[PATCH v7 01/11] target/riscv: Add basic definitions and CSRs for SMMPT

This patch lays the groundwork for the SMMPT (Supervisor Domains Access
Protection) extension by introducing its fundamental components.

It adds:
- New CPU configuration flags, `ext_smmpt` and `ext_smsdid`, to enable
  the extension.
- Bit-field definitions for the `mmpt` CSR in `cpu_bits.h`.
- The `mmpt` and `msdcfg` CSR numbers and their read/write handlers in
  `csr.c`.
- New fields in `CPUArchState` to store the state of these new CSRs.
- A new translation failure reason `TRANSLATE_MPT_FAIL`.

This provides the necessary infrastructure for the core MPT logic and
MMU integration that will follow.

Co-authored-by: Huang Tao <[email protected]>
Co-authored-by: TANG Tiancheng <[email protected]>
Signed-off-by: LIU Zhiwei <[email protected]>
---
 target/riscv/cpu.h                |  8 +++
 target/riscv/cpu_bits.h           | 24 ++++++++
 target/riscv/cpu_cfg_fields.h.inc |  2 +
 target/riscv/riscv_smmpt.h        | 21 +++++++
 target/riscv/tcg/csr.c            | 99 +++++++++++++++++++++++++++++++
 5 files changed, 154 insertions(+)
 create mode 100644 target/riscv/riscv_smmpt.h

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index c9dfa7daff..8825e1c186 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -139,6 +139,7 @@ enum {
     TRANSLATE_PMP_FAIL,
     TRANSLATE_G_STAGE_FAIL,
     TRANSLATE_PMA_FAIL,
+    TRANSLATE_MPT_FAIL
 };
 
 /* Extension context status */
@@ -184,6 +185,7 @@ extern RISCVCPUImpliedExtsRule *riscv_multi_ext_implied_rules[];
 
 #if !defined(CONFIG_USER_ONLY)
 #include "tcg/pmp.h"
+#include "riscv_smmpt.h"
 #endif
 
 #define RV_VLEN_MAX 1024
@@ -521,6 +523,12 @@ struct CPUArchState {
     uint64_t rnmip;
     uint64_t rnmi_irqvec;
     uint64_t rnmi_excpvec;
+
+    /* Smsdid */
+    uint32_t mptmode;
+    uint32_t sdid;
+    uint64_t mptppn;
+    uint32_t msdcfg;
 #endif
 
     /* Fields from here on are preserved across CPU reset. */
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index 3f146a43fe..4ed4843e3d 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -1166,4 +1166,28 @@ typedef enum CTRType {
 #define MCONTEXT64                         0x0000000000001FFFULL
 #define MCONTEXT32_HCONTEXT                0x0000007F
 #define MCONTEXT64_HCONTEXT                0x0000000000003FFFULL
+
+/* Smsdid */
+#define CSR_MMPT        0x382
+#define CSR_MSDCFG      0x74E
+
+/*
+ * MMPT register layout for MXLEN=32:
+ * MODE[31:30], 0[29:28], SDID[27:22], PPN[21:0]
+ */
+#define MMPT_MODE_MASK_32   0xC0000000
+#define MMPT_MODE_SHIFT_32  30
+#define MMPT_SDID_MASK_32   0x0FC00000
+#define MMPT_SDID_SHIFT_32  22
+#define MMPT_PPN_MASK_32    0x003FFFFF
+
+/*
+ * MMPT register layout for MXLEN=64:
+ * MODE[63:60], 0[59:58], SDID[57:52], 0[51:44], PPN[43:0]
+ */
+#define MMPT_MODE_MASK_64   0xF000000000000000ULL
+#define MMPT_MODE_SHIFT_64  60
+#define MMPT_SDID_MASK_64   0x03F0000000000000ULL
+#define MMPT_SDID_SHIFT_64  52
+#define MMPT_PPN_MASK_64    0x00000FFFFFFFFFFFULL
 #endif
diff --git a/target/riscv/cpu_cfg_fields.h.inc b/target/riscv/cpu_cfg_fields.h.inc
index 9eb47af0a7..6b616388be 100644
--- a/target/riscv/cpu_cfg_fields.h.inc
+++ b/target/riscv/cpu_cfg_fields.h.inc
@@ -63,6 +63,8 @@ BOOL_FIELD(ext_smpmpmt)
 BOOL_FIELD(ext_svrsw60t59b)
 BOOL_FIELD(ext_svvptc)
 BOOL_FIELD(ext_svukte)
+BOOL_FIELD(ext_smmpt)
+BOOL_FIELD(ext_smsdid)
 BOOL_FIELD(ext_zdinx)
 BOOL_FIELD(ext_zaamo)
 BOOL_FIELD(ext_zacas)
diff --git a/target/riscv/riscv_smmpt.h b/target/riscv/riscv_smmpt.h
new file mode 100644
index 0000000000..74dcccf4be
--- /dev/null
+++ b/target/riscv/riscv_smmpt.h
@@ -0,0 +1,21 @@
+/*
+ * QEMU RISC-V Smmpt (Memory Protection Table)
+ *
+ * Copyright (c) 2024 Alibaba Group. All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef RISCV_SMMPT_H
+#define RISCV_SMMPT_H
+
+typedef enum {
+    SMMPTBARE = 0,
+    SMMPT34   = 1,
+    SMMPT43   = 2,
+    SMMPT52   = 3,
+    SMMPT64   = 4,
+    SMMPTMAX
+} mpt_mode_t;
+
+#endif
diff --git a/target/riscv/tcg/csr.c b/target/riscv/tcg/csr.c
index 36f2004bc5..8ffe85caa9 100644
--- a/target/riscv/tcg/csr.c
+++ b/target/riscv/tcg/csr.c
@@ -821,6 +821,15 @@ static RISCVException rnmi(CPURISCVState *env, int csrno)
 
