diff --git a/arch/xtensa/core/prep_c.c b/arch/xtensa/core/prep_c.c
index 990915c5a46..6dbab69f50f 100644
--- a/arch/xtensa/core/prep_c.c
+++ b/arch/xtensa/core/prep_c.c
@@ -13,6 +13,13 @@ extern FUNC_NORETURN void z_cstart(void);
 /* defined by the SoC in case of CONFIG_SOC_HAS_RUNTIME_NUM_CPUS=y */
 extern void soc_num_cpus_init(void);
 
+/* Make sure the platform configuration matches what the toolchain
+ * thinks the hardware is doing.
+ */
+#ifdef CONFIG_DCACHE_LINE_SIZE
+BUILD_ASSERT(CONFIG_DCACHE_LINE_SIZE == XCHAL_DCACHE_LINESIZE);
+#endif
+
 /**
  *
  * @brief Prepare to and run C code
diff --git a/boards/qemu/xtensa/Kconfig.defconfig b/boards/qemu/xtensa/Kconfig.defconfig
index 081971b5e81..c94da322385 100644
--- a/boards/qemu/xtensa/Kconfig.defconfig
+++ b/boards/qemu/xtensa/Kconfig.defconfig
@@ -9,4 +9,8 @@ config BUILD_OUTPUT_BIN
 config IPM_CONSOLE_STACK_SIZE
 	default 2048 if IPM_CONSOLE_RECEIVER
 
+# Must match XCHAL_DCACHE_LINESIZE form core-isa.h
+config DCACHE_LINE_SIZE
+	default 32
+
 endif # BOARD_QEMU_XTENSA