diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 36e3e5fdaf..be9746d361 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -113,6 +113,7 @@ const RISCVIsaExtData isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(zihintntl, PRIV_VERSION_1_10_0, ext_zihintntl),
     ISA_EXT_DATA_ENTRY(zihintpause, PRIV_VERSION_1_10_0, ext_zihintpause),
     ISA_EXT_DATA_ENTRY(zihpm, PRIV_VERSION_1_12_0, ext_zihpm),
+    ISA_EXT_DATA_ENTRY(zilsd, PRIV_VERSION_1_12_0, ext_zilsd),
     ISA_EXT_DATA_ENTRY(zmmul, PRIV_VERSION_1_12_0, ext_zmmul),
     ISA_EXT_DATA_ENTRY(za64rs, PRIV_VERSION_1_12_0, has_priv_1_11),
     ISA_EXT_DATA_ENTRY(zaamo, PRIV_VERSION_1_12_0, ext_zaamo),
@@ -132,6 +133,7 @@ const RISCVIsaExtData isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(zce, PRIV_VERSION_1_12_0, ext_zce),
     ISA_EXT_DATA_ENTRY(zcmp, PRIV_VERSION_1_12_0, ext_zcmp),
     ISA_EXT_DATA_ENTRY(zcmt, PRIV_VERSION_1_12_0, ext_zcmt),
+    ISA_EXT_DATA_ENTRY(zclsd, PRIV_VERSION_1_12_0, ext_zclsd),
     ISA_EXT_DATA_ENTRY(zba, PRIV_VERSION_1_12_0, ext_zba),
     ISA_EXT_DATA_ENTRY(zbb, PRIV_VERSION_1_12_0, ext_zbb),
     ISA_EXT_DATA_ENTRY(zbc, PRIV_VERSION_1_12_0, ext_zbc),
@@ -1492,6 +1494,7 @@ const RISCVCPUMultiExtConfig riscv_cpu_extensions[] = {
 
     MULTI_EXT_CFG_BOOL("zicntr", ext_zicntr, true),
     MULTI_EXT_CFG_BOOL("zihpm", ext_zihpm, true),
+    MULTI_EXT_CFG_BOOL("zilsd", ext_zilsd, false),
 
     MULTI_EXT_CFG_BOOL("zba", ext_zba, true),
     MULTI_EXT_CFG_BOOL("zbb", ext_zbb, true),
@@ -1531,6 +1534,7 @@ const RISCVCPUMultiExtConfig riscv_cpu_extensions[] = {
     MULTI_EXT_CFG_BOOL("zcmp", ext_zcmp, false),
     MULTI_EXT_CFG_BOOL("zcmt", ext_zcmt, false),
     MULTI_EXT_CFG_BOOL("zicond", ext_zicond, false),
+    MULTI_EXT_CFG_BOOL("zclsd", ext_zclsd, false),
 
     /* Vector cryptography extensions */
     MULTI_EXT_CFG_BOOL("zvbb", ext_zvbb, false),
diff --git a/target/riscv/cpu_cfg.h b/target/riscv/cpu_cfg.h
index cb750154bd..76ae1e95d7 100644
--- a/target/riscv/cpu_cfg.h
+++ b/target/riscv/cpu_cfg.h
@@ -51,6 +51,7 @@ struct RISCVCPUConfig {
     bool ext_zcf;
     bool ext_zcmp;
     bool ext_zcmt;
+    bool ext_zclsd;
     bool ext_zk;
     bool ext_zkn;
     bool ext_zknd;
@@ -71,6 +72,7 @@ struct RISCVCPUConfig {
     bool ext_zihintntl;
     bool ext_zihintpause;
     bool ext_zihpm;
+    bool ext_zilsd;
     bool ext_ztso;
     bool ext_smstateen;
     bool ext_sstc;
diff --git a/target/riscv/insn16.decode b/target/riscv/insn16.decode
index b96c534e73..bcd94e41e1 100644
--- a/target/riscv/insn16.decode
+++ b/target/riscv/insn16.decode
@@ -130,10 +130,14 @@ sw                110  ... ... .. ... 00 @cs_w
 {
   ld              011  ... ... .. ... 00 @cl_d
   c_flw           011  ... ... .. ... 00 @cl_w
+  # *** Zclsd Extension ***
+  zclsd_ld        011  ... ... .. ... 00 @cl_d
 }
 {
   sd              111  ... ... .. ... 00 @cs_d
   c_fsw           111  ... ... .. ... 00 @cs_w
+  # *** Zclsd Extension ***
+  zclsd_sd        111  ... ... .. ... 00 @cs_d
 }
 
