On Tue, May 05, 2009 at 03:08:40PM +0300, Avi Kivity wrote: > Michael S. Tsirkin wrote: >> On Tue, May 05, 2009 at 02:57:10PM +0300, Avi Kivity wrote: >> >>> Michael S. Tsirkin wrote: >>> >>>> On Tue, May 05, 2009 at 08:04:15AM -0300, Marcelo Tosatti wrote: >>>> >>>>> On Tue, May 05, 2009 at 01:30:28PM +0300, Michael S. Tsirkin wrote: >>>>> >>>>>> The new KVM_ASSIGN_SET_MSIX_NR and KVM_ASSIGN_SET_MSIX_ENTRY ioctls have >>>>>> been merged for 2.6.30. However, I note that PCI spec allows devices to >>>>>> support multiple vectors with MSI as well (support will be in linux >>>>>> 2.6.30). >>>>>> >>>>>> Even though qemu for now only uses a single vector with MSI, it would >>>>>> seem that it's better to make the kernel/user interface generic straight >>>>>> away rather than add more ioctls later. What do you think? It might not >>>>>> be too late to fix this for 2.6.30. >>>>>> >>>>> Can't you use more than one KVM_ASSIGN_SET_MSIX_ENTRY call per assigned >>>>> device? >>>>> >>>> Sure, but only one KVM_ASSIGN_SET_MSIX_NR. >>>> >>>> >>> MSIX_NR is the size of the table, while MSIX_ENTRY updates a single >>> entry, if I read the code correctly. >>> >> >> Right. So we'll need something like this for MSI as well. >> Actually maybe MSIX_NR MSIX_ENTRY should be renamed to MSI_NR / MSI_ENTRY >> and changed to do the right thing depending on the IRQ type? >> > > Works for me. Sheng, is there a reason why it wasn't done like this? > > btw, it could be further simplified by using irqfd. Instead of the host > device tying directly into kvm, it could just trigger an eventfd; and we > could terminate the eventfd either in kvm (irqfd) or in qemu. This probably is outside the scope for 2.6.30 :) -- MST -- 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
