On Sun, Jan 02, 2011 at 12:26:11PM +0200, Avi Kivity wrote: > On 12/31/2010 05:05 AM, Sheng Yang wrote: > >> > >> Existing code does not support PBA in assigned devices, so at least it's > >> not a regression there, and the virtio spec says nothing about this so > >> we should be fine. > > > >I agree. At least it's not a regression. And in fact we haven't seen any device > >driver use this. I've checked Linux kernel code, found no one used PCI_MSIX_PBA or > >msix_pba_offset_reg(). > > > >I guess it's fine to get MSI-X mask part in first, then deal with PBA part if > >necessary - though we haven't seen any driver use it so far. It won't be worse > >with this patch anyway... > > In a way it is worse because before, the fix would belong in user > space, which is easier to test and distribute. Now we have to fix > it in the kernel. > > However I recognize that drivers which rely on the pending bit are > rare/nonexistent (likely on in preboot environments where interrupts > are hard), so even if we do code it, it will likely be incorrect > (certainly without a test). > > So I'll accept the patch without PBA. Michael, what about > supporting virtio? Can we base something on this patch? I don't see how userspace can send interrupts with this interface unfortunately. We also need irqfd support ... > -- > error compiling committee.c: too many arguments to function -- 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
