From 2d9ce177e68645945e3366cfe2d66ee3c28cd4f2 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Thu, 19 Jul 2007 14:30:14 +0300 Subject: [PATCH] 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 Signed-off-by: Linus Torvalds --- arch/i386/Kconfig.cpu | 5 ----- arch/i386/defconfig | 1 - arch/um/defconfig | 1 - drivers/kvm/Kconfig | 1 - include/asm-i386/cmpxchg.h | 14 +++++--------- include/asm-i386/required-features.h | 2 +- 6 files changed, 6 insertions(+), 18 deletions(-) diff --git a/arch/i386/Kconfig.cpu b/arch/i386/Kconfig.cpu index 9cbe76c3aa..11a24d54f2 100644 --- a/arch/i386/Kconfig.cpu +++ b/arch/i386/Kconfig.cpu @@ -297,11 +297,6 @@ config X86_POPAD_OK depends on !M386 default y -config X86_CMPXCHG64 - bool - depends on X86_PAE - default y - config X86_ALIGNMENT_16 bool depends on MWINCHIP3D || MWINCHIP2 || MWINCHIPC6 || MCYRIXIII || X86_ELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1 diff --git a/arch/i386/defconfig b/arch/i386/defconfig index 1a3a2217b7..0ac62cdcd3 100644 --- a/arch/i386/defconfig +++ b/arch/i386/defconfig @@ -166,7 +166,6 @@ CONFIG_X86_WP_WORKS_OK=y CONFIG_X86_INVLPG=y CONFIG_X86_BSWAP=y CONFIG_X86_POPAD_OK=y -CONFIG_X86_CMPXCHG64=y CONFIG_X86_GOOD_APIC=y CONFIG_X86_INTEL_USERCOPY=y CONFIG_X86_USE_PPRO_CHECKSUM=y diff --git a/arch/um/defconfig b/arch/um/defconfig index a25cd25d55..1e0f677c2f 100644 --- a/arch/um/defconfig +++ b/arch/um/defconfig @@ -52,7 +52,6 @@ CONFIG_X86_WP_WORKS_OK=y CONFIG_X86_INVLPG=y CONFIG_X86_BSWAP=y CONFIG_X86_POPAD_OK=y -CONFIG_X86_CMPXCHG64=y CONFIG_X86_GOOD_APIC=y CONFIG_X86_USE_PPRO_CHECKSUM=y CONFIG_X86_TSC=y diff --git a/drivers/kvm/Kconfig b/drivers/kvm/Kconfig index 33fa28a8c1..2f661e5f0d 100644 --- a/drivers/kvm/Kconfig +++ b/drivers/kvm/Kconfig @@ -11,7 +11,6 @@ if VIRTUALIZATION config KVM tristate "Kernel-based Virtual Machine (KVM) support" depends on X86 && EXPERIMENTAL - depends on X86_CMPXCHG64 || 64BIT ---help--- Support hosting fully virtualized guest machines using hardware virtualization extensions. You will need a fairly recent diff --git a/include/asm-i386/cmpxchg.h b/include/asm-i386/cmpxchg.h index 7adcef0cd5..64dcdf4611 100644 --- a/include/asm-i386/cmpxchg.h +++ b/include/asm-i386/cmpxchg.h @@ -3,14 +3,16 @@ #include /* 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 @@ static inline void __set_64bit_var (unsigned long long *ptr, __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 @@ static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old, }) #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 @@ static inline unsigned long long __cmpxchg64_local(volatile void *ptr, ((__typeof__(*(ptr)))__cmpxchg64_local((ptr),(unsigned long long)(o),\ (unsigned long long)(n))) #endif - -#endif diff --git a/include/asm-i386/required-features.h b/include/asm-i386/required-features.h index 65848a0070..618feb98f9 100644 --- a/include/asm-i386/required-features.h +++ b/include/asm-i386/required-features.h @@ -29,7 +29,7 @@ # define NEED_CMOV 0 #endif -#ifdef CONFIG_X86_CMPXCHG64 +#ifdef CONFIG_X86_PAE # define NEED_CX8 (1<<(X86_FEATURE_CX8 & 31)) #else # define NEED_CX8 0 -- 2.39.5