Re: [PATCH] test/py: efi_capsule: Handle expected reset after capsule on disk

[Simon Glass <sjg@chromium.org>]

Hi Masami,

On Wed, 16 Mar 2022 at 00:09, Masami Hiramatsu
<masami.hiramatsu@linaro.org> wrote:
>
> Hi Simon,
>
> 2022年3月16日(水) 12:13 Simon Glass <sjg@chromium.org>:
> >
> > Hi Masami,
> >
> > On Tue, 15 Mar 2022 at 02:36, Masami Hiramatsu
> > <masami.hiramatsu@linaro.org> wrote:
> > >
> > > Hi Simon,
> > >
> > > 2022年3月15日(火) 14:04 Simon Glass <sjg@chromium.org>:
> > > >
> > > > Hi Masami,
> > > >
> > > > On Mon, 14 Mar 2022 at 18:40, Masami Hiramatsu
> > > > <masami.hiramatsu@linaro.org> wrote:
> > > > >
> > > > > Hi Simon,
> > > > >
> > > > > 2022年3月15日(火) 3:24 Simon Glass <sjg@chromium.org>:
> > > > > >
> > > > > > > > OK, well 'reset by a user' presumably starts the board up and then
> > > > > > > > runs some code to do the update in U-Boot? Is that right? If so, we
> > > > > > > > just need to trigger that update from the test. We don't need to test
> > > > > > > > the actual reset, at least not with sandbox. As I said, we need to
> > > > > > > > write the code so that it is easy to test.
> > > > > > >
> > > > > > > Actually, we already have that command, "efidebug capsule disk-update"
> > > > > > > which kicks the capsule update code even without the 'reset by a
> > > > > > > user'. So we can just kick this command for checking whether the
> > > > > > > U-Boot UEFI code correctly find the capsule file from ESP which
> > > > > > > specified by UEFI vars.
> > > > > > >
> > > > > > > However, the 'capsule update on-disk' feature is also expected (and
> > > > > > > defined in the spec?) to run when the UEFI subsystem is initialized.
> > > > > > > This behavior will not be tested if we skip the 'reset by a user'. I
> > > > > > > guess Takahiro's current test case tries to check it.
> > > > > >
> > > > > > The 'UEFI subsystem is intialised' is a problem, actually, since if it
> > > > > > were better integrated into driver model, it would not have separate
> > > > > > structures or they would be present and enabled when driver model is.
> > > > > > I hope that it can be fixed and Takahiro's series is a start in that
> > > > > > direction.
> > > > >
> > > > > OK.
> > > > >
> > > > > > But as to a test that an update is called when UEFI starts, that seems
> > > > > > like a single line of code. Sure it is nice to test it, but it is much
> > > > > > more important to test the installation of the update and the
> > > > > > execution of the update. I suppose another way to test that is  to
> > > > > > shut down the UEFI subsystem and start it up?
> > > > >
> > > > > Yes, currently we call do_reset() after install the capsule file.
> > > > > (This reset can be avoided if we replace it with
> > > > > sysreset_walk_halt(SYSRESET_COLD) as you said, right?)
> > > > >
> > > > > Here is how I tested it on my machine;
> > > > >
> > > > > > usb start
> > > > > > fatload usb 0 $kernel_addr_r test.cap
> > > > > > fatwrite mmc 0 $fileaddr EFI/UpdateCapsule/test.cap $filesize
> > > > > > efidebug capsule disk-update
> > > > > (run install process and reboot the machine)
> > > > >
> > > > > So, if we can avoid the last reset, we can test the below without
> > > > > reset on sandbox (depends on scenarios).
> > > > > - confirm that the capsule update on disk can find the capsule file
> > > > > from ESP specified by the BOOTXXXX EFI variable.
> > > > > - confirm that the capsule update on disk writes the firmware
> > > > > correctly to the storage which specified by DFU.
> > > > > - confirm that the capsule update on disk success if the capsule image
> > > > > type is supported.
> > > > > - confirm that the capsule update on disk fails if the capsule image
> > > > > type is not supported.
> > > > > - confirm that the capsule update on disk will reboot after update
> > > > > even if the update is failed.
> > > > >
> > > > > The only spec we can not test is
> > > > > - confirm that the capsule update on disk is kicked when the UEFI is
> > > > > initialized.
> > > >
> > > > Even that could be tested, by installing an update and then initing UEFI?
> > >
> > > yeah, if the UEFI is not initialized yet, we can run some UEFI related
> > > command (e.g. printenv -e) instead of efidebug capsule... to execute
> > > the capsule update on disk.
> > > But anyway, this is only available at the first time. We need a way to
> > > reset UEFI subsystem without system reset.
> >
> > Yes. It is certainly possible, but I'm not sure how easy it is.
> > Perhaps just drop all the EFI data structures and run the EFI init
> > again? We have something similar with driver model. See
> > dm_test_pre_run()
>
> EFI has the ExitBootServices call, but I'm not sure it is actually
> clear all resources. Maybe we need to check what resources are
> released by the ExitBootServices.
>
> > > > > >
> > > > > > Anyway we should design subsystems so they are easy to test.
> > > > >
> > > > > Here I guess you mean the unit test, not system test, am I correct?
> > > >
> > > > Yes. Easy testing is so important for developer productivity and
> > > > happiness. It is fine to have large system/functional tests as a fall
> > > > back or catch-all, but they tend to test the happy path only. When
> > > > they fail, they are hard to debug because they cover such as large
> > > > area of the code and they often have complex setup requirements so are
> > > > hard to run manually.
> > > >
> > > > My hope is that all the functionality should be covered by unit tests
> > > > or integration tests, so that system/functional almost never fail.
> > >
> > > My another question is how small is the granularity of the unit test.
> > > As I showed, the UEFI capsule update needs to prepare a capsule file
> > > installed in the storage.
> > > That seems to be very system-level. But you think that is still be a unit test?
> > > (I expected that the 'Unit test' is something like KUnit in Linux)
> >
> > Well I am using your terminology here. Technically many of the U-Boot
> > tests (executed by 'ut' command) are not really unit tests. They bring
> > in a lot of code and run one test case using it.
>
> OK.
>
> >
> > For example, one of the tests brings up the USB subsystem, including a
> > fake USB stick, then checks it can read data from the stick, using the
> > USB stack.
>
> So the fake USB stick data is generated in the build process?
> If so, we also can build a fake ESP master image which already
> includes a capsule file.
>
> > Another one writes some things to the emulated display and then checks
> > that the correct pixels are there.
> >
> > Perhaps a better name would be integration test. But the point is that
> > we can run these tests very, very quickly and (setup aside) without
> > outside influence, or without restarting the executable, etc.
>
> OK.
> BTW, as you said above, when we run such integration test for EFI
> which includes to run sysreset, before that sandbox will switch the
> sysreset driver for resetting EFI to avoid restarting it?

Yes. The UEFI update seems quite monolithic from what I am hearing.
Could it be split into a few separate U-Boot commands, liike:

- efi update prepare  (set up the update somewhere)
- efi update exec (do the update)

Regards,
SImon