On Tue, 16 Jun 2026 at 14:06, Ludwig Nussel <[email protected]> wrote: > > On 6/16/26 12:32, Ilias Apalodimas wrote: > > On Tue, 16 Jun 2026 at 12:39, Ludwig Nussel <[email protected]> > > wrote: > >> > >> On 6/15/26 15:25, Ilias Apalodimas wrote: > >>> On Mon, 15 Jun 2026 at 16:09, Ilias Apalodimas > >>> <[email protected]> wrote: > >>>> > >>>> Hi Ludwig, > >>>> > >>>> [...] > >>>> > >>>>>>>> > >>>>>>>> I'd like the eventlog to be initialized before calling this (look > >>>>>>>> below). > >>>>>>> > >>>>>>> What if I removed the log parameter from those tcg2_* functions > >>>>>>> instead? > >>>>>>> The event log belongs to the tpm device IMO, so should be initialized > >>>>>>> with the device. > >>>>>> > >>>>>> Measured boot EventLogs etc are primarily described by the TCG specs & > >>>>>> EFI and we only have a specification for it there. The DT describes on > >>>>>> how to pass it over to linux with sml-base etc. > >>>>>> However, in the EFI case the Eventlog is allocated as ACPI memory. So > >>>>>> you cannot allocate the EventLog a priori, until you figure out what > >>>>>> method you are using to boot. We also have use cases people using it > >>>>>> only for RNG, due to limited memory, so we can't just allocate it on > >>>>>> the device bringup. And lastly... Some first stage bootloaders do not > >>>>>> initialize the TPM & drivers. What they do is prepare an EventLog and > >>>>>> expect U-Boot to replay it once the TPM is up and running. In that > >>>>>> case we obviously need to preserve what we have instead of starting > >>>>>> from scratch. > >>>>> > >>>>> Ack, we are on the same page here. > >>>>> > >>>>>> My main concern is that I *don't* want the EFI and non-EFI code to > >>>>>> deviate. I have some patches that I am playing around for quite some > >>>>>> time and rebased them last week for this reason [1]. If you think > >>>>>> those help your use case or make your life easier feel free to include > >>>>>> them. > >>>>> > >>>>> Good idea and orthogonal to what I am doing I think. This duplication in > >>>>> EFI stressed my brain too but I can't care about EFI right now :-) > >>>> > >>>> It is, but the deviation in EFI is pretty minimal atm. > >>>> - EFI calls tcg2_log_prepare_buffer instead of tcg2_measurement_init() > >>>> -- That's what my patches fix > >>>> - EFI has it's own version of tcg2_measure_event() -- That's easy to > >>>> fix as well,. > >>>> > >>>>> > >>>>> IIUC you are centering the change around calling > >>>>> tcg2_log_prepare_buffer() in efi_init_event_log(). What do you think > >>>>> about aiming for tcg2_measurement_init() as central starting point > >>>>> instead? > >>>>> That would allow to remove even more duplicated code. > >>>>> It should be sufficient to have tcg2_measurement_init() accept an > >>>>> optional pointer to pre-allocated log buffer memory. Attached patch > >>>>> maybe explains the idea better (just as idea, won't compile). > >>>> > >>>> I agree. In fact I mistyped the functions names on my previous > >>>> email.... I really meant tcg2_measurement_init(). The patchset I > >>>> pointed you to already converts tcg2_log_prepare_buffer() to static. > >>> > >>> Replying to myself here, but.. In order to do that you do need the > >>> unification patches. tcg2_measurement_init() will need to allocate the > >>> appropriate buffer depending on EFI or not. > >> > >> So this is how it would look like with your patches on top: > >> [...] > >> > >> IMO the untangle patch is not needed. Does that look sensible? > > > > You can skip the untangle patch the way you've changed efi_tcg2.c, that's > > fine. > > > > However, there's a few issues I tested for > > - A u32 err; that's not needed in EFI anymore > > - tcg2_measurement_init() calls tcg2_log_prepare_buffer, with NULL. I > > suspect you meant to call with elog, since the EFI booting is now > > broken and the kernel complains about an incomplete EventLog > > Oops. Yes, that was a mistake. > > > [...] But > > since we've gone through that effort, wouldn't it make more sense to > > have tcg2_measurement_init() set the priv->log if the pointer is valid > > and provided? > > Yes, the series paves the way for further refactoring :-) The efi path > shouldn't have the 'static struct tcg2_event_log event_log' anymore IMO. > Should be sufficient to hand the allocated buffer to > tcg2_measurement_init() and access the log structure in functions that > need it though 'dev'.
Exactly. > Refactoring (and testing) the EFI path is out of > scope for me at the moment though. Fair enough, I've sidetracked you enough already. > > Anyway, do you want me to submit your two patches as part of the series > or you want to follow up yourself? Carry them over imho, they were rotting in my branches for 1+ years, but I never had the chance to send them. Your patches were a good reason to rebase and revive them and they fit right in as can only rely on tcg2_measurement_init now. I'll test/check the v4. I haven't gone through your changes in depth but they seemed reasonable, so I think this is fairly close on getting in Thanks for the patience /Ilias > > cu > Ludwig > > -- > Ludwig Nussel > Siemens AG > www.siemens.com
