Following up on this cross-posted message, I will send two patch sets, one for QEMU (to qemu-devel) and another for OVMF (to edk2-devel). With both in place, OVMF supports multiple PCI root buses, and SeaBIOS recognizes boot options that reference devices behind PXBs.
* Background. Since the last such "bundled" posting, which was http://thread.gmane.org/gmane.comp.emulators.qemu/342206 PXB fixes for QEMU, and extra root buses for OVMF with subthreads [edk2] [PATCH 00/21] OvmfPkg: support extra PCI root buses [qemu-devel] [PATCH 0/4] PXB tweaks and fixes I have posted no updated OVMF series, and posted two updated QEMU series: http://thread.gmane.org/gmane.comp.emulators.qemu/343098 [qemu-devel] [PATCH v2 0/4] PXB tweaks and fixes http://thread.gmane.org/gmane.comp.emulators.qemu/343150 [qemu-devel] [PATCH v3 0/6] PXB tweaks and fixes Version 3 of the QEMU series looked okay-ish for a while. Michael applied the first two of those patches, and (I believe) was planning to investigate the 3rd patch ("hw/pci-bridge: create interrupt-less, hotplug-less bridge for PXB"). Plus, I requested Markus's feedback on some "core" QOM stuff. Other than that, everything seemed to work fine between QEMU and OVMF. In the topmost reference I had named a boot option matching problem (as point (7)) and I was writing code for that in the then-upcoming OVMF patches (planned for OVMF v2). In parallel Marcel turned his attention to SeaBIOS, in order to address the same boot order issue in it. Marcel posted: http://thread.gmane.org/gmane.comp.emulators.qemu/343284 [SeaBIOS] [PATCH] pci: fixes to allow booting from extra root pci buses. http://thread.gmane.org/gmane.comp.emulators.qemu/343298 [SeaBIOS] [PATCH V2] pci: fixes to allow booting from extra root pci buses. In the resultant discussion with Kevin, it became clear that minimally some special casing for QEMU would be necessary in the SeaBIOS patch (because SeaBIOS was already handling extra PCI root buses, and differently from how we had expected). Sticking with the existing code was preferred however. The main issue was that SeaBIOS expected the *serial numbers* of the extra PCI root buses in the boot order OFW devpaths, while QEMU was offering the *bus numbers* themselves. Although the bus numbers in question are permanent (and not guest-assigned) on QEMU, this wasn't a good match for SeaBIOS: on physical hardware, Coreboot assigns the extra root bus numbers (before launching SeaBIOS), and SeaBIOS considers only the serial numbers stable (as long as the hardware config itself is stable). Here's an example: serial number bus number of extra root bus of extra root bus SeaBIOS :) SeaBIOS :( ----------------- ----------------- 0x1 0x7 0x2 0xB 0x3 0xF The serial numbers always start at 1, are consecutive, and they order the extra root buses based on the bus numbers, increasingly. * New stuff. The two series I'm about to post (QEMU v4 and OVMF v2), supersede *all* of the above. No changes are necessary for SeaBIOS. QEMU applies a transformation from the right column to the left column when formatting the OFW nodes. SeaBIOS consumes those nodes directly, while OVMF applies an inverse transform for boot order matching. ( Internally, OVMF sticks with the right column in the UID fields of the ACPI_HID_DEVICE_PATH nodes (also known as "PciRoot(UID)" nodes) that it creates alongside the extra PCI root bridge IO protocols, for the extra root buses. This equality is important because those ACPI_HID_DEVICE_PATH.UID fields must in turn match, by requirement of the UEFI spec, the UIDs placed into the SSDT by QEMU's ACPI generator. Therefore, I had to choose between picking the PciRoot(UID) values from the left column -- which would have necessitated parallel changes to QEMU's ACPI generator -- vs. implementing a reverse transform in OVMF's boot order matching. I chose the latter. ) Summary: - no ACPI changes in QEMU - no SeaBIOS changes - re-verified interrupt line assignments between SeaBIOS and OVMF: they continue to match - retested Windows Server 2012 R2 boot & networking on OVMF (with NIC behind PXB) - regression-tested the "extra root bus"-less case on OVMF - booted a Fedora CD-ROM on a virtio-scsi HBA on a PXB with SeaBIOS (with -boot strict=on) Thanks Laszlo ------------------------------------------------------------------------------ _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel
