On 05/17/16 04:03, Ruiyu Ni wrote: > The patch serials refined the PciBus code and adds a new feature following > PI spec 1.4a to not improperly degrade resource. > > Ruiyu Ni (4): > MdeModulePkg/PciBus: use better name for local variables. > MdeModulePkg/PciBus: Remove unused fields in PCI_BAR > MdeModulePkg/PciBus: Use shorter global variable name > MdeModulePkg/PciBus: do not improperly degrade resource > > MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c | 6 +-- > MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.h | 5 +- > .../Bus/Pci/PciBusDxe/PciEnumeratorSupport.c | 58 > +++++++++++++++++----- > .../Bus/Pci/PciBusDxe/PciResourceSupport.c | 26 ++++++---- > 4 files changed, 65 insertions(+), 30 deletions(-) >
* Please add the following reference to patch #4: https://mantis.uefi.org/mantis/view.php?id=1529 * I'm interested in this work primarily due to GPU assignment to QEMU/KVM virtual machines. So I built OVMF applied with these patches, and checked if they made a difference for the PCI resource map, with an Nvidia GTX750 assigned to the guest. There's no difference; the 256MB BAR is still allocated under 4GB. * Apparently, EFI_INCOMPATIBLE_PCI_DEVICE_SUPPORT_PROTOCOL must be a singleton protocol; it should come from the platform firmware, not from the option ROM. In that case, how could OVMF implement this protocol, so that such a GPU BAR would be allocated high? Looking at the CheckDevice() spec, I guess we could hard-code some PCI vendor and device IDs, and set AddrSpaceGranularity to 64. However, that's the only thing we should do; I don't think we should do the rest of the PCI BAR probing. ... The only thing I'd like to say to the resource allocator is, If CSM is disabled, then please don't degrade the MMIO64 BARs of this device, just because it has an oprom. (In fact, the device is not an incompatible PCI device.) * By following the links in Mantis #1529 (recursively), I arrived at a message that points to the following driver: MdeModulePkg/Bus/Pci/IncompatiblePciDeviceSupportDxe OVMF does not include this driver at the moment. It is a small driver and I guess we could fork it for OvmfPkg, but how should we fill in the "mIncompatiblePciDeviceList" array? Thanks Laszlo _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
