On 29/03/2015 22:56, Eugene Korenevsky wrote: > cpuid_maxphyaddr() which performs lot of memory accesses is called extensively > across KVM, especially in nVMX code. > This patch adds cached value of maxphyaddr to vcpu.arch to reduce the pressure onto > CPU cache and simplify the code of cpuid_maxphyaddr() callers. The cached value is > initialized in kvm_arch_vcpu_init() and reloaded every time CPUID is updated by > usermode. It is obvious that these reloads occur infrequently. > > Signed-off-by: Eugene Korenevsky <ekorenevsky@xxxxxxxxx> > --- > arch/x86/include/asm/kvm_host.h | 4 +++- > arch/x86/kvm/cpuid.c | 33 ++++++++++++++++++--------------- > arch/x86/kvm/cpuid.h | 6 ++++++ > arch/x86/kvm/x86.c | 2 ++ > 4 files changed, 29 insertions(+), 16 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index a236e39..2362a60 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -431,6 +431,9 @@ struct kvm_vcpu_arch { > > int cpuid_nent; > struct kvm_cpuid_entry2 cpuid_entries[KVM_MAX_CPUID_ENTRIES]; > + > + int maxphyaddr; > + > /* emulate context */ > > struct x86_emulate_ctxt emulate_ctxt; > @@ -1128,7 +1131,6 @@ int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) > int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end); > int kvm_test_age_hva(struct kvm *kvm, unsigned long hva); > void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); > -int cpuid_maxphyaddr(struct kvm_vcpu *vcpu); > int kvm_cpu_has_injectable_intr(struct kvm_vcpu *v); > int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu); > int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu); > diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c > index 8a80737..59b69f6 100644 > --- a/arch/x86/kvm/cpuid.c > +++ b/arch/x86/kvm/cpuid.c > @@ -104,6 +104,9 @@ int kvm_update_cpuid(struct kvm_vcpu *vcpu) > ((best->eax & 0xff00) >> 8) != 0) > return -EINVAL; > > + /* Update physical-address width */ > + vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu); > + > kvm_pmu_cpuid_update(vcpu); > return 0; > } > @@ -135,6 +138,21 @@ static void cpuid_fix_nx_cap(struct kvm_vcpu *vcpu) > } > } > > +int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu) > +{ > + struct kvm_cpuid_entry2 *best; > + > + best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0); > + if (!best || best->eax < 0x80000008) > + goto not_found; > + best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0); > + if (best) > + return best->eax & 0xff; > +not_found: > + return 36; > +} > +EXPORT_SYMBOL_GPL(cpuid_query_maxphyaddr); > + > /* when an old userspace process fills a new kernel module */ > int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu, > struct kvm_cpuid *cpuid, > @@ -757,21 +775,6 @@ struct kvm_cpuid_entry2 *kvm_find_cpuid_entry(struct kvm_vcpu *vcpu, > } > EXPORT_SYMBOL_GPL(kvm_find_cpuid_entry); > > -int cpuid_maxphyaddr(struct kvm_vcpu *vcpu) > -{ > - struct kvm_cpuid_entry2 *best; > - > - best = kvm_find_cpuid_entry(vcpu, 0x80000000, 0); > - if (!best || best->eax < 0x80000008) > - goto not_found; > - best = kvm_find_cpuid_entry(vcpu, 0x80000008, 0); > - if (best) > - return best->eax & 0xff; > -not_found: > - return 36; > -} > -EXPORT_SYMBOL_GPL(cpuid_maxphyaddr); > - > /* > * If no match is found, check whether we exceed the vCPU's limit > * and return the content of the highest valid _standard_ leaf instead. > diff --git a/arch/x86/kvm/cpuid.h b/arch/x86/kvm/cpuid.h > index 4452eed..78b61b4 100644 > --- a/arch/x86/kvm/cpuid.h > +++ b/arch/x86/kvm/cpuid.h > @@ -20,6 +20,12 @@ int kvm_vcpu_ioctl_get_cpuid2(struct kvm_vcpu *vcpu, > struct kvm_cpuid_entry2 __user *entries); > void kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx, u32 *ecx, u32 *edx); > > +int cpuid_query_maxphyaddr(struct kvm_vcpu *vcpu); > + > +static inline int cpuid_maxphyaddr(struct kvm_vcpu *vcpu) > +{ > + return vcpu->arch.maxphyaddr; > +} > > static inline bool guest_cpuid_has_xsave(struct kvm_vcpu *vcpu) > { > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index bd7a70b..084e1d5 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -7289,6 +7289,8 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) > vcpu->arch.guest_supported_xcr0 = 0; > vcpu->arch.guest_xstate_size = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET; > > + vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu); > + > kvm_async_pf_hash_reset(vcpu); > kvm_pmu_init(vcpu); > > Applied series, thanks. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html