[v9,4/5] riscv: Introduce satp mode hw capabilities

Currently, the max satp mode is set with the only constraint that it must be
implemented in QEMU, i.e. set in valid_vm_1_10_[32|64].

But we actually need to add another level of constraint: what the hw is
actually capable of, because currently, a linux booting on a sifive-u54
boots in sv57 mode which is incompatible with the cpu's sv39 max
capability.

So add a new bitmap to RISCVSATPMap which contains this capability and
initialize it in every XXX_cpu_init.

Finally:
- valid_vm_1_10_[32|64] constrains which satp mode the CPU can use
- the CPU hw capabilities constrains what the user may select
- the user's selection then constrains what's available to the guest
  OS.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
 target/riscv/cpu.c | 79 +++++++++++++++++++++++++++++++---------------
 target/riscv/cpu.h |  8 +++--
 2 files changed, 60 insertions(+), 27 deletions(-)

On Tue, Jan 31, 2023 at 10:41 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
>
> Currently, the max satp mode is set with the only constraint that it must be
> implemented in QEMU, i.e. set in valid_vm_1_10_[32|64].
>
> But we actually need to add another level of constraint: what the hw is
> actually capable of, because currently, a linux booting on a sifive-u54
> boots in sv57 mode which is incompatible with the cpu's sv39 max
> capability.
>
> So add a new bitmap to RISCVSATPMap which contains this capability and
> initialize it in every XXX_cpu_init.
>
> Finally:
> - valid_vm_1_10_[32|64] constrains which satp mode the CPU can use
> - the CPU hw capabilities constrains what the user may select
> - the user's selection then constrains what's available to the guest
>   OS.
>
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>  target/riscv/cpu.c | 79 +++++++++++++++++++++++++++++++---------------
>  target/riscv/cpu.h |  8 +++--
>  2 files changed, 60 insertions(+), 27 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 3a7a1746aa..6dd76355ec 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -292,26 +292,36 @@ const char *satp_mode_str(uint8_t satp_mode, bool is_32_bit)
>      g_assert_not_reached();
>  }
>
> -/* Sets the satp mode to the max supported */
> -static void set_satp_mode_default_map(RISCVCPU *cpu)
> +static void set_satp_mode_max_supported(RISCVCPU *cpu,
> +                                        uint8_t satp_mode)
>  {
>      bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
> +    const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
>
> -    if (riscv_feature(&cpu->env, RISCV_FEATURE_MMU)) {
> -        cpu->cfg.satp_mode.map |=
> -                        (1 << satp_mode_from_str(rv32 ? "sv32" : "sv57"));
> -    } else {
> -        cpu->cfg.satp_mode.map |= (1 << satp_mode_from_str("mbare"));
> +    for (int i = 0; i <= satp_mode; ++i) {
> +        if (valid_vm[i]) {
> +            cpu->cfg.satp_mode.supported |= (1 << i);
> +        }
>      }
>  }
>
> +/* Set the satp mode to the max supported */
> +static void set_satp_mode_default_map(RISCVCPU *cpu)
> +{
> +    cpu->cfg.satp_mode.map = cpu->cfg.satp_mode.supported;
> +}
> +
>  static void riscv_any_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>  #if defined(TARGET_RISCV32)
>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>  #elif defined(TARGET_RISCV64)
>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>  #endif
>      set_priv_version(env, PRIV_VERSION_1_12_0);
>      register_cpu_props(obj);
> @@ -321,18 +331,24 @@ static void riscv_any_cpu_init(Object *obj)
>  static void rv64_base_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>      /* We set this in the realise function */
>      set_misa(env, MXL_RV64, 0);
>      register_cpu_props(obj);
>      /* Set latest version of privileged specification */
>      set_priv_version(env, PRIV_VERSION_1_12_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>  }
>
>  static void rv64_sifive_u_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV39);
>  }
>
>  static void rv64_sifive_e_cpu_init(Object *obj)
> @@ -343,6 +359,7 @@ static void rv64_sifive_e_cpu_init(Object *obj)
>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVC | RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
>      cpu->cfg.mmu = false;
> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>  }
>
>  static void rv128_base_cpu_init(Object *obj)
> @@ -354,28 +371,36 @@ static void rv128_base_cpu_init(Object *obj)
>          exit(EXIT_FAILURE);
>      }
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);

