On Wed, Nov 12, 2008 at 11:51:04AM -0800, Jesse Barnes wrote: > On Tuesday, November 11, 2008 9:37 pm Yuji Shimada wrote: > > As I have not received a reply to my mail of November 6, 2008, I am > > resending it herewith. > > > > This patch adds the function that reassigns page-aligned memory > > resources to device, to linux. > > > > I created this patch for xen's dom0 linux. It have already been > > included in xen's dom0 linux. It is useful when we assign I/O device > > to HVM domain using pci passthrough, because page-aligned memory > > resource is required for pci passthrough. It is also useful for > > KVM. So I submit it to linux-pci ML. > > Ok, so the fundamental requirement here is to assign PCI devices to guests, > right? That means PCI resources be aligned to a page boundary and take up at > least a page so that no other resources will fall into the same page, right? > > So you add a quirk to unassign the resources of the device(s) in question and > let the core reassign them according to your new constraints. So far, so > good. > > Like Matthew said, reassigning at runtime should be possible, but can be a > little trickier since your configuration has to disallow driver binding (or > unbind everything) until after you've done your reassignments. For v11n > setups that doesn't seem wholly unreasonable, but probably isn't as convenient > as simply doing it at startup time. > > Anyway, comments on your patch below. > > > To reassign page-aligned memory resources to device, please add boot > > parameter of linux as follows. > > > > reassigndev=00:1d.7,01:00.0 > > > > reassigndev= Specifies device to reassign page-aligned > > memory resources. PCI-PCI bridge can be > > specified, if resource windows need to be > > expanded. > > I'd call this pagealignbars= or something instead, since you're not just > reassigning things (that happens anyway for conflicting resources and for > quirked devices), you're making sure that resources really are page aligned. > It should probably also be part of the pci= parameter; besides your code for > parsing out PCI device specifiers might be handy in the future (I was > surprised my quick look didn't find some other boot option that already did > it). As I said before, for a different patch recently, you can't use pci device ids as a kernel command line option as they are not stable and the user/distro never knows them ahead of time. Please do this dynamically while the kernel is running instead, if you really have to do this. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
