From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NmP6R-0001lc-7s for qemu-devel@nongnu.org; Tue, 02 Mar 2010 05:13:23 -0500 Received: from [199.232.76.173] (port=34115 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NmP6Q-0001kq-El for qemu-devel@nongnu.org; Tue, 02 Mar 2010 05:13:22 -0500 Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim 4.60) (envelope-from ) id 1NmP6O-0008N1-KE for qemu-devel@nongnu.org; Tue, 02 Mar 2010 05:13:22 -0500 Received: from mx1.redhat.com ([209.132.183.28]:63010) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1NmP6O-0008Mx-87 for qemu-devel@nongnu.org; Tue, 02 Mar 2010 05:13:20 -0500 Date: Tue, 2 Mar 2010 12:09:57 +0200 From: "Michael S. Tsirkin" Subject: Re: [Qemu-devel] [PATCH] VirtIO: Fix QEMU crash during Windows PNP tests Message-ID: <20100302100957.GA6150@redhat.com> References: <1252935086-8856-1-git-send-email-yvugenfi@redhat.com> <20100301112637.GH16909@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100301112637.GH16909@redhat.com> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gleb Natapov Cc: Yan Vugenfirer , Alexander Graf , "qemu-devel@nongnu.org Developers" On Mon, Mar 01, 2010 at 01:26:37PM +0200, Gleb Natapov wrote: > On Mon, Mar 01, 2010 at 12:14:43PM +0100, Alexander Graf wrote: > > > > On 14.09.2009, at 15:31, Yan Vugenfirer wrote: > > > > > Signed-off-by: Yan Vugenfirer > > > > > > --- > > > hw/virtio-pci.c | 14 ++++++++++++-- > > > 1 files changed, 12 insertions(+), 2 deletions(-) > > > > > > diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c > > > index f812ab7..a0a22c4 100644 > > > --- a/hw/virtio-pci.c > > > +++ b/hw/virtio-pci.c > > > @@ -364,8 +364,17 @@ static void virtio_map(PCIDevice *pci_dev, int region_num, > > > static void virtio_write_config(PCIDevice *pci_dev, uint32_t address, > > > uint32_t val, int len) > > > { > > > + VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev); > > > + > > > + if (PCI_COMMAND == address) { > > > + if (!(val & PCI_COMMAND_MASTER)) { > > > + proxy->vdev->status &= ~VIRTIO_CONFIG_S_DRIVER_OK; > > > > This part breaks PCI hotplug with Linux guests. > > > > What happens is the following: > Looks like something is broken even without this patch. > > > > > (qemu) pci_add auto nic model=virtio,vlan=0 > > - Virtio dev 1 -> write config (0) > > - Virtio dev 1 -> write config (0x3) > > - Virtio dev 1 -> set status explicitly to OK > Why Linux doesn't enable bus mastering on this device? I fixed this, and Rusty said he has applied the patch, but it seems the patch got lost later: http://lkml.org/lkml/2009/11/29/73 Alexander, could you please check whether applying this patch fixes hotplug for you? If yes I will queue it up for 2.6.34. > > > > (qemu) pci_add auto storage file=/tmp/image.raw,if=virtio > > - Virtio dev 1 -> write config (0x3) > Why Linux touches unrelated device's config space? > > > -> Unset DRIVER_OK bit > > -> network device becomes unresponsive > > - Virtio dev 2 -> write config (0) > > - Virtio dev 2 -> write config (0x3) > > - Virtio dev 2 -> set status explicitly to OK > > > > > > Please either revert this patch or provide a proper fix. > > > > Alex > > -- > Gleb.