[v8,12/14] target/riscv: rvk: add CSR support for Zkr

Commit Message

Weiwei Li March 1, 2022, 11:58 a.m. UTC

- add SEED CSR
   - add USEED, SSEED fields for MSECCFG CSR

Co-authored-by: Ruibo Lu <[e-mail]>
Co-authored-by: Zewen Ye <[e-mail]>
Signed-off-by: Weiwei Li <[e-mail]>
Signed-off-by: Junqiang Wang <[e-mail]>
---
 target/riscv/cpu_bits.h |  9 ++++++
 target/riscv/csr.c      | 71 +++++++++++++++++++++++++++++++++++++++++
 target/riscv/pmp.h      |  8 +++--
 3 files changed, 85 insertions(+), 3 deletions(-)

Patch

diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 0fe01d7da5..d0a4a16c73 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -446,6 +446,9 @@ 
 #define CSR_VSPMMASK        0x2c1
 #define CSR_VSPMBASE        0x2c2
 
+/* Crypto Extension */
+#define CSR_SEED            0x015
+
 /* mstatus CSR bits */
 #define MSTATUS_UIE         0x00000001
 #define MSTATUS_SIE         0x00000002
@@ -760,4 +763,10 @@  typedef enum RISCVException {
 #define HVICTL_VALID_MASK                  \
     (HVICTL_VTI | HVICTL_IID | HVICTL_IPRIOM | HVICTL_IPRIO)
 
+/* seed CSR bits */
+#define SEED_OPST                        (0b11 << 30)
+#define SEED_OPST_BIST                   (0b00 << 30)
+#define SEED_OPST_WAIT                   (0b01 << 30)
+#define SEED_OPST_ES16                   (0b10 << 30)
+#define SEED_OPST_DEAD                   (0b11 << 30)
 #endif
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index aea82dff4a..8ceee8e87b 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -23,6 +23,8 @@ 
 #include "cpu.h"
 #include "qemu/main-loop.h"
 #include "exec/exec-all.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)
@@ -291,6 +293,39 @@  static RISCVException epmp(CPURISCVState *env, int csrno)
 }
 #endif
 
+/* Predicates */
+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)
+    if (riscv_has_ext(env, RVS) && riscv_has_ext(env, RVH)) {
+        /* Hypervisor extension is supported */
+        if (riscv_cpu_virt_enabled(env) && (env->priv != PRV_M)) {
+            if (env->mseccfg & MSECCFG_SSEED) {
+                return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
+            } else {
+                return RISCV_EXCP_ILLEGAL_INST;
+            }
+        }
+    }
+    if (env->priv == PRV_M) {
+        return RISCV_EXCP_NONE;
+    } 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)
@@ -2861,6 +2896,39 @@  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)
+{
+    if (!write_mask) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    uint16_t random_v;
+    Error *random_e = NULL;
+    int random_r;
+
+    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);
+        *ret_value = SEED_OPST_DEAD;
+    } else {
+        *ret_value = random_v | SEED_OPST_ES16;
+    }
+
+    return RISCV_EXCP_NONE;
+}
+
 /*
  * riscv_csrrw - read and/or update control and status register
  *
@@ -3087,6 +3155,9 @@  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  },
diff --git a/target/riscv/pmp.h b/target/riscv/pmp.h
index a9a0b363a7..83135849bb 100644
--- a/target/riscv/pmp.h
+++ b/target/riscv/pmp.h
@@ -37,9 +37,11 @@  typedef enum {
 } pmp_am_t;
 
 typedef enum {
-    MSECCFG_MML  = 1 << 0,
-    MSECCFG_MMWP = 1 << 1,
-    MSECCFG_RLB  = 1 << 2
+    MSECCFG_MML   = 1 << 0,
+    MSECCFG_MMWP  = 1 << 1,
+    MSECCFG_RLB   = 1 << 2,
+    MSECCFG_USEED = 1 << 8,
+    MSECCFG_SSEED = 1 << 9
 } mseccfg_field_t;
 
 typedef struct {