Each of these patches stands on it's own, but they all touch the same file and therefore build on each other to some extent. The first patch allows vfio-pci to accept a list of IDs as a module parameter, exactly like pci-stub. This is really useful to get vfio-pci bound to devices that are intended to be used exclusively by userspace without more complex scripts (particuarly with modprobe.d softdep, pre loading).
The 2nd patch allows a module option to disable VGA access if vfio-pci is configured with VGA support. By itself this doesn't do much, but with patch 5, we add a VGA arbiter client that will opt-out devices from arbitration if the user cannot access VGA regions of the device. If you have extra GPUs in your system exclusively for use via vfio-pci and don't depend on VGA resource access, this opt-out can allow host graphics to enable DRI2 support as if the additional GPUs weren't there. This depends on https://lkml.org/lkml/2015/2/24/430 or else vga arbiter support gets ugly (still looking for an Ack there). The other interesting feature here is idle power management. It's possible that there are extra devices in a host that are used exclusively via vfio-pci and that those devices are not used 100% of the time. To be power conscious we can put devices into a low power state when they're not actively being used. This doesn't always save much, or necessarily any power, but we can at least try. I'll also note that the last patch makes use of pci_bus_max_busnr() which seems to be in flux with some current upstream patches. I don't really care if we use pci_bus_max_busnr() or some replacement for it, so long as pci-core allows a way to determine the bus number range below a bridge so I can determine if there's more than one VGA device below it. Comments welcome. Thanks, Alex --- Alex Williamson (5): vfio-pci: Allow PCI IDs to be specified as module options vfio-pci: Add module option to disable VGA region access vfio-pci: Remove warning if try-reset fails vfio-pci: Move idle devices to D3hot power state vfio-pci: Add VGA arbiter client drivers/vfio/pci/vfio_pci.c | 174 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 157 insertions(+), 17 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