nits: for consistency with other cpu_init, needs a blank line after this

>      /* We set this in the realise function */
>      set_misa(env, MXL_RV128, 0);
>      register_cpu_props(obj);
>      /* Set latest version of privileged specification */
>      set_priv_version(env, PRIV_VERSION_1_12_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>  }
>  #else
>  static void rv32_base_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>      /* We set this in the realise function */
>      set_misa(env, MXL_RV32, 0);
>      register_cpu_props(obj);
>      /* Set latest version of privileged specification */
>      set_priv_version(env, PRIV_VERSION_1_12_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>  }
>
>  static void rv32_sifive_u_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>  }
>
>  static void rv32_sifive_e_cpu_init(Object *obj)
> @@ -386,6 +411,7 @@ static void rv32_sifive_e_cpu_init(Object *obj)
>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVC | RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
>      cpu->cfg.mmu = false;
> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>  }
>
>  static void rv32_ibex_cpu_init(Object *obj)
> @@ -396,6 +422,7 @@ static void rv32_ibex_cpu_init(Object *obj)
>      set_misa(env, MXL_RV32, RVI | RVM | RVC | RVU);
>      set_priv_version(env, PRIV_VERSION_1_11_0);
>      cpu->cfg.mmu = false;
> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>      cpu->cfg.epmp = true;
>  }
>
> @@ -407,6 +434,7 @@ static void rv32_imafcu_nommu_cpu_init(Object *obj)
>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVC | RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
>      cpu->cfg.mmu = false;
> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>  }
>  #endif
>
> @@ -698,8 +726,9 @@ static void riscv_cpu_disas_set_info(CPUState *s, disassemble_info *info)
>  static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp)
>  {
>      bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
> -    const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
> -    uint8_t satp_mode_max;
> +    uint8_t satp_mode_map_max;
> +    uint8_t satp_mode_supported_max =
> +                        satp_mode_max_from_map(cpu->cfg.satp_mode.supported);
>
>      if (cpu->cfg.satp_mode.map == 0) {
>          if (cpu->cfg.satp_mode.init == 0) {
> @@ -712,9 +741,10 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp)
>               * valid_vm_1_10_32/64.
>               */
>              for (int i = 1; i < 16; ++i) {
> -                if ((cpu->cfg.satp_mode.init & (1 << i)) && valid_vm[i]) {
> +                if ((cpu->cfg.satp_mode.init & (1 << i)) &&
> +                    (cpu->cfg.satp_mode.supported & (1 << i))) {
>                      for (int j = i - 1; j >= 0; --j) {
> -                        if (valid_vm[j]) {
> +                        if (cpu->cfg.satp_mode.supported & (1 << j)) {
>                              cpu->cfg.satp_mode.map |= (1 << j);
>                              break;
>                          }
> @@ -725,37 +755,36 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp)
>          }
>      }
>
> -    /* Make sure the configuration asked is supported by qemu */
> -    for (int i = 0; i < 16; ++i) {
> -        if ((cpu->cfg.satp_mode.map & (1 << i)) && !valid_vm[i]) {
> -            error_setg(errp, "satp_mode %s is not valid",
> -                       satp_mode_str(i, rv32));
> -            return;
> -        }
> +    satp_mode_map_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
> +
> +    /* Make sure the user asked for a supported configuration (HW and qemu) */
> +    if (satp_mode_map_max > satp_mode_supported_max) {
> +        error_setg(errp, "satp_mode %s is higher than hw max capability %s",
> +                   satp_mode_str(satp_mode_map_max, rv32),
> +                   satp_mode_str(satp_mode_supported_max, rv32));
> +        return;
>      }
>
>      /*
>       * Make sure the user did not ask for an invalid configuration as per
>       * the specification.
>       */
> -    satp_mode_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
> -
>      if (!rv32) {
> -        for (int i = satp_mode_max - 1; i >= 0; --i) {
> +        for (int i = satp_mode_map_max - 1; i >= 0; --i) {
>              if (!(cpu->cfg.satp_mode.map & (1 << i)) &&
>                  (cpu->cfg.satp_mode.init & (1 << i)) &&
> -                valid_vm[i]) {
> +                (cpu->cfg.satp_mode.supported & (1 << i))) {
>                  error_setg(errp, "cannot disable %s satp mode if %s "
>                             "is enabled", satp_mode_str(i, false),
> -                           satp_mode_str(satp_mode_max, false));
> +                           satp_mode_str(satp_mode_map_max, false));
>                  return;
>              }
>          }
>      }
>
>      /* Finally expand the map so that all valid modes are set */
> -    for (int i = satp_mode_max - 1; i >= 0; --i) {
> -        if (valid_vm[i]) {
> +    for (int i = satp_mode_map_max - 1; i >= 0; --i) {
> +        if (cpu->cfg.satp_mode.supported & (1 << i)) {
>              cpu->cfg.satp_mode.map |= (1 << i);
>          }
>      }
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index e37177db5c..b591122099 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -416,13 +416,17 @@ struct RISCVCPUClass {
>
>  /*
>   * map is a 16-bit bitmap: the most significant set bit in map is the maximum
> - * satp mode that is supported.
> + * satp mode that is supported. It may be chosen by the user and must respect
> + * what qemu implements (valid_1_10_32/64) and what the hw is capable of
> + * (supported bitmap below).
>   *
>   * init is a 16-bit bitmap used to make sure the user selected a correct
>   * configuration as per the specification.
> + *
> + * supported is a 16-bit bitmap used to reflect the hw capabilities.
>   */
>  typedef struct {
> -    uint16_t map, init;
> +    uint16_t map, init, supported;
>  } RISCVSATPMap;
>
>  struct RISCVCPUConfig {
> --

Otherwise,
Reviewed-by: Bin Meng <bmeng@tinylab.org>

On Tue, Jan 31, 2023 at 10:36 PM Alexandre Ghiti <alexghiti@rivosinc.com>
wrote:

> Currently, the max satp mode is set with the only constraint that it must
> be
> implemented in QEMU, i.e. set in valid_vm_1_10_[32|64].
>
> But we actually need to add another level of constraint: what the hw is
> actually capable of, because currently, a linux booting on a sifive-u54
> boots in sv57 mode which is incompatible with the cpu's sv39 max
> capability.
>
> So add a new bitmap to RISCVSATPMap which contains this capability and
> initialize it in every XXX_cpu_init.
>
> Finally:
> - valid_vm_1_10_[32|64] constrains which satp mode the CPU can use
> - the CPU hw capabilities constrains what the user may select
> - the user's selection then constrains what's available to the guest
>   OS.
>
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>  target/riscv/cpu.c | 79 +++++++++++++++++++++++++++++++---------------
>  target/riscv/cpu.h |  8 +++--
>  2 files changed, 60 insertions(+), 27 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 3a7a1746aa..6dd76355ec 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -292,26 +292,36 @@ const char *satp_mode_str(uint8_t satp_mode, bool
> is_32_bit)
>      g_assert_not_reached();
>  }
>
> -/* Sets the satp mode to the max supported */
> -static void set_satp_mode_default_map(RISCVCPU *cpu)
> +static void set_satp_mode_max_supported(RISCVCPU *cpu,
> +                                        uint8_t satp_mode)
>  {
>      bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
> +    const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
>

This will break user-mode QEMU.
valid_vm_1_10_32 and valid_vm_1_10_64 are defined in !CONFIG_USER_ONLY
section.
This issue also exists in patch 3.
You have to move valid_vm_1_10_32 and valid_vm_1_10_64 out from
!CONFIG_USER_ONLY.

