diff options
Diffstat (limited to 'target/riscv/csr.c')
| -rw-r--r-- | target/riscv/csr.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/target/riscv/csr.c b/target/riscv/csr.c index 1c2d3f7193..3500e07f92 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -24,6 +24,8 @@ #include "qemu/main-loop.h" #include "exec/exec-all.h" #include "sysemu/cpu-timers.h" +#include "qemu/guest-random.h" +#include "qapi/error.h" /* CSR function table public API */ void riscv_get_csr_ops(int csrno, riscv_csr_operations *ops) @@ -301,6 +303,46 @@ static RISCVException debug(CPURISCVState *env, int csrno) } #endif +static RISCVException seed(CPURISCVState *env, int csrno) +{ + RISCVCPU *cpu = env_archcpu(env); + + if (!cpu->cfg.ext_zkr) { + return RISCV_EXCP_ILLEGAL_INST; + } + +#if !defined(CONFIG_USER_ONLY) + /* + * With a CSR read-write instruction: + * 1) The seed CSR is always available in machine mode as normal. + * 2) Attempted access to seed from virtual modes VS and VU always raises + * an exception(virtual instruction exception only if mseccfg.sseed=1). + * 3) Without the corresponding access control bit set to 1, any attempted + * access to seed from U, S or HS modes will raise an illegal instruction + * exception. + */ + if (env->priv == PRV_M) { + return RISCV_EXCP_NONE; + } else if (riscv_cpu_virt_enabled(env)) { + if (env->mseccfg & MSECCFG_SSEED) { + return RISCV_EXCP_VIRT_INSTRUCTION_FAULT; + } else { + return RISCV_EXCP_ILLEGAL_INST; + } + } else { + if (env->priv == PRV_S && (env->mseccfg & MSECCFG_SSEED)) { + return RISCV_EXCP_NONE; + } else if (env->priv == PRV_U && (env->mseccfg & MSECCFG_USEED)) { + return RISCV_EXCP_NONE; + } else { + return RISCV_EXCP_ILLEGAL_INST; + } + } +#else + return RISCV_EXCP_NONE; +#endif +} + /* User Floating-Point CSRs */ static RISCVException read_fflags(CPURISCVState *env, int csrno, target_ulong *val) @@ -3044,6 +3086,41 @@ static RISCVException write_upmbase(CPURISCVState *env, int csrno, #endif +/* Crypto Extension */ +static RISCVException rmw_seed(CPURISCVState *env, int csrno, + target_ulong *ret_value, + target_ulong new_value, + target_ulong write_mask) +{ + uint16_t random_v; + Error *random_e = NULL; + int random_r; + target_ulong rval; + + random_r = qemu_guest_getrandom(&random_v, 2, &random_e); + if (unlikely(random_r < 0)) { + /* + * Failed, for unknown reasons in the crypto subsystem. + * The best we can do is log the reason and return a + * failure indication to the guest. There is no reason + * we know to expect the failure to be transitory, so + * indicate DEAD to avoid having the guest spin on WAIT. + */ + qemu_log_mask(LOG_UNIMP, "%s: Crypto failure: %s", + __func__, error_get_pretty(random_e)); + error_free(random_e); + rval = SEED_OPST_DEAD; + } else { + rval = random_v | SEED_OPST_ES16; + } + + if (ret_value) { + *ret_value = rval; + } + + return RISCV_EXCP_NONE; +} + /* * riscv_csrrw - read and/or update control and status register * @@ -3282,6 +3359,9 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = { [CSR_TIME] = { "time", ctr, read_time }, [CSR_TIMEH] = { "timeh", ctr32, read_timeh }, + /* Crypto Extension */ + [CSR_SEED] = { "seed", seed, NULL, NULL, rmw_seed }, + #if !defined(CONFIG_USER_ONLY) /* Machine Timers and Counters */ [CSR_MCYCLE] = { "mcycle", any, read_instret }, |