[PATCH v12 00/25] Linux RISC-V AIA Support

[Björn Töpel]

Björn Töpel <bjorn at kernel.org> writes:

> Anup Patel <apatel at ventanamicro.com> writes:
>
>> The RISC-V AIA specification is ratified as-per the RISC-V international
>> process. The latest ratified AIA specifcation can be found at:
>> https://github.com/riscv/riscv-aia/releases/download/1.0/riscv-interrupts-1.0.pdf
>>
>> At a high-level, the AIA specification adds three things:
>> 1) AIA CSRs
>>    - Improved local interrupt support
>> 2) Incoming Message Signaled Interrupt Controller (IMSIC)
>>    - Per-HART MSI controller
>>    - Support MSI virtualization
>>    - Support IPI along with virtualization
>> 3) Advanced Platform-Level Interrupt Controller (APLIC)
>>    - Wired interrupt controller
>>    - In MSI-mode, converts wired interrupt into MSIs (i.e. MSI generator)
>>    - In Direct-mode, injects external interrupts directly into HARTs
>>
>> For an overview of the AIA specification, refer the AIA virtualization
>> talk at KVM Forum 2022:
>> https://static.sched.com/hosted_files/kvmforum2022/a1/AIA_Virtualization_in_KVM_RISCV_final.pdf
>> https://www.youtube.com/watch?v=r071dL8Z0yo
>>
>> To test this series, use QEMU v7.2 (or higher) and OpenSBI v1.2 (or higher).
>>
>> These patches can also be found in the riscv_aia_v12 branch at:
>> https://github.com/avpatel/linux.git
>>
>> Changes since v11:
>>  - Rebased on Linux-6.8-rc1
>>  - Included kernel/irq related patches from "genirq, irqchip: Convert ARM
>>    MSI handling to per device MSI domains" series by Thomas.
>>    (PATCH7, PATCH8, PATCH9, PATCH14, PATCH16, PATCH17, PATCH18, PATCH19,
>>     PATCH20, PATCH21, PATCH22, PATCH23, and PATCH32 of
>>     https://lore.kernel.org/linux-arm-kernel/20221121135653.208611233@linutronix.de/)
>>  - Updated APLIC MSI-mode driver to use the new WIRED_TO_MSI mechanism.
>>  - Updated IMSIC driver to support per-device MSI domains for PCI and
>>    platform devices.
>
> Thanks for working on this, Anup! I'm still reviewing the patches.
>
> I'm hitting a boot hang in text patching, with this series applied on
> 6.8-rc2. IPI issues?

Not text patching! One cpu spinning in smp_call_function_many_cond() and
the others are in cpu_relax(). Smells like IPI...