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Date: Tue, 4 Feb 2014 13:06:53 -0800 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, mtosatti@...hat.com, Paolo Bonzini <pbonzini@...hat.com> Subject: [PATCH 3.12 012/133] x86, kvm: cache the base of the KVM cpuid leaves 3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Bonzini <pbonzini@...hat.com> commit 1c300a40772dae829b91dad634999a6a522c0829 upstream. It is unnecessary to go through hypervisor_cpuid_base every time a leaf is found (which will be every time a feature is requested after the next patch). Fixes: 1085ba7f552d84aa8ac0ae903fa8d0cc2ff9f79d Cc: mtosatti@...hat.com Signed-off-by: Paolo Bonzini <pbonzini@...hat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- arch/x86/include/asm/kvm_para.h | 22 ++++++---------------- arch/x86/kernel/kvm.c | 27 +++++++++++++++++++++++++++ 2 files changed, 33 insertions(+), 16 deletions(-) --- a/arch/x86/include/asm/kvm_para.h +++ b/arch/x86/include/asm/kvm_para.h @@ -85,28 +85,13 @@ static inline long kvm_hypercall4(unsign return ret; } -static inline uint32_t kvm_cpuid_base(void) -{ - if (boot_cpu_data.cpuid_level < 0) - return 0; /* So we don't blow up on old processors */ - - if (cpu_has_hypervisor) - return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0); - - return 0; -} - -static inline bool kvm_para_available(void) -{ - return kvm_cpuid_base() != 0; -} - static inline unsigned int kvm_arch_para_features(void) { return cpuid_eax(KVM_CPUID_FEATURES); } #ifdef CONFIG_KVM_GUEST +bool kvm_para_available(void); void __init kvm_guest_init(void); void kvm_async_pf_task_wait(u32 token); void kvm_async_pf_task_wake(u32 token); @@ -126,6 +111,11 @@ static inline void kvm_spinlock_init(voi #define kvm_async_pf_task_wait(T) do {} while(0) #define kvm_async_pf_task_wake(T) do {} while(0) +static inline bool kvm_para_available(void) +{ + return 0; +} + static inline u32 kvm_read_and_reset_pf_reason(void) { return 0; --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -500,6 +500,33 @@ void __init kvm_guest_init(void) #endif } +static noinline uint32_t __kvm_cpuid_base(void) +{ + if (boot_cpu_data.cpuid_level < 0) + return 0; /* So we don't blow up on old processors */ + + if (cpu_has_hypervisor) + return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0); + + return 0; +} + +static inline uint32_t kvm_cpuid_base(void) +{ + static int kvm_cpuid_base = -1; + + if (kvm_cpuid_base == -1) + kvm_cpuid_base = __kvm_cpuid_base(); + + return kvm_cpuid_base; +} + +bool kvm_para_available(void) +{ + return kvm_cpuid_base() != 0; +} +EXPORT_SYMBOL_GPL(kvm_para_available); + static uint32_t __init kvm_detect(void) { return kvm_cpuid_base(); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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