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

[Björn Töpel]

Anup Patel <apatel at ventanamicro.com> writes:

> On Tue, Jan 30, 2024 at 1:22 PM Björn Töpel <bjorn at kernel.org> wrote:
>>
>> 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...
>
> I tried bootefi from U-Boot multiple times but can't reproduce the
> issue you are seeing.

Thanks! I can reproduce without EFI, and simpler command-line:

qemu-system-riscv64 \
  -bios /path/to/fw_dynamic.bin \
  -kernel /path/to/Image \
  -append 'earlycon console=tty0 console=ttyS0' \
  -machine virt,aia=aplic-imsic \
  -no-reboot -nodefaults -nographic \
  -smp 4 \
  -object rng-random,filename=/dev/urandom,id=rng0 \
  -device virtio-rng-device,rng=rng0 \
  -m 4G -chardev stdio,id=char0 -serial chardev:char0

I can reproduce with your upstream riscv_aia_v12 plus the config in the
gist [1], and all latest QEMU/OpenSBI:

QEMU: 11be70677c70 ("Merge tag 'pull-vfio-20240129' of https://github.com/legoater/qemu into staging")
OpenSBI: bb90a9ebf6d9 ("lib: sbi: Print number of debug triggers found")
Linux: d9b9d6eb987f ("MAINTAINERS: Add entry for RISC-V AIA drivers")

Removing ",aia=aplic-imsic" from the CLI above completes the boot (i.e.
panicking about missing root mount ;-))


Björn

[1] https://gist.githubusercontent.com/bjoto/bac563e6dcaab68dba1a5eaf675d51aa/raw/ff6208fb17f27819dbe97ace7d034f385d2db657/gistfile1.txt