On Wed, Sep 24, 2025 at 7:19 PM Djordje Todorovic
<[email protected]> wrote:
>
> This is needed for riscv based CPUs by MIPS since those may have
> sparse hart-ID layouts. ACLINT and APLIC still assume a dense
> range, and if a hart is missing, this causes NULL derefs.
>
> Signed-off-by: Chao-ying Fu <[email protected]>
> Signed-off-by: Djordje Todorovic <[email protected]>
> Reviewed-by: Daniel Henrique Barboza <[email protected]>

Reviewed-by: Alistair Francis <[email protected]>

Alistair

> ---
>  hw/intc/riscv_aclint.c | 18 ++++++++++++++++--
>  hw/intc/riscv_aplic.c  | 13 ++++++++++---
>  2 files changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/hw/intc/riscv_aclint.c b/hw/intc/riscv_aclint.c
> index 4623cfa029..e3e019e605 100644
> --- a/hw/intc/riscv_aclint.c
> +++ b/hw/intc/riscv_aclint.c
> @@ -297,7 +297,12 @@ static void riscv_aclint_mtimer_realize(DeviceState 
> *dev, Error **errp)
>      s->timecmp = g_new0(uint64_t, s->num_harts);
>      /* Claim timer interrupt bits */
>      for (i = 0; i < s->num_harts; i++) {
> -        RISCVCPU *cpu = RISCV_CPU(cpu_by_arch_id(s->hartid_base + i));
> +        CPUState *cpu_by_hartid = cpu_by_arch_id(s->hartid_base + i);
> +        if (cpu_by_hartid == NULL) {
> +            /* Valid for sparse hart layouts - skip this hart ID */
> +            continue;
> +        }
> +        RISCVCPU *cpu = RISCV_CPU(cpu_by_hartid);
>          if (riscv_cpu_claim_interrupts(cpu, MIP_MTIP) < 0) {
>              error_report("MTIP already claimed");
>              exit(1);
> @@ -486,7 +491,12 @@ static void riscv_aclint_swi_realize(DeviceState *dev, 
> Error **errp)
>
>      /* Claim software interrupt bits */
>      for (i = 0; i < swi->num_harts; i++) {
> -        RISCVCPU *cpu = RISCV_CPU(qemu_get_cpu(swi->hartid_base + i));
> +        CPUState *cpu_by_hartid = cpu_by_arch_id(swi->hartid_base + i);
> +        if (cpu_by_hartid == NULL) {
> +            /* Valid for sparse hart layouts - skip this hart ID */
> +            continue;
> +        }
> +        RISCVCPU *cpu = RISCV_CPU(cpu_by_hartid);
>          /* We don't claim mip.SSIP because it is writable by software */
>          if (riscv_cpu_claim_interrupts(cpu, swi->sswi ? 0 : MIP_MSIP) < 0) {
>              error_report("MSIP already claimed");
> @@ -550,6 +560,10 @@ DeviceState *riscv_aclint_swi_create(hwaddr addr, 
> uint32_t hartid_base,
>
>      for (i = 0; i < num_harts; i++) {
>          CPUState *cpu = cpu_by_arch_id(hartid_base + i);
> +        if (cpu == NULL) {
> +            /* Valid for sparse hart layouts - skip this hart ID */
> +            continue;
> +        }
>          RISCVCPU *rvcpu = RISCV_CPU(cpu);
>
>          qdev_connect_gpio_out(dev, i,
> diff --git a/hw/intc/riscv_aplic.c b/hw/intc/riscv_aplic.c
> index a1d9fa5085..77cec8ece9 100644
> --- a/hw/intc/riscv_aplic.c
> +++ b/hw/intc/riscv_aplic.c
> @@ -903,9 +903,12 @@ static void riscv_aplic_realize(DeviceState *dev, Error 
> **errp)
>          if (!aplic->msimode) {
>              /* Claim the CPU interrupt to be triggered by this APLIC */
>              for (i = 0; i < aplic->num_harts; i++) {
> -                RISCVCPU *cpu;
> -
> -                cpu = RISCV_CPU(cpu_by_arch_id(aplic->hartid_base + i));
> +                CPUState *temp = cpu_by_arch_id(aplic->hartid_base + i);
> +                if (temp == NULL) {
> +                    /* Valid for sparse hart layouts - skip this hart ID */
> +                    continue;
> +                }
> +                RISCVCPU *cpu = RISCV_CPU(temp);
>                  if (riscv_cpu_claim_interrupts(cpu,
>                      (aplic->mmode) ? MIP_MEIP : MIP_SEIP) < 0) {
>                      error_report("%s already claimed",
> @@ -1088,6 +1091,10 @@ DeviceState *riscv_aplic_create(hwaddr addr, hwaddr 
> size,
>          if (!msimode) {
>              for (i = 0; i < num_harts; i++) {
>                  CPUState *cpu = cpu_by_arch_id(hartid_base + i);
> +                if (cpu == NULL) {
> +                    /* Valid for sparse hart layouts - skip this hart ID */
> +                    continue;
> +                }
>
>                  qdev_connect_gpio_out_named(dev, NULL, i,
>                                              qdev_get_gpio_in(DEVICE(cpu),
> --
> 2.34.1
>

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