Michael S. Tsirkin
2013-Feb-07 11:33 UTC
[Qemu-devel] Headsup: windows virtio networking does not work on current git
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 at 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 at 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
Vadim Rozenfeld
2013-Feb-07 11:46 UTC
[Qemu-devel] Headsup: windows virtio networking does not work on current git
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 at 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 at 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. > >