     return RISCV_EXCP_ILLEGAL_INST;
 }
+
+static RISCVException smsdid(CPURISCVState *env, int csrno)
+{
+    if (riscv_cpu_cfg(env)->ext_smsdid) {
+        return RISCV_EXCP_NONE;
+    }
+
+    return RISCV_EXCP_ILLEGAL_INST;
+}
 #endif
 
 static RISCVException seed(CPURISCVState *env, int csrno)
@@ -5568,6 +5577,93 @@ static RISCVException write_mnstatus(CPURISCVState *env, int csrno,
     return RISCV_EXCP_NONE;
 }
 
+static RISCVException read_mmpt(CPURISCVState *env, int csrno,
+                                target_ulong *val)
+{
+    if (riscv_cpu_xlen(env) == 32) {
+        uint32_t value = 0;
+        value |= env->mptmode << MMPT_MODE_SHIFT_32;
+        value |= (env->sdid << MMPT_SDID_SHIFT_32) & MMPT_SDID_MASK_32;
+        value |= env->mptppn & MMPT_PPN_MASK_32;
+        *val = value;
+    } else if (riscv_cpu_xlen(env) == 64) {
+        uint64_t value_64 = 0;
+        uint32_t mode_value = env->mptmode;
+        /* mpt_mode_t convert to mmpt.mode value */
+        if (mode_value) {
+            mode_value -= SMMPT43 - SMMPT34;
+        }
+        value_64 |= (uint64_t)mode_value << MMPT_MODE_SHIFT_64;
+        value_64 |= ((uint64_t)env->sdid << MMPT_SDID_SHIFT_64)
+                    & MMPT_SDID_MASK_64;
+        value_64 |= (uint64_t)env->mptppn & MMPT_PPN_MASK_64;
+        *val = value_64;
+    } else {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_mmpt(CPURISCVState *env, int csrno,
+                                 target_ulong val, uintptr_t ra)
+{
+    uint32_t mode_value = 0;
+    if (!riscv_cpu_cfg(env)->ext_smmpt) {
+        goto set_remaining_fields_zero;
+    }
+
+    if (riscv_cpu_xlen(env) == 32) {
+        mode_value = (val & MMPT_MODE_MASK_32) >> MMPT_MODE_SHIFT_32;
+        /* If mode is bare, the remaining fields in mmpt must be zero */
+        if (mode_value == SMMPTBARE) {
+            goto set_remaining_fields_zero;
+        } else if (mode_value <= SMMPT34) {
+            /* Only write the legal value */
+            env->mptmode = mode_value;
+        }
+        env->sdid = (val & MMPT_SDID_MASK_32) >> MMPT_SDID_SHIFT_32;
+        env->mptppn = val & MMPT_PPN_MASK_32;
+    } else if (riscv_cpu_xlen(env) == 64) {
+        mode_value = (val & MMPT_MODE_MASK_64) >> MMPT_MODE_SHIFT_64;
+        if (mode_value == SMMPTBARE) {
+            goto set_remaining_fields_zero;
+        } else if (mode_value < SMMPTMAX) {
+            /* convert to mpt_mode_t */
+            mode_value += SMMPT43 - SMMPT34;
+            env->mptmode = mode_value;
+        }
+        env->sdid = (val & MMPT_SDID_MASK_64) >> MMPT_SDID_SHIFT_64;
+        env->mptppn = val & MMPT_PPN_MASK_64;
+        /* Smmpt64: root table PPN bits 2:0 must be zero (32KiB alignment) */
+        if (env->mptmode == SMMPT64) {
+            env->mptppn &= ~(uint64_t)0x7;
+        }
+    } else {
+        return RISCV_EXCP_ILLEGAL_INST;
+    }
+    return RISCV_EXCP_NONE;
+
+set_remaining_fields_zero:
+    env->sdid = 0;
+    env->mptmode = SMMPTBARE;
+    env->mptppn = 0;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException read_msdcfg(CPURISCVState *env, int csrno,
+                                   target_ulong *val)
+{
+    *val = env->msdcfg;
+    return RISCV_EXCP_NONE;
+}
+
+static RISCVException write_msdcfg(CPURISCVState *env, int csrno,
+                                    target_ulong val, uintptr_t ra)
+{
+    env->msdcfg = val;
+    return RISCV_EXCP_NONE;
+}
+
 #endif
 
 /* Crypto Extension */
@@ -6769,6 +6865,9 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
                              write_mhpmcounterh                         },
     [CSR_SCOUNTOVF]      = { "scountovf", sscofpmf,  read_scountovf,
                              .min_priv_ver = PRIV_VERSION_1_12_0 },
+    /* Supervisor Domain Identifier and Protection Registers */
+    [CSR_MMPT] =    { "mmpt",   smsdid,  read_mmpt,   write_mmpt   },
+    [CSR_MSDCFG] =  { "msdcfg", smsdid,  read_msdcfg, write_msdcfg },
 
 #endif /* !CONFIG_USER_ONLY */
 };
-- 
2.43.0