Kernel boots with PLIC, but fails to boot when using IMSIC+APLIC (MSI mode)

General - Software
1

Hi everyone,

I’m working on MSI support. Here’s my issue:

  • Kernel boots fine with PLIC enabled.
  • Kernel fails to boot with PLIC disabled + APLIC+IMSIC (MSI mode) enabled.

My device tree:

/*plic0: plic@PLIC_UNIT {
  compatible = "riscv,plic0", "sifive,plic-1.0.0";
  reg = <PLIC_CTRL>;
  interrupt-controller;
  #interrupt-cells = <1>;
  #address-cells = <0>;
  riscv,ndev = <31>;
  riscv,max-priority = <7>;
  interrupts-extended = <&cpu0_hlic 11 &cpu0_hlic 9
                         &cpu1_hlic 11 &cpu1_hlic 9>;
};*/

imsic0: imsic@MSIC_UNIT {
  compatible = "qemu,imsics", "riscv,imsics";
  reg = <MSIC_CTRL>;
  interrupt-controller;
  #interrupt-cells = <0>;
  msi-controller;
  #msi-cells = <0>;
  riscv,num-ids = <127>;
  interrupts-extended = <&cpu0_hlic 9 &cpu1_hlic 9>;
};

aplic0: aplic@APIC_UNIT {
  compatible = "riscv,aplic", "qemu,aplic";
  reg = <APIC_CTRL>;
  interrupt-controller;
  #interrupt-cells = <1>;
  #address-cells = <0>;
  riscv,num-sources = <32>;
//interrupts-extended = <&cpu0_hlic 9 &cpu1_hlic 9>; // Direct mode
  msi-parent = <&imsic0>; // MSI mode
};

Any help would be appreciated!

2

No expert on DTS’s but this is what I have been running in a small system, this boots in simulation on Linux 6.13 and 7.

    IMSIC_MLEVEL: interrupt-controller@f8600000 {
      compatible = "riscv,imsicm";
      reg = <0x0 0xf8600000 0x0 0x40000>;
      interrupt-controller;
      #interrupt-cells = <0>;
      #address-cells = <0>;
      interrupts-extended = <
        &CPU0_intc 11
      >;
      msi-controller;
      riscv,num-ids = <63>;
    };
    IMSIC_SLEVEL: interrupt-controller@f8640000 {
      compatible = "riscv,imsics";
      reg = <0x0 0xf8640000 0x0 0x40000>;
      interrupt-controller;
      #interrupt-cells = <0>;
      #address-cells = <0>;
      interrupts-extended = <
        &CPU0_intc 9
      >;
      msi-controller;
      riscv,num-ids = <63>;
     riscv,guest-index-bits = <5>;
    };
    ROOT_APLIC: interrupt-controller@f8500000 {
      compatible = "riscv,aplic";
      #interrupt-cells = <0x2>;
      #address-cells = <0x0>;
      riscv,children = <&M_APLIC>;
      riscv,num-sources = <31>;
      riscv,delegation = <&M_APLIC 1 31>;
      riscv,delegate = <&M_APLIC 1 31>;
      reg = <0x0 0xf8500000 0x0 0x8000>;
      msi-parent = <&IMSIC_MLEVEL>;
      interrupt-controller;
    };
    M_APLIC: interrupt-controller@f8508000 {
      compatible = "riscv,aplic";
      #interrupt-cells = <0x2>;
      #address-cells = <0x0>;
      riscv,children = <&S_APLIC>;
      riscv,num-sources = <31>;
      riscv,delegation = <&S_APLIC 1 31>;
      riscv,delegate = <&S_APLIC 1 31>;
      reg = <0x0 0xf8508000 0x0 0x8000>;
      msi-parent = <&IMSIC_MLEVEL>;
      interrupt-controller;
    };
    S_APLIC: interrupt-controller@f8510000 {
      compatible = "riscv,aplic";
      #interrupt-cells = <0x2>;
      #address-cells = <0x0>;
      riscv,num-sources = <31>;
      reg = <0x0 0xf8510000 0x0 0x8000>;
      msi-parent = <&IMSIC_SLEVEL>;
      interrupt-controller;
    };
    clint@b0000000 {
      compatible = "riscv,clint0";
      reg-names = "control";
      interrupts-extended = <&CPU0_intc 3 &CPU0_intc 7 >;
      reg = <0x0 0xb0000000 0x0 0x100000>;
    };
3

Hi JonathanJ,

Thank you so much for the help! I tried your DTS config and it works! Now my system boots fine with PLIC disabled + APLIC+IMSIC(MSI mode) enabled.

Greatly appreciate your support!