Re: optee-based efi runtime variable service on TI j784s4 platforms

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On Mon, 11 Nov 2024 at 10:21, Enric Balletbo i Serra
<eballetb@xxxxxxxxxx> wrote:
>
> Hi Ilias,
>
> On Sat, Nov 9, 2024 at 1:31 AM Ilias Apalodimas
> <ilias.apalodimas@xxxxxxxxxx> wrote:
> >
> > On Fri, 8 Nov 2024 at 23:11, Enric Balletbo i Serra <eballetb@xxxxxxxxxx> wrote:
> > >
> > > Hi Ilias,
> > >
> > > Thanks for your quick answer.
> > >
> > > On Fri, Nov 8, 2024 at 4:48 PM Ilias Apalodimas
> > > <ilias.apalodimas@xxxxxxxxxx> wrote:
> > > >
> > > > Hi Enric,
> > > >
> > > > On Fri, 8 Nov 2024 at 12:26, Enric Balletbo i Serra <eballetb@xxxxxxxxxx> wrote:
> > > > >
> > > > > Hi all,
> > > > >
> > > > > I'm looking for any advice/clue to help me to progress on enabling
> > > > > TEE-base EFI Runtime Variable Service on TI a j784s4 platforms.
> > > > >
> > > > > I basically followed the steps described in u-boot documentation [1],
> > > > > I enabled some debugging messages but I think I'm at the point that
> > > > > the problem might be in the StandaloneMM application, and I'm not sure
> > > > > how to debug it.
> > > > >
> > > > > What I see is that when I run the tee-supplicant daemon, it looks like
> > > > > the tee_client_open_session() call loops forever and the tee_stmm_efi
> > > > > driver never ends to probe.
> > > > >
> > > > > With debug enabled I got the following messages.
> > > >
> > > > I assume reading and storing variables already works in U-Boot right?
> > > >
> > >
> > > Reading and storing variables to the RPMB partition in U-Boot works,
> > > that's using the mmc rpmb command from u-boot,
> >
> > Are you talking about env variables? Perhaps you store them in the mmc
> > and not the RPMB partition?
> > There's some information here [0]
> >
> > > But setting
> > > CONFIG_EFI_MM_COMM_TEE=y in u-boot I end with a similar behaviour
> > > (although I'm not able to debug at u-boot level) What I see is that
> > > u-boot gets stuck
> > > when bootefi bootmgr is invoqued. I can also reproduce the issue with
> > > bootefi hello.
> > >
> > > => run bootcmd
> > >   Scanning for bootflows in all bootdevs
> > >   Seq  Method       State   Uclass    Part  Name                      Filename
> > >   ---  -----------  ------  --------  ----  ------------------------
> > > ----------------
> > >   Scanning global bootmeth 'efi_mgr':
> > > ( gets stuck here)
> > >
> > > or
> > >
> > > => bootefi hello
> > > (gets stuck)
> > >
> > > To debug I disabled CONFIG_EFI_MM_COMM_TEE to not get stuck and bypass
> > > the error and go to Linux. My understanding is that
> > > CONFIG_EFI_MM_COMM_TEE is only required to read/write efi variables at
> > > u-boot level but OPTEE is running the StandaloneMM service. Am I
> > > right?
> >
> > U-Boot has two ways of storing EFI variables [0] . You can either
> > store them in a file or the RPMB partition. The correct thing to do,
> > since you want to use the RPMB, is enable CONFIG_EFI_MM_COMM_TEE. I am
> > not sure why the hand happens, but one thing we can improve is figure
> > out why it hangs and print a useful message.
> > There are a number of reasons that might lead to a failure. Is the
> > RPMB key programmed on your board? Have a look at this [1] in case it
> > helps
> >
> > >
> > > > >
> > > > > # tee-supplicant
> > > > > D/TC:? 0 tee_ta_init_session_with_context:557 Re-open trusted service
> > > > > 7011a688-ddde-4053-a5a9-7b3c4ddf13b8
> > > > > D/TC:? 0 load_stmm:297 stmm load address 0x40004000
> > > > > D/TC:? 0 spm_handle_scall:859 Received FFA version
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> > > > > D/TC:? 0 spm_handle_scall:867 Received FFA direct request
> >
> > If I had to guess, OP-TEE doesn't store the variables in the RPMB, can
> > you compile it with a bit more debugging enabled?
> >
>
> Here is a log with CFG_TEE_CORE_LOG_LEVEL=4, CFG_TEE_CORE_DEBUG=y and
> CFG_TEE_TA_LOG_LEVEL=4
>
> https://paste.centos.org/view/eed83a5b
>
> At the beginning of the log I see
>
> D/TC:0 0 check_ta_store:449 TA store: "REE"
>
> Which looks wrong to me as I built optee with:
>   CFG_REE_FS=n
>   CFG_RPMB_FS_DEV_ID=0
>   CFG_RPMB_FS=y