 # *** RV32/64C Standard Extension (Quadrant 1) ***
@@ -207,10 +211,14 @@ sw                110 .  .....  ..... 10 @c_swsp
   c64_illegal     011 -  00000  ----- 10 # c.ldsp, RES rd=0
   ld              011 .  .....  ..... 10 @c_ldsp
   c_flw           011 .  .....  ..... 10 @c_lwsp
+  # *** Zclsd Extension ***
+  zclsd_ldsp      011 .  .....  ..... 10 @c_ldsp
 }
 {
   sd              111 .  .....  ..... 10 @c_sdsp
   c_fsw           111 .  .....  ..... 10 @c_swsp
+  # *** Zclsd Extension ***
+  zclsd_sd        111 .  .....  ..... 10 @c_sdsp
 }
 
 # *** RV64 and RV32 Zcb Extension ***
diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
index f22df04cfd..f6f4b7950b 100644
--- a/target/riscv/insn32.decode
+++ b/target/riscv/insn32.decode
@@ -169,8 +169,16 @@ csrrci   ............     ..... 111 ..... 1110011 @csr
 
 # *** RV64I Base Instruction Set (in addition to RV32I) ***
 lwu      ............   ..... 110 ..... 0000011 @i
-ld       ............   ..... 011 ..... 0000011 @i
-sd       ....... .....  ..... 011 ..... 0100011 @s
+{
+  ld       ............   ..... 011 ..... 0000011 @i
+  # *** Zilsd instructions ***
+  zilsd_ld ............   ..... 011 ..... 0000011 @i
+}
+{
+  sd       ....... .....  ..... 011 ..... 0100011 @s
+  # *** Zilsd instructions ***
+  zilsd_sd ....... .....  ..... 011 ..... 0100011 @s
+}
 addiw    ............   ..... 000 ..... 0011011 @i
 slliw    0000000 .....  ..... 001 ..... 0011011 @sh5
 srliw    0000000 .....  ..... 101 ..... 0011011 @sh5
diff --git a/target/riscv/insn_trans/trans_zilsd.c.inc b/target/riscv/insn_trans/trans_zilsd.c.inc
new file mode 100644
index 0000000000..1e3ab362de
--- /dev/null
+++ b/target/riscv/insn_trans/trans_zilsd.c.inc
@@ -0,0 +1,112 @@
+/*
+ * RISC-V translation routines for the Zilsd & Zclsd Extension.
+ *
+ * Copyright (c) 2024 Nucleisys, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define REQUIRE_ZILSD(ctx) do {    \
+    if (!ctx->cfg_ptr->ext_zilsd)  \
+        return false;              \
+} while (0)
+
+#define REQUIRE_ZCLSD(ctx) do {    \
+    if (!ctx->cfg_ptr->ext_zclsd)  \
+        return false;              \
+} while (0)
+
+static bool gen_load_i64(DisasContext *ctx, arg_ld *a)
+{
+    if ((a->rd) % 2) {
+        return false;
+    }
+
+    TCGv dest_low = dest_gpr(ctx, a->rd);
+    TCGv dest_high = dest_gpr(ctx, a->rd + 1);
+    TCGv addr = get_address(ctx, a->rs1, a->imm);
+    TCGv_i64 tmp = tcg_temp_new_i64();
+
+    tcg_gen_qemu_ld_i64(tmp, addr, ctx->mem_idx, MO_TESQ);
+
+    if (a->rd == 0) {
+        return true;
+    }
+
+    tcg_gen_extr_i64_tl(dest_low, dest_high, tmp);
+
+    gen_set_gpr(ctx, a->rd, dest_low);
+    gen_set_gpr(ctx, a->rd + 1, dest_high);
+
+    return true;
+}
+
+static bool trans_zilsd_ld(DisasContext *ctx, arg_zilsd_ld *a)
+{
+    REQUIRE_32BIT(ctx);
+    REQUIRE_ZILSD(ctx);
+    return gen_load_i64(ctx, a);
