[v2,5/6] target/riscv: Add *envcfg* CSRs support

The RISC-V privileged specification v1.12 defines few execution
environment configuration CSRs that can be used enable/disable
extensions per privilege levels.

Add the basic support for these CSRs.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
 target/riscv/cpu.h      |  6 +++
 target/riscv/cpu_bits.h | 39 ++++++++++++++++++
 target/riscv/csr.c      | 87 +++++++++++++++++++++++++++++++++++++++++
 target/riscv/machine.c  | 24 ++++++++++++
 4 files changed, 156 insertions(+)

在 2022/2/5 上午8:36, Atish Patra 写道:
> The RISC-V privileged specification v1.12 defines few execution
> environment configuration CSRs that can be used enable/disable
> extensions per privilege levels.
>
> Add the basic support for these CSRs.
>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>
> ---
>   target/riscv/cpu.h      |  6 +++
>   target/riscv/cpu_bits.h | 39 ++++++++++++++++++
>   target/riscv/csr.c      | 87 +++++++++++++++++++++++++++++++++++++++++
>   target/riscv/machine.c  | 24 ++++++++++++
>   4 files changed, 156 insertions(+)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 0741f9822cf0..675f8716b239 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -303,6 +303,12 @@ struct CPURISCVState {
>       target_ulong spmbase;
>       target_ulong upmmask;
>       target_ulong upmbase;
> +
> +    /* CSRs for execution enviornment configuration */
> +
> +    uint64_t menvcfg;
> +    target_ulong senvcfg;
> +    uint64_t henvcfg;
>   #endif
>   
>       float_status fp_status;
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index 89440241632a..58a0a8d69f72 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -202,6 +202,9 @@
>   #define CSR_STVEC           0x105
>   #define CSR_SCOUNTEREN      0x106
>   
> +/* Supervisor Configuration CSRs */
> +#define CSR_SENVCFG         0x10A
> +
>   /* Supervisor Trap Handling */
>   #define CSR_SSCRATCH        0x140
>   #define CSR_SEPC            0x141
> @@ -247,6 +250,10 @@
>   #define CSR_HTIMEDELTA      0x605
>   #define CSR_HTIMEDELTAH     0x615
>   
> +/* Hypervisor Configuration CSRs */
> +#define CSR_HENVCFG         0x60A
> +#define CSR_HENVCFGH        0x61A
> +
>   /* Virtual CSRs */
>   #define CSR_VSSTATUS        0x200
>   #define CSR_VSIE            0x204
> @@ -290,6 +297,10 @@
>   #define CSR_VSIEH           0x214
>   #define CSR_VSIPH           0x254
>   
> +/* Machine Configuration CSRs */
> +#define CSR_MENVCFG         0x30A
> +#define CSR_MENVCFGH        0x31A
> +
>   /* Enhanced Physical Memory Protection (ePMP) */
>   #define CSR_MSECCFG         0x747
>   #define CSR_MSECCFGH        0x757
> @@ -654,6 +665,34 @@ typedef enum RISCVException {
>   #define PM_EXT_CLEAN    0x00000002ULL
>   #define PM_EXT_DIRTY    0x00000003ULL
>   
> +/* Execution enviornment configuration bits */
> +#define MENVCFG_FIOM                       BIT(0)
> +#define MENVCFG_CBIE                       (3UL << 4)
> +#define MENVCFG_CBCFE                      BIT(6)
> +#define MENVCFG_CBZE                       BIT(7)
> +#define MENVCFG_PBMTE                      BIT(62)
> +#define MENVCFG_STCE                       BIT(63)
> +
> +/* For RV32 */
> +#define MENVCFGH_PBMTE                     BIT(30)
> +#define MENVCFGH_STCE                      BIT(31)
> +
> +#define SENVCFG_FIOM                       MENVCFG_FIOM
> +#define SENVCFG_CBIE                       MENVCFG_CBIE
> +#define SENVCFG_CBCFE                      MENVCFG_CBCFE
> +#define SENVCFG_CBZE                       MENVCFG_CBZE
> +
> +#define HENVCFG_FIOM                       MENVCFG_FIOM
> +#define HENVCFG_CBIE                       MENVCFG_CBIE
> +#define HENVCFG_CBCFE                      MENVCFG_CBCFE
> +#define HENVCFG_CBZE                       MENVCFG_CBZE
> +#define HENVCFG_PBMTE                      MENVCFG_PBMTE
> +#define HENVCFG_STCE                       MENVCFG_STCE
> +
> +/* For RV32 */
> +#define HENVCFGH_PBMTE                      MENVCFGH_PBMTE
> +#define HENVCFGH_STCE                       MENVCFGH_STCE
> +
>   /* Offsets for every pair of control bits per each priv level */
>   #define XS_OFFSET    0ULL
>   #define U_OFFSET     2ULL
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 4366e5e95ce8..88c839a5ffaa 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -1366,6 +1366,81 @@ static RISCVException write_mtval(CPURISCVState *env, int csrno,
>       return RISCV_EXCP_NONE;
>   }
>   
> +/* Execution environment configuration setup */
> +static RISCVException read_menvcfg(CPURISCVState *env, int csrno,
> +                                 target_ulong *val)
> +{
> +    *val = env->menvcfg;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_menvcfg(CPURISCVState *env, int csrno,
> +                                  target_ulong val)
> +{
> +    env->menvcfg = val;
> +    return RISCV_EXCP_NONE;
> +}
> +

I think mask write to ignore the reserved fields  is better here.

