diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index 66350e6a6ca5a2dc7254c577764fc0be17564cb0..e13027247c90b7ad5d4b19919f7c118a4a19b398 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -361,6 +361,8 @@ restore_all:
 	TRACE_IRQS_IRET
 restore_all_notrace:
 #ifdef CONFIG_X86_ESPFIX32
+	ALTERNATIVE	"jmp restore_nocheck", "", X86_BUG_ESPFIX
+
 	movl	PT_EFLAGS(%esp), %eax		# mix EFLAGS, SS and CS
 	/*
 	 * Warning: PT_OLDSS(%esp) contains the wrong/random values if we
@@ -387,19 +389,6 @@ ENTRY(iret_exc	)
 
 #ifdef CONFIG_X86_ESPFIX32
 ldt_ss:
-#ifdef CONFIG_PARAVIRT
-	/*
-	 * The kernel can't run on a non-flat stack if paravirt mode
-	 * is active.  Rather than try to fixup the high bits of
-	 * ESP, bypass this code entirely.  This may break DOSemu
-	 * and/or Wine support in a paravirt VM, although the option
-	 * is still available to implement the setting of the high
-	 * 16-bits in the INTERRUPT_RETURN paravirt-op.
-	 */
-	cmpl	$0, pv_info+PARAVIRT_enabled
-	jne	restore_nocheck
-#endif
-
 /*
  * Setup and switch to ESPFIX stack
  *
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 6663fae71b123d6b46566e8bcbdb087248b973cc..d11a3aaafd96bb609a7e9fa0cc9d49d57fb9dc4d 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -286,4 +286,12 @@
 #define X86_BUG_CLFLUSH_MONITOR	X86_BUG(7) /* AAI65, CLFLUSH required before MONITOR */
 #define X86_BUG_SYSRET_SS_ATTRS	X86_BUG(8) /* SYSRET doesn't fix up SS attrs */
 
+#ifdef CONFIG_X86_32
+/*
+ * 64-bit kernels don't use X86_BUG_ESPFIX.  Make the define conditional
+ * to avoid confusion.
+ */
+#define X86_BUG_ESPFIX		X86_BUG(9) /* "" IRET to 16-bit SS corrupts ESP/RSP high bits */
+#endif
+
 #endif /* _ASM_X86_CPUFEATURES_H */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 079d83fc64888fdd408fa025f926ffd1da90f70f..d8337f34b5f40b304ad76a0682369d8a91f59ecc 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -802,6 +802,31 @@ static void detect_nopl(struct cpuinfo_x86 *c)
 	clear_cpu_cap(c, X86_FEATURE_NOPL);
 #else
 	set_cpu_cap(c, X86_FEATURE_NOPL);
+#endif
+
+	/*
+	 * ESPFIX is a strange bug.  All real CPUs have it.  Paravirt
+	 * systems that run Linux at CPL > 0 may or may not have the
+	 * issue, but, even if they have the issue, there's absolutely
+	 * nothing we can do about it because we can't use the real IRET
+	 * instruction.
+	 *
+	 * NB: For the time being, only 32-bit kernels support
+	 * X86_BUG_ESPFIX as such.  64-bit kernels directly choose
+	 * whether to apply espfix using paravirt hooks.  If any
+	 * non-paravirt system ever shows up that does *not* have the
+	 * ESPFIX issue, we can change this.
+	 */
+#ifdef CONFIG_X86_32
+#ifdef CONFIG_PARAVIRT
+	do {
+		extern void native_iret(void);
+		if (pv_cpu_ops.iret == native_iret)
+			set_cpu_bug(c, X86_BUG_ESPFIX);
+	} while (0);
+#else
+	set_cpu_bug(c, X86_BUG_ESPFIX);
+#endif
 #endif
 }