+}
+
+static bool trans_zclsd_ld(DisasContext *ctx, arg_zclsd_ld *a)
+{
+    REQUIRE_32BIT(ctx);
+    REQUIRE_ZCLSD(ctx);
+    return gen_load_i64(ctx, a);
+}
+
+static bool trans_zclsd_ldsp(DisasContext *ctx, arg_zclsd_ldsp *a)
+{
+    REQUIRE_32BIT(ctx);
+    REQUIRE_ZCLSD(ctx);
+
+    if (a->rd == 0) {
+        return false;
+    }
+    return gen_load_i64(ctx, a);
+}
+
+static bool gen_store_i64(DisasContext *ctx, arg_sd *a)
+{
+    if ((a->rs2) % 2) {
+        return false;
+    }
+
+    TCGv data_low = get_gpr(ctx, a->rs2, EXT_NONE);
+    TCGv data_high = get_gpr(ctx, a->rs2 + 1, EXT_NONE);
+    TCGv addr = get_address(ctx, a->rs1, a->imm);
+    TCGv_i64 tmp = tcg_temp_new_i64();
+
+    if (a->rs2 == 0) {
+        tmp = tcg_constant_i64(0);
+    } else {
+        tcg_gen_concat_tl_i64(tmp, data_low, data_high);
+    }
+    tcg_gen_qemu_st_i64(tmp, addr, ctx->mem_idx, MO_TESQ);
+
+    return true;
+}
+
+static bool trans_zilsd_sd(DisasContext *ctx, arg_zilsd_sd *a)
+{
+    REQUIRE_32BIT(ctx);
+    REQUIRE_ZILSD(ctx);
+    return gen_store_i64(ctx, a);
+}
+
+static bool trans_zclsd_sd(DisasContext *ctx, arg_zclsd_sd *a)
+{
+    REQUIRE_32BIT(ctx);
+    REQUIRE_ZCLSD(ctx);
+    return gen_store_i64(ctx, a);
+}
diff --git a/target/riscv/tcg/tcg-cpu.c b/target/riscv/tcg/tcg-cpu.c
index b5b95e052d..bb15e5737c 100644
--- a/target/riscv/tcg/tcg-cpu.c
+++ b/target/riscv/tcg/tcg-cpu.c
@@ -721,6 +721,26 @@ void riscv_cpu_validate_set_extensions(RISCVCPU *cpu, Error **errp)
         cpu->pmu_avail_ctrs = 0;
     }
 
+    if (cpu->cfg.ext_zilsd && riscv_has_ext(env, RVC)) {
+        cpu_cfg_ext_auto_update(cpu, CPU_CFG_OFFSET(ext_zclsd), true);
+    }
+
+    if (cpu->cfg.ext_zclsd) {
+        cpu_cfg_ext_auto_update(cpu, CPU_CFG_OFFSET(ext_zca), true);
+        cpu_cfg_ext_auto_update(cpu, CPU_CFG_OFFSET(ext_zilsd), true);
+
+        if (riscv_has_ext(env, RVC) && riscv_has_ext(env, RVF)) {
+            error_setg(errp,
+                    "Zclsd cannot be supported together with C and F extension");
+            return;
+        }
+        if (cpu->cfg.ext_zcf) {
+            error_setg(errp,
+                    "Zclsd cannot be supported together with Zcf extension");
+            return;
+        }
+    }
+
     /*
      * Disable isa extensions based on priv spec after we
      * validated and set everything we need.
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 9ff09ebdb6..be148ef3c6 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -1113,6 +1113,7 @@ static uint32_t opcode_at(DisasContextBase *dcbase, target_ulong pc)
 /* Include the auto-generated decoder for 16 bit insn */
 #include "decode-insn16.c.inc"
 #include "insn_trans/trans_rvzce.c.inc"
+#include "insn_trans/trans_zilsd.c.inc"
 
 /* Include decoders for factored-out extensions */
 #include "decode-XVentanaCondOps.c.inc"
