On Wed, Feb 23, 2022 at 8:09 AM Atish Patra <ati...@rivosinc.com> wrote:
>
> 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 <ati...@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
Alistair
> ---
> target/riscv/cpu.h | 5 ++
> target/riscv/cpu_bits.h | 39 +++++++++++++++
> target/riscv/csr.c | 107 ++++++++++++++++++++++++++++++++++++++++
> target/riscv/machine.c | 24 +++++++++
> 4 files changed, 175 insertions(+)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 0741f9822cf0..e5c8694cf081 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -303,6 +303,11 @@ 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 18fe17b62f51..ff7e36596447 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -1366,6 +1366,101 @@ 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)
> +{
> + uint64_t mask = MENVCFG_FIOM | MENVCFG_CBIE | MENVCFG_CBCFE |
> MENVCFG_CBZE;
> +
> + if (riscv_cpu_mxl(env) == MXL_RV64) {
> + mask |= MENVCFG_PBMTE | MENVCFG_STCE;
> + }
> + env->menvcfg = (env->menvcfg & ~mask) | (val & mask);
> +
> + return RISCV_EXCP_NONE;
> +}
> +
> +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 mask = MENVCFG_PBMTE | MENVCFG_STCE;
> + uint64_t valh = (uint64_t)val << 32;
> +
> + env->menvcfg = (env->menvcfg & ~mask) | (valh & mask);
> +
> + 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)
> +{
> + uint64_t mask = SENVCFG_FIOM | SENVCFG_CBIE | SENVCFG_CBCFE |
> SENVCFG_CBZE;
> +
> + env->senvcfg = (env->senvcfg & ~mask) | (val & mask);
> +
> + 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)
> +{
> + uint64_t mask = HENVCFG_FIOM | HENVCFG_CBIE | HENVCFG_CBCFE |
> HENVCFG_CBZE;
> +
> + if (riscv_cpu_mxl(env) == MXL_RV64) {
> + mask |= HENVCFG_PBMTE | HENVCFG_STCE;
> + }
> +
> + env->henvcfg = (env->henvcfg & ~mask) | (val & mask);
> +
> + 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 mask = HENVCFG_PBMTE | HENVCFG_STCE;
> + uint64_t valh = (uint64_t)val << 32;
> +
> + env->henvcfg = (env->henvcfg & ~mask) | (valh & mask);
> +
> + 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 +3164,18 @@ 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
> }
> };
> --
> 2.30.2
>
>
