Re: [PATCH v16 0/9] Linux RISC-V AIA Support

[Dawei Li]

Hi Anup,

Thanks for the great work on AIA!

Firstly I must apologize for the top posting cuz I miss the series mail for
my inbox. And for the record, I am replying to [1].

After I checkout riscv_aia_v16 branch at https://github.com/avpatel/linux.git,
some call traces about spurious interrupt are screaming:

[    1.244292] irq 11: nobody cared (try booting with the "irqpoll" option)
[    1.244707] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.8.0-rc6-00055-gd7d4d086b79a #14
[    1.244932] Hardware name: riscv-virtio,qemu (DT)
[    1.245130] Call Trace:
[    1.245337] [<ffffffff80005f32>] dump_backtrace+0x1c/0x24
[    1.245559] [<ffffffff809023f4>] show_stack+0x2c/0x38
[    1.245761] [<ffffffff8090ec8c>] dump_stack_lvl+0x3c/0x54
[    1.245979] [<ffffffff8090ecb8>] dump_stack+0x14/0x1c
[    1.246116] [<ffffffff8090368c>] __report_bad_irq+0x3e/0xae
[    1.246276] [<ffffffff8006a938>] note_interrupt+0x1f4/0x23e
[    1.246382] [<ffffffff800679e2>] handle_irq_event_percpu+0x42/0x50
[    1.246508] [<ffffffff80067a2c>] handle_irq_event+0x3c/0x68
[    1.246628] [<ffffffff8006b7a4>] handle_fasteoi_irq+0xac/0x176
[    1.246788] [<ffffffff80066c3c>] generic_handle_domain_irq+0x1c/0x2a
[    1.246928] [<ffffffff80473f0e>] imsic_handle_irq+0x72/0x12a
[    1.247041] [<ffffffff80066c3c>] generic_handle_domain_irq+0x1c/0x2a
[    1.247165] [<ffffffff80472470>] riscv_intc_aia_irq+0x26/0x38
[    1.247291] [<ffffffff8090ed0a>] handle_riscv_irq+0x4a/0x74
[    1.247430] [<ffffffff80918af6>] call_on_irq_stack+0x32/0x40
[    1.247626] handlers:
[    1.247721] [<000000004ebb6fe3>] vm_interrupt
[    1.248314] Disabling IRQ #11
[    1.303510] irq 12: nobody cared (try booting with the "irqpoll" option)
[    1.303700] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.8.0-rc6-00055-gd7d4d086b79a #14
[    1.304768] Hardware name: riscv-virtio,qemu (DT)
[    1.305460] Call Trace:
[    1.305868] [<ffffffff80005f32>] dump_backtrace+0x1c/0x24
[    1.306621] [<ffffffff809023f4>] show_stack+0x2c/0x38
[    1.307295] [<ffffffff8090ec8c>] dump_stack_lvl+0x3c/0x54
[    1.308025] [<ffffffff8090ecb8>] dump_stack+0x14/0x1c
[    1.308698] [<ffffffff8090368c>] __report_bad_irq+0x3e/0xae
[    1.309698] [<ffffffff8006a938>] note_interrupt+0x1f4/0x23e
[    1.310568] [<ffffffff800679e2>] handle_irq_event_percpu+0x42/0x50
[    1.311542] [<ffffffff80067a2c>] handle_irq_event+0x3c/0x68
[    1.312298] [<ffffffff8006b7a4>] handle_fasteoi_irq+0xac/0x176
[    1.313127] [<ffffffff80066c3c>] generic_handle_domain_irq+0x1c/0x2a
[    1.315375] [<ffffffff80473f0e>] imsic_handle_irq+0x72/0x12a
[    1.316163] [<ffffffff80066c3c>] generic_handle_domain_irq+0x1c/0x2a
[    1.317078] [<ffffffff80472470>] riscv_intc_aia_irq+0x26/0x38
[    1.318036] [<ffffffff8090ed0a>] handle_riscv_irq+0x4a/0x74
[    1.318934] [<ffffffff8090f3e6>] do_irq+0x4a/0x4c
[    1.319831] [<ffffffff809189ac>] ret_from_exception+0x0/0x64
[    1.320860] [<ffffffff8091845c>] _raw_spin_unlock_irqrestore+0x1a/0x2e
[    1.321887] [<ffffffff80473d06>] imsic_local_timer_callback+0x50/0x5c
[    1.322957] [<ffffffff8008ade4>] call_timer_fn.isra.0+0x14/0x5e
[    1.323781] [<ffffffff8008b44a>] run_timer_softirq+0x388/0x3a8
[    1.324579] [<ffffffff80918c7e>] __do_softirq+0x100/0x252
[    1.325304] [<ffffffff80018464>] irq_exit_rcu+0x7c/0xa6
[    1.326126] [<ffffffff8090ed24>] handle_riscv_irq+0x64/0x74
[    1.327535] [<ffffffff80918af6>] call_on_irq_stack+0x32/0x40
[    1.328703] handlers:
[    1.330724] [<000000008b6c4f15>] serial8250_interrupt
[    1.331573] Disabling IRQ #12
[    1.350231] Run /sbin/init as init process

And I take a look on /proc/interrupts, spurious interrupts are happening:
~ # cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3       CPU4       CPU5       CPU6       CPU7       CPU8       CPU9       CPU10      CPU11      CPU12      CPU13      CPU14      CPU15
 10:         83        222        350        163         71        101        193         68         54         60        174         50         51         48         48         46  RISC-V INTC   5 Edge      riscv-timer
 11:     100001          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0  APLIC-MSI-d000000.aplic   8 Level   -fasteoi   virtio0
 12:          0     100000          0          0          0          0          0          0          0          0          0          0          0          0          0          0  APLIC-MSI-d000000.aplic  10 Level   -fasteoi   ttyS0
 13:          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0  APLIC-MSI-d000000.aplic  11 Level   -fasteoi   101000.rtc
IPI0:         3          8          4          7          7          6          5          4          7          7          7          5          6         10          4          5  Rescheduling interrupts
IPI1:       727        517        431        448        497        456        514        476        488        466        455        456        443        443        439        433  Function call interrupts
IPI2:         0          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0  CPU stop interrupts
IPI3:         0          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0  CPU stop (for crash dump) interrupts
IPI4:         0          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0  IRQ work interrupts
IPI5:         0          0          0          0          0          0          0          0          0          0          0          0          0          0          0          0  Timer broadcast interrupts

But when I switched back to V15, everything is fine.

Here are some of info _maybe_ helpful:
kernel: d7d4d086b79a11ad8bbcaf732c7830faa3f3192f
qemu: e1007b6bab5cf97705bf4f2aaec1f607787355b8
qemu cmdline: qemu-system-riscv64 -M virt,aia=aplic-imsic -m 256M -nographic -kernel ~/src/linux/arch/riscv/boot/Image -drive file=rootfs.img,format=raw,id=hd0  -device virtio-blk-device,drive=hd0 -append "root=/dev/vda rw console=ttyS0" -smp 16
config: defconfig(make ARCH=riscv defconfig)

And I am happy to provide any extra info if needed.

After I take a git diff and check your changelog:
[Quoting from [1]]
 - Simplified aplic_msi_irq_eoi() in PATCH7 based on the section "4.9.2 Special
   consideration for level-sensitive interrupt sources"  of the RISC-V AIA
   specification and also provided handler name.

I apologize if I miss something.

[1] https://lore.kernel.org/lkml/20240307140307.646078-1-apatel@xxxxxxxxxxxxxxxx/

Thanks,

        Dawei