Regards,
Frank Chang


> -    if (riscv_feature(&cpu->env, RISCV_FEATURE_MMU)) {
> -        cpu->cfg.satp_mode.map |=
> -                        (1 << satp_mode_from_str(rv32 ? "sv32" : "sv57"));
> -    } else {
> -        cpu->cfg.satp_mode.map |= (1 << satp_mode_from_str("mbare"));
> +    for (int i = 0; i <= satp_mode; ++i) {
> +        if (valid_vm[i]) {
> +            cpu->cfg.satp_mode.supported |= (1 << i);
> +        }
>      }
>  }
>
> +/* Set the satp mode to the max supported */
> +static void set_satp_mode_default_map(RISCVCPU *cpu)
> +{
> +    cpu->cfg.satp_mode.map = cpu->cfg.satp_mode.supported;
> +}
> +
>  static void riscv_any_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>  #if defined(TARGET_RISCV32)
>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>  #elif defined(TARGET_RISCV64)
>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>  #endif
>      set_priv_version(env, PRIV_VERSION_1_12_0);
>      register_cpu_props(obj);
> @@ -321,18 +331,24 @@ static void riscv_any_cpu_init(Object *obj)
>  static void rv64_base_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>      /* We set this in the realise function */
>      set_misa(env, MXL_RV64, 0);
>      register_cpu_props(obj);
>      /* Set latest version of privileged specification */
>      set_priv_version(env, PRIV_VERSION_1_12_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>  }
>
>  static void rv64_sifive_u_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVS |
> RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV39);
>  }
>
>  static void rv64_sifive_e_cpu_init(Object *obj)
> @@ -343,6 +359,7 @@ static void rv64_sifive_e_cpu_init(Object *obj)
>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVC | RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
>      cpu->cfg.mmu = false;
> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>  }
>
>  static void rv128_base_cpu_init(Object *obj)
> @@ -354,28 +371,36 @@ static void rv128_base_cpu_init(Object *obj)
>          exit(EXIT_FAILURE);
>      }
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
>      /* We set this in the realise function */
>      set_misa(env, MXL_RV128, 0);
>      register_cpu_props(obj);
>      /* Set latest version of privileged specification */
>      set_priv_version(env, PRIV_VERSION_1_12_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>  }
>  #else
>  static void rv32_base_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>      /* We set this in the realise function */
>      set_misa(env, MXL_RV32, 0);
>      register_cpu_props(obj);
>      /* Set latest version of privileged specification */
>      set_priv_version(env, PRIV_VERSION_1_12_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>  }
>
>  static void rv32_sifive_u_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVD | RVC | RVS |
> RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>  }
>
>  static void rv32_sifive_e_cpu_init(Object *obj)
> @@ -386,6 +411,7 @@ static void rv32_sifive_e_cpu_init(Object *obj)
>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVC | RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
>      cpu->cfg.mmu = false;
> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>  }
>
>  static void rv32_ibex_cpu_init(Object *obj)
> @@ -396,6 +422,7 @@ static void rv32_ibex_cpu_init(Object *obj)
>      set_misa(env, MXL_RV32, RVI | RVM | RVC | RVU);
>      set_priv_version(env, PRIV_VERSION_1_11_0);
>      cpu->cfg.mmu = false;
> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>      cpu->cfg.epmp = true;
>  }
>
> @@ -407,6 +434,7 @@ static void rv32_imafcu_nommu_cpu_init(Object *obj)
>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVC | RVU);
>      set_priv_version(env, PRIV_VERSION_1_10_0);
>      cpu->cfg.mmu = false;
> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>  }
>  #endif
>
> @@ -698,8 +726,9 @@ static void riscv_cpu_disas_set_info(CPUState *s,
> disassemble_info *info)
>  static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp)
>  {
>      bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
> -    const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
> -    uint8_t satp_mode_max;
> +    uint8_t satp_mode_map_max;
> +    uint8_t satp_mode_supported_max =
> +
> satp_mode_max_from_map(cpu->cfg.satp_mode.supported);
>
>      if (cpu->cfg.satp_mode.map == 0) {
>          if (cpu->cfg.satp_mode.init == 0) {
> @@ -712,9 +741,10 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU
> *cpu, Error **errp)
>               * valid_vm_1_10_32/64.
>               */
>              for (int i = 1; i < 16; ++i) {
> -                if ((cpu->cfg.satp_mode.init & (1 << i)) && valid_vm[i]) {
> +                if ((cpu->cfg.satp_mode.init & (1 << i)) &&
> +                    (cpu->cfg.satp_mode.supported & (1 << i))) {
>                      for (int j = i - 1; j >= 0; --j) {
> -                        if (valid_vm[j]) {
> +                        if (cpu->cfg.satp_mode.supported & (1 << j)) {
>                              cpu->cfg.satp_mode.map |= (1 << j);
>                              break;
>                          }
> @@ -725,37 +755,36 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU
> *cpu, Error **errp)
>          }
>      }
>
> -    /* Make sure the configuration asked is supported by qemu */
> -    for (int i = 0; i < 16; ++i) {
> -        if ((cpu->cfg.satp_mode.map & (1 << i)) && !valid_vm[i]) {
> -            error_setg(errp, "satp_mode %s is not valid",
> -                       satp_mode_str(i, rv32));
> -            return;
> -        }
> +    satp_mode_map_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
> +
> +    /* Make sure the user asked for a supported configuration (HW and
> qemu) */
> +    if (satp_mode_map_max > satp_mode_supported_max) {
> +        error_setg(errp, "satp_mode %s is higher than hw max capability
> %s",
> +                   satp_mode_str(satp_mode_map_max, rv32),
> +                   satp_mode_str(satp_mode_supported_max, rv32));
> +        return;
>      }
>
>      /*
>       * Make sure the user did not ask for an invalid configuration as per
>       * the specification.
>       */
> -    satp_mode_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
> -
>      if (!rv32) {
> -        for (int i = satp_mode_max - 1; i >= 0; --i) {
> +        for (int i = satp_mode_map_max - 1; i >= 0; --i) {
>              if (!(cpu->cfg.satp_mode.map & (1 << i)) &&
>                  (cpu->cfg.satp_mode.init & (1 << i)) &&
> -                valid_vm[i]) {
> +                (cpu->cfg.satp_mode.supported & (1 << i))) {
>                  error_setg(errp, "cannot disable %s satp mode if %s "
>                             "is enabled", satp_mode_str(i, false),
> -                           satp_mode_str(satp_mode_max, false));
> +                           satp_mode_str(satp_mode_map_max, false));
>                  return;
>              }
>          }
>      }
>
>      /* Finally expand the map so that all valid modes are set */
> -    for (int i = satp_mode_max - 1; i >= 0; --i) {
> -        if (valid_vm[i]) {
> +    for (int i = satp_mode_map_max - 1; i >= 0; --i) {
> +        if (cpu->cfg.satp_mode.supported & (1 << i)) {
>              cpu->cfg.satp_mode.map |= (1 << i);
>          }
>      }
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index e37177db5c..b591122099 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -416,13 +416,17 @@ struct RISCVCPUClass {
>
>  /*
>   * map is a 16-bit bitmap: the most significant set bit in map is the
> maximum
> - * satp mode that is supported.
> + * satp mode that is supported. It may be chosen by the user and must
> respect
> + * what qemu implements (valid_1_10_32/64) and what the hw is capable of
> + * (supported bitmap below).
>   *
>   * init is a 16-bit bitmap used to make sure the user selected a correct
>   * configuration as per the specification.
> + *
> + * supported is a 16-bit bitmap used to reflect the hw capabilities.
>   */
>  typedef struct {
> -    uint16_t map, init;
> +    uint16_t map, init, supported;
>  } RISCVSATPMap;
>
>  struct RISCVCPUConfig {
> --
> 2.37.2
>
>
>

