diff --git a/include/sbi/sbi_hartmask.h b/include/sbi/sbi_hartmask.h
index 200ab6e5..da6821ee 100644
--- a/include/sbi/sbi_hartmask.h
+++ b/include/sbi/sbi_hartmask.h
@@ -20,7 +20,11 @@
  * also represents the maximum number of HART ids generic OpenSBI
  * can handle.
  */
+#ifdef CONFIG_HARTMASK_MAX_BITS
+#define SBI_HARTMASK_MAX_BITS		CONFIG_HARTMASK_MAX_BITS
+#else
 #define SBI_HARTMASK_MAX_BITS		128
+#endif
 
 /** Representation of hartmask */
 struct sbi_hartmask {
diff --git a/lib/sbi/Kconfig b/lib/sbi/Kconfig
index e76aecca..24132eaa 100644
--- a/lib/sbi/Kconfig
+++ b/lib/sbi/Kconfig
@@ -2,6 +2,15 @@
 
 menu "Generic SBI Support"
 
+config HARTMASK_MAX_BITS
+	int "Maximum number of hart mask bits (32-512)"
+	range 32 512
+	default 256
+	help
+	  The hartmask is indexed using physical hart IDs so this setting
+	  also represents the maximum number of hart IDs generic OpenSBI
+	  can handle.
+
 config DEFAULT_HART_STACK_SIZE
 	int "Default per-HART stack size (bytes)"
 	range 8192 1048576