On 27.08.2025 19:47, Andrew Cooper wrote: > On 22/08/2025 2:47 pm, Teddy Astie wrote: >> Currently, hvmloader uses SMBIOS 2.4, however, when using OVMF, the >> SMBIOS is patched to 2.8, which has clarified the UUID format (as GUID). >> >> In Linux, if the SMBIOS version is >= 2.6, the GUID format is used, else >> (undefined as per SMBIOS spec), big endian is used (used by Xen). Therefore, >> you have a endian mismatch causing the UUIDs to mismatch in the guest. >> >> $ cat /sys/hypervisor/uuid >> e865e63f-3d30-4f0b-83e0-8fdfc1e30eb7 >> $ cat /sys/devices/virtual/dmi/id/product_uuid >> 3fe665e8-303d-0b4f-83e0-8fdfc1e30eb7 >> $ cat /sys/devices/virtual/dmi/id/product_serial >> e865e63f-3d30-4f0b-83e0-8fdfc1e30eb7 >> >> This patch updates the SMBIOS version from 2.4 to 2.6 and fixup the UUID >> written in the table; which effectively fix this endianness mismatch with >> OVMF; while the UUID displayed by Linux is still the same for SeaBIOS. >> >> Signed-off-by: Teddy Astie <teddy.as...@vates.tech> >> --- >> This effectively changes the UUID seen with UEFI guests as it was >> actually inconsistent with SeaBIOS and SMBIOS expectations. >> --- > > I agree this is a real bug and needs fixing.
Hmm, I didn't realize this is a bug, and hence put the patch off as 4.22 material. If there is a bug being fixed: Teddy, please add a Fixes: tag. Jan
