On Tuesday, 28 Apr 2020 at 14:23, Wanpeng Li <[email protected]> wrote: > > From: Wanpeng Li <[email protected]> > > This patch implements tscdealine msr emulation fastpath, after wrmsr > tscdeadline vmexit, handle it as soon as possible and vmentry immediately > without checking various kvm stuff when possible. > > Tested-by: Haiwei Li <[email protected]> > Cc: Haiwei Li <[email protected]> > Signed-off-by: Wanpeng Li <[email protected]> > --- > arch/x86/kvm/lapic.c | 18 ++++++++++++------ > arch/x86/kvm/vmx/vmx.c | 12 ++++++++---- > arch/x86/kvm/x86.c | 30 ++++++++++++++++++++++++------ > 3 files changed, 44 insertions(+), 16 deletions(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index 38f7dc9..3589237 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -1593,7 +1593,7 @@ static void kvm_apic_inject_pending_timer_irqs(struct kvm_lapic *apic) > } > } > > -static void apic_timer_expired(struct kvm_lapic *apic) > +static void apic_timer_expired(struct kvm_lapic *apic, bool from_timer_fn) > { > struct kvm_vcpu *vcpu = apic->vcpu; > struct kvm_timer *ktimer = &apic->lapic_timer; > @@ -1604,6 +1604,12 @@ static void apic_timer_expired(struct kvm_lapic *apic) > if (apic_lvtt_tscdeadline(apic) || ktimer->hv_timer_in_use) > ktimer->expired_tscdeadline = ktimer->tscdeadline; > > + if (!from_timer_fn && vcpu->arch.apicv_active) { > + WARN_ON(kvm_get_running_vcpu() != vcpu); > + kvm_apic_inject_pending_timer_irqs(apic); > + return; > + } > + > if (kvm_use_posted_timer_interrupt(apic->vcpu)) { > if (apic->lapic_timer.timer_advance_ns) > __kvm_wait_lapic_expire(vcpu); > @@ -1643,7 +1649,7 @@ static void start_sw_tscdeadline(struct kvm_lapic *apic) > expire = ktime_sub_ns(expire, ktimer->timer_advance_ns); > hrtimer_start(&ktimer->timer, expire, HRTIMER_MODE_ABS_HARD); > } else > - apic_timer_expired(apic); > + apic_timer_expired(apic, false); > > local_irq_restore(flags); > } > @@ -1751,7 +1757,7 @@ static void start_sw_period(struct kvm_lapic *apic) > > if (ktime_after(ktime_get(), > apic->lapic_timer.target_expiration)) { > - apic_timer_expired(apic); > + apic_timer_expired(apic, false); > > if (apic_lvtt_oneshot(apic)) > return; > @@ -1813,7 +1819,7 @@ static bool start_hv_timer(struct kvm_lapic *apic) > if (atomic_read(&ktimer->pending)) { > cancel_hv_timer(apic); > } else if (expired) { > - apic_timer_expired(apic); > + apic_timer_expired(apic, false); > cancel_hv_timer(apic); > } > } > @@ -1863,7 +1869,7 @@ void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu) > goto out; > WARN_ON(swait_active(&vcpu->wq)); > cancel_hv_timer(apic); > - apic_timer_expired(apic); > + apic_timer_expired(apic, false); > > if (apic_lvtt_period(apic) && apic->lapic_timer.period) { > advance_periodic_target_expiration(apic); > @@ -2369,7 +2375,7 @@ static enum hrtimer_restart apic_timer_fn(struct hrtimer *data) > struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer); > struct kvm_lapic *apic = container_of(ktimer, struct kvm_lapic, lapic_timer); > > - apic_timer_expired(apic); > + apic_timer_expired(apic, true); > > if (lapic_is_periodic(apic)) { > advance_periodic_target_expiration(apic); > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index ce19b0e..bb5c4f1 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -5994,7 +5994,8 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) > if (exit_fastpath == EXIT_FASTPATH_SKIP_EMUL_INS) { > kvm_skip_emulated_instruction(vcpu); Can we move this kvm_skip_emulated_instruction to handle_fastpath_set_msr_irqoff? This will keep the style consistent. > return 1; > - } > + } else if (exit_fastpath == EXIT_FASTPATH_NOP) > + return 1; > > if (exit_reason >= kvm_vmx_max_exit_handlers) > goto unexpected_vmexit; > @@ -6605,6 +6606,7 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) > struct vcpu_vmx *vmx = to_vmx(vcpu); > unsigned long cr3, cr4; > > +REENTER_GUEST: > /* Record the guest's net vcpu time for enforced NMI injections. */ > if (unlikely(!enable_vnmi && > vmx->loaded_vmcs->soft_vnmi_blocked)) > @@ -6779,10 +6781,12 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) > > exit_fastpath = vmx_exit_handlers_fastpath(vcpu); > if (exit_fastpath == EXIT_FASTPATH_REENTER_GUEST) { > - if (!kvm_vcpu_exit_request(vcpu)) > + if (!kvm_vcpu_exit_request(vcpu)) { > vmx_sync_pir_to_irr(vcpu); > - else > - exit_fastpath = EXIT_FASTPATH_NOP; > + /* static call is better with retpolines */ > + goto REENTER_GUEST; > + } > + exit_fastpath = EXIT_FASTPATH_NOP; > } > > return exit_fastpath; > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index afe052c..f3a5fe4 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -1616,27 +1616,45 @@ static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data > return 1; > } > > +static int handle_fastpath_set_tscdeadline(struct kvm_vcpu *vcpu, u64 data) > +{ > + if (!kvm_x86_ops.set_hv_timer || > + kvm_mwait_in_guest(vcpu->kvm) || > + kvm_can_post_timer_interrupt(vcpu)) > + return 1; > + > + kvm_set_lapic_tscdeadline_msr(vcpu, data); > + return 0; > +} > + > fastpath_t handle_fastpath_set_msr_irqoff(struct kvm_vcpu *vcpu) > { > u32 msr = kvm_rcx_read(vcpu); > u64 data; > - int ret = 0; > + int ret = EXIT_FASTPATH_NONE; > > switch (msr) { > case APIC_BASE_MSR + (APIC_ICR >> 4): > data = kvm_read_edx_eax(vcpu); > - ret = handle_fastpath_set_x2apic_icr_irqoff(vcpu, data); > + if (!handle_fastpath_set_x2apic_icr_irqoff(vcpu, data)) > + ret = EXIT_FASTPATH_SKIP_EMUL_INS; > + break; > + case MSR_IA32_TSCDEADLINE: > + data = kvm_read_edx_eax(vcpu); > + if (!handle_fastpath_set_tscdeadline(vcpu, data)) > + ret