On 01/21/2015 10:23 AM, Catalin Marinas wrote: > I have some questions for the ACPI and EFI folk: > > 1. When booting with ACPI, are the EFI run-time services required for > anything? If yes, Xen may have a bigger problem Yes. At least for some things. For example, installing an Operating System would require that you make runtime services calls to set the BootOrder/BootNext variables, and so on. Further, we use the GetTime service and EFI based reboot to avoid having special drivers. I had those added to SBBR as requirements for that reason. > 2. Could a boot loader (either kernel doing kexec or Xen) emulate the > EFI system/config tables and still make them useful to the kernel but > without EFI_BOOT or EFI_RUNTIME_SERVICES? Yes. But again, without the other required pieces (including the services function pointers in the systab which are required) you'd crash soon after boot trying to make those calls. We saw this with e.g. RTC in early firmwares. One of the reasons we've been hitting every service and establishing a reliance upon them immediately is to allow third party EFI vendors to notice when they've got any firmware bugs. Jon. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
