[v2] target/riscv: Support Smpmpmt extension

[PATCH v2] target/riscv: Support Smpmpmt extension

Jay Chang posted 1 patch 1 week ago

Diff against v1
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Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20251107023136.89181-1-jay.chang@sifive.com

Maintainers: Palmer Dabbelt <palmer@dabbelt.com>, Alistair Francis <alistair.francis@wdc.com>, Weiwei Li <liwei1518@gmail.com>, Daniel Henrique Barboza <dbarboza@ventanamicro.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>

target/riscv/cpu.c                |  2 ++
target/riscv/cpu_cfg_fields.h.inc |  1 +
target/riscv/pmp.c                | 12 ++++++++++++
target/riscv/pmp.h                |  1 +
4 files changed, 16 insertions(+)

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[PATCH v2] target/riscv: Support Smpmpmt extension

Posted by Jay Chang 1 week ago

The Smpmpmt extension provides a mechanism to control memory attributes
at the granularity of PMP (Physical Memory Protection) registers, similar
to how Svpbmt controls memory attributes at the page level.

Version 0.6
https://github.com/riscv/riscv-isa-manual/blob/smpmpmt/src/smpmpmt.adoc#svpbmt

Signed-off-by: Jay Chang <jay.chang@sifive.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>

---
v2:
    Place smpmpmt in the correct riscv,isa order.

Signed-off-by: Jay Chang <jay.chang@sifive.com>
---
 target/riscv/cpu.c                |  2 ++
 target/riscv/cpu_cfg_fields.h.inc |  1 +
 target/riscv/pmp.c                | 12 ++++++++++++
 target/riscv/pmp.h                |  1 +
 4 files changed, 16 insertions(+)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index ae8b721e55..0760ee7d9e 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -203,6 +203,7 @@ const RISCVIsaExtData isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(smcsrind, PRIV_VERSION_1_13_0, ext_smcsrind),
     ISA_EXT_DATA_ENTRY(smdbltrp, PRIV_VERSION_1_13_0, ext_smdbltrp),
     ISA_EXT_DATA_ENTRY(smepmp, PRIV_VERSION_1_12_0, ext_smepmp),
+    ISA_EXT_DATA_ENTRY(smpmpmt, PRIV_VERSION_1_12_0, ext_smpmpmt),
     ISA_EXT_DATA_ENTRY(smrnmi, PRIV_VERSION_1_12_0, ext_smrnmi),
     ISA_EXT_DATA_ENTRY(smmpm, PRIV_VERSION_1_13_0, ext_smmpm),
     ISA_EXT_DATA_ENTRY(smnpm, PRIV_VERSION_1_13_0, ext_smnpm),
@@ -1262,6 +1263,7 @@ const RISCVCPUMultiExtConfig riscv_cpu_extensions[] = {
     MULTI_EXT_CFG_BOOL("svinval", ext_svinval, false),
     MULTI_EXT_CFG_BOOL("svnapot", ext_svnapot, false),
     MULTI_EXT_CFG_BOOL("svpbmt", ext_svpbmt, false),
+    MULTI_EXT_CFG_BOOL("smpmpmt", ext_smpmpmt, false),
     MULTI_EXT_CFG_BOOL("svrsw60t59b", ext_svrsw60t59b, false),
     MULTI_EXT_CFG_BOOL("svvptc", ext_svvptc, true),
 
diff --git a/target/riscv/cpu_cfg_fields.h.inc b/target/riscv/cpu_cfg_fields.h.inc
index a154ecdc79..b1096da664 100644
--- a/target/riscv/cpu_cfg_fields.h.inc
+++ b/target/riscv/cpu_cfg_fields.h.inc
@@ -57,6 +57,7 @@ BOOL_FIELD(ext_svadu)
 BOOL_FIELD(ext_svinval)
 BOOL_FIELD(ext_svnapot)
 BOOL_FIELD(ext_svpbmt)
+BOOL_FIELD(ext_smpmpmt)
 BOOL_FIELD(ext_svrsw60t59b)
 BOOL_FIELD(ext_svvptc)
 BOOL_FIELD(ext_svukte)
diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
index 3ef62d26ad..52a7677683 100644
--- a/target/riscv/pmp.c
+++ b/target/riscv/pmp.c
@@ -165,6 +165,18 @@ static bool pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val)
                           "ignoring pmpcfg write - invalid\n");
         } else {
             uint8_t a_field = pmp_get_a_field(val);
+
+            if (!riscv_cpu_cfg(env)->ext_smpmpmt) {
+                /* If smpmpmt not supported, clear the MTMATCH bit */
+                val &= ~PMP_MTMATCH;
+            } else if ((val & PMP_MTMATCH) == PMP_MTMATCH) {
+                /*
+                 * If trying to set reserved value (0x3) for MT field,
+                 * preserve the original MT field from current config.
+                 */
+                val = (val & ~PMP_MTMATCH) |
+                    (env->pmp_state.pmp[pmp_index].cfg_reg & PMP_MTMATCH);
+            }
             /*
              * When granularity g >= 1 (i.e., granularity > 4 bytes),
              * the NA4 (Naturally Aligned 4-byte) mode is not selectable
diff --git a/target/riscv/pmp.h b/target/riscv/pmp.h
index 271cf24169..467fb6b4b1 100644
--- a/target/riscv/pmp.h
+++ b/target/riscv/pmp.h
@@ -29,6 +29,7 @@ typedef enum {
     PMP_WRITE = 1 << 1,
     PMP_EXEC  = 1 << 2,
     PMP_AMATCH = (3 << 3),
+    PMP_MTMATCH = (3 << 5),
     PMP_LOCK  = 1 << 7
 } pmp_priv_t;
 
-- 
2.48.1