Re: [Qemu-devel] Headsup: windows virtio networking does not work on current git

Re: [Qemu-devel] Headsup: windows virtio networking does not work on current git

[Michael S. Tsirkin]

On Thu, Feb 07, 2013 at 09:53:39PM +1100, Vadim Rozenfeld wrote:
> On Thu, 2013-02-07 at 12:18 +0200, Michael S. Tsirkin wrote:
> > On Thu, Feb 07, 2013 at 08:24:10PM +1100, Vadim Rozenfeld wrote:
> > > On Thu, 2013-02-07 at 11:33 +1030, Rusty Russell wrote:
> > > > Vadim Rozenfeld <vrozenfe@redhat.com> writes:
> > > > > On Tue, 2013-02-05 at 13:58 +0200, Michael S. Tsirkin wrote:
> > > > >> On Tue, Feb 05, 2013 at 03:45:38PM +0400, Michael Tokarev wrote:
> > > > >>  Is it really
> > > > >> > that bad that the config space size changed?  Why it has this effect?
> > > > > Because in this case it's hard to distinguish between resource's
> > > > > corruption and HW update.
> > > > 
> > > > But it's also true that if we'd incremented revid you'd have the same
> > > > failure in this case, right?
> > > 
> > > It depends. If we have explicitly specified revision id in inf file and
> > > this id doesn't mach the new revision id, Windows will not try to load
> > > the "incompatible" driver, and finish up with "device driver not found"
> > > dialog.
> > > 
> > > Best regards,
> > > Vadim.
> > >   
> > > > 
> > > > Cheers,
> > > > Rusty.
> > 
> > Well that's all in theory, in practice it does not look like revision ID
> > is specified in the NetKVM inf so this won't work?
> > 
> > From what I see this inf specifies:
> > 
> > NetKVM/wlh/netkvm.inf:%kvmnet6.DeviceDesc%    = kvmnet6.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> > NetKVM/wxp/netkvm.inf:%kvmnet5.DeviceDesc%    = kvmnet5.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> > NetKVM/wxp/netkvm2k.inf:%kvmnet5.DeviceDesc%    = kvmnet5.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> > 
> > So we can tweak any of vendor device and subsystem id.
> > 
> Unfortunately, it won't. Only balloon has revision id, specified as a
> part of device HW descriptor. But it's only because virtio doesn't use 
> revision ids. Otherwise it differential will be there. 

So your driver will load and attempt to work on rev=2 devices?
If yes it's a bug.  virtio spec specifies revision id as an ABI version.
Linux driver does:

        if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
                printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
                       VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
                return -ENODEV;
        }


> > 
> > Changing subsystem vendor ID actually will be completely
> > transparent to linux which for some reason looks at the
> > subsystem device ID (why? no idea) but not the subsystem vendor ID.
> > Of course this requires a valid vendor ID, getting this
> > costs $3000 I think.
> > We could tweak device ID too but that might break some other guests
> > which don't copy the crazy 'replace device id with subsystem device id'
> > logic from Linux.
> > 
> 

Apropos, would you guys like to start to copy your patches to
virtualization@lists.linux-foundation.org?
If you do, you might get some review and feedback, allowing
us to catch such forward compatibility issues earlier.

Of course it's your project so entirely up to you.


-- 
MST

Re: [Qemu-devel] Headsup: windows virtio networking does not work on current git

[Vadim Rozenfeld]

On Thu, 2013-02-07 at 13:33 +0200, Michael S. Tsirkin wrote:
> On Thu, Feb 07, 2013 at 09:53:39PM +1100, Vadim Rozenfeld wrote:
> > On Thu, 2013-02-07 at 12:18 +0200, Michael S. Tsirkin wrote:
> > > On Thu, Feb 07, 2013 at 08:24:10PM +1100, Vadim Rozenfeld wrote:
> > > > On Thu, 2013-02-07 at 11:33 +1030, Rusty Russell wrote:
> > > > > Vadim Rozenfeld <vrozenfe@redhat.com> writes:
> > > > > > On Tue, 2013-02-05 at 13:58 +0200, Michael S. Tsirkin wrote:
> > > > > >> On Tue, Feb 05, 2013 at 03:45:38PM +0400, Michael Tokarev wrote:
> > > > > >>  Is it really
> > > > > >> > that bad that the config space size changed?  Why it has this effect?
> > > > > > Because in this case it's hard to distinguish between resource's
> > > > > > corruption and HW update.
> > > > > 
> > > > > But it's also true that if we'd incremented revid you'd have the same
> > > > > failure in this case, right?
> > > > 
> > > > It depends. If we have explicitly specified revision id in inf file and
> > > > this id doesn't mach the new revision id, Windows will not try to load
> > > > the "incompatible" driver, and finish up with "device driver not found"
> > > > dialog.
> > > > 
> > > > Best regards,
> > > > Vadim.
> > > >   
> > > > > 
> > > > > Cheers,
> > > > > Rusty.
> > > 
> > > Well that's all in theory, in practice it does not look like revision ID
> > > is specified in the NetKVM inf so this won't work?
> > > 
> > > From what I see this inf specifies:
> > > 
> > > NetKVM/wlh/netkvm.inf:%kvmnet6.DeviceDesc%    = kvmnet6.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> > > NetKVM/wxp/netkvm.inf:%kvmnet5.DeviceDesc%    = kvmnet5.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> > > NetKVM/wxp/netkvm2k.inf:%kvmnet5.DeviceDesc%    = kvmnet5.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> > > 
> > > So we can tweak any of vendor device and subsystem id.
> > > 
> > Unfortunately, it won't. Only balloon has revision id, specified as a
> > part of device HW descriptor. But it's only because virtio doesn't use 
> > revision ids. Otherwise it differential will be there. 
> 
> So your driver will load and attempt to work on rev=2 devices?