Hi Frank,

On Wed, Feb 1, 2023 at 4:49 PM Frank Chang <frank.chang@sifive.com> wrote:
>
> On Tue, Jan 31, 2023 at 10:36 PM Alexandre Ghiti <alexghiti@rivosinc.com> wrote:
>>
>> Currently, the max satp mode is set with the only constraint that it must be
>> implemented in QEMU, i.e. set in valid_vm_1_10_[32|64].
>>
>> But we actually need to add another level of constraint: what the hw is
>> actually capable of, because currently, a linux booting on a sifive-u54
>> boots in sv57 mode which is incompatible with the cpu's sv39 max
>> capability.
>>
>> So add a new bitmap to RISCVSATPMap which contains this capability and
>> initialize it in every XXX_cpu_init.
>>
>> Finally:
>> - valid_vm_1_10_[32|64] constrains which satp mode the CPU can use
>> - the CPU hw capabilities constrains what the user may select
>> - the user's selection then constrains what's available to the guest
>>   OS.
>>
>> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
>> ---
>>  target/riscv/cpu.c | 79 +++++++++++++++++++++++++++++++---------------
>>  target/riscv/cpu.h |  8 +++--
>>  2 files changed, 60 insertions(+), 27 deletions(-)
>>
>> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
>> index 3a7a1746aa..6dd76355ec 100644
>> --- a/target/riscv/cpu.c
>> +++ b/target/riscv/cpu.c
>> @@ -292,26 +292,36 @@ const char *satp_mode_str(uint8_t satp_mode, bool is_32_bit)
>>      g_assert_not_reached();
>>  }
>>
>> -/* Sets the satp mode to the max supported */
>> -static void set_satp_mode_default_map(RISCVCPU *cpu)
>> +static void set_satp_mode_max_supported(RISCVCPU *cpu,
>> +                                        uint8_t satp_mode)
>>  {
>>      bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
>> +    const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
>
>
> This will break user-mode QEMU.
> valid_vm_1_10_32 and valid_vm_1_10_64 are defined in !CONFIG_USER_ONLY section.
> This issue also exists in patch 3.
> You have to move valid_vm_1_10_32 and valid_vm_1_10_64 out from !CONFIG_USER_ONLY.

Indeed, good catch, thanks! Rather than moving valid_vm_1_10_[32|64],
I'm going to try to surround all the satp handling inside #ifdef
CONFIG_USER_ONLY. But if it's too cumbersome, I'll do as you suggest.

