On Mon, Jun 15, 2009 at 09:24:32AM -0500, Anthony Liguori wrote: > Dor Laor wrote: >> Libvirt does not support r2d. I hope it won't start to support it. > > It supports mips, sparc, and ppc machines now. I don't see why it > wouldn't support r2d. For ppcemb, I expect this same problem to occur. > This sort of restriction is going to be common with embedded boards. > >> We can have default values for these types of devices or something >> like pci_addr=auto. > > Why wouldn't libvirt always use pci_addr=auto? If the only argument for > having libvirt do pci slot allocation is error messages, can't we find a > nice way to allow libvirt to create friendly error messages when QEMU > fails? > >>> If you let QEMU allocate which PCI slot a device goes in, we can hide >>> this detail from libvirt. If you have libvirt do PCI slot allocation >>> by default, it has to know about this restriction in the r2d board >>> unless you have a clever way to express this sort of information. >>> >>> Once QEMU has allocated a device to a slot, libvirt can do a good job >>> maintaining that relationship. >>> >> >> The end user should have a mechanism to control device slot >> positioning. For example, if you have several pci devices, some >> get high rate of interrupts and some not, if you want to optimize you >> guest you should isolate the high rate 'interesting' devices. >> This is something the user will need to do. I agree that the default >> behavior might be 'auto' > > I'm not at all arguing against pci_addr. I'm arguing about how libvirt > should use it with respect to the "genesis" use-case where libvirt has > no specific reason to choose one PCI slot over another. In that case, > I'm merely advocating that we want to let QEMU make the decision. The allocation code could be moved out into a library, and libvirt could link with it (ducks). > Regards, > > Anthony Liguori _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
