| Message ID | 20210922000533.713300-11-seanjc@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | perf: KVM: Fix, optimize, and clean up callbacks | expand |
On 22/09/21 02:05, Sean Christopherson wrote: > Use the generic kvm_running_vcpu plus a new 'handling_intr_from_guest' > variable in kvm_arch_vcpu instead of the semi-redundant current_vcpu. > kvm_before/after_interrupt() must be called while the vCPU is loaded, > (which protects against preemption), thus kvm_running_vcpu is guaranteed > to be non-NULL when handling_intr_from_guest is non-zero. > > Switching to kvm_get_running_vcpu() will allows moving KVM's perf > callbacks to generic code, and the new flag will be used in a future > patch to more precisely identify the "NMI from guest" case. > > Signed-off-by: Sean Christopherson <seanjc@google.com> > --- > arch/x86/include/asm/kvm_host.h | 3 +-- > arch/x86/kvm/pmu.c | 2 +- > arch/x86/kvm/x86.c | 21 ++++++++++++--------- > arch/x86/kvm/x86.h | 10 ++++++---- > 4 files changed, 20 insertions(+), 16 deletions(-) > > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h > index 1080166fc0cf..2d86a2dfc775 100644 > --- a/arch/x86/include/asm/kvm_host.h > +++ b/arch/x86/include/asm/kvm_host.h > @@ -763,6 +763,7 @@ struct kvm_vcpu_arch { > unsigned nmi_pending; /* NMI queued after currently running handler */ > bool nmi_injected; /* Trying to inject an NMI this entry */ > bool smi_pending; /* SMI queued after currently running handler */ > + u8 handling_intr_from_guest; > > struct kvm_mtrr mtrr_state; > u64 pat; > @@ -1874,8 +1875,6 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu); > int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err); > void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu); > > -unsigned int kvm_guest_state(void); > - > void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, > u32 size); > bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu); > diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c > index 5b68d4188de0..eef48258e50f 100644 > --- a/arch/x86/kvm/pmu.c > +++ b/arch/x86/kvm/pmu.c > @@ -87,7 +87,7 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event, > * woken up. So we should wake it, but this is impossible from > * NMI context. Do it from irq work instead. > */ > - if (!kvm_guest_state()) > + if (!kvm_handling_nmi_from_guest(pmc->vcpu)) > irq_work_queue(&pmc_to_pmu(pmc)->irq_work); > else > kvm_make_request(KVM_REQ_PMI, pmc->vcpu); > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index 6cc66466f301..24a6faa07442 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -8264,15 +8264,17 @@ static void kvm_timer_init(void) > kvmclock_cpu_online, kvmclock_cpu_down_prep); > } > > -DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu); > -EXPORT_PER_CPU_SYMBOL_GPL(current_vcpu); > +static inline bool kvm_pmi_in_guest(struct kvm_vcpu *vcpu) > +{ > + return vcpu && vcpu->arch.handling_intr_from_guest; > +} > > -unsigned int kvm_guest_state(void) > +static unsigned int kvm_guest_state(void) > { > - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); > + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); > unsigned int state; > > - if (!vcpu) > + if (!kvm_pmi_in_guest(vcpu)) > return 0; > > state = PERF_GUEST_ACTIVE; > @@ -8284,9 +8286,10 @@ unsigned int kvm_guest_state(void) > > static unsigned long kvm_guest_get_ip(void) > { > - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); > + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); > > - if (WARN_ON_ONCE(!vcpu)) > + /* Retrieving the IP must be guarded by a call to kvm_guest_state(). */ > + if (WARN_ON_ONCE(!kvm_pmi_in_guest(vcpu))) > return 0; > > return kvm_rip_read(vcpu); > @@ -8294,10 +8297,10 @@ static unsigned long kvm_guest_get_ip(void) > > static unsigned int kvm_handle_intel_pt_intr(void) > { > - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); > + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); > > /* '0' on failure so that the !PT case can use a RET0 static call. */ > - if (!vcpu) > + if (!kvm_pmi_in_guest(vcpu)) > return 0; > > kvm_make_request(KVM_REQ_PMI, vcpu); > diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h > index 7d66d63dc55a..a9c107e7c907 100644 > --- a/arch/x86/kvm/x86.h > +++ b/arch/x86/kvm/x86.h > @@ -387,18 +387,20 @@ static inline bool kvm_cstate_in_guest(struct kvm *kvm) > return kvm->arch.cstate_in_guest; > } > > -DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu); > - > static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu) > { > - __this_cpu_write(current_vcpu, vcpu); > + WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 