Thanks again,

Alex

>
> Regards,
> Frank Chang
>
>>
>> -    if (riscv_feature(&cpu->env, RISCV_FEATURE_MMU)) {
>> -        cpu->cfg.satp_mode.map |=
>> -                        (1 << satp_mode_from_str(rv32 ? "sv32" : "sv57"));
>> -    } else {
>> -        cpu->cfg.satp_mode.map |= (1 << satp_mode_from_str("mbare"));
>> +    for (int i = 0; i <= satp_mode; ++i) {
>> +        if (valid_vm[i]) {
>> +            cpu->cfg.satp_mode.supported |= (1 << i);
>> +        }
>>      }
>>  }
>>
>> +/* Set the satp mode to the max supported */
>> +static void set_satp_mode_default_map(RISCVCPU *cpu)
>> +{
>> +    cpu->cfg.satp_mode.map = cpu->cfg.satp_mode.supported;
>> +}
>> +
>>  static void riscv_any_cpu_init(Object *obj)
>>  {
>>      CPURISCVState *env = &RISCV_CPU(obj)->env;
>> +    RISCVCPU *cpu = RISCV_CPU(obj);
>> +
>>  #if defined(TARGET_RISCV32)
>>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
>> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>>  #elif defined(TARGET_RISCV64)
>>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
>> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>>  #endif
>>      set_priv_version(env, PRIV_VERSION_1_12_0);
>>      register_cpu_props(obj);
>> @@ -321,18 +331,24 @@ static void riscv_any_cpu_init(Object *obj)
>>  static void rv64_base_cpu_init(Object *obj)
>>  {
>>      CPURISCVState *env = &RISCV_CPU(obj)->env;
>> +    RISCVCPU *cpu = RISCV_CPU(obj);
>> +
>>      /* We set this in the realise function */
>>      set_misa(env, MXL_RV64, 0);
>>      register_cpu_props(obj);
>>      /* Set latest version of privileged specification */
>>      set_priv_version(env, PRIV_VERSION_1_12_0);
>> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>>  }
>>
>>  static void rv64_sifive_u_cpu_init(Object *obj)
>>  {
>>      CPURISCVState *env = &RISCV_CPU(obj)->env;
>> +    RISCVCPU *cpu = RISCV_CPU(obj);
>> +
>>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
>>      set_priv_version(env, PRIV_VERSION_1_10_0);
>> +    set_satp_mode_max_supported(cpu, VM_1_10_SV39);
>>  }
>>
>>  static void rv64_sifive_e_cpu_init(Object *obj)
>> @@ -343,6 +359,7 @@ static void rv64_sifive_e_cpu_init(Object *obj)
>>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVC | RVU);
>>      set_priv_version(env, PRIV_VERSION_1_10_0);
>>      cpu->cfg.mmu = false;
>> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>>  }
>>
>>  static void rv128_base_cpu_init(Object *obj)
>> @@ -354,28 +371,36 @@ static void rv128_base_cpu_init(Object *obj)
>>          exit(EXIT_FAILURE);
>>      }
>>      CPURISCVState *env = &RISCV_CPU(obj)->env;
>> +    RISCVCPU *cpu = RISCV_CPU(obj);
>>      /* We set this in the realise function */
>>      set_misa(env, MXL_RV128, 0);
>>      register_cpu_props(obj);
>>      /* Set latest version of privileged specification */
>>      set_priv_version(env, PRIV_VERSION_1_12_0);
>> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
>>  }
>>  #else
>>  static void rv32_base_cpu_init(Object *obj)
>>  {
>>      CPURISCVState *env = &RISCV_CPU(obj)->env;
>> +    RISCVCPU *cpu = RISCV_CPU(obj);
>> +
>>      /* We set this in the realise function */
>>      set_misa(env, MXL_RV32, 0);
>>      register_cpu_props(obj);
>>      /* Set latest version of privileged specification */
>>      set_priv_version(env, PRIV_VERSION_1_12_0);
>> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>>  }
>>
>>  static void rv32_sifive_u_cpu_init(Object *obj)
>>  {
>>      CPURISCVState *env = &RISCV_CPU(obj)->env;
>> +    RISCVCPU *cpu = RISCV_CPU(obj);
>> +
>>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
>>      set_priv_version(env, PRIV_VERSION_1_10_0);
>> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
>>  }
>>
>>  static void rv32_sifive_e_cpu_init(Object *obj)
>> @@ -386,6 +411,7 @@ static void rv32_sifive_e_cpu_init(Object *obj)
>>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVC | RVU);
>>      set_priv_version(env, PRIV_VERSION_1_10_0);
>>      cpu->cfg.mmu = false;
>> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>>  }
>>
>>  static void rv32_ibex_cpu_init(Object *obj)
>> @@ -396,6 +422,7 @@ static void rv32_ibex_cpu_init(Object *obj)
>>      set_misa(env, MXL_RV32, RVI | RVM | RVC | RVU);
>>      set_priv_version(env, PRIV_VERSION_1_11_0);
>>      cpu->cfg.mmu = false;
>> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>>      cpu->cfg.epmp = true;
>>  }
>>
>> @@ -407,6 +434,7 @@ static void rv32_imafcu_nommu_cpu_init(Object *obj)
>>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVC | RVU);
>>      set_priv_version(env, PRIV_VERSION_1_10_0);
>>      cpu->cfg.mmu = false;
>> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
>>  }
>>  #endif
>>
>> @@ -698,8 +726,9 @@ static void riscv_cpu_disas_set_info(CPUState *s, disassemble_info *info)
>>  static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp)
>>  {
>>      bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
>> -    const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
>> -    uint8_t satp_mode_max;
>> +    uint8_t satp_mode_map_max;
>> +    uint8_t satp_mode_supported_max =
>> +                        satp_mode_max_from_map(cpu->cfg.satp_mode.supported);
>>
>>      if (cpu->cfg.satp_mode.map == 0) {
>>          if (cpu->cfg.satp_mode.init == 0) {
>> @@ -712,9 +741,10 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp)
>>               * valid_vm_1_10_32/64.
>>               */
>>              for (int i = 1; i < 16; ++i) {
>> -                if ((cpu->cfg.satp_mode.init & (1 << i)) && valid_vm[i]) {
>> +                if ((cpu->cfg.satp_mode.init & (1 << i)) &&
>> +                    (cpu->cfg.satp_mode.supported & (1 << i))) {
>>                      for (int j = i - 1; j >= 0; --j) {
>> -                        if (valid_vm[j]) {
>> +                        if (cpu->cfg.satp_mode.supported & (1 << j)) {
>>                              cpu->cfg.satp_mode.map |= (1 << j);
>>                              break;
>>                          }
>> @@ -725,37 +755,36 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp)
>>          }
>>      }
>>
>> -    /* Make sure the configuration asked is supported by qemu */
>> -    for (int i = 0; i < 16; ++i) {
>> -        if ((cpu->cfg.satp_mode.map & (1 << i)) && !valid_vm[i]) {
>> -            error_setg(errp, "satp_mode %s is not valid",
>> -                       satp_mode_str(i, rv32));
>> -            return;
>> -        }
>> +    satp_mode_map_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
>> +
>> +    /* Make sure the user asked for a supported configuration (HW and qemu) */
>> +    if (satp_mode_map_max > satp_mode_supported_max) {
>> +        error_setg(errp, "satp_mode %s is higher than hw max capability %s",
>> +                   satp_mode_str(satp_mode_map_max, rv32),
>> +                   satp_mode_str(satp_mode_supported_max, rv32));
>> +        return;
>>      }
>>
>>      /*
>>       * Make sure the user did not ask for an invalid configuration as per
>>       * the specification.
>>       */
>> -    satp_mode_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
>> -
>>      if (!rv32) {
>> -        for (int i = satp_mode_max - 1; i >= 0; --i) {
>> +        for (int i = satp_mode_map_max - 1; i >= 0; --i) {
>>              if (!(cpu->cfg.satp_mode.map & (1 << i)) &&
>>                  (cpu->cfg.satp_mode.init & (1 << i)) &&
>> -                valid_vm[i]) {
>> +                (cpu->cfg.satp_mode.supported & (1 << i))) {
>>                  error_setg(errp, "cannot disable %s satp mode if %s "
>>                             "is enabled", satp_mode_str(i, false),
>> -                           satp_mode_str(satp_mode_max, false));
>> +                           satp_mode_str(satp_mode_map_max, false));
>>                  return;
>>              }
>>          }
>>      }
>>
>>      /* Finally expand the map so that all valid modes are set */
>> -    for (int i = satp_mode_max - 1; i >= 0; --i) {
>> -        if (valid_vm[i]) {
>> +    for (int i = satp_mode_map_max - 1; i >= 0; --i) {
>> +        if (cpu->cfg.satp_mode.supported & (1 << i)) {
>>              cpu->cfg.satp_mode.map |= (1 << i);
>>          }
>>      }
>> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
>> index e37177db5c..b591122099 100644
>> --- a/target/riscv/cpu.h
>> +++ b/target/riscv/cpu.h
>> @@ -416,13 +416,17 @@ struct RISCVCPUClass {
>>
>>  /*
>>   * map is a 16-bit bitmap: the most significant set bit in map is the maximum
>> - * satp mode that is supported.
>> + * satp mode that is supported. It may be chosen by the user and must respect
>> + * what qemu implements (valid_1_10_32/64) and what the hw is capable of
>> + * (supported bitmap below).
>>   *
>>   * init is a 16-bit bitmap used to make sure the user selected a correct
>>   * configuration as per the specification.
>> + *
>> + * supported is a 16-bit bitmap used to reflect the hw capabilities.
>>   */
>>  typedef struct {
>> -    uint16_t map, init;
>> +    uint16_t map, init, supported;
>>  } RISCVSATPMap;
>>
>>  struct RISCVCPUConfig {
>> --
>> 2.37.2
>>
>>