Yes it does look wrong. Our compilation flags are
CFG_RPMB_FS=y CFG_RPMB_FS_DEV_ID=0 CFG_RPMB_WRITE_KEY=y
CFG_RPMB_TESTKEY=y CFG_REE_FS=n CFG_CORE_ARM64_PA_BITS=48
CFG_SCTLR_ALIGNMENT_CHECK=n

The testkey etc aren't required if your board has a way of reading the
RPMB key from a secure location -- in fact, using the testkey is not
secure. Is the RPMB programmed on your board? Also can you make sure
CFG_RPMB_FS_DEV_ID needs to be 0? How many sd interfaces your board
has?
IOW in U-Boot does 'mmc dev 0 && mmc info' print information for the
RPMB partition?

Thanks
/Ilias
>
> I'll try to add some more prints to verify if REE is used as a store
> system, I assume this should say something about RPMB. Am I right with
> this?


>
> > > > >
> > > > > And tracing the function calls gives me that:
> > > > >
> > > > >       tee_stmm_efi_probe() {
> > > > >              tee_client_open_context() {
> > > > >                optee_get_version() {
> > > > >                  tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                } (ret=0xd)
> > > > >                tee_ctx_match(); (ret=0x1)
> > > > >                optee_smc_open() {
> > > > >                  tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                  optee_open() {
> > > > >                    tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                  } (ret=0x0)
> > > > >                } (ret=0x0)
> > > > >              } (ret=0xffff000004e71c80)
> > > > >              tee_client_open_session() {
> > > > >                optee_open_session() {
> > > > >                  tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                  optee_get_msg_arg() {
> > > > >                    tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                    tee_shm_get_va(); (ret=0xffff000002909000)
> > > > >                  } (ret=0xffff000002909000)
> > > > >                  tee_session_calc_client_uuid(); (ret=0x0)
> > > > >                  optee_to_msg_param(); (ret=0x0)
> > > > >                  optee_smc_do_call_with_arg() {
> > > > >                    tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                    tee_shm_get_va(); (ret=0xffff000002909000)
> > > > >                    tee_shm_get_va(); (ret=0xffff000002909060)
> > > > >                    optee_cq_wait_init(); (ret=0xffff000002e55910)
> > > > >                    optee_smccc_smc(); (ret=0xffff0004)
> > > > >                    tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                    optee_smccc_smc(); (ret=0xffff0004)
> > > > >                    tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                    optee_smccc_smc(); (ret=0xffff0004)
> > > > >                    tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                    optee_smccc_smc(); (ret=0xffff0004)
> > > > >                    tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                    optee_smccc_smc(); (ret=0xffff0004)
> > > > >      ... continues sending this forever ...
> > > > >      ... Hit ^C to stop recording ...
> > > > >                    tee_get_drvdata(); (ret=0xffff000002e55800)
> > > > >                    optee_smccc_smc() {
> > > > >
> > > > > [1] https://docs.u-boot.org/en/latest/develop/uefi/uefi.html#using-op-tee-for-efi-variables
> > > > >
> > > > > Thanks in advance,
> > > >
> > > > The most common problem with this is miscompiling the tee_supplicant
> > > > application.
> > > > Since we don't know if the system has an RPMB, we emulate it in the
> > > > tee_supplicant. How did you get the supplicant and can you check if it
> > > > was compiled with RPMB_EMU=0 or 1?
> > > >
> > >
> > > I'm using the tee-supplicant provided by the fedora package which is
> > > built with ` -DRPMB_EMU=0`, I think that's correct, right?
> > >
> >
> > Yes, this is correct. We fixed the Fedora package to compile the
> > supplicant correctly a while back.
> >
> > [0] https://www.linaro.org/blog/uefi-secureboot-in-u-boot/
> > [1] https://apalos.github.io/Protected%20UEFI%20variables%20with%20U-Boot.html#Protected%20UEFI%20variables%20with%20U-Boot
> >
> >
> > Regards
> > /Ilias
> > > Thanks,
> > >    Enric
> > >
> > > > Thanks
> > > > /Ilias
> > > >
> > > > >    Enric
> > > > >
> > > >
> > >
> >
>





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