From: Kaiwen Xue <kaiwenx@rivosinc.com>

Since xiselect and xireg also will be of use in sxcsrind, AIA should
have its own separated interface when those CSRs are accessed.

Signed-off-by: Kaiwen Xue <kaiwenx@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
 target/riscv/csr.c | 165 ++++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 139 insertions(+), 26 deletions(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 9846770820f4..52e0139fc99c 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -29,6 +29,7 @@
 #include "sysemu/cpu-timers.h"
 #include "qemu/guest-random.h"
 #include "qapi/error.h"
+#include <stdbool.h>
 
 /* CSR function table public API */
 void riscv_get_csr_ops(int csrno, riscv_csr_operations *ops)
@@ -305,6 +306,15 @@ static RISCVException aia_any32(CPURISCVState *env, int csrno)
     return any32(env, csrno);
 }
 
+static RISCVException csrind_or_aia_any(CPURISCVState *env, int csrno)
+{
+    if (!riscv_cpu_cfg(env)->ext_smaia && !riscv_cpu_cfg(env)->ext_smcsrind) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    return any(env, csrno);
+}
+
 static RISCVException smode(CPURISCVState *env, int csrno)
 {
     if (riscv_has_ext(env, RVS)) {
@@ -341,6 +351,30 @@ static RISCVException aia_smode32(CPURISCVState *env, int csrno)
     return smode32(env, csrno);
 }
 
+static bool csrind_extensions_present(CPURISCVState *env)
+{
+    return riscv_cpu_cfg(env)->ext_smcsrind || riscv_cpu_cfg(env)->ext_sscsrind;
+}
+
+static bool aia_extensions_present(CPURISCVState *env)
+{
+    return riscv_cpu_cfg(env)->ext_smaia || riscv_cpu_cfg(env)->ext_ssaia;
+}
+
+static bool csrind_or_aia_extensions_present(CPURISCVState *env)
+{
+    return csrind_extensions_present(env) || aia_extensions_present(env);
+}
+
+static RISCVException csrind_or_aia_smode(CPURISCVState *env, int csrno)
+{
+    if (!csrind_or_aia_extensions_present(env)) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    return smode(env, csrno);
+}
+
 static RISCVException hmode(CPURISCVState *env, int csrno)
 {
     if (riscv_has_ext(env, RVH)) {
@@ -360,6 +394,15 @@ static RISCVException hmode32(CPURISCVState *env, int csrno)
 
 }
 
+static RISCVException csrind_or_aia_hmode(CPURISCVState *env, int csrno)
+{
+    if (!csrind_or_aia_extensions_present(env)) {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+
+    return hmode(env, csrno);
+}
+
 static RISCVException umode(CPURISCVState *env, int csrno)
 {
     if (riscv_has_ext(env, RVU)) {
@@ -1966,6 +2009,22 @@ static int aia_xlate_vs_csrno(CPURISCVState *env, int csrno)
     };
 }
 
+static int csrind_xlate_vs_csrno(CPURISCVState *env, int csrno)
+{
+    if (!env->virt_enabled) {
+        return csrno;
+    }
+
+    switch (csrno) {
+    case CSR_SISELECT:
+        return CSR_VSISELECT;
+    case CSR_SIREG:
+        return CSR_VSIREG;
+    default:
+        return csrno;
+    };
+}
+
 static RISCVException rmw_xiselect(CPURISCVState *env, int csrno,
                                    target_ulong *val, target_ulong new_val,
                                    target_ulong wr_mask)
@@ -1973,7 +2032,7 @@ static RISCVException rmw_xiselect(CPURISCVState *env, int csrno,
     target_ulong *iselect;
 
     /* Translate CSR number for VS-mode */
-    csrno = aia_xlate_vs_csrno(env, csrno);
+    csrno = csrind_xlate_vs_csrno(env, csrno);
 
     /* Find the iselect CSR based on CSR number */
     switch (csrno) {
@@ -2002,6 +2061,12 @@ static RISCVException rmw_xiselect(CPURISCVState *env, int csrno,
     return RISCV_EXCP_NONE;
 }
 
+static bool xiselect_aia_range(target_ulong isel)
+{
+    return (ISELECT_IPRIO0 <= isel && isel <= ISELECT_IPRIO15) ||
+           (ISELECT_IMSIC_FIRST <= isel && isel <= ISELECT_IMSIC_LAST);
+}
+
 static int rmw_iprio(target_ulong xlen,
                      target_ulong iselect, uint8_t *iprio,
                      target_ulong *val, target_ulong new_val,
@@ -2047,45 +2112,44 @@ static int rmw_iprio(target_ulong xlen,
     return 0;
 }
 
-static RISCVException rmw_xireg(CPURISCVState *env, int csrno,
-                                target_ulong *val, target_ulong new_val,
-                                target_ulong wr_mask)
+static RISCVException rmw_xireg_aia(CPURISCVState *env, int csrno,
+                         target_ulong isel, target_ulong *val,
+                         target_ulong new_val, target_ulong wr_mask)
 {
-    bool virt, isel_reserved;
-    uint8_t *iprio;
+    bool virt = false, isel_reserved = false;
     int ret = -EINVAL;
-    target_ulong priv, isel, vgein;
-
-    /* Translate CSR number for VS-mode */
-    csrno = aia_xlate_vs_csrno(env, csrno);
+    uint8_t *iprio;
+    target_ulong priv, vgein;
 