All virtio-win drivers (net, serial, block, and scsi), except for
balloon will.
 
> If yes it's a bug.  virtio spec specifies revision id as an ABI version.
> Linux driver does:
> 
>         if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
>                 printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
>                        VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
>                 return -ENODEV;
>         }
> 
> 
> > > 
> > > Changing subsystem vendor ID actually will be completely
> > > transparent to linux which for some reason looks at the
> > > subsystem device ID (why? no idea) but not the subsystem vendor ID.
> > > Of course this requires a valid vendor ID, getting this
> > > costs $3000 I think.
> > > We could tweak device ID too but that might break some other guests
> > > which don't copy the crazy 'replace device id with subsystem device id'
> > > logic from Linux.
> > > 
> > 
> 
> Apropos, would you guys like to start to copy your patches to
> virtualization@lists.linux-foundation.org?
> If you do, you might get some review and feedback, allowing
> us to catch such forward compatibility issues earlier.
> 
> Of course it's your project so entirely up to you.
> 
> 

Re: [Qemu-devel] Headsup: windows virtio networking does not work on current git

[Yan Vugenfirer]

On Feb 7, 2013, at 1:46 PM, Vadim Rozenfeld wrote:

> On Thu, 2013-02-07 at 13:33 +0200, Michael S. Tsirkin wrote:
>> On Thu, Feb 07, 2013 at 09:53:39PM +1100, Vadim Rozenfeld wrote:
>>> On Thu, 2013-02-07 at 12:18 +0200, Michael S. Tsirkin wrote:
>>>> On Thu, Feb 07, 2013 at 08:24:10PM +1100, Vadim Rozenfeld wrote:
>>>>> On Thu, 2013-02-07 at 11:33 +1030, Rusty Russell wrote:
>>>>>> Vadim Rozenfeld <vrozenfe@redhat.com> writes:
>>>>>>> On Tue, 2013-02-05 at 13:58 +0200, Michael S. Tsirkin wrote:
>>>>>>>> On Tue, Feb 05, 2013 at 03:45:38PM +0400, Michael Tokarev wrote:
>>>>>>>> Is it really
>>>>>>>>> that bad that the config space size changed?  Why it has this effect?
>>>>>>> Because in this case it's hard to distinguish between resource's
>>>>>>> corruption and HW update.
>>>>>> 
>>>>>> But it's also true that if we'd incremented revid you'd have the same
>>>>>> failure in this case, right?
>>>>> 
>>>>> It depends. If we have explicitly specified revision id in inf file and
>>>>> this id doesn't mach the new revision id, Windows will not try to load
>>>>> the "incompatible" driver, and finish up with "device driver not found"
>>>>> dialog.
>>>>> 
>>>>> Best regards,
>>>>> Vadim.
>>>>> 
>>>>>> 
>>>>>> Cheers,
>>>>>> Rusty.
>>>> 
>>>> Well that's all in theory, in practice it does not look like revision ID
>>>> is specified in the NetKVM inf so this won't work?
>>>> 
>>>> From what I see this inf specifies:
>>>> 
>>>> NetKVM/wlh/netkvm.inf:%kvmnet6.DeviceDesc%    = kvmnet6.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
>>>> NetKVM/wxp/netkvm.inf:%kvmnet5.DeviceDesc%    = kvmnet5.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
>>>> NetKVM/wxp/netkvm2k.inf:%kvmnet5.DeviceDesc%    = kvmnet5.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
>>>> 
>>>> So we can tweak any of vendor device and subsystem id.
>>>> 
>>> Unfortunately, it won't. Only balloon has revision id, specified as a
>>> part of device HW descriptor. But it's only because virtio doesn't use 
>>> revision ids. Otherwise it differential will be there. 
>> 
>> So your driver will load and attempt to work on rev=2 devices?
> 
> All virtio-win drivers (net, serial, block, and scsi), except for
> balloon will.
> 
>> If yes it's a bug.  virtio spec specifies revision id as an ABI version.
>> Linux driver does:
>> 
>>        if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
>>                printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
>>                       VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
>>                return -ENODEV;
>>        }
>> 

We can add it from next release. Provided that everyone understand the consequences especially for boot devices (virtio-block and virtio-scsi).


