[RFC PATCH v2 4/4] target/riscv: smstateen check for AIA/IMSIC

[Mayuresh Chitale <mchitale@ventanamicro.com>]

If smstateen is implemented then accesses to AIA
registers CSRS, IMSIC CSRs and other IMSIC registers
is controlled by setting of corresponding bits in
mstateen/hstateen registers. Otherwise an illegal
instruction trap or virtual instruction trap is
generated.

Signed-off-by: Mayuresh Chitale <mchitale@ventanamicro.com>
---
 target/riscv/csr.c | 248 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 246 insertions(+), 2 deletions(-)

diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index 5959adc9b3..cfdda8dc2b 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -68,6 +68,53 @@ static RISCVException smstateen_acc_ok(CPURISCVState *env, int mode, int bit)
     return RISCV_EXCP_NONE;
 }
 
+static RISCVException smstateen_aia_acc_ok(CPURISCVState *env, int csrno)
+{
+    int bit, mode;
+
+    switch (csrno) {
+    case CSR_SSETEIPNUM:
+    case CSR_SCLREIPNUM:
+    case CSR_SSETEIENUM:
+    case CSR_SCLREIENUM:
+    case CSR_STOPEI:
+    case CSR_VSSETEIPNUM:
+    case CSR_VSCLREIPNUM:
+    case CSR_VSSETEIENUM:
+    case CSR_VSCLREIENUM:
+    case CSR_VSTOPEI:
+    case CSR_HSTATUS:
+        mode = PRV_S;
+        bit = SMSTATEEN0_IMSIC;
+        break;
+
+    case CSR_SIEH:
+    case CSR_SIPH:
+    case CSR_HVIPH:
+    case CSR_HVICTL:
+    case CSR_HVIPRIO1:
+    case CSR_HVIPRIO2:
+    case CSR_HVIPRIO1H:
+    case CSR_HVIPRIO2H:
+    case CSR_VSIEH:
+    case CSR_VSIPH:
+        mode = PRV_S;
+        bit = SMSTATEEN0_AIA;
+        break;
+
+    case CSR_SISELECT:
+    case CSR_VSISELECT:
+        mode = PRV_S;
+        bit = SMSTATEEN0_SVSLCT;
+        break;
+
+    default:
+        return RISCV_EXCP_NONE;
+    }
+
+    return smstateen_acc_ok(env, mode, bit);
+}
+
 static RISCVException fs(CPURISCVState *env, int csrno)
 {
 #if !defined(CONFIG_USER_ONLY)
@@ -1402,6 +1449,13 @@ static int rmw_xiselect(CPURISCVState *env, int csrno, target_ulong *val,
                         target_ulong new_val, target_ulong wr_mask)
 {
     target_ulong *iselect;
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
 
     /* Translate CSR number for VS-mode */
     csrno = aia_xlate_vs_csrno(env, csrno);
@@ -1484,7 +1538,9 @@ static int rmw_xireg(CPURISCVState *env, int csrno, target_ulong *val,
     bool virt;
     uint8_t *iprio;
     int ret = -EINVAL;
-    target_ulong priv, isel, vgein;
+    target_ulong priv, isel, vgein = 0;
+    CPUState *cs = env_cpu(env);
+    RISCVCPU *cpu = RISCV_CPU(cs);
 
     /* Translate CSR number for VS-mode */
     csrno = aia_xlate_vs_csrno(env, csrno);
@@ -1513,11 +1569,20 @@ static int rmw_xireg(CPURISCVState *env, int csrno, target_ulong *val,
     };
 
     /* Find the selected guest interrupt file */
-    vgein = (virt) ? get_field(env->hstatus, HSTATUS_VGEIN) : 0;
+    if (virt) {
+        if (!cpu->cfg.ext_smstateen ||
+                (env->hstateen[0] & 1UL << SMSTATEEN0_IMSIC)) {
+            vgein = get_field(env->hstatus, HSTATUS_VGEIN);
+        }
+    }
 
     if (ISELECT_IPRIO0 <= isel && isel <= ISELECT_IPRIO15) {
         /* Local interrupt priority registers not available for VS-mode */
         if (!virt) {
+            if (priv == PRV_S && cpu->cfg.ext_smstateen &&
+                !(env->hstateen[0] & 1UL << SMSTATEEN0_AIA)) {
+                goto done;
+            }
             ret = rmw_iprio(riscv_cpu_mxl_bits(env),
                             isel, iprio, val, new_val, wr_mask,
                             (priv == PRV_M) ? IRQ_M_EXT : IRQ_S_EXT);
@@ -1551,6 +1616,13 @@ static int rmw_xsetclreinum(CPURISCVState *env, int csrno, target_ulong *val,
     int ret = -EINVAL;
     bool set, pend, virt;
     target_ulong priv, isel, vgein, xlen, nval, wmask;
+    RISCVException excp;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    excp = smstateen_aia_acc_ok(env, csrno);
+    if (excp != RISCV_EXCP_NONE) {
+        return excp;
+    }
 
