Re: [PATCH 2/2] efi: Stop using StdErr

[Jan Beulich <jbeulich@xxxxxxxx>]

On 05.08.2025 18:32, Ross Lagerwall wrote:
> Xen's use of StdErr is inconsistent. Some boot errors are reported using
> PrintErr() which uses StdErr and some are reported using blexit() which
> uses StdOut.

... with PrintErrMesg() having

    StdOut = StdErr;

apparently to address at least some of the inconsistencies. Perhaps
blexit(), when not passed NULL, should similarly override StdOut.

> On my test system using OVMF, StdErr is not displayed on the emulated
> screen. Looking at other EFI applications, StdErr is just used for debug
> messages if at all.

That's hardly how StdErr was meant to be used. And at the risk of being
flamed for saying so, looking at other EFI applications (without saying
of what prominence or origin they are) can hardly serve as a justification.
If OVMF doesn't set up StdErr correctly (despite being configured / set up
correctly), and if that can't be fixed there, imo what you want as a
workaround is a command line option to override StdErr by StdOut even when
SystemTable->StdErr is non-NULL.

Along the lines of the comment further up, inconsistencies in the use of
StdErr vs StdOut may want addressing (separately).

But of course, not being EFI maintainer anymore, all of what I said above
may be deemed entirely meaningless by the new maintainers.

Jan