On Mon, Nov 18, 2013 at 2:26 AM, Wei Liu <wei.l...@citrix.com> wrote: > On Sat, Nov 16, 2013 at 06:11:20PM -0800, Jordan Justen wrote: >> My first choice would be to add a PCD to MdeModulePkg/MdeModulePkg.dec >> that prevents enumeration in >> MdeModulePkg/Bus/Pci/PciBusDxe/PciBusDxe.inf, and continue to use this >> main driver. But, I don't know how easy those changes would be to >> make. It probably would also mean changing >> PcAtChipsetPkg/PciHostBridgeDxe/PciHostBridgeDxe.inf by looking at the >> same PCD. If some OVMF environments require enumeration, and some >> don't then this would allow us to choose what will happen at runtime. > > Second thought on this. > > The main advantage to have a runtime Pcd over build time static > configuration is that we can use single binary for all OVMF use cases. > However currently Xen hvmloader statically embeds firmware blobs in > itself so it doesn't really matter if OVMF is configurable at runtime. > So this option will not benifit much unless we overhaul toolstack (libxl > and hvmloader) to support loading additional firmware blobs.
This is a good argument. I definitely wanted to keep a single OVMF build working for Xen & QEMU if possible, but it seems like there is little value if it is not easy to load a different version in Xen. It seems that Xen supporting flash emulation will raise a few uncomfortable questions. (Well, that is not exclusive to Xen. :) > And per Andrew Fish: > > "The > https://svn.code.sf.net/p/edk2/code/trunk/edk2/MdeModulePkg/Bus/Pci/PciBusDxe/ > driver assumes you are following the PI Spec model and a full PCI > enumeration is requires and a set of chipset/platform specific protocols > are provided to make the PCI enumerate code generic." > > So I'm not quite sure whether to stop enumeration in MdeModulePkg is the > right choice. Obviously the PCD should default to enumeration, but I think there is still value in not duplicating the module assuming there is a lot of code overlap. It would be nice to continue to use the same module that most platform use. -Jordan ------------------------------------------------------------------------------ Shape the Mobile Experience: Free Subscription Software experts and developers: Be at the forefront of tech innovation. Intel(R) Software Adrenaline delivers strategic insight and game-changing conversations that shape the rapidly evolving mobile landscape. Sign up now. http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk _______________________________________________ edk2-devel mailing list edk2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/edk2-devel