     /* Translate CSR number for VS-mode */
     csrno = aia_xlate_vs_csrno(env, csrno);
@@ -1669,6 +1741,13 @@ static int rmw_xtopei(CPURISCVState *env, int csrno, target_ulong *val,
     bool virt;
     int ret = -EINVAL;
     target_ulong priv, vgein;
+    RISCVException excp;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    excp = smstateen_aia_acc_ok(env, csrno);
+    if (excp != RISCV_EXCP_NONE) {
+        return excp;
+    }
 
     /* Translate CSR number for VS-mode */
     csrno = aia_xlate_vs_csrno(env, csrno);
@@ -2014,6 +2093,12 @@ static RISCVException write_mstateen(CPURISCVState *env, int csrno,
         wr_mask |= 1UL << SMSTATEEN0_FCSR;
     }
 
+    if (riscv_feature(env, RISCV_FEATURE_AIA)) {
+        wr_mask |= (1UL << SMSTATEEN0_IMSIC)
+                | (1UL << SMSTATEEN0_AIA)
+                | (1UL << SMSTATEEN0_SVSLCT);
+    }
+
     write_smstateen(env, reg, wr_mask, new_val);
 
     return RISCV_EXCP_NONE;
@@ -2042,6 +2127,12 @@ static RISCVException write_mstateenh(CPURISCVState *env, int csrno,
         wr_mask |= 1UL << SMSTATEEN0_FCSR;
     }
 
+    if (riscv_feature(env, RISCV_FEATURE_AIA)) {
+        wr_mask |= (1UL << SMSTATEEN0_IMSIC)
+                | (1UL << SMSTATEEN0_AIA)
+                | (1UL << SMSTATEEN0_SVSLCT);
+    }
+
     write_smstateen(env, reg, wr_mask, val);
 
     return RISCV_EXCP_NONE;
@@ -2067,6 +2158,12 @@ static RISCVException write_hstateen(CPURISCVState *env, int csrno,
         wr_mask |= 1UL << SMSTATEEN0_FCSR;
     }
 
+    if (riscv_feature(env, RISCV_FEATURE_AIA)) {
+        wr_mask |= (1UL << SMSTATEEN0_IMSIC)
+                | (1UL << SMSTATEEN0_AIA)
+                | (1UL << SMSTATEEN0_SVSLCT);
+    }
+
     reg = &env->hstateen[index];
     wr_mask &= env->mstateen[index];
     write_smstateen(env, reg, wr_mask, new_val);
@@ -2095,6 +2192,12 @@ static RISCVException write_hstateenh(CPURISCVState *env, int csrno,
         wr_mask |= 1UL << SMSTATEEN0_FCSR;
     }
 
+    if (riscv_feature(env, RISCV_FEATURE_AIA)) {
+        wr_mask |= (1UL << SMSTATEEN0_IMSIC)
+                | (1UL << SMSTATEEN0_AIA)
+                | (1UL << SMSTATEEN0_SVSLCT);
+    }
+
     reg = &env->hstateen[index];
     val = (uint64_t)new_val << 32;
     val |= *reg & 0xFFFFFFFF;
@@ -2288,6 +2391,12 @@ static RISCVException rmw_vsieh(CPURISCVState *env, int csrno,
     uint64_t rval;
     RISCVException ret;
 
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     ret = rmw_vsie64(env, csrno, &rval,
         ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
     if (ret_val) {
@@ -2342,6 +2451,12 @@ static RISCVException rmw_sieh(CPURISCVState *env, int csrno,
     uint64_t rval;
     RISCVException ret;
 
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     ret = rmw_sie64(env, csrno, &rval,
         ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
     if (ret_val) {
@@ -2504,6 +2619,12 @@ static RISCVException rmw_vsiph(CPURISCVState *env, int csrno,
     uint64_t rval;
     RISCVException ret;
 
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     ret = rmw_vsip64(env, csrno, &rval,
         ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
     if (ret_val) {
@@ -2558,6 +2679,12 @@ static RISCVException rmw_siph(CPURISCVState *env, int csrno,
     uint64_t rval;
     RISCVException ret;
 
