From 3bee0e40106df7926e38464d0e9f34a57a0a01ad Mon Sep 17 00:00:00 2001 From: Mayuresh Chitale Date: Sun, 16 Oct 2022 18:17:22 +0530 Subject: [PATCH] target/riscv: Add smstateen support Smstateen extension specifies a mechanism to close the potential covert channels that could cause security issues. This patch adds the CSRs defined in the specification and the corresponding predicates and read/write functions. Signed-off-by: Mayuresh Chitale Reviewed-by: Weiwei Li Reviewed-by: Alistair Francis Message-Id: <20221016124726.102129-2-mchitale@ventanamicro.com> Signed-off-by: Alistair Francis --- target/riscv/cpu.h | 4 + target/riscv/cpu_bits.h | 37 +++++ target/riscv/csr.c | 316 ++++++++++++++++++++++++++++++++++++++++ target/riscv/machine.c | 21 +++ 4 files changed, 378 insertions(+) diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h index 443d15a47c..5cac0c5eec 100644 --- a/target/riscv/cpu.h +++ b/target/riscv/cpu.h @@ -366,6 +366,9 @@ struct CPUArchState { /* CSRs for execution enviornment configuration */ uint64_t menvcfg; + uint64_t mstateen[SMSTATEEN_MAX_COUNT]; + uint64_t hstateen[SMSTATEEN_MAX_COUNT]; + uint64_t sstateen[SMSTATEEN_MAX_COUNT]; target_ulong senvcfg; uint64_t henvcfg; #endif @@ -441,6 +444,7 @@ struct RISCVCPUConfig { bool ext_ifencei; bool ext_icsr; bool ext_zihintpause; + bool ext_smstateen; bool ext_sstc; bool ext_svinval; bool ext_svnapot; diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h index d8f5f0abed..8b0d7e20ea 100644 --- a/target/riscv/cpu_bits.h +++ b/target/riscv/cpu_bits.h @@ -197,6 +197,12 @@ /* Supervisor Configuration CSRs */ #define CSR_SENVCFG 0x10A +/* Supervisor state CSRs */ +#define CSR_SSTATEEN0 0x10C +#define CSR_SSTATEEN1 0x10D +#define CSR_SSTATEEN2 0x10E +#define CSR_SSTATEEN3 0x10F + /* Supervisor Trap Handling */ #define CSR_SSCRATCH 0x140 #define CSR_SEPC 0x141 @@ -244,6 +250,16 @@ #define CSR_HENVCFG 0x60A #define CSR_HENVCFGH 0x61A +/* Hypervisor state CSRs */ +#define CSR_HSTATEEN0 0x60C +#define CSR_HSTATEEN0H 0x61C +#define CSR_HSTATEEN1 0x60D +#define CSR_HSTATEEN1H 0x61D +#define CSR_HSTATEEN2 0x60E +#define CSR_HSTATEEN2H 0x61E +#define CSR_HSTATEEN3 0x60F +#define CSR_HSTATEEN3H 0x61F + /* Virtual CSRs */ #define CSR_VSSTATUS 0x200 #define CSR_VSIE 0x204 @@ -289,6 +305,27 @@ #define CSR_MENVCFG 0x30A #define CSR_MENVCFGH 0x31A +/* Machine state CSRs */ +#define CSR_MSTATEEN0 0x30C +#define CSR_MSTATEEN0H 0x31C +#define CSR_MSTATEEN1 0x30D +#define CSR_MSTATEEN1H 0x31D +#define CSR_MSTATEEN2 0x30E +#define CSR_MSTATEEN2H 0x31E +#define CSR_MSTATEEN3 0x30F +#define CSR_MSTATEEN3H 0x31F + +/* Common defines for all smstateen */ +#define SMSTATEEN_MAX_COUNT 4 +#define SMSTATEEN0_CS (1ULL << 0) +#define SMSTATEEN0_FCSR (1ULL << 1) +#define SMSTATEEN0_HSCONTXT (1ULL << 57) +#define SMSTATEEN0_IMSIC (1ULL << 58) +#define SMSTATEEN0_AIA (1ULL << 59) +#define SMSTATEEN0_SVSLCT (1ULL << 60) +#define SMSTATEEN0_HSENVCFG (1ULL << 62) +#define SMSTATEEN_STATEEN (1ULL << 63) + /* Enhanced Physical Memory Protection (ePMP) */ #define CSR_MSECCFG 0x747 #define CSR_MSECCFGH 0x757 diff --git a/target/riscv/csr.c b/target/riscv/csr.c index 5c9a7ee287..c861424e85 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -283,6 +283,72 @@ static RISCVException umode32(CPURISCVState *env, int csrno) return umode(env, csrno); } +static RISCVException mstateen(CPURISCVState *env, int csrno) +{ + CPUState *cs = env_cpu(env); + RISCVCPU *cpu = RISCV_CPU(cs); + + if (!cpu->cfg.ext_smstateen) { + return RISCV_EXCP_ILLEGAL_INST; + } + + return any(env, csrno); +} + +static RISCVException hstateen_pred(CPURISCVState *env, int csrno, int base) +{ + CPUState *cs = env_cpu(env); + RISCVCPU *cpu = RISCV_CPU(cs); + + if (!cpu->cfg.ext_smstateen) { + return RISCV_EXCP_ILLEGAL_INST; + } + + if (env->priv < PRV_M) { + if (!