Anup Patel <apatel@xxxxxxxxxxxxxxxx> writes: > On Tue, Jan 30, 2024 at 8:18 PM Björn Töpel <bjorn@xxxxxxxxxx> wrote: >> >> Björn Töpel <bjorn@xxxxxxxxxx> writes: >> >> > Anup Patel <apatel@xxxxxxxxxxxxxxxx> writes: >> > >> >> On Tue, Jan 30, 2024 at 1:22 PM Björn Töpel <bjorn@xxxxxxxxxx> wrote: >> >>> >> >>> Björn Töpel <bjorn@xxxxxxxxxx> writes: >> >>> >> >>> > Anup Patel <apatel@xxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxxx/) >> >>> >> - 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 ;-)) >> >> More context; The hang is during a late initcall, where an ftrace direct >> (register_ftrace_direct()) modification is done. >> >> Stop machine is used to call into __ftrace_modify_call(). Then into the >> arch specific patch_text_nosync(), where flush_icache_range() hangs in >> flush_icache_all(). From "on_each_cpu(ipi_remote_fence_i, NULL, 1);" to >> on_each_cpu_cond_mask() "smp_call_function_many_cond(mask, func, info, >> scf_flags, cond_func);" which never returns from "csd_lock_wait(csd)" >> right before the end of the function. >> >> Any ideas? Disabling CONFIG_HID_BPF, that does the early ftrace code >> patching fixes the boot hang, but it does seem related to IPI... >> > Looks like flush_icache_all() does not use the IPIs (on_each_cpu() > and friends) correctly. > > On other hand, the flush_icache_mm() does the right thing by > doing local flush on the current CPU and IPI based flush on other > CPUs. > > Can you try the following patch ? > > diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c > index 55a34f2020a8..a3dfbe4de832 100644 > --- a/arch/riscv/mm/cacheflush.c > +++ b/arch/riscv/mm/cacheflush.c > @@ -19,12 +19,18 @@ static void ipi_remote_fence_i(void *info) > > void flush_icache_all(void) > { > + cpumask_t others; > + > local_flush_icache_all(); > > + cpumask_andnot(&others, cpu_online_mask, cpumask_of(smp_processor_id())); > + if (cpumask_empty(&others)) > + return; > + > if (IS_ENABLED(CONFIG_RISCV_SBI) && !riscv_use_ipi_for_rfence()) > - sbi_remote_fence_i(NULL); > + sbi_remote_fence_i(&others); > else > - on_each_cpu(ipi_remote_fence_i, NULL, 1); > + on_each_cpu_mask(&others, ipi_remote_fence_i, NULL, 1); > } > EXPORT_SYMBOL(flush_icache_all); Unfortunately, I see the same hang. LMK if you'd like me to try anything else. Björn