>> 
>>>> 
>>>> Changing subsystem vendor ID actually will be completely
>>>> transparent to linux which for some reason looks at the
>>>> subsystem device ID (why? no idea) but not the subsystem vendor ID.
>>>> Of course this requires a valid vendor ID, getting this
>>>> costs $3000 I think.
>>>> We could tweak device ID too but that might break some other guests
>>>> which don't copy the crazy 'replace device id with subsystem device id'
>>>> logic from Linux.
>>>> 
>>> 
>> 
>> Apropos, would you guys like to start to copy your patches to
>> virtualization@lists.linux-foundation.org?
>> If you do, you might get some review and feedback, allowing
>> us to catch such forward compatibility issues earlier.
>> 
>> Of course it's your project so entirely up to you.
>> 
>> 
> 
> 

Re: [Qemu-devel] Headsup: windows virtio networking does not work on current git

[Michael S. Tsirkin]

On Thu, Feb 07, 2013 at 03:02:45PM +0200, Yan Vugenfirer wrote:
> 
> On Feb 7, 2013, at 1:46 PM, Vadim Rozenfeld wrote:
> 
> > On Thu, 2013-02-07 at 13:33 +0200, Michael S. Tsirkin wrote:
> >> On Thu, Feb 07, 2013 at 09:53:39PM +1100, Vadim Rozenfeld wrote:
> >>> On Thu, 2013-02-07 at 12:18 +0200, Michael S. Tsirkin wrote:
> >>>> On Thu, Feb 07, 2013 at 08:24:10PM +1100, Vadim Rozenfeld wrote:
> >>>>> On Thu, 2013-02-07 at 11:33 +1030, Rusty Russell wrote:
> >>>>>> Vadim Rozenfeld <vrozenfe@redhat.com> writes:
> >>>>>>> On Tue, 2013-02-05 at 13:58 +0200, Michael S. Tsirkin wrote:
> >>>>>>>> On Tue, Feb 05, 2013 at 03:45:38PM +0400, Michael Tokarev wrote:
> >>>>>>>> Is it really
> >>>>>>>>> that bad that the config space size changed?  Why it has this effect?
> >>>>>>> Because in this case it's hard to distinguish between resource's
> >>>>>>> corruption and HW update.
> >>>>>> 
> >>>>>> But it's also true that if we'd incremented revid you'd have the same
> >>>>>> failure in this case, right?
> >>>>> 
> >>>>> It depends. If we have explicitly specified revision id in inf file and
> >>>>> this id doesn't mach the new revision id, Windows will not try to load
> >>>>> the "incompatible" driver, and finish up with "device driver not found"
> >>>>> dialog.
> >>>>> 
> >>>>> Best regards,
> >>>>> Vadim.
> >>>>> 
> >>>>>> 
> >>>>>> Cheers,
> >>>>>> Rusty.
> >>>> 
> >>>> Well that's all in theory, in practice it does not look like revision ID
> >>>> is specified in the NetKVM inf so this won't work?
> >>>> 
> >>>> From what I see this inf specifies:
> >>>> 
> >>>> NetKVM/wlh/netkvm.inf:%kvmnet6.DeviceDesc%    = kvmnet6.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> >>>> NetKVM/wxp/netkvm.inf:%kvmnet5.DeviceDesc%    = kvmnet5.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> >>>> NetKVM/wxp/netkvm2k.inf:%kvmnet5.DeviceDesc%    = kvmnet5.ndi, PCI\VEN_1AF4&DEV_1000&SUBSYS_00011AF4
> >>>> 
> >>>> So we can tweak any of vendor device and subsystem id.
> >>>> 
> >>> Unfortunately, it won't. Only balloon has revision id, specified as a
> >>> part of device HW descriptor. But it's only because virtio doesn't use 
> >>> revision ids. Otherwise it differential will be there. 
> >> 
> >> So your driver will load and attempt to work on rev=2 devices?
> > 
> > All virtio-win drivers (net, serial, block, and scsi), except for
> > balloon will.
> > 
> >> If yes it's a bug.  virtio spec specifies revision id as an ABI version.
> >> Linux driver does:
> >> 
> >>        if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
> >>                printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
> >>                       VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
> >>                return -ENODEV;
> >>        }
> >> 
> 
> We can add it from next release. Provided that everyone understand the consequences especially for boot devices (virtio-block and virtio-scsi).
> 

Same as Linux - guest won't boot.

> >> 
> >>>> 
> >>>> Changing subsystem vendor ID actually will be completely
> >>>> transparent to linux which for some reason looks at the
> >>>> subsystem device ID (why? no idea) but not the subsystem vendor ID.
> >>>> Of course this requires a valid vendor ID, getting this
> >>>> costs $3000 I think.
> >>>> We could tweak device ID too but that might break some other guests
> >>>> which don't copy the crazy 'replace device id with subsystem device id'
> >>>> logic from Linux.
> >>>> 
> >>> 
> >> 
> >> Apropos, would you guys like to start to copy your patches to
> >> virtualization@lists.linux-foundation.org?
> >> If you do, you might get some review and feedback, allowing
> >> us to catch such forward compatibility issues earlier.
> >> 
> >> Of course it's your project so entirely up to you.
> >> 
> >> 
> > 
> >