[PATCH v2 2/4] bootflow: bootmeth_efi: Don't set bootdev again

[Shantur Rathore]

Hi Simon,

On Sat, Nov 18, 2023 at 5:11 PM Simon Glass <sjg at chromium.org> wrote:
>
> +Ilias too as this involves a design decision
>
> Hi Shantur,
>
> On Fri, 17 Nov 2023 at 14:22, Shantur Rathore <i at shantur.com> wrote:
> >
> > efi_set_bootdev is already called as part of tftp while doing dhcp_run()
>
> Is that in tftp_complete() ?
>
> > Doing this again crashes U-boot and we don't need to call again.
>
> U-Boot
>
> The problem is that we might scan for 4 bootflows, then later decide
> which one to boot. So we cannot know which one it will be until that
> point.
>
> The hack is needed so that it actually tells EFI about the right one.
>
> The addition of EFI hacks when reading files (i.e. the code in
> tftp_complete()) is a real problem, unfortunately. I understand that
> it was a convenient hack, but with standard boot we really don't want
> it to do that. We end up calling it multiple times for bootflows that
> won't be used.
>
> So I believe the fix is to be able to disable those calls, leaving it
> to bootstd.
>
> I'm not sure of the best way to do that. Perhaps we should have a
> function like bootstd_scanning() which returns a bool indicating that
> bootstd is scanning? If that is true then no efi_set_bootdev() calls
> are made? We could have a flag in 'struct bootstd_priv' which is set
> before bootflow_check() is called and cleared afterwards.
>
> As to how this should be done with standard boot, we should create a
> function like efi_start_app() and pass it the information we need.
> That function should do the equivalent of the 'bootefi' command,
> except programmatically, with no prior state hanging around.
>
> As to when we might be able to do that, we need more refactoring of
> the bootm code. There is a start on this [1] but it likely needs 2-3
> more series before it might be possible.
>
> So for now, I think bootstd_scanning() is the best approach. If you
> are not sure about that, I can send a patch.
>

My apologies, the fix I submitted is incorrect.
After reading your explanation, I started thinking on why dhcp can
call this multiple times but bootmethod can't.

There it was clear that the issue bflow->fname is null when we call
this function.
The correct fix should be below

+       /* bootfile should be setup by dhcp by now*/
+       bootfile_name = env_get("bootfile");
+       if (!bootfile_name)
+               return log_msg_ret("bootfile_name", ret);
+       bflow->fname = strdup(bootfile_name);
+
    /* do the hideous EFI hack */
    efi_set_bootdev("Net", "", bflow->fname, map_sysmem(addr, 0),
                    bflow->size);

I have a patch ready for this which I will send but I have some
queries regarding that.
As I sent this a series of patches out of which 2 were reviewed,
should I send a new version for the whole series even though 2 are not
going to be changed?
Another thing, should I send them as a reply to the original email or
a new thread?

Kind regards,
Shantur