Re: [PATCH v4 11/22] target/riscv: Implement AIA hvictl and hviprioX CSRs

[Alistair Francis]

On Tue, Oct 26, 2021 at 5:39 PM Anup Patel <anup.patel@wdc.com> wrote:
>
> The AIA hvictl and hviprioX CSRs allow hypervisor to control
> interrupts visible at VS-level. This patch implements AIA hvictl
> and hviprioX CSRs.
>
> Signed-off-by: Anup Patel <anup.patel@wdc.com>
> ---
>  target/riscv/cpu.h     |   1 +
>  target/riscv/csr.c     | 126 +++++++++++++++++++++++++++++++++++++++++
>  target/riscv/machine.c |   2 +
>  3 files changed, 129 insertions(+)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 718a95e864..21d9c536ef 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -196,6 +196,7 @@ struct CPURISCVState {
>      uint64_t htimedelta;
>
>      /* Hypervisor controlled virtual interrupt priorities */
> +    target_ulong hvictl;
>      uint8_t hviprio[64];
>
>      /* Virtual CSRs */
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 3a7d89ac34..46d0cabbde 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -219,6 +219,15 @@ static RISCVException hmode32(CPURISCVState *env, int 
> csrno)
>
>  }
>
> +static int aia_hmode(CPURISCVState *env, int csrno)
> +{
> +    if (!riscv_feature(env, RISCV_FEATURE_AIA)) {
> +        return RISCV_EXCP_ILLEGAL_INST;
> +     }
> +
> +     return hmode(env, csrno);
> +}
> +
>  static int aia_hmode32(CPURISCVState *env, int csrno)
>  {
>      if (!riscv_feature(env, RISCV_FEATURE_AIA)) {
> @@ -1031,6 +1040,9 @@ static RISCVException rmw_sie64(CPURISCVState *env, int 
> csrno,
>      uint64_t mask = env->mideleg & S_MODE_INTERRUPTS;
>
>      if (riscv_cpu_virt_enabled(env)) {
> +        if (env->hvictl & HVICTL_VTI) {
> +            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> +        }
>          ret = rmw_vsie64(env, CSR_VSIE, ret_val, new_val, wr_mask);
>      } else {
>          ret = rmw_mie64(env, csrno, ret_val, new_val, wr_mask & mask);
> @@ -1229,6 +1241,9 @@ static RISCVException rmw_sip64(CPURISCVState *env, int 
> csrno,
>      uint64_t mask = env->mideleg & sip_writable_mask;
>
>      if (riscv_cpu_virt_enabled(env)) {
> +        if (env->hvictl & HVICTL_VTI) {
> +            return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
> +        }
>          ret = rmw_vsip64(env, CSR_VSIE, ret_val, new_val, wr_mask);
>      } else {
>          ret = rmw_mip64(env, csrno, ret_val, new_val, wr_mask & mask);
> @@ -1615,6 +1630,110 @@ static RISCVException write_htimedeltah(CPURISCVState 
> *env, int csrno,
>      return RISCV_EXCP_NONE;
>  }
>
> +static int read_hvictl(CPURISCVState *env, int csrno, target_ulong *val)
> +{
> +    *val = env->hvictl;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static int write_hvictl(CPURISCVState *env, int csrno, target_ulong val)
> +{
> +    env->hvictl = val & HVICTL_VALID_MASK;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static int read_hvipriox(CPURISCVState *env, int first_index,
> +                         uint8_t *iprio, target_ulong *val)
> +{
> +    int i, irq, rdzero, num_irqs = 4 * (TARGET_LONG_BITS / 32);

You should be checking the CPUs xlen instead of using the hardcoded
TARGET_LONG_BITS here.