The same to other  *envcfg* csrs.

> +static RISCVException read_menvcfgh(CPURISCVState *env, int csrno,
> +                                 target_ulong *val)
> +{
> +    *val = env->menvcfg >> 32;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_menvcfgh(CPURISCVState *env, int csrno,
> +                                  target_ulong val)
> +{
> +    uint64_t valh = (uint64_t)val << 32;
> +    env->menvcfg |= valh;
> +

The original high32 of menvcfg should be cleared before ' | ' valh.

Similar for henvcfgh.

Regards,

Weiwei Li

> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException read_senvcfg(CPURISCVState *env, int csrno,
> +                                 target_ulong *val)
> +{
> +    *val = env->senvcfg;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_senvcfg(CPURISCVState *env, int csrno,
> +                                  target_ulong val)
> +{
> +    env->senvcfg = val;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException read_henvcfg(CPURISCVState *env, int csrno,
> +                                 target_ulong *val)
> +{
> +    *val = env->henvcfg;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_henvcfg(CPURISCVState *env, int csrno,
> +                                  target_ulong val)
> +{
> +    env->henvcfg = val;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException read_henvcfgh(CPURISCVState *env, int csrno,
> +                                 target_ulong *val)
> +{
> +    *val = env->henvcfg >> 32;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_henvcfgh(CPURISCVState *env, int csrno,
> +                                  target_ulong val)
> +{
> +    uint64_t valh = (uint64_t)val << 32;
> +    env->henvcfg |= valh;
> +
> +    return RISCV_EXCP_NONE;
> +}
> +
>   static RISCVException rmw_mip64(CPURISCVState *env, int csrno,
>                                   uint64_t *ret_val,
>                                   uint64_t new_val, uint64_t wr_mask)
> @@ -3069,6 +3144,18 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
>       [CSR_MVIPH]    = { "mviph",    aia_any32, read_zero,  write_ignore },
>       [CSR_MIPH]     = { "miph",     aia_any32, NULL, NULL, rmw_miph     },
>   
> +    /* Execution environment configuration */
> +    [CSR_MENVCFG]  = { "menvcfg",  any,   read_menvcfg,  write_menvcfg,
> +                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
> +    [CSR_MENVCFGH] = { "menvcfgh", any32, read_menvcfgh, write_menvcfgh,
> +                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
> +    [CSR_SENVCFG]  = { "senvcfg",  smode, read_senvcfg,  write_senvcfg,
> +                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
> +    [CSR_HENVCFG]  = { "henvcfg",  hmode, read_henvcfg, write_henvcfg,
> +                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
> +    [CSR_HENVCFGH] = { "henvcfgh", hmode32, read_henvcfgh, write_henvcfgh,
> +                                          .min_priv_ver = PRIV_VERSION_1_12_0 },
> +
>       /* Supervisor Trap Setup */
>       [CSR_SSTATUS]    = { "sstatus",    smode, read_sstatus,    write_sstatus, NULL,
>                                                 read_sstatus_i128                 },
> diff --git a/target/riscv/machine.c b/target/riscv/machine.c
> index 9895930b2976..4a50a05937fa 100644
> --- a/target/riscv/machine.c
> +++ b/target/riscv/machine.c
> @@ -220,6 +220,29 @@ static const VMStateDescription vmstate_kvmtimer = {
>       }
>   };
>   
> +/* TODO: henvcfg need both hyper_needed & envcfg_needed */
> +static bool envcfg_needed(void *opaque)
> +{
> +    RISCVCPU *cpu = opaque;
> +    CPURISCVState *env = &cpu->env;
> +
> +    return (env->priv_ver >= PRIV_VERSION_1_12_0 ? 1 : 0);
> +}
> +
> +static const VMStateDescription vmstate_envcfg = {
> +    .name = "cpu/envcfg",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .needed = envcfg_needed,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT64(env.menvcfg, RISCVCPU),
> +        VMSTATE_UINTTL(env.senvcfg, RISCVCPU),
> +        VMSTATE_UINT64(env.henvcfg, RISCVCPU),
> +
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
>   const VMStateDescription vmstate_riscv_cpu = {
>       .name = "cpu",
>       .version_id = 3,
> @@ -280,6 +303,7 @@ const VMStateDescription vmstate_riscv_cpu = {
>           &vmstate_pointermasking,
>           &vmstate_rv128,
>           &vmstate_kvmtimer,
> +        &vmstate_envcfg,
>           NULL
>       }
>   };