[PATCH v3 0/3] Add support for Supervisor Software Events extension

[Clément Léger]

On 06/04/2024 08:10, Anup Patel wrote:
> On Fri, Apr 5, 2024 at 10:28 PM Samuel Holland
> <samuel.holland at sifive.com> wrote:
>>
>> Hi Anup,
>>
>> On 2024-04-05 6:46 AM, Anup Patel wrote:
>>> On Thu, Mar 21, 2024 at 9:27 PM Clément Léger <cleger at rivosinc.com> wrote:
>>>>
>>>> The SBI Supervisor Software Events (SSE) extensions provides a mechanism
>>>> to inject software events from an SBI implementation to supervisor
>>>> software such that it preempts all other supervisor level traps and
>>>> interrupts [1]. This series implements the V3 version of the spec.
>>>>
>>>> Various events are defined and can be send asynchronously to supervisor
>>>> software (RAS, PMU, DEBUG, Asynchronous page fault) from SBI as well
>>>> as platform specific events. Events can be either local (per-hart) or
>>>> global. Events can be nested on top of each other based on priority and
>>>> can interrupt the supervisor mode at any time.
>>>>
>>>> This implementation can be tested using kvm-unit-tests [2] with the
>>>> following commands:
>>>>
>>>> Build kvm-unit-tests:
>>>>
>>>> $ git clone https://github.com/clementleger/kvm-unit-tests.git
>>>> $ cd kvm-unit-tests
>>>> $ git switch dev/cleger/sse
>>>> $ ./configure --arch=riscv64 --cross-prefix=$CROSS_COMPILE
>>>> $ make
>>>>
>>>> Run using Qemu:
>>>>
>>>> $ ./qemu-system-riscv64 \
>>>>         -smp 4 \
>>>>         -M virt \
>>>>         -cpu rv64 \
>>>>         -nographic \
>>>>         -serial mon:stdio \
>>>>         -bios <opensbi>/build/platform/generic/firmware/fw_jump.bin \
>>>>         -kernel <kvm-unit-tests>/riscv/sbi_sse.flat
>>>>
>>>> An implementation of a SSE "client" in linux is available [3].
>>>> This series can be found on github [5].
>>>>
>>>> Link: https://lists.riscv.org/g/tech-prs/message/798 [1]
>>>> Link: https://github.com/clementleger/kvm-unit-tests/tree/dev/cleger/sse [2]
>>>> Link: https://github.com/rivosinc/linux/tree/dev/cleger/sse [3]
>>>> Link: http://lists.infradead.org/pipermail/opensbi/2024-March/006670.html [4]
>>>> Link: https://github.com/rivosinc/opensbi/tree/dev/cleger/sse_v3 [5]
>>>>
>>>> ---
>>>>
>>>> Changes from v3:
>>>>  - Changes to follow v3 SSE specification
>>>>  - Use masks instead of struct with bitfields for status
>>>>  - Rework locking
>>>>  - SSE pending event processing is now done upon returning to previous
>>>>    mode
>>>>
>>>> v2: http://lists.infradead.org/pipermail/opensbi/2024-January/006223.html
>>>>
>>>> Changes from v2:
>>>>  - Move local/global event count initialization out of sse_global_init()
>>>>  - Remove PMU_IRQ_CLEAR SBI call and clear IRQ on SSE event completion
>>>>  - Change SBI_ERR_X to SBI_EXX defines
>>>>  - Add guards for invalid __riscv_xlen values
>>>>  - Update parameters passing (a6, a7)
>>>>
>>>> v1: http://lists.infradead.org/pipermail/opensbi/2023-November/006015.html
>>>>
>>>> Changes from v1:
>>>>  - Implemented SSE Spec v2
>>>>  - Change event state checking (Xiang W)
>>>>
>>>> Clément Léger (3):
>>>>   lib: sbi: Add support for Supervisor Software Events extension
>>>>   lib: sbi: Implement SBI SSE extension
>>>>   lib: sbi: Add SSE support for PMU events
>>>
>>> Reviewed-by: Anup Patel <anup at brainfault.org>
>>>
>>> Applied this series to the riscv/opensbi repo.
>>
>> I don't think this series is ready to apply yet, considering that the extension
>> specification has not even been merged. Or is the master branch not expected to
>> be forward-compatible with the SBI spec?
> 
> Please go ahead and send patches for your recent comments
> on this series. There was no comment on this series for quite
> some time and Himanshu already tested it hence it was merged.
> 
> Regards,
> Anup


Hi

I'll address Samuel comments in some new commits since it was merged. I
was not expecting it to be merged without a bit more reviewing though
but I guess it will allow us to make progress faster on SSE then.

Thanks,

Clément

> 
> 
>>
>> Regards,
>> Samuel
>>
>>> Thanks,
>>> Anup
>>>
>>>>
>>>>  include/sbi/sbi_ecall_interface.h |   79 +-
>>>>  include/sbi/sbi_error.h           |    2 +
>>>>  include/sbi/sbi_pmu.h             |    3 +
>>>>  include/sbi/sbi_sse.h             |   94 +++
>>>>  lib/sbi/Kconfig                   |    4 +
>>>>  lib/sbi/objects.mk                |    4 +
>>>>  lib/sbi/sbi_ecall_sse.c           |   57 ++
>>>>  lib/sbi/sbi_init.c                |   13 +
>>>>  lib/sbi/sbi_pmu.c                 |   51 ++
>>>>  lib/sbi/sbi_sse.c                 | 1131 +++++++++++++++++++++++++++++
>>>>  lib/sbi/sbi_trap.c                |   11 +
>>>>  11 files changed, 1448 insertions(+), 1 deletion(-)
>>>>  create mode 100644 include/sbi/sbi_sse.h
>>>>  create mode 100644 lib/sbi/sbi_ecall_sse.c
>>>>  create mode 100644 lib/sbi/sbi_sse.c
>>>>
>>>> --
>>>> 2.43.0
>>>>
>>>>
>>>> --
>>>> opensbi mailing list
>>>> opensbi at lists.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/opensbi
>>>
>>