Alistair

> +
> +    /* First index has to be multiple of numbe of irqs per register */
> +    if (first_index % num_irqs) {
> +        return (riscv_cpu_virt_enabled(env)) ?
> +               RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
> +    }
> +
> +    /* Fill-up return value */
> +    *val = 0;
> +    for (i = 0; i < num_irqs; i++) {
> +        if (riscv_cpu_hviprio_index2irq(first_index + i, &irq, &rdzero)) {
> +            continue;
> +        }
> +        if (rdzero) {
> +            continue;
> +        }
> +        *val |= ((target_ulong)iprio[irq]) << (i * 8);
> +    }
> +
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static int write_hvipriox(CPURISCVState *env, int first_index,
> +                          uint8_t *iprio, target_ulong val)
> +{
> +    int i, irq, rdzero, num_irqs = 4 * (TARGET_LONG_BITS / 32);
> +
> +    /* First index has to be multiple of numbe of irqs per register */
> +    if (first_index % num_irqs) {
> +        return (riscv_cpu_virt_enabled(env)) ?
> +               RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
> +    }
> +
> +    /* Fill-up priority arrary */
> +    for (i = 0; i < num_irqs; i++) {
> +        if (riscv_cpu_hviprio_index2irq(first_index + i, &irq, &rdzero)) {
> +            continue;
> +        }
> +        if (rdzero) {
> +            iprio[irq] = 0;
> +        } else {
> +            iprio[irq] = (val >> (i * 8)) & 0xff;
> +        }
> +    }
> +
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static int read_hviprio1(CPURISCVState *env, int csrno, target_ulong *val)
> +{
> +    return read_hvipriox(env, 0, env->hviprio, val);
> +}
> +
> +static int write_hviprio1(CPURISCVState *env, int csrno, target_ulong val)
> +{
> +    return write_hvipriox(env, 0, env->hviprio, val);
> +}
> +
> +static int read_hviprio1h(CPURISCVState *env, int csrno, target_ulong *val)
> +{
> +    return read_hvipriox(env, 4, env->hviprio, val);
> +}
> +
> +static int write_hviprio1h(CPURISCVState *env, int csrno, target_ulong val)
> +{
> +    return write_hvipriox(env, 4, env->hviprio, val);
> +}
> +
> +static int read_hviprio2(CPURISCVState *env, int csrno, target_ulong *val)
> +{
> +    return read_hvipriox(env, 8, env->hviprio, val);
> +}
> +
> +static int write_hviprio2(CPURISCVState *env, int csrno, target_ulong val)
> +{
> +    return write_hvipriox(env, 8, env->hviprio, val);
> +}
> +
> +static int read_hviprio2h(CPURISCVState *env, int csrno, target_ulong *val)
> +{
> +    return read_hvipriox(env, 12, env->hviprio, val);
> +}
> +
> +static int write_hviprio2h(CPURISCVState *env, int csrno, target_ulong val)
> +{
> +    return write_hvipriox(env, 12, env->hviprio, val);
> +}
> +
>  /* Virtual CSR Registers */
>  static RISCVException read_vsstatus(CPURISCVState *env, int csrno,
>                                      target_ulong *val)
> @@ -2005,9 +2124,16 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
>      [CSR_MTVAL2]      = { "mtval2",      hmode,   read_mtval2,      
> write_mtval2      },
>      [CSR_MTINST]      = { "mtinst",      hmode,   read_mtinst,      
> write_mtinst      },
>
> +    /* Virtual Interrupts and Interrupt Priorities (H-extension with AIA) */
> +    [CSR_HVICTL]      = { "hvictl",      aia_hmode, read_hvictl, 
> write_hvictl },
> +    [CSR_HVIPRIO1]    = { "hviprio1",    aia_hmode, read_hviprio1,   
> write_hviprio1 },
> +    [CSR_HVIPRIO2]    = { "hviprio2",    aia_hmode, read_hviprio2,   
> write_hviprio2 },
> +
>      /* Hypervisor and VS-Level High-Half CSRs (H-extension with AIA) */
>      [CSR_HIDELEGH]    = { "hidelegh",    aia_hmode32, NULL, NULL, 
> rmw_hidelegh },
>      [CSR_HVIPH]       = { "hviph",       aia_hmode32, NULL, NULL, rmw_hviph 
> },
> +    [CSR_HVIPRIO1H]   = { "hviprio1h",   aia_hmode32, read_hviprio1h, 
> write_hviprio1h },
> +    [CSR_HVIPRIO2H]   = { "hviprio2h",   aia_hmode32, read_hviprio2h, 
> write_hviprio2h },
>      [CSR_VSIEH]       = { "vsieh",       aia_hmode32, NULL, NULL, rmw_vsieh 
> },
>      [CSR_VSIPH]       = { "vsiph",       aia_hmode32, NULL, NULL, rmw_vsiph 
> },
>
> diff --git a/target/riscv/machine.c b/target/riscv/machine.c
> index 7356d70be6..bc20960260 100644
> --- a/target/riscv/machine.c
> +++ b/target/riscv/machine.c
> @@ -116,6 +116,8 @@ static const VMStateDescription vmstate_hyper = {
>          VMSTATE_UINTTL(env.hgeie, RISCVCPU),
>          VMSTATE_UINTTL(env.hgeip, RISCVCPU),
>          VMSTATE_UINT64(env.htimedelta, RISCVCPU),
> +
> +        VMSTATE_UINTTL(env.hvictl, RISCVCPU),
>          VMSTATE_UINT8_ARRAY(env.hviprio, RISCVCPU, 64),
>
>          VMSTATE_UINT64(env.vsstatus, RISCVCPU),
> --
> 2.25.1
>
>