mirror of https://github.com/acidanthera/audk.git
9116c9c5d8
QEMU's ACPI table generator can only create meaningful _CRS objects -- apertures -- for the root buses if all of the PCI devices behind those buses are actively decoding their IO and MMIO resources, at the time of the firmware fetching the "etc/table-loader" fw_cfg file. This is not a QEMU error; QEMU follows the definition of BARs (which are meaningless when decoding is disabled). Currently we hook up AcpiPlatformDxe to the PCI Bus driver's gEfiPciEnumerationCompleteProtocolGuid cue. Unfortunately, when the PCI Bus driver installs this protocol, it's *still* not the right time for fetching "etc/table-loader": although resources have been allocated and BARs have been programmed with them, the PCI Bus driver has also cleared IO and MMIO decoding in the command registers of the devices. Furthermore, we couldn't reenable IO and MMIO decoding temporarily in our gEfiPciEnumerationCompleteProtocolGuid callback even if we wanted to, because at that time the PCI Bus driver has not produced PciIo instances yet. Our Platform BDSes are responsible for connecting the root bridges, hence they know exactly when the PciIo instances become available -- not when PCI enumeration completes (signaled by the above protocol), but when the ConnectController() calls return. This is when our Platform BDSes should explicitly cue in AcpiPlatformDxe. Then AcpiPlatformDxe can temporarily enable IO and MMIO decoding for all devices, while it contacts QEMU for the ACPI payload. This patch introduces the event group GUID that we'll use for unleashing AcpiPlatformDxe from our Platform BDSes. Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Jordan Justen <jordan.l.justen@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Jordan Justen <jordan.l.justen@intel.com> |
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| Guid | ||
| IndustryStandard | ||
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| Protocol | ||
| Register | ||
| OvmfPlatforms.h | ||