diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h
index ba32af062f61d69164a792630e3257c8cdc6deb5..7bfc85bbb8ffc0578011ceac2c08548bd140ade3 100644
--- a/arch/x86/include/asm/alternative.h
+++ b/arch/x86/include/asm/alternative.h
@@ -52,6 +52,12 @@ struct alt_instr {
 	u8  padlen;		/* length of build-time padding */
 } __packed;
 
+/*
+ * Debug flag that can be tested to see whether alternative
+ * instructions were patched in already:
+ */
+extern int alternatives_patched;
+
 extern void alternative_instructions(void);
 extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end);
 
diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index 31a002ad5aeb715811ed7e41b6bdf35c99052d65..ab2c507b58b65d9909116878b611faf78c592474 100644
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -119,7 +119,7 @@ static inline int xsave_state(struct xsave_struct *fx)
 	u32 hmask = mask >> 32;
 	int err = 0;
 
-	WARN_ON(system_state == SYSTEM_BOOTING);
+	WARN_ON(!alternatives_patched);
 
 	/*
 	 * If xsaves is enabled, xsaves replaces xsaveopt because
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index aef65319316065eab845f35141682c3550f18a22..7fe0972353769a49243d514493c8a0d9d207ccbe 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -21,6 +21,10 @@
 #include <asm/io.h>
 #include <asm/fixmap.h>
 
+int __read_mostly alternatives_patched;
+
+EXPORT_SYMBOL_GPL(alternatives_patched);
+
 #define MAX_PATCH_LEN (255-1)
 
 static int __initdata_or_module debug_alternative;
@@ -627,6 +631,7 @@ void __init alternative_instructions(void)
 	apply_paravirt(__parainstructions, __parainstructions_end);
 
 	restart_nmi();
+	alternatives_patched = 1;
 }
 
 /**