Re: [PATCH v6 0/5] target/riscv: Add Smrnmi support.

["Clément Léger" <cleger@rivosinc.com>]

On 11/10/2024 13:38, Daniel Henrique Barboza wrote:
> Hi Tommy,
> 
> 
> Do you plan to send a new version of this work soon? This series is a
> prerequisite
> of "target/riscv: Add support for Smdbltrp and Ssdbltrp extensions" and
> we need
> this series merged first. We have minor comments from Clément and

Hi Henrique,

If that's easier, I can still remove the dependency on Smrnmi and add
support for that later.

Clément

> Alistair so
> hopefully it shouldn't be too much work.
> 
> The code freeze for 9.2 will happen in the first/second week of
> November, so if you
> could send a new version to be merged in the next PR that would be great.
> 
> 
> Thanks,
> 
> Daniel
> 
> 
> 
> On 9/2/24 4:13 AM, Tommy Wu wrote:
>> This patchset added support for Smrnmi Extension in RISC-V.
>>
>> There are four new CSRs and one new instruction added to allow NMI to be
>> resumable in RISC-V, which are:
>>
>> =============================================================
>>    * mnscratch (0x740)
>>    * mnepc     (0x741)
>>    * mncause   (0x742)
>>    * mnstatus  (0x744)
>> =============================================================
>>    * mnret: To return from RNMI interrupt/exception handler.
>> =============================================================
>>
>> RNMI also has higher priority than any other interrupts or exceptions
>> and cannot be disabled by software.
>>
>> RNMI may be used to route to other devices such as Bus Error Unit or
>> Watchdog Timer in the future.
>>
>> The interrupt/exception trap handler addresses of RNMI are
>> implementation defined.
>>
>> If anyone wants to test the patches, we can use the customized
>> OpenSBI[1],
>> and the customized QEMU[2].
>>
>> We implemented a PoC RNMI trap handler in the customized OpenSBI.
>> In the customized QEMU, we use the Smrnmi patches and the patch from
>> Damien Hedde[3]. The patch from Damien Hedde can be used to inject
>> the RNMI signal with the qmp command.
>>
>> [1] https://github.com/TommyWu-fdgkhdkgh/opensbi/tree/dev/twu/master
>> [2] https://github.com/TommyWu-fdgkhdkgh/qemu/tree/dev/twu/master
>> [3] https://lists.gnu.org/archive/html/qemu-devel/2019-06/msg06232.html
>>
>> Test commands :
>> $ ./build/qemu-system-riscv64 -M virt -cpu rv64,smrnmi=true,
>> rnmi-interrupt-vector={Offset of the RNMI handler in the customized
>> OpenSBI.} -m 4G -smp 2 -serial mon:stdio -serial null -nographic
>> -bios fw_jump.elf -kernel Image -initrd rootfs.cpio
>> -qmp unix:/tmp/qmp-sock,server,wait=off
>>
>> Use qmp command to inject the RNMI interrupt.
>> $ ./scripts/qmp/qmp-shell /tmp/qmp-sock
>> (QEMU)  gpio-set path=/machine/soc0/harts[0] gpio=riscv.cpu.rnmi
>> number=0 value=true
>>
>> (QEMU)  gpio-set path=/machine/soc0/harts[0] gpio=riscv.cpu.rnmi
>> number=0 value=false
>>
>> Changelog:
>>
>> v6
>>    * Delete the redundant code in `riscv_cpu_do_interrupt`.
>>    ( Thank Alvin for the suggestion. )
>>    * Split the shared code in `helper_mret` and `helper_mnret` into a
>>      helper function `check_ret_from_m_mode`.
>>    ( Thank Alistair for the suggestion. )
>>
>> v5
>>    * Move the patch that adds the Smrnmi extension to the last patch.
>>    ( Thank Alistair for the suggestion. )
>>    * Implement an M-mode software PoC for this with implemented handlers.
>>    ( Thank Andrew Jones for the suggestion. )
>>    * Add a commit message to all patches of the series.
>>    ( Thank Andrew Jones for the suggestion. )
>>
>> v4
>>    * Fix some coding style issues.
>>    ( Thank Daniel for the suggestions. )
>>
>> v3
>>    * Update to the newest version of Smrnmi extension specification.
>>
>> v2
>>    * split up the series into more commits for convenience of review.
>>    * add missing rnmi_irqvec and rnmi_excpvec properties to riscv_harts.
>>
>> Tommy Wu (5):
>>    target/riscv: Add `ext_smrnmi` in the RISCVCPUConfig.
>>    target/riscv: Handle Smrnmi interrupt and exception.
>>    target/riscv: Add Smrnmi CSRs.
>>    target/riscv: Add Smrnmi mnret instruction.
>>    target/riscv: Add Smrnmi cpu extension.
>>
>>   hw/riscv/riscv_hart.c                         | 18 ++++
>>   include/hw/riscv/riscv_hart.h                 |  4 +
>>   target/riscv/cpu.c                            | 18 ++++
>>   target/riscv/cpu.h                            | 10 +++
>>   target/riscv/cpu_bits.h                       | 23 ++++++
>>   target/riscv/cpu_cfg.h                        |  1 +
>>   target/riscv/cpu_helper.c                     | 80 ++++++++++++++++--
>>   target/riscv/csr.c                            | 82 +++++++++++++++++++
>>   target/riscv/helper.h                         |  1 +
>>   target/riscv/insn32.decode                    |  3 +
>>   .../riscv/insn_trans/trans_privileged.c.inc   | 12 +++
>>   target/riscv/op_helper.c                      | 49 +++++++++--
>>   12 files changed, 291 insertions(+), 10 deletions(-)
>>