[PATCH v4 4/4] target/riscv: Force disable extensions if priv spec version does not match

[Anup Patel <apatel@ventanamicro.com>]

We should disable extensions in riscv_cpu_realize() if minimum required
priv spec version is not satisfied. This also ensures that machines with
priv spec v1.11 (or lower) cannot enable H, V, and various multi-letter
extensions.

Fixes: a775398be2e ("target/riscv: Add isa extenstion strings to the
device tree")
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 target/riscv/cpu.c | 57 ++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 52 insertions(+), 5 deletions(-)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 9f9c27a3f5..953ba2e445 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -43,9 +43,13 @@ static const char riscv_single_letter_exts[] = "IEMAFDQCPVH";
 
 struct isa_ext_data {
     const char *name;
-    bool enabled;
+    int min_version;
+    bool *enabled;
 };
 
+#define ISA_EDATA_ENTRY(name, prop) {#name, PRIV_VERSION_1_10_0, &cpu->cfg.prop}
+#define ISA_EDATA_ENTRY2(name, min_ver, prop) {#name, min_ver, &cpu->cfg.prop}
+
 const char * const riscv_int_regnames[] = {
   "x0/zero", "x1/ra",  "x2/sp",  "x3/gp",  "x4/tp",  "x5/t0",   "x6/t1",
   "x7/t2",   "x8/s0",  "x9/s1",  "x10/a0", "x11/a1", "x12/a2",  "x13/a3",
@@ -513,8 +517,42 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
     CPURISCVState *env = &cpu->env;
     RISCVCPUClass *mcc = RISCV_CPU_GET_CLASS(dev);
     CPUClass *cc = CPU_CLASS(mcc);
-    int priv_version = -1;
+    int i, priv_version = -1;
     Error *local_err = NULL;
+    struct isa_ext_data isa_edata_arr[] = {
+        ISA_EDATA_ENTRY2(h, PRIV_VERSION_1_12_0, ext_h),
+        ISA_EDATA_ENTRY2(v, PRIV_VERSION_1_12_0, ext_v),
+        ISA_EDATA_ENTRY2(zicsr, PRIV_VERSION_1_10_0, ext_icsr),
+        ISA_EDATA_ENTRY2(zifencei, PRIV_VERSION_1_10_0, ext_ifencei),
+        ISA_EDATA_ENTRY2(zfh, PRIV_VERSION_1_12_0, ext_zfh),
+        ISA_EDATA_ENTRY2(zfhmin, PRIV_VERSION_1_12_0, ext_zfhmin),
+        ISA_EDATA_ENTRY2(zfinx, PRIV_VERSION_1_12_0, ext_zfinx),
+        ISA_EDATA_ENTRY2(zdinx, PRIV_VERSION_1_12_0, ext_zdinx),
+        ISA_EDATA_ENTRY2(zba, PRIV_VERSION_1_12_0, ext_zba),
+        ISA_EDATA_ENTRY2(zbb, PRIV_VERSION_1_12_0, ext_zbb),
+        ISA_EDATA_ENTRY2(zbc, PRIV_VERSION_1_12_0, ext_zbc),
+        ISA_EDATA_ENTRY2(zbkb, PRIV_VERSION_1_12_0, ext_zbkb),
+        ISA_EDATA_ENTRY2(zbkc, PRIV_VERSION_1_12_0, ext_zbkc),
+        ISA_EDATA_ENTRY2(zbkx, PRIV_VERSION_1_12_0, ext_zbkx),
+        ISA_EDATA_ENTRY2(zbs, PRIV_VERSION_1_12_0, ext_zbs),
+        ISA_EDATA_ENTRY2(zk, PRIV_VERSION_1_12_0, ext_zk),
+        ISA_EDATA_ENTRY2(zkn, PRIV_VERSION_1_12_0, ext_zkn),
+        ISA_EDATA_ENTRY2(zknd, PRIV_VERSION_1_12_0, ext_zknd),
+        ISA_EDATA_ENTRY2(zkne, PRIV_VERSION_1_12_0, ext_zkne),
+        ISA_EDATA_ENTRY2(zknh, PRIV_VERSION_1_12_0, ext_zknh),
+        ISA_EDATA_ENTRY2(zkr, PRIV_VERSION_1_12_0, ext_zkr),
+        ISA_EDATA_ENTRY2(zks, PRIV_VERSION_1_12_0, ext_zks),
+        ISA_EDATA_ENTRY2(zksed, PRIV_VERSION_1_12_0, ext_zksed),
+        ISA_EDATA_ENTRY2(zksh, PRIV_VERSION_1_12_0, ext_zksh),
+        ISA_EDATA_ENTRY2(zkt, PRIV_VERSION_1_12_0, ext_zkt),
+        ISA_EDATA_ENTRY2(zve32f, PRIV_VERSION_1_12_0, ext_zve32f),
+        ISA_EDATA_ENTRY2(zve64f, PRIV_VERSION_1_12_0, ext_zve64f),
+        ISA_EDATA_ENTRY2(zhinx, PRIV_VERSION_1_12_0, ext_zhinx),
+        ISA_EDATA_ENTRY2(zhinxmin, PRIV_VERSION_1_12_0, ext_zhinxmin),
+        ISA_EDATA_ENTRY2(svinval, PRIV_VERSION_1_12_0, ext_svinval),
+        ISA_EDATA_ENTRY2(svnapot, PRIV_VERSION_1_12_0, ext_svnapot),
+        ISA_EDATA_ENTRY2(svpbmt, PRIV_VERSION_1_12_0, ext_svpbmt),
+    };
 
     cpu_exec_realizefn(cs, &local_err);
     if (local_err != NULL) {
@@ -541,6 +579,17 @@ static void riscv_cpu_realize(DeviceState *dev, Error **errp)
         set_priv_version(env, priv_version);
     }
 
+    /* Force disable extensions if priv spec version does not match */
+    for (i = 0; i < ARRAY_SIZE(isa_edata_arr); i++) {
+        if (*isa_edata_arr[i].enabled &&
+            (env->priv_ver < isa_edata_arr[i].min_version)) {
+            *isa_edata_arr[i].enabled = false;
+            warn_report("disabling %s extension for hart 0x%lx because "
+                        "privilege spec version does not match",
+                        isa_edata_arr[i].name, (unsigned long)env->mhartid);
+        }
+    }
+
     if (cpu->cfg.mmu) {
         riscv_set_feature(env, RISCV_FEATURE_MMU);
     }
@@ -1011,8 +1060,6 @@ static void riscv_cpu_class_init(ObjectClass *c, void *data)
     device_class_set_props(dc, riscv_cpu_properties);
 }
 
-#define ISA_EDATA_ENTRY(name, prop) {#name, cpu->cfg.prop}
-
 static void riscv_isa_string_ext(RISCVCPU *cpu, char **isa_str, int max_str_len)
 {
     char *old = *isa_str;
@@ -1071,7 +1118,7 @@ static void riscv_isa_string_ext(RISCVCPU *cpu, char **isa_str, int max_str_len)
     };
 
     for (i = 0; i < ARRAY_SIZE(isa_edata_arr); i++) {
-        if (isa_edata_arr[i].enabled) {
+        if (*isa_edata_arr[i].enabled) {
             new = g_strconcat(old, "_", isa_edata_arr[i].name, NULL);
             g_free(old);
             old = new;
-- 
2.34.1