diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index def27a53f2..c541924214 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -111,6 +111,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(svpbmt, true, PRIV_VERSION_1_12_0, ext_svpbmt),
     ISA_EXT_DATA_ENTRY(xtheadba, true, PRIV_VERSION_1_11_0, ext_xtheadba),
     ISA_EXT_DATA_ENTRY(xtheadbb, true, PRIV_VERSION_1_11_0, ext_xtheadbb),
+    ISA_EXT_DATA_ENTRY(xtheadbs, true, PRIV_VERSION_1_11_0, ext_xtheadbs),
     ISA_EXT_DATA_ENTRY(xtheadcmo, true, PRIV_VERSION_1_11_0, ext_xtheadcmo),
     ISA_EXT_DATA_ENTRY(xtheadsync, true, PRIV_VERSION_1_11_0, ext_xtheadsync),
     ISA_EXT_DATA_ENTRY(xventanacondops, true, PRIV_VERSION_1_12_0, ext_XVentanaCondOps),
@@ -1094,6 +1095,7 @@ static Property riscv_cpu_extensions[] = {
     /* Vendor-specific custom extensions */
     DEFINE_PROP_BOOL("xtheadba", RISCVCPU, cfg.ext_xtheadba, false),
     DEFINE_PROP_BOOL("xtheadbb", RISCVCPU, cfg.ext_xtheadbb, false),
+    DEFINE_PROP_BOOL("xtheadbs", RISCVCPU, cfg.ext_xtheadbs, false),
     DEFINE_PROP_BOOL("xtheadcmo", RISCVCPU, cfg.ext_xtheadcmo, false),
     DEFINE_PROP_BOOL("xtheadsync", RISCVCPU, cfg.ext_xtheadsync, false),
     DEFINE_PROP_BOOL("xventanacondops", RISCVCPU, cfg.ext_XVentanaCondOps, false),
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index be86c2fb95..876eaebd0e 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -475,6 +475,7 @@ struct RISCVCPUConfig {
     /* Vendor-specific custom extensions */
     bool ext_xtheadba;
     bool ext_xtheadbb;
+    bool ext_xtheadbs;
     bool ext_xtheadcmo;
     bool ext_xtheadsync;
     bool ext_XVentanaCondOps;
diff --git a/target/riscv/insn_trans/trans_xthead.c.inc b/target/riscv/insn_trans/trans_xthead.c.inc
index ebfab90dd9..bc1605445d 100644
--- a/target/riscv/insn_trans/trans_xthead.c.inc
+++ b/target/riscv/insn_trans/trans_xthead.c.inc
@@ -28,6 +28,12 @@
     }                                            \
 } while (0)
 
+#define REQUIRE_XTHEADBS(ctx) do {               \
+    if (!ctx->cfg_ptr->ext_xtheadbs) {           \
+        return false;                            \
+    }                                            \
+} while (0)
+
 #define REQUIRE_XTHEADCMO(ctx) do {              \
     if (!ctx->cfg_ptr->ext_xtheadcmo) {          \
         return false;                            \
@@ -191,6 +197,15 @@ static bool trans_th_tstnbz(DisasContext *ctx, arg_th_tstnbz *a)
     return gen_unary(ctx, a, EXT_ZERO, gen_th_tstnbz);
 }
 
+/* XTheadBs */
+
+/* th.tst is an alternate encoding for bexti (from Zbs) */
+static bool trans_th_tst(DisasContext *ctx, arg_th_tst *a)
+{
+    REQUIRE_XTHEADBS(ctx);
+    return gen_shift_imm_tl(ctx, a, EXT_NONE, gen_bext);
+}
+
 /* XTheadCmo */
 
 static inline int priv_level(DisasContext *ctx)
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 387ef0ad8b..880324e617 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -133,7 +133,8 @@ static bool always_true_p(DisasContext *ctx  __attribute__((__unused__)))
 static bool has_xthead_p(DisasContext *ctx  __attribute__((__unused__)))
 {
     return ctx->cfg_ptr->ext_xtheadba || ctx->cfg_ptr->ext_xtheadbb ||
-           ctx->cfg_ptr->ext_xtheadcmo || ctx->cfg_ptr->ext_xtheadsync;
+           ctx->cfg_ptr->ext_xtheadbs || ctx->cfg_ptr->ext_xtheadcmo ||
+           ctx->cfg_ptr->ext_xtheadsync;
 }
 
 #define MATERIALISE_EXT_PREDICATE(ext)  \
diff --git a/target/riscv/xthead.decode b/target/riscv/xthead.decode
index 8cd140891b..8494805611 100644
--- a/target/riscv/xthead.decode
+++ b/target/riscv/xthead.decode
@@ -58,6 +58,9 @@ th_rev           1000001 00000 ..... 001 ..... 0001011 @r2
 th_revw          1001000 00000 ..... 001 ..... 0001011 @r2
 th_tstnbz        1000000 00000 ..... 001 ..... 0001011 @r2
 
+# XTheadBs
+th_tst           100010 ...... ..... 001 ..... 0001011 @sh6
+
 # XTheadCmo
 th_dcache_call   0000000 00001 00000 000 00000 0001011
 th_dcache_ciall  0000000 00011 00000 000 00000 0001011