On 05.06.2025 14:14, Andrew Cooper wrote: > On 05/06/2025 1:02 pm, Jan Beulich wrote: >> On 05.06.2025 13:16, Andrew Cooper wrote: >>> The format of the buildid is a property of the binary, not a property of how >>> it was loaded. This fixes buildid recognition when starting xen.efi from >>> it's >>> MB2 entrypoint. >>> >>> Suggested-by: Ross Lagerwall <ross.lagerw...@citrix.com> >>> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com> >> I'll pick this up without a Fixes: tag, but I think it ought to have one. (I >> didn't check whether MB2 or build-id support came later, hence introducing >> the >> issue.) > > MB2+EFI came long before any buildid support. If you want a fixes tag, > it's eee5909e9d1
That commit talks of an earlier hack, though. And no, MB2 work came later, albeit still in the 4.9 dev window (commit 9180f53655245). >>> --- a/xen/common/version.c >>> +++ b/xen/common/version.c >>> @@ -203,8 +203,11 @@ void __init xen_build_init(void) >>> rc = xen_build_id_check(n, sz, &build_id_p, &build_id_len); >>> >>> #ifdef CONFIG_X86 >>> - /* Alternatively we may have a CodeView record from an EFI build. */ >>> - if ( rc && efi_enabled(EFI_LOADER) ) >>> + /* >>> + * xen.efi built with a new enough toolchain will have a CodeView >>> record, >>> + * not an ELF note. >>> + */ >>> + if ( rc ) >> Instead of dropping the efi_enabled(), I think you want to replace EFI_LOADER >> by EFI_BOOT. > > No - that's differently buggy. I suppose the commit message wasn't > clear enough? > > We'd still have a CodeView record if we booted xen.efi using it's MB2 > entrypoint without the EFI extensions. Hmm, if that's a possible mode of operation (as said in reply to Marek, I wasn't aware of that) - yes. > This really is a property of being a PE32+ binary, and nothing to do > with EFI. Which still can be checked for without having this code path being taken for xen.gz, too: You could e.g. check for &efi > &_end. That's firmly an image property (yet I expect you're going to sigh about yet another hack). Jan
