[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] VirtIO: Fix QEMU crash during Windows PNP tests
From: |
Gleb Natapov |
Subject: |
Re: [Qemu-devel] [PATCH] VirtIO: Fix QEMU crash during Windows PNP tests |
Date: |
Mon, 1 Mar 2010 13:26:37 +0200 |
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 <address@hidden>
> >
> > ---
> > 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?
>
> (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.