On Wed, 2011-11-09 at 10:47 +0000, Pawel Moll wrote: > On Wed, 2011-11-09 at 10:20 +0000, Sasha Levin wrote: > > > > I'm also wondering it it's ok to move virtio configuration out of virtio > > > > space and into PCI space for archs that don't have PCI (such as ARM). > > Just a note - ARM-based chips can by all means have PCI (grep -r PCI > arch/arm/ ;-). The fact is that most of the SOCs available on the market > don't have it, but this is slowly changing. > > The main architectural difference is that ARM doesn't provide separate > I/O space so the PCI I/O space is usually remapped somewhere into normal > address space (grep -r "#define __io_address" arch/arm/) > > > > > Would it mean they get stuck with legacy configuration (and no new > > > > features)? Or is there an alternative for them? > > > > > > The change only affects the layout of virtio PCI. Arches that don't > > > have PCI don't use virtio PCI, presumably? > > > > > > BTW, the spec only covers x86 ATM, this needs to be fixed. > > > > From what I see there is a WIP by Pawel Moll <pawel.moll@xxxxxxx> to add > > virtio platform drivers which get virtio working on ARM for example, and > > by Peter Maydell <peter.maydell@xxxxxxxxxx> to modify the spec to > > support MMIO access (besides PCI). > > Yep, it's actually already in 3.2-rc1 (drivers/virtio/virtio_mmio.c) and > in the spec (see Appendix X). And actually the control registers layout > I used was originally based on the PCI "legacy" headers (slightly > simplified), but evolved a bit since. My understanding is that the > changes Michael is proposing affect the PCI device interface only so > they shouldn't affect "my" interface. I didn't know it's in already, might be interesting adding support to it to x86 userspace tools. I thought you used the 'legacy' layout, which is why I was worried that these changed might cause problems for you - but from what I see you have a different layout there, so as you said, it shouldn't cause any issues there. > > By the way, I vaguely remember Peter mentioning that he got the PCI > device "experimentally" running some time ago on one of the PCI-enabled > ARM platform models (realview or versatile)... -- Sasha. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
