On 01.06.2011, at 13:13, Avi Kivity wrote: > On 06/01/2011 12:56 PM, Alexander Graf wrote: >> On 01.06.2011, at 09:30, Gerd Hoffmann wrote: >> >> > Hi, >> > >> >> 0xE0000000 is hard-coded in the DSDT for both piix and q35 as below. >> >> If the range is determined dynamically, the area also needs to be >> >> updated somehow dynamically. >> >> >> >> ... >> >> Name (_CRS, ResourceTemplate () >> >> ... >> >> DWordMemory (ResourceProducer, PosDecode, MinFixed, >> >> MaxFixed, NonCacheable, ReadWrite, >> >> 0x00000000, // Address Space Granularity >> >> 0xE0000000, // Address Range Minimum >> >> 0xFEBFFFFF, // Address Range Maximum >> >> 0x00000000, // Address Translation Offset >> >> 0x1EC00000, // Address Length >> >> ,, , AddressRangeMemory, TypeStatic) >> > >> > Uhm, indeed. I know next to nothing about ACPI though. Ideas anyone how >> > this could be done? >> >> We're facing similar issues on PPC. The equivalent of the DSDT there is the >> device tree, which is currently passed in as binary blob and slightly >> appended for dynamic configuration. I'd much rather like to see it fully >> generated inside of Qemu from all the information we have available there, >> so we don't run into consistency issues. >> >> This will be even more required when we pass through SoC devices to the >> guest, which are not on a PCI bus. Without specifying them in the DT, the >> guest doesn't know about them. X86 has a similar issue. Take a look at the >> HPET for example. If you don't want an HPET inside the guest, the DSDT needs >> to be modified. So you need to change things at 2 places - the DSDT and Qemu. >> >> I don't know how much work it would be to generate the DSDT dynamically from >> Qemu, but IMHO that's the sanest way to make things flexible. We could >> probably even extract most information from the Qdev tree. >> > > Generating the DSDT dynamically is hard, but the DSDT itself is dynamic. You > can make any function talk to the firmware configuration interface and return > results that depend on the information there.
Does that hold true for nodes as well? I thought you can only use 'functions' for specific elements? Alex