-    /* Decode register details from CSR number */
-    virt = false;
-    isel_reserved = false;
+    /* VS-mode CSR number passed in has already been translated */
     switch (csrno) {
     case CSR_MIREG:
+        if (!riscv_cpu_cfg(env)->ext_smaia) {
+            goto done;
+        }
         iprio = env->miprio;
-        isel = env->miselect;
         priv = PRV_M;
         break;
     case CSR_SIREG:
-        if (env->priv == PRV_S && env->mvien & MIP_SEIP &&
+        if (!riscv_cpu_cfg(env)->ext_ssaia ||
+            (env->priv == PRV_S && env->mvien & MIP_SEIP &&
             env->siselect >= ISELECT_IMSIC_EIDELIVERY &&
-            env->siselect <= ISELECT_IMSIC_EIE63) {
+            env->siselect <= ISELECT_IMSIC_EIE63)) {
             goto done;
         }
         iprio = env->siprio;
-        isel = env->siselect;
         priv = PRV_S;
         break;
     case CSR_VSIREG:
+        if (!riscv_cpu_cfg(env)->ext_ssaia) {
+            goto done;
+        }
         iprio = env->hviprio;
-        isel = env->vsiselect;
         priv = PRV_S;
         virt = true;
         break;
     default:
-         goto done;
+        goto done;
     };
 
     /* Find the selected guest interrupt file */
@@ -2116,10 +2180,54 @@ static RISCVException rmw_xireg(CPURISCVState *env, int csrno,
     }
 
 done:
+    /*
+     * If AIA is not enabled, illegal instruction exception is always
+     * returned regardless of whether we are in VS-mode or not
+     */
     if (ret) {
         return (env->virt_enabled && virt && !isel_reserved) ?
                RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
     }
+
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException rmw_xireg(CPURISCVState *env, int csrno,
+                                target_ulong *val, target_ulong new_val,
+                                target_ulong wr_mask)
+{
+    bool virt = false;
+    int ret = -EINVAL;
+    target_ulong isel;
+
+    /* Translate CSR number for VS-mode */
+    csrno = csrind_xlate_vs_csrno(env, csrno);
+
+    /* Decode register details from CSR number */
+    switch (csrno) {
+    case CSR_MIREG:
+        isel = env->miselect;
+        break;
+    case CSR_SIREG:
+        isel = env->siselect;
+        break;
+    case CSR_VSIREG:
+        isel = env->vsiselect;
+        virt = true;
+        break;
+    default:
+         goto done;
+    };
+
+    if (xiselect_aia_range(isel)) {
+        return rmw_xireg_aia(env, csrno, isel, val, new_val, wr_mask);
+    }
+
+done:
+    if (ret) {
+        return (env->virt_enabled && virt) ?
+               RISCV_EXCP_VIRT_INSTRUCTION_FAULT : RISCV_EXCP_ILLEGAL_INST;
+    }
     return RISCV_EXCP_NONE;
 }
 
@@ -5065,8 +5173,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_MIP]      = { "mip",      any,  NULL,    NULL, rmw_mip        },
 
     /* Machine-Level Window to Indirectly Accessed Registers (AIA) */
-    [CSR_MISELECT] = { "miselect", aia_any,   NULL, NULL,    rmw_xiselect },
-    [CSR_MIREG]    = { "mireg",    aia_any,   NULL, NULL,    rmw_xireg },
+    [CSR_MISELECT] = { "miselect", csrind_or_aia_any,   NULL, NULL,
+                       rmw_xiselect                                    },
+    [CSR_MIREG]    = { "mireg",    csrind_or_aia_any,   NULL, NULL,
+                       rmw_xireg                                       },
 
     /* Machine-Level Interrupts (AIA) */
     [CSR_MTOPEI]   = { "mtopei",   aia_any, NULL, NULL, rmw_xtopei },
@@ -5184,8 +5294,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_SATP]     = { "satp",     satp, read_satp,     write_satp     },
 
     /* Supervisor-Level Window to Indirectly Accessed Registers (AIA) */
-    [CSR_SISELECT]   = { "siselect",   aia_smode, NULL, NULL, rmw_xiselect },
-    [CSR_SIREG]      = { "sireg",      aia_smode, NULL, NULL, rmw_xireg },
+    [CSR_SISELECT]   = { "siselect",   csrind_or_aia_smode, NULL, NULL,
+                         rmw_xiselect                                       },
+    [CSR_SIREG]      = { "sireg",      csrind_or_aia_smode, NULL, NULL,
+                         rmw_xireg                                          },
 
     /* Supervisor-Level Interrupts (AIA) */
     [CSR_STOPEI]     = { "stopei",     aia_smode, NULL, NULL, rmw_xtopei },
@@ -5264,9 +5376,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     /*
      * VS-Level Window to Indirectly Accessed Registers (H-extension with AIA)
      */
-    [CSR_VSISELECT]   = { "vsiselect",   aia_hmode, NULL, NULL,
-                          rmw_xiselect                                     },
-    [CSR_VSIREG]      = { "vsireg",      aia_hmode, NULL, NULL, rmw_xireg  },
+    [CSR_VSISELECT]   = { "vsiselect",   csrind_or_aia_hmode, NULL, NULL,
+                          rmw_xiselect                                      },
+    [CSR_VSIREG]      = { "vsireg",      csrind_or_aia_hmode, NULL, NULL,
+                          rmw_xireg                                         },
 
     /* VS-Level Interrupts (H-extension with AIA) */
     [CSR_VSTOPEI]     = { "vstopei",     aia_hmode, NULL, NULL, rmw_xtopei },

-- 
2.34.1