On Thu, Feb 2, 2023 at 9:01 PM Alexandre Ghiti <alexghiti@rivosinc.com>
wrote:

> Hi Frank,
>
> On Wed, Feb 1, 2023 at 4:49 PM Frank Chang <frank.chang@sifive.com> wrote:
> >
> > On Tue, Jan 31, 2023 at 10:36 PM Alexandre Ghiti <alexghiti@rivosinc.com>
> wrote:
> >>
> >> Currently, the max satp mode is set with the only constraint that it
> must be
> >> implemented in QEMU, i.e. set in valid_vm_1_10_[32|64].
> >>
> >> But we actually need to add another level of constraint: what the hw is
> >> actually capable of, because currently, a linux booting on a sifive-u54
> >> boots in sv57 mode which is incompatible with the cpu's sv39 max
> >> capability.
> >>
> >> So add a new bitmap to RISCVSATPMap which contains this capability and
> >> initialize it in every XXX_cpu_init.
> >>
> >> Finally:
> >> - valid_vm_1_10_[32|64] constrains which satp mode the CPU can use
> >> - the CPU hw capabilities constrains what the user may select
> >> - the user's selection then constrains what's available to the guest
> >>   OS.
> >>
> >> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> >> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> >> ---
> >>  target/riscv/cpu.c | 79 +++++++++++++++++++++++++++++++---------------
> >>  target/riscv/cpu.h |  8 +++--
> >>  2 files changed, 60 insertions(+), 27 deletions(-)
> >>
> >> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> >> index 3a7a1746aa..6dd76355ec 100644
> >> --- a/target/riscv/cpu.c
> >> +++ b/target/riscv/cpu.c
> >> @@ -292,26 +292,36 @@ const char *satp_mode_str(uint8_t satp_mode, bool
> is_32_bit)
> >>      g_assert_not_reached();
> >>  }
> >>
> >> -/* Sets the satp mode to the max supported */
> >> -static void set_satp_mode_default_map(RISCVCPU *cpu)
> >> +static void set_satp_mode_max_supported(RISCVCPU *cpu,
> >> +                                        uint8_t satp_mode)
> >>  {
> >>      bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
> >> +    const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
> >
> >
> > This will break user-mode QEMU.
> > valid_vm_1_10_32 and valid_vm_1_10_64 are defined in !CONFIG_USER_ONLY
> section.
> > This issue also exists in patch 3.
> > You have to move valid_vm_1_10_32 and valid_vm_1_10_64 out from
> !CONFIG_USER_ONLY.
>
> Indeed, good catch, thanks! Rather than moving valid_vm_1_10_[32|64],
> I'm going to try to surround all the satp handling inside #ifdef
> CONFIG_USER_ONLY. But if it's too cumbersome, I'll do as you suggest.
>

Hi Alex,

I think surrounding all the satp handling inside #ifdef is okay,
since satp is not been used in user-mode QEMU.