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     ret = rmw_sip64(env, csrno, &rval,
         ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
     if (ret_val) {
@@ -2748,6 +2875,10 @@ static RISCVException read_hstatus(CPURISCVState *env, int csrno,
 static RISCVException write_hstatus(CPURISCVState *env, int csrno,
                                     target_ulong val)
 {
+    if (smstateen_aia_acc_ok(env, csrno) != RISCV_EXCP_NONE) {
+        val &= ~HSTATUS_VGEIN;
+    }
+
     env->hstatus = val;
     if (riscv_cpu_mxl(env) != MXL_RV32 && get_field(val, HSTATUS_VSXL) != 2) {
         qemu_log_mask(LOG_UNIMP, "QEMU does not support mixed HSXLEN options.");
@@ -2808,6 +2939,12 @@ static RISCVException rmw_hidelegh(CPURISCVState *env, int csrno,
     uint64_t rval;
     RISCVException ret;
 
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     ret = rmw_hideleg64(env, csrno, &rval,
         ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
     if (ret_val) {
@@ -2854,6 +2991,12 @@ static RISCVException rmw_hviph(CPURISCVState *env, int csrno,
     uint64_t rval;
     RISCVException ret;
 
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     ret = rmw_hvip64(env, csrno, &rval,
         ((uint64_t)new_val) << 32, ((uint64_t)wr_mask) << 32);
     if (ret_val) {
@@ -2908,6 +3051,13 @@ static RISCVException write_hcounteren(CPURISCVState *env, int csrno,
 static RISCVException read_hgeie(CPURISCVState *env, int csrno,
                                  target_ulong *val)
 {
+    RISCVException ret;
+
+    ret = smstateen_acc_ok(env, PRV_S, SMSTATEEN0_IMSIC);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     if (val) {
         *val = env->hgeie;
     }
@@ -2917,6 +3067,13 @@ static RISCVException read_hgeie(CPURISCVState *env, int csrno,
 static RISCVException write_hgeie(CPURISCVState *env, int csrno,
                                   target_ulong val)
 {
+    RISCVException ret;
+
+    ret = smstateen_acc_ok(env, PRV_S, SMSTATEEN0_IMSIC);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     /* Only GEILEN:1 bits implemented and BIT0 is never implemented */
     val &= ((((target_ulong)1) << env->geilen) - 1) << 1;
     env->hgeie = val;
@@ -2956,6 +3113,13 @@ static RISCVException write_htinst(CPURISCVState *env, int csrno,
 static RISCVException read_hgeip(CPURISCVState *env, int csrno,
                                  target_ulong *val)
 {
+    RISCVException ret;
+
+    ret = smstateen_acc_ok(env, PRV_S, SMSTATEEN0_IMSIC);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     if (val) {
         *val = env->hgeip;
     }
@@ -3026,12 +3190,28 @@ static RISCVException write_htimedeltah(CPURISCVState *env, int csrno,
 
 static int read_hvictl(CPURISCVState *env, int csrno, target_ulong *val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     *val = env->hvictl;
     return RISCV_EXCP_NONE;
 }
 
 static int write_hvictl(CPURISCVState *env, int csrno, target_ulong val)
 {
+    RISCVException ret = RISCV_EXCP_NONE;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     env->hvictl = val & HVICTL_VALID_MASK;
     return RISCV_EXCP_NONE;
 }
@@ -3090,41 +3270,105 @@ static int write_hvipriox(CPURISCVState *env, int first_index,
 
 static int read_hviprio1(CPURISCVState *env, int csrno, target_ulong *val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     return read_hvipriox(env, 0, env->hviprio, val);
 }
 
 static int write_hviprio1(CPURISCVState *env, int csrno, target_ulong val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     return write_hvipriox(env, 0, env->hviprio, val);
 }
 
 static int read_hviprio1h(CPURISCVState *env, int csrno, target_ulong *val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     return read_hvipriox(env, 4, env->hviprio, val);
 }
 
 static int write_hviprio1h(CPURISCVState *env, int csrno, target_ulong val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     return write_hvipriox(env, 4, env->hviprio, val);
 }
 
 static int read_hviprio2(CPURISCVState *env, int csrno, target_ulong *val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     return read_hvipriox(env, 8, env->hviprio, val);
 }
 
 static int write_hviprio2(CPURISCVState *env, int csrno, target_ulong val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     return write_hvipriox(env, 8, env->hviprio, val);
 }
 
 static int read_hviprio2h(CPURISCVState *env, int csrno, target_ulong *val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     return read_hvipriox(env, 12, env->hviprio, val);
 }
 
 static int write_hviprio2h(CPURISCVState *env, int csrno, target_ulong val)
 {
+    RISCVException ret;
+
+    /* Check if smstateen is enabled and this access is allowed */
+    ret = smstateen_aia_acc_ok(env, csrno);
+    if (ret != RISCV_EXCP_NONE) {
+        return ret;
+    }
+
     return write_hvipriox(env, 12, env->hviprio, val);
 }
 
-- 
2.17.1