Re: fwupd support under Xen - firmware updates with the UEFI capsule

[Jan Beulich <jbeulich@xxxxxxxx>]

On 28.07.2020 09:41, Norbert Kaminski wrote:
> I'm trying to add support for the firmware updates with the UEFI capsule in
> Qubes OS. I've got the troubles with reading ESRT (EFI System Resource Table)
> in the dom0, which is based on the EFI memory map. The EFI_MEMMAP is not
> enabled despite the loaded drivers (CONFIG_EFI, CONFIG_EFI_ESRT) and kernel
> cmdline parameters (add_efi_memmap):
>
> ```
> [    3.451249] efi: EFI_MEMMAP is not enabled.
> ```
It is, according to my understanding, a layering violation to expose
the EFI memory map to Dom0. It's not supposed to make use of this
information in any way. Hence any functionality depending on its use
also needs to be implemented in the hypervisor, with Dom0 making a
suitable hypercall to access this functionality. (And I find it
quite natural to expect that Xen gets involved in an update of the
firmware of a system.)

Jan