Regards,
Frank Chang


>
> Thanks again,
>
> Alex
>
> >
> > Regards,
> > Frank Chang
> >
> >>
> >> -    if (riscv_feature(&cpu->env, RISCV_FEATURE_MMU)) {
> >> -        cpu->cfg.satp_mode.map |=
> >> -                        (1 << satp_mode_from_str(rv32 ? "sv32" :
> "sv57"));
> >> -    } else {
> >> -        cpu->cfg.satp_mode.map |= (1 << satp_mode_from_str("mbare"));
> >> +    for (int i = 0; i <= satp_mode; ++i) {
> >> +        if (valid_vm[i]) {
> >> +            cpu->cfg.satp_mode.supported |= (1 << i);
> >> +        }
> >>      }
> >>  }
> >>
> >> +/* Set the satp mode to the max supported */
> >> +static void set_satp_mode_default_map(RISCVCPU *cpu)
> >> +{
> >> +    cpu->cfg.satp_mode.map = cpu->cfg.satp_mode.supported;
> >> +}
> >> +
> >>  static void riscv_any_cpu_init(Object *obj)
> >>  {
> >>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> >> +    RISCVCPU *cpu = RISCV_CPU(obj);
> >> +
> >>  #if defined(TARGET_RISCV32)
> >>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
> >>  #elif defined(TARGET_RISCV64)
> >>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
> >>  #endif
> >>      set_priv_version(env, PRIV_VERSION_1_12_0);
> >>      register_cpu_props(obj);
> >> @@ -321,18 +331,24 @@ static void riscv_any_cpu_init(Object *obj)
> >>  static void rv64_base_cpu_init(Object *obj)
> >>  {
> >>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> >> +    RISCVCPU *cpu = RISCV_CPU(obj);
> >> +
> >>      /* We set this in the realise function */
> >>      set_misa(env, MXL_RV64, 0);
> >>      register_cpu_props(obj);
> >>      /* Set latest version of privileged specification */
> >>      set_priv_version(env, PRIV_VERSION_1_12_0);
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
> >>  }
> >>
> >>  static void rv64_sifive_u_cpu_init(Object *obj)
> >>  {
> >>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> >> +    RISCVCPU *cpu = RISCV_CPU(obj);
> >> +
> >>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVS |
> RVU);
> >>      set_priv_version(env, PRIV_VERSION_1_10_0);
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_SV39);
> >>  }
> >>
> >>  static void rv64_sifive_e_cpu_init(Object *obj)
> >> @@ -343,6 +359,7 @@ static void rv64_sifive_e_cpu_init(Object *obj)
> >>      set_misa(env, MXL_RV64, RVI | RVM | RVA | RVC | RVU);
> >>      set_priv_version(env, PRIV_VERSION_1_10_0);
> >>      cpu->cfg.mmu = false;
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
> >>  }
> >>
> >>  static void rv128_base_cpu_init(Object *obj)
> >> @@ -354,28 +371,36 @@ static void rv128_base_cpu_init(Object *obj)
> >>          exit(EXIT_FAILURE);
> >>      }
> >>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> >> +    RISCVCPU *cpu = RISCV_CPU(obj);
> >>      /* We set this in the realise function */
> >>      set_misa(env, MXL_RV128, 0);
> >>      register_cpu_props(obj);
> >>      /* Set latest version of privileged specification */
> >>      set_priv_version(env, PRIV_VERSION_1_12_0);
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_SV57);
> >>  }
> >>  #else
> >>  static void rv32_base_cpu_init(Object *obj)
> >>  {
> >>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> >> +    RISCVCPU *cpu = RISCV_CPU(obj);
> >> +
> >>      /* We set this in the realise function */
> >>      set_misa(env, MXL_RV32, 0);
> >>      register_cpu_props(obj);
> >>      /* Set latest version of privileged specification */
> >>      set_priv_version(env, PRIV_VERSION_1_12_0);
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
> >>  }
> >>
> >>  static void rv32_sifive_u_cpu_init(Object *obj)
> >>  {
> >>      CPURISCVState *env = &RISCV_CPU(obj)->env;
> >> +    RISCVCPU *cpu = RISCV_CPU(obj);
> >> +
> >>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVD | RVC | RVS |
> RVU);
> >>      set_priv_version(env, PRIV_VERSION_1_10_0);
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_SV32);
> >>  }
> >>
> >>  static void rv32_sifive_e_cpu_init(Object *obj)
> >> @@ -386,6 +411,7 @@ static void rv32_sifive_e_cpu_init(Object *obj)
> >>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVC | RVU);
> >>      set_priv_version(env, PRIV_VERSION_1_10_0);
> >>      cpu->cfg.mmu = false;
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
> >>  }
> >>
> >>  static void rv32_ibex_cpu_init(Object *obj)
> >> @@ -396,6 +422,7 @@ static void rv32_ibex_cpu_init(Object *obj)
> >>      set_misa(env, MXL_RV32, RVI | RVM | RVC | RVU);
> >>      set_priv_version(env, PRIV_VERSION_1_11_0);
> >>      cpu->cfg.mmu = false;
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
> >>      cpu->cfg.epmp = true;
> >>  }
> >>
> >> @@ -407,6 +434,7 @@ static void rv32_imafcu_nommu_cpu_init(Object *obj)
> >>      set_misa(env, MXL_RV32, RVI | RVM | RVA | RVF | RVC | RVU);
> >>      set_priv_version(env, PRIV_VERSION_1_10_0);
> >>      cpu->cfg.mmu = false;
> >> +    set_satp_mode_max_supported(cpu, VM_1_10_MBARE);
> >>  }
> >>  #endif
> >>
> >> @@ -698,8 +726,9 @@ static void riscv_cpu_disas_set_info(CPUState *s,
> disassemble_info *info)
> >>  static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu, Error **errp)
> >>  {
> >>      bool rv32 = riscv_cpu_mxl(&cpu->env) == MXL_RV32;
> >> -    const bool *valid_vm = rv32 ? valid_vm_1_10_32 : valid_vm_1_10_64;
> >> -    uint8_t satp_mode_max;
> >> +    uint8_t satp_mode_map_max;
> >> +    uint8_t satp_mode_supported_max =
> >> +
> satp_mode_max_from_map(cpu->cfg.satp_mode.supported);
> >>
> >>      if (cpu->cfg.satp_mode.map == 0) {
> >>          if (cpu->cfg.satp_mode.init == 0) {
> >> @@ -712,9 +741,10 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU
> *cpu, Error **errp)
> >>               * valid_vm_1_10_32/64.
> >>               */
> >>              for (int i = 1; i < 16; ++i) {
> >> -                if ((cpu->cfg.satp_mode.init & (1 << i)) &&
> valid_vm[i]) {
> >> +                if ((cpu->cfg.satp_mode.init & (1 << i)) &&
> >> +                    (cpu->cfg.satp_mode.supported & (1 << i))) {
> >>                      for (int j = i - 1; j >= 0; --j) {
> >> -                        if (valid_vm[j]) {
> >> +                        if (cpu->cfg.satp_mode.supported & (1 << j)) {
> >>                              cpu->cfg.satp_mode.map |= (1 << j);
> >>                              break;
> >>                          }
> >> @@ -725,37 +755,36 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU
> *cpu, Error **errp)
> >>          }
> >>      }
> >>
> >> -    /* Make sure the configuration asked is supported by qemu */
> >> -    for (int i = 0; i < 16; ++i) {
> >> -        if ((cpu->cfg.satp_mode.map & (1 << i)) && !valid_vm[i]) {
> >> -            error_setg(errp, "satp_mode %s is not valid",
> >> -                       satp_mode_str(i, rv32));
> >> -            return;
> >> -        }
> >> +    satp_mode_map_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
> >> +
> >> +    /* Make sure the user asked for a supported configuration (HW and
> qemu) */
> >> +    if (satp_mode_map_max > satp_mode_supported_max) {
> >> +        error_setg(errp, "satp_mode %s is higher than hw max
> capability %s",
> >> +                   satp_mode_str(satp_mode_map_max, rv32),
> >> +                   satp_mode_str(satp_mode_supported_max, rv32));
> >> +        return;
> >>      }
> >>
> >>      /*
> >>       * Make sure the user did not ask for an invalid configuration as
> per
> >>       * the specification.
> >>       */
> >> -    satp_mode_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
> >> -
> >>      if (!rv32) {
> >> -        for (int i = satp_mode_max - 1; i >= 0; --i) {
> >> +        for (int i = satp_mode_map_max - 1; i >= 0; --i) {
> >>              if (!(cpu->cfg.satp_mode.map & (1 << i)) &&
> >>                  (cpu->cfg.satp_mode.init & (1 << i)) &&
> >> -                valid_vm[i]) {
> >> +                (cpu->cfg.satp_mode.supported & (1 << i))) {
> >>                  error_setg(errp, "cannot disable %s satp mode if %s "
> >>                             "is enabled", satp_mode_str(i, false),
> >> -                           satp_mode_str(satp_mode_max, false));
> >> +                           satp_mode_str(satp_mode_map_max, false));
> >>                  return;
> >>              }
> >>          }
> >>      }
> >>
> >>      /* Finally expand the map so that all valid modes are set */
> >> -    for (int i = satp_mode_max - 1; i >= 0; --i) {
> >> -        if (valid_vm[i]) {
> >> +    for (int i = satp_mode_map_max - 1; i >= 0; --i) {
> >> +        if (cpu->cfg.satp_mode.supported & (1 << i)) {
> >>              cpu->cfg.satp_mode.map |= (1 << i);
> >>          }
> >>      }
> >> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> >> index e37177db5c..b591122099 100644
> >> --- a/target/riscv/cpu.h
> >> +++ b/target/riscv/cpu.h
> >> @@ -416,13 +416,17 @@ struct RISCVCPUClass {
> >>
> >>  /*
> >>   * map is a 16-bit bitmap: the most significant set bit in map is the
> maximum
> >> - * satp mode that is supported.
> >> + * satp mode that is supported. It may be chosen by the user and must
> respect
> >> + * what qemu implements (valid_1_10_32/64) and what the hw is capable
> of
> >> + * (supported bitmap below).
> >>   *
> >>   * init is a 16-bit bitmap used to make sure the user selected a
> correct
> >>   * configuration as per the specification.
> >> + *
> >> + * supported is a 16-bit bitmap used to reflect the hw capabilities.
> >>   */
> >>  typedef struct {
> >> -    uint16_t map, init;
> >> +    uint16_t map, init, supported;
> >>  } RISCVSATPMap;
> >>
> >>  struct RISCVCPUConfig {
> >> --
> >> 2.37.2
> >>
> >>
>