[ RFC v2 1/9] target/riscv: Fix PMU CSR predicate function

[Atish Patra]

Currently, the predicate function for PMU related CSRs only works if
virtualization is enabled. Ideally, they should check the mcountern
bits before cycle/minstret/hpmcounterx access. The predicate function
also calculates the counter index incorrectly for hpmcounterx.

Signed-off-by: Atish Patra <atish.pa...@wdc.com>
---
 target/riscv/csr.c | 62 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 58 insertions(+), 4 deletions(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 9a4ed18ac597..0515d851b948 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -62,12 +62,64 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
 #if !defined(CONFIG_USER_ONLY)
     CPUState *cs = env_cpu(env);
     RISCVCPU *cpu = RISCV_CPU(cs);
+    int ctr_index;
 
     if (!cpu->cfg.ext_counters) {
         /* The Counters extensions is not enabled */
         return RISCV_EXCP_ILLEGAL_INST;
     }
 
+    if (env->priv == PRV_S) {
+        switch (csrno) {
+        case CSR_CYCLE:
+            if (!get_field(env->mcounteren, HCOUNTEREN_CY)) {
+                return RISCV_EXCP_ILLEGAL_INST;
+            }
+            break;
+        case CSR_TIME:
+            if (!get_field(env->mcounteren, HCOUNTEREN_TM)) {
+                return RISCV_EXCP_ILLEGAL_INST;
+            }
+            break;
+        case CSR_INSTRET:
+            if (!get_field(env->mcounteren, HCOUNTEREN_IR)) {
+                return RISCV_EXCP_ILLEGAL_INST;
+            }
+            break;
+        case CSR_HPMCOUNTER3...CSR_HPMCOUNTER31:
+            ctr_index = csrno - CSR_HPMCOUNTER3 + 3;
+            if (!get_field(env->mcounteren, 1 << ctr_index)) {
+                return RISCV_EXCP_ILLEGAL_INST;
+            }
+            break;
+        }
+        if (riscv_cpu_is_32bit(env)) {
+            switch (csrno) {
+            case CSR_CYCLEH:
+                if (!get_field(env->mcounteren, HCOUNTEREN_CY)) {
+                    return RISCV_EXCP_ILLEGAL_INST;
+                }
+                break;
+            case CSR_TIMEH:
+                if (!get_field(env->mcounteren, HCOUNTEREN_TM)) {
+                    return RISCV_EXCP_ILLEGAL_INST;
+                }
+                break;
+            case CSR_INSTRETH:
+                if (!get_field(env->mcounteren, HCOUNTEREN_IR)) {
+                    return RISCV_EXCP_ILLEGAL_INST;
+                }
+                break;
+            case CSR_HPMCOUNTER3H...CSR_HPMCOUNTER31H:
+                ctr_index = csrno - CSR_HPMCOUNTER3H + 3;
+                if (!get_field(env->mcounteren, 1 << ctr_index)) {
+                    return RISCV_EXCP_ILLEGAL_INST;
+                }
+                break;
+            }
+        }
+    }
+
     if (riscv_cpu_virt_enabled(env)) {
         switch (csrno) {
         case CSR_CYCLE:
@@ -89,8 +141,9 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
             }
             break;
         case CSR_HPMCOUNTER3...CSR_HPMCOUNTER31:
-            if (!get_field(env->hcounteren, 1 << (csrno - CSR_HPMCOUNTER3)) &&
-                get_field(env->mcounteren, 1 << (csrno - CSR_HPMCOUNTER3))) {
+            ctr_index = csrno - CSR_HPMCOUNTER3 + 3;
+            if (!get_field(env->hcounteren, 1 << ctr_index) &&
+                get_field(env->mcounteren, 1 << ctr_index)) {
                 return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
             }
             break;
@@ -116,8 +169,9 @@ static RISCVException ctr(CPURISCVState *env, int csrno)
                 }
                 break;
             case CSR_HPMCOUNTER3H...CSR_HPMCOUNTER31H:
-                if (!get_field(env->hcounteren, 1 << (csrno - 
CSR_HPMCOUNTER3H)) &&
-                    get_field(env->mcounteren, 1 << (csrno - 
CSR_HPMCOUNTER3H))) {
+                ctr_index = csrno - CSR_HPMCOUNTER3H + 3;
+                if (!get_field(env->hcounteren, 1 << ctr_index) &&
+                    get_field(env->mcounteren, 1 << ctr_index)) {
                     return RISCV_EXCP_VIRT_INSTRUCTION_FAULT;
                 }
                 break;
-- 
2.31.1