On Tue, Sep 29, 2015 at 6:03 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 09/27/2015 12:06 AM, Ingo Molnar wrote: >> >> * Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: >> >>>> If we allocate the EFI runtime as a single virtual memory block then issues >>>> like rounding between sections does not even come up as a problem: we map the >>>> original offsets and sizes byte by byte. >>> >>> Well, by that reasoning, we should not call SetVirtualAddressMap() in the first >>> place, and just use the 1:1 mapping UEFI uses natively. This is more than >>> feasible on arm64, and I actually fought hard against using >>> SetVirtualAddressMap() at all, but I was overruled by others. I think this is >>> also trivially possible on X64, since the 1:1 mapping is already active >>> alongside the VA mapping. >> >> Could we please re-list all the arguments pro and contra of 1:1 physical mappings, >> in a post that also explains the background so that more people can chime in, not >> just people versed in EFI internals? It's very much possible that a bad decision >> was made. >> > > Pro: by far the sanest way to map the UEFI tables. > Con: doesn't actually work (breaks on several known platforms.) Can we at least do 1:1 without an offset on arm64? Given that Linux seems to be more of a reference on arm64 than Windows is, maybe that would give everyone something vaguely sane to work with. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