1); > } > > static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu) > { > - __this_cpu_write(current_vcpu, NULL); > + WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 0); > } > > +static inline bool kvm_handling_nmi_from_guest(struct kvm_vcpu *vcpu) > +{ > + return !!vcpu->arch.handling_intr_from_guest; > +} > > static inline bool kvm_pat_valid(u64 data) > { > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 1080166fc0cf..2d86a2dfc775 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -763,6 +763,7 @@ struct kvm_vcpu_arch { unsigned nmi_pending; /* NMI queued after currently running handler */ bool nmi_injected; /* Trying to inject an NMI this entry */ bool smi_pending; /* SMI queued after currently running handler */ + u8 handling_intr_from_guest; struct kvm_mtrr mtrr_state; u64 pat; @@ -1874,8 +1875,6 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu); int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err); void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu); -unsigned int kvm_guest_state(void); - void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size); bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu); diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c index 5b68d4188de0..eef48258e50f 100644 --- a/arch/x86/kvm/pmu.c +++ b/arch/x86/kvm/pmu.c @@ -87,7 +87,7 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event, * woken up. So we should wake it, but this is impossible from * NMI context. Do it from irq work instead. */ - if (!kvm_guest_state()) + if (!kvm_handling_nmi_from_guest(pmc->vcpu)) irq_work_queue(&pmc_to_pmu(pmc)->irq_work); else kvm_make_request(KVM_REQ_PMI, pmc->vcpu); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6cc66466f301..24a6faa07442 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8264,15 +8264,17 @@ static void kvm_timer_init(void) kvmclock_cpu_online, kvmclock_cpu_down_prep); } -DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu); -EXPORT_PER_CPU_SYMBOL_GPL(current_vcpu); +static inline bool kvm_pmi_in_guest(struct kvm_vcpu *vcpu) +{ + return vcpu && vcpu->arch.handling_intr_from_guest; +} -unsigned int kvm_guest_state(void) +static unsigned int kvm_guest_state(void) { - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); unsigned int state; - if (!vcpu) + if (!kvm_pmi_in_guest(vcpu)) return 0; state = PERF_GUEST_ACTIVE; @@ -8284,9 +8286,10 @@ unsigned int kvm_guest_state(void) static unsigned long kvm_guest_get_ip(void) { - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); - if (WARN_ON_ONCE(!vcpu)) + /* Retrieving the IP must be guarded by a call to kvm_guest_state(). */ + if (WARN_ON_ONCE(!kvm_pmi_in_guest(vcpu))) return 0; return kvm_rip_read(vcpu); @@ -8294,10 +8297,10 @@ static unsigned long kvm_guest_get_ip(void) static unsigned int kvm_handle_intel_pt_intr(void) { - struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu); + struct kvm_vcpu *vcpu = kvm_get_running_vcpu(); /* '0' on failure so that the !PT case can use a RET0 static call. */ - if (!vcpu) + if (!kvm_pmi_in_guest(vcpu)) return 0; kvm_make_request(KVM_REQ_PMI, vcpu); diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 7d66d63dc55a..a9c107e7c907 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -387,18 +387,20 @@ static inline bool kvm_cstate_in_guest(struct kvm *kvm) return kvm->arch.cstate_in_guest; } -DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu); - static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu) { - __this_cpu_write(current_vcpu, vcpu); + WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 1); } static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu) { - __this_cpu_write(current_vcpu, NULL); + WRITE_ONCE(vcpu->arch.handling_intr_from_guest, 0); } +static inline bool kvm_handling_nmi_from_guest(struct kvm_vcpu *vcpu) +{ + return !!vcpu->arch.handling_intr_from_guest; +} static inline bool kvm_pat_valid(u64 data) {
Use the generic kvm_running_vcpu plus a new 'handling_intr_from_guest' variable in kvm_arch_vcpu instead of the semi-redundant current_vcpu. kvm_before/after_interrupt() must be called while the vCPU is loaded, (which protects against preemption), thus kvm_running_vcpu is guaranteed to be non-NULL when handling_intr_from_guest is non-zero. Switching to kvm_get_running_vcpu() will allows moving KVM's perf callbacks to generic code, and the new flag will be used in a future patch to more precisely identify the "NMI from guest" case. Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/include/asm/kvm_host.h | 3 +-- arch/x86/kvm/pmu.c | 2 +- arch/x86/kvm/x86.c | 21 ++++++++++++--------- arch/x86/kvm/x86.h | 10 ++++++---- 4 files changed, 20 insertions(+), 16 deletions(-)