(env->mstateen[csrno - base] & SMSTATEEN_STATEEN)) { + return RISCV_EXCP_ILLEGAL_INST; + } + } + + return hmode(env, csrno); +} + +static RISCVException hstateen(CPURISCVState *env, int csrno) +{ + return hstateen_pred(env, csrno, CSR_HSTATEEN0); +} + +static RISCVException hstateenh(CPURISCVState *env, int csrno) +{ + return hstateen_pred(env, csrno, CSR_HSTATEEN0H); +} + +static RISCVException sstateen(CPURISCVState *env, int csrno) +{ + bool virt = riscv_cpu_virt_enabled(env); + int index = csrno - CSR_SSTATEEN0; + CPUState *cs = env_cpu(env); + RISCVCPU *cpu = RISCV_CPU(cs); + + if (!cpu->cfg.ext_smstateen) { + return RISCV_EXCP_ILLEGAL_INST; + } + + if (env->priv < PRV_M) { + if (!(env->mstateen[index] & SMSTATEEN_STATEEN)) { + return RISCV_EXCP_ILLEGAL_INST; + } + + if (virt) { + if (!(env->hstateen[index] & SMSTATEEN_STATEEN)) { + return RISCV_EXCP_VIRT_INSTRUCTION_FAULT; + } + } + } + + return smode(env, csrno); +} + /* Checks if PointerMasking registers could be accessed */ static RISCVException pointer_masking(CPURISCVState *env, int csrno) { @@ -1861,6 +1927,197 @@ static RISCVException write_henvcfgh(CPURISCVState *env, int csrno, return RISCV_EXCP_NONE; } +static RISCVException read_mstateen(CPURISCVState *env, int csrno, + target_ulong *val) +{ + *val = env->mstateen[csrno - CSR_MSTATEEN0]; + + return RISCV_EXCP_NONE; +} + +static RISCVException write_mstateen(CPURISCVState *env, int csrno, + uint64_t wr_mask, target_ulong new_val) +{ + uint64_t *reg; + + reg = &env->mstateen[csrno - CSR_MSTATEEN0]; + *reg = (*reg & ~wr_mask) | (new_val & wr_mask); + + return RISCV_EXCP_NONE; +} + +static RISCVException write_mstateen0(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + uint64_t wr_mask = SMSTATEEN_STATEEN; + + return write_mstateen(env, csrno, wr_mask, new_val); +} + +static RISCVException write_mstateen_1_3(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + return write_mstateen(env, csrno, SMSTATEEN_STATEEN, new_val); +} + +static RISCVException read_mstateenh(CPURISCVState *env, int csrno, + target_ulong *val) +{ + *val = env->mstateen[csrno - CSR_MSTATEEN0H] >> 32; + + return RISCV_EXCP_NONE; +} + +static RISCVException write_mstateenh(CPURISCVState *env, int csrno, + uint64_t wr_mask, target_ulong new_val) +{ + uint64_t *reg, val; + + reg = &env->mstateen[csrno - CSR_MSTATEEN0H]; + val = (uint64_t)new_val << 32; + val |= *reg & 0xFFFFFFFF; + *reg = (*reg & ~wr_mask) | (val & wr_mask); + + return RISCV_EXCP_NONE; +} + +static RISCVException write_mstateen0h(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + uint64_t wr_mask = SMSTATEEN_STATEEN; + + return write_mstateenh(env, csrno, wr_mask, new_val); +} + +static RISCVException write_mstateenh_1_3(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + return write_mstateenh(env, csrno, SMSTATEEN_STATEEN, new_val); +} + +static RISCVException read_hstateen(CPURISCVState *env, int csrno, + target_ulong *val) +{ + int index = csrno - CSR_HSTATEEN0; + + *val = env->hstateen[index] & env->mstateen[index]; + + return RISCV_EXCP_NONE; +} + +static RISCVException write_hstateen(CPURISCVState *env, int csrno, + uint64_t mask, target_ulong new_val) +{ + int index = csrno - CSR_HSTATEEN0; + uint64_t *reg, wr_mask; + + reg = &env->hstateen[index]; + wr_mask = env->mstateen[index] & mask; + *reg = (*reg & ~wr_mask) | (new_val & wr_mask); + + return RISCV_EXCP_NONE; +} + +static RISCVException write_hstateen0(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + uint64_t wr_mask = SMSTATEEN_STATEEN; + + return write_hstateen(env, csrno, wr_mask, new_val); +} + +static RISCVException write_hstateen_1_3(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + return write_hstateen(env, csrno, SMSTATEEN_STATEEN, new_val); +} + +static RISCVException read_hstateenh(CPURISCVState *env, int csrno, + target_ulong *val) +{ + int index = csrno - CSR_HSTATEEN0H; + + *val = (env->hstateen[index] >> 32) & (env->mstateen[index] >> 32); + + return RISCV_EXCP_NONE; +} + +static RISCVException write_hstateenh(CPURISCVState *env, int csrno, + uint64_t mask, target_ulong new_val) +{ + int index = csrno - CSR_HSTATEEN0H; + uint64_t *reg, wr_mask, val; + + reg = &env->hstateen[index]; + val = (uint64_t)new_val << 32; + val |= *reg & 0xFFFFFFFF; + wr_mask = env->mstateen[index] & mask; + *reg = (*reg & ~wr_mask) | (val & wr_mask); + + return RISCV_EXCP_NONE; +} + +static RISCVException write_hstateen0h(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + uint64_t wr_mask = SMSTATEEN_STATEEN; + + return write_hstateenh(env, csrno, wr_mask, new_val); +} + +static RISCVException write_hstateenh_1_3(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + return write_hstateenh(env, csrno, SMSTATEEN_STATEEN, new_val); +} + +static RISCVException read_sstateen(CPURISCVState *env, int csrno, + target_ulong *val) +{ + bool virt = riscv_cpu_virt_enabled(env); + int index = csrno - CSR_SSTATEEN0; + + *val = env->sstateen[index] & env->mstateen[index]; + if (virt) { + *val &= env->hstateen[index]; + } + + return RISCV_EXCP_NONE; +} + +static RISCVException write_sstateen(CPURISCVState *env, int csrno, + uint64_t mask, target_ulong new_val) +{ + bool virt = riscv_cpu_virt_enabled(env); + int index = csrno - CSR_SSTATEEN0; + uint64_t wr_mask; + uint64_t *reg; + + wr_mask = env->mstateen[index] & mask; + if (virt) { + wr_mask &= env->hstateen[index]; + } + + reg = &env->sstateen[index]; + *reg = (*reg & ~wr_mask) | (new_val & wr_mask); + + return RISCV_EXCP_NONE; +} + +static RISCVException write_sstateen0(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + uint64_t wr_mask = SMSTATEEN_STATEEN; + + return write_sstateen(env, csrno, wr_mask, new_val); +} + +static RISCVException write_sstateen_1_3(CPURISCVState *env, int csrno, + target_ulong new_val) +{ + return write_sstateen(env, csrno, SMSTATEEN_STATEEN, new_val); +} + static RISCVException rmw_mip64(CPURISCVState *env, int csrno, uint64_t *ret_val, uint64_t new_val, uint64_t wr_mask) @@ -3744,6 +4001,65 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = { [CSR_HENVCFGH] = { "henvcfgh", hmode32, read_henvcfgh, write_henvcfgh, .min_priv_ver = PRIV_VERSION_1_12_0 }, + /* Smstateen extension CSRs */ + [CSR_MSTATEEN0] = { "mstateen0", mstateen, read_mstateen, write_mstateen0, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_MSTATEEN0H] = { "mstateen0h", mstateen, read_mstateenh, + write_mstateen0h, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_MSTATEEN1] = { "mstateen1", mstateen, read_mstateen, + write_mstateen_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_MSTATEEN1H] = { "mstateen1h", mstateen, read_mstateenh, + write_mstateenh_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_MSTATEEN2] = { "mstateen2", mstateen, read_mstateen, + write_mstateen_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_MSTATEEN2H] = { "mstateen2h", mstateen, read_mstateenh, + write_mstateenh_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_MSTATEEN3] = { "mstateen3", mstateen, read_mstateen, + write_mstateen_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_MSTATEEN3H] = { "mstateen3h", mstateen, read_mstateenh, + write_mstateenh_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_HSTATEEN0] = { "hstateen0", hstateen, read_hstateen, write_hstateen0, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_HSTATEEN0H] = { "hstateen0h", hstateenh, read_hstateenh, + write_hstateen0h, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_HSTATEEN1] = { "hstateen1", hstateen, read_hstateen, + write_hstateen_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_HSTATEEN1H] = { "hstateen1h", hstateenh, read_hstateenh, + write_hstateenh_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_HSTATEEN2] = { "hstateen2", hstateen, read_hstateen, + write_hstateen_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_HSTATEEN2H] = { "hstateen2h", hstateenh, read_hstateenh, + write_hstateenh_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_HSTATEEN3] = { "hstateen3", hstateen, read_hstateen, + write_hstateen_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_HSTATEEN3H] = { "hstateen3h", hstateenh, read_hstateenh, + write_hstateenh_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_SSTATEEN0] = { "sstateen0", sstateen, read_sstateen, write_sstateen0, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_SSTATEEN1] = { "sstateen1", sstateen, read_sstateen, + write_sstateen_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_SSTATEEN2] = { "sstateen2", sstateen, read_sstateen, + write_sstateen_1_3, + .min_priv_ver = PRIV_VERSION_1_12_0 }, + [CSR_SSTATEEN3] = { "sstateen3", sstateen, read_sstateen, + write_sstateen_1_3, + .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 c2a94a82b3..e687f9fce0 100644 --- a/target/riscv/machine.c +++ b/target/riscv/machine.c @@ -253,6 +253,26 @@ static int riscv_cpu_post_load(void *opaque, int version_id) return 0; } +static bool smstateen_needed(void *opaque) +{ + RISCVCPU *cpu = opaque; + + return cpu->cfg.ext_smstateen; +} + +static const VMStateDescription vmstate_smstateen = { + .name = "cpu/smtateen", + .version_id = 1, + .minimum_version_id = 1, + .needed = smstateen_needed, + .fields = (VMStateField[]) { + VMSTATE_UINT64_ARRAY(env.mstateen, RISCVCPU, 4), + VMSTATE_UINT64_ARRAY(env.hstateen, RISCVCPU, 4), + VMSTATE_UINT64_ARRAY(env.sstateen, RISCVCPU, 4), + VMSTATE_END_OF_LIST() + } +}; + static bool envcfg_needed(void *opaque) { RISCVCPU *cpu = opaque; @@ -364,6 +384,7 @@ const VMStateDescription vmstate_riscv_cpu = { &vmstate_kvmtimer, &vmstate_envcfg, &vmstate_debug, + &vmstate_smstateen, NULL } };