 2013 04:40:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VK2Rq-0001f9-JQ for qemu-devel@nongnu.org; Thu, 12 Sep 2013 04:40:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49220) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VK2Rq-0001ex-7i for qemu-devel@nongnu.org; Thu, 12 Sep 2013 04:40:22 -0400 Date: Thu, 12 Sep 2013 11:42:17 +0300 From: "Michael S. Tsirkin" Message-ID: <20130912084217.GB18836@redhat.com> References: <52317A12.10206@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <52317A12.10206@redhat.com> Subject: Re: [Qemu-devel] MSI-X doesn't work when running Windows as guest List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gal Hammer Cc: qemu-devel@nongnu.org, Anthony Liguori , ehabkost@redhat.com On Thu, Sep 12, 2013 at 11:23:46AM +0300, Gal Hammer wrote: > Hi, > > I've notice that the virtio-serial Windows' driver doesn't use MSI-X > vectors when running using upstream qemu or > qemu-kvm-1.2.2-13.fc18.x86_64. The same VM works with MSI-X when > using qemu-kvm-0.12.1.2-2.355.el6.x86_64. > > From what I saw, Windows is trying to enable MSI-X by writing a 2 > bytes value to device's PCI-config address 66h. > > So when everything works well the flow goes like this: > > pci_default_write_config value: 8000 len: 2 > pci_default_write_config value: 1 len: 2 > msix_enabled 0 (67) > pci_default_write_config value: e107 len: 2 > pci_default_write_config value: 1 len: 2 > msix_enabled 0 (67) > pci_default_write_config value: 8001 len: 2 > msix_enabled 1 (67) > > But on upstream it goes: > > pci_default_write_config addr: 66 value: 8000 size: 2 > pci_default_write_config addr: 66 value: 1 size: 2 > msix_enabled 0 (67) > pci_default_write_config addr: 66 value: e307 size: 2 (NOTE: Value > is diffrent!). > pci_default_write_config addr: 66 value: 1 size: 2 > msix_enabled 0 (67) > > (NOTE: Missing the write of 8001). > > My qemu's command line: > > ---< snip >--- > > /usr/bin/qemu-kvm -m 1G -smp 2 -enable-kvm -usb -device usb-tablet \ > -device > ide-drive,drive=drive-virtio0-0-0,id=virtio0-0-0,bootindex=1 \ > -drive file=win7_32_viorng.qcow2,if=none,id=drive-virtio0-0-0,format=qcow2,werror=stop,rerror=stop,cache=none > \ > -monitor stdio \ > -vga qxl -spice id=on,disable-ticketing,port=5903 \ > -device virtio-serial-pci,id=virtio-serial0,vectors=2 \ > -chardev spicevmc,id=spicechannel0,name=vdagent > > ---< snip >--- > > Thanks, > > Gal. So it's a known change from qemu-kvm to qemu. With qemu-kvm the default cpu was kvm64. With qemu the default cpu is qemu64 even if you use -enable-kvm. Not an issue for libvirt as that specifies -cpu, but will be an issue for command-line users. Maybe we should change the default for new machine types and when -enable-kvm is specified? Eduardo? Anthony? -- MST