i386: Allow KVM on i386 nonpae
Currently, CONFIG_X86_CMPXCHG64 both enables boot-time checking of
the cmpxchg64b feature and enables compilation of the set_64bit() family.
Since the option is dependent on PAE, and since KVM depends on set_64bit(),
this effectively disables KVM on i386 nopae.
Simplify by removing the config option altogether: the boot check is made
dependent on CONFIG_X86_PAE directly, and the set_64bit() family is exposed
without constraints. It is up to users to check for the feature flag (KVM
does not as virtualiation extensions imply its existence).
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-i386/cmpxchg.h b/include/asm-i386/cmpxchg.h
index 7adcef0..64dcdf4 100644
--- a/include/asm-i386/cmpxchg.h
+++ b/include/asm-i386/cmpxchg.h
@@ -3,14 +3,16 @@
#include <linux/bitops.h> /* for LOCK_PREFIX */
+/*
+ * Note: if you use set64_bit(), __cmpxchg64(), or their variants, you
+ * you need to test for the feature in boot_cpu_data.
+ */
+
#define xchg(ptr,v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v),(ptr),sizeof(*(ptr))))
struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((struct __xchg_dummy *)(x))
-
-#ifdef CONFIG_X86_CMPXCHG64
-
/*
* The semantics of XCHGCMP8B are a bit strange, this is why
* there is a loop and the loading of %%eax and %%edx has to
@@ -65,8 +67,6 @@
__set_64bit(ptr, (unsigned int)(value), (unsigned int)((value)>>32ULL) ) : \
__set_64bit(ptr, ll_low(value), ll_high(value)) )
-#endif
-
/*
* Note: no "lock" prefix even on SMP: xchg always implies lock anyway
* Note 2: xchg has side effect, so that attribute volatile is necessary,
@@ -252,8 +252,6 @@
})
#endif
-#ifdef CONFIG_X86_CMPXCHG64
-
static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long long old,
unsigned long long new)
{
@@ -289,5 +287,3 @@
((__typeof__(*(ptr)))__cmpxchg64_local((ptr),(unsigned long long)(o),\
(unsigned long long)(n)))
#endif
-
-#endif