From 1c300a40772dae829b91dad634999a6a522c0829 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 27 Jan 2014 14:49:40 +0100 Subject: x86, kvm: cache the base of the KVM cpuid leaves 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: stable@vger.kernel.org Cc: mtosatti@redhat.com Signed-off-by: Paolo Bonzini --- arch/x86/kernel/kvm.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'arch/x86/kernel/kvm.c') diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 6dd802c6d780..0823003770fc 100644 --- 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(); -- cgit From 77f01bdfa5e55dc19d3eb747181d2730a9bb3ca8 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Mon, 27 Jan 2014 14:51:44 +0100 Subject: x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101 When Hyper-V hypervisor leaves are present, KVM must relocate its own leaves at 0x40000100, because Windows does not look for Hyper-V leaves at indices other than 0x40000000. In this case, the KVM features are at 0x40000101, but the old code would always look at 0x40000001. Fix by using kvm_cpuid_base(). This also requires making the function non-inline, since kvm_cpuid_base() is static. Fixes: 1085ba7f552d84aa8ac0ae903fa8d0cc2ff9f79d Cc: stable@vger.kernel.org Cc: mtosatti@redhat.com Signed-off-by: Paolo Bonzini --- arch/x86/kernel/kvm.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'arch/x86/kernel/kvm.c') diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 0823003770fc..f81cadebcc0e 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -527,6 +527,11 @@ bool kvm_para_available(void) } EXPORT_SYMBOL_GPL(kvm_para_available); +unsigned int kvm_arch_para_features(void) +{ + return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES); +} + static uint32_t __init kvm_detect(void) { return kvm_cpuid_base(); -- cgit