On Mon, Jan 23, 2023 at 10:03:24AM +0100, Alexandre Ghiti 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, we have the following chain of constraints:
>
> Qemu capability > HW capability > User choice > Software capability
>
> Signed-off-by: Alexandre Ghiti <alexgh...@rivosinc.com>
> ---
> target/riscv/cpu.c | 78 +++++++++++++++++++++++++++++++---------------
> target/riscv/cpu.h | 8 +++--
> 2 files changed, 59 insertions(+), 27 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index e409e6ab64..19a37fee2b 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -292,24 +292,39 @@ 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(RISCVCPU *cpu, bool is_32_bit)
> +static void set_satp_mode_max_supported(RISCVCPU *cpu,
> + const char *satp_mode_str,
> + bool is_32_bit)
I'd drop 'is_32_bit' and get it from 'cpu', which would "clean up" all the
callsites by getting rid of all the true/false stuff. Also, why take the
string instead of the VM_1_10_SV* define?
> {
> - if (riscv_feature(&cpu->env, RISCV_FEATURE_MMU)) {
> - cpu->cfg.satp_mode.map |=
> - (1 << satp_mode_from_str(is_32_bit ? "sv32" :
> "sv57"));
> - } else {
> - cpu->cfg.satp_mode.map |= (1 << satp_mode_from_str("mbare"));
> + uint8_t satp_mode = satp_mode_from_str(satp_mode_str);
> + const bool *valid_vm = is_32_bit ? valid_vm_1_10_32 : valid_vm_1_10_64;
> +
> + for (int i = 0; i <= satp_mode; ++i) {
> + if (valid_vm[i]) {
> + cpu->cfg.satp_mode.supported |= (1 << i);
> + }
> }
> }
>
> +/* Sets the satp mode to the max supported */
> +static void set_satp_mode_default(RISCVCPU *cpu)
> +{
> + uint8_t satp_mode = satp_mode_max_from_map(cpu->cfg.satp_mode.supported);
> +
> + cpu->cfg.satp_mode.map |= (1 << satp_mode);
Let's do 'cpu->cfg.satp_mode.map = cpu->cfg.satp_mode.supported' to make
sure 'map' has all supported bits set for property probing.
> +}
> +
> 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, "sv32", true);
> #elif defined(TARGET_RISCV64)
> set_misa(env, MXL_RV64, RVI | RVM | RVA | RVF | RVD | RVC | RVU);
> + set_satp_mode_max_supported(cpu, "sv57", false);
> #endif
> set_priv_version(env, PRIV_VERSION_1_12_0);
> register_cpu_props(obj);
> @@ -319,18 +334,24 @@ 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, "sv57", false);
> }
>
> 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, "sv39", false);
> }
>
> static void rv64_sifive_e_cpu_init(Object *obj)
> @@ -341,6 +362,7 @@ 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, "mbare", false);
> }
>
> static void rv128_base_cpu_init(Object *obj)
> @@ -352,11 +374,13 @@ 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, "sv57", false);
> }
> #else
> static void rv32_base_cpu_init(Object *obj)
> @@ -367,13 +391,17 @@ static void rv32_base_cpu_init(Object *obj)
> 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, "sv32", true);
> }
>
> 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, "sv32", true);
> }
>
> static void rv32_sifive_e_cpu_init(Object *obj)
> @@ -384,6 +412,7 @@ 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, "mbare", true);
> }
>
> static void rv32_ibex_cpu_init(Object *obj)
> @@ -394,6 +423,7 @@ 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, "mbare", true);
> cpu->cfg.epmp = true;
> }
>
> @@ -405,6 +435,7 @@ 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, "mbare", true);
> }
> #endif
>
> @@ -696,7 +727,9 @@ 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_map_max =
> satp_mode_max_from_map(cpu->cfg.satp_mode.map);
> + uint8_t satp_mode_supported_max =
> + satp_mode_max_from_map(cpu->cfg.satp_mode.supported);
>
> if (cpu->cfg.satp_mode.map == 0) {
> /*
> @@ -704,7 +737,7 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu,
> Error **errp)
> * satp mode.
> */
> if (cpu->cfg.satp_mode.init == 0) {
> - set_satp_mode_default(cpu, rv32);
> + set_satp_mode_default(cpu);
> } else {
> /*
> * Find the lowest level that was disabled and then enable the
> @@ -714,9 +747,9 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu,
> Error **errp)
> for (int i = 1; i < 16; ++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))) {
> 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;
> }
> @@ -727,13 +760,12 @@ 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;
> - }
> + /* 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;
> }
>
> /*
> @@ -741,17 +773,13 @@ static void riscv_cpu_satp_mode_finalize(RISCVCPU *cpu,
> Error **errp)
> * the specification.
> */
> if (!rv32) {
> - uint8_t satp_mode_max;
> -
> - satp_mode_max = satp_mode_max_from_map(cpu->cfg.satp_mode.map);
> -
> - 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;
> }
> }
> 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
>
Thanks,
drew
