Re: [edk2-devel] [PATCH v2 2/2] ArmVirtPkg/ArmVirtQemu: Avoid early ID map on ThunderX

["Ard Biesheuvel" <ardb@kernel.org>]

On Tue, 7 Feb 2023 at 13:58, Oliver Steffen <osteffen@redhat.com> wrote:
>
> On Tue, Feb 7, 2023 at 12:57 PM Ard Biesheuvel <ardb@kernel.org> wrote:
>>
>> On Tue, 7 Feb 2023 at 11:51, Oliver Steffen <osteffen@redhat.com> wrote:
>> >
>> > On Thu, Feb 2, 2023 at 12:09 PM Oliver Steffen <osteffen@redhat.com> wrote:
>> >>
>> >>
>> >> On Wed, Feb 1, 2023 at 2:29 PM Ard Biesheuvel <ardb@kernel.org> wrote:
>> >>>
>> >>> On Wed, 1 Feb 2023 at 13:59, Oliver Steffen <osteffen@redhat.com> wrote:
>> >>> >
>> >>> > On Wed, Feb 1, 2023 at 12:52 PM Ard Biesheuvel <ardb@kernel.org> wrote:
>> >>> >>
>> >>> >> On Wed, 1 Feb 2023 at 10:14, Oliver Steffen <osteffen@redhat.com> wrote:
>> >>> >> >
>> >>
>> >> [...]
>> >>>
>> >>> >> > I am sorry, this story does not seem to be over yet.
>> >>> >> >
>> >>> >> > We are using the Erratum patch and also included the commit 406504c7 in
>> >>> >> > the kernel.
>> >>> >> > Now the firmware crashes sometimes (10 out of 89 tests).
>> >>> >> >
>> >>> >>
>> >>> >> Thanks for the report. Is this still on ThunderX2?
>> >>> >>
>> >>> >> > Any hints are very welcome!
>> >>> >> >
>> >>> >>
>> >>> >> Do  you have access to those build artifacts?
>> >>> >
>> >>> >
>> >>> > https://kojihub.stream.centos.org/kojifiles/work/tasks/5251/1835251/edk2-aarch64-20221207gitfff6d81270b5-4.el9.test.noarch.rpm
>> >>> >
>> >>> > and/or here:
>> >>> >
>> >>> > https://kojihub.stream.centos.org/koji/taskinfo?taskID=1835251
>> >>> >
>> >>> > Source for reference:
>> >>> > https://gitlab.com/redhat/centos-stream/src/edk2/-/merge_requests/24
>> >>> >
>> >>>
>> >>> Any chance the .dll files (which are actually ELF executables) have
>> >>> been preserved somewhere?
>> >>
>> >> Here is the build folder (~90MB):
>> >> https://gitlab.com/osteffen/thunderx2-debug/-/raw/main/armvirt-thunderx2-issue.tar.xz
>> >>
>> >> I am waiting for the tests with the additional debug output to run.
>> >
>> >
>> > We reran the test suite with the Erratum and the additional debug
>> > output enabled.  Strangely, the problem does not occur anymore, the
>> > firmware boots up normally.
>> >
>> > We retried the tests without the additional debug output.
>> > RHEL ships two firmware flavors for AARCH64: a silent and a verbose
>> > version.
>>
>> Are these RELEASE vs DEBUG builds?
>
>
> All builds are DEBUG, just the amount of information printed on
> the serial is different (almost zero for the "silent" one.)
>
>>
>> > Both were tried. We see no problems with the verbose
>> > one. The silent one fails noticeably more often if a software TPM device
>> > is present.
>> >
>>
>> This smells like some missing cache or TLB maintenance - the verbose
>> one exits to the host much more often, and likely relies on cache/TLB
>> maintenance occurring in the hypervisor.
>>
>> So the build always includes TPM support but the issue only occurs
>> when the sw TPM is actually exposed by QEMU?
>
>
> Yes.
> All builds include support for TPM, but the issue occurs more frequently
> if a sw TPM is exposed by QEMU.
>

Any chance you could provide a specific command line for launching
QEMU? I am trying to reproduce this, but I am not making any progress.

>>
>> > Could this be related to how much stuff is going on in the early phase
>> > of the firmware (when logging is enabled: formatting of messages and
>> > sending to serial port...) ?
>> >
>>
>> I'll try to see if I can rig something up that logs into a buffer
>> rather than straight to the serial, and dump it all out when handling
>> the crash
>>

This takes a bit more time than I can afford to spend on this atm, and
I'd like to be able to reproduce before I go down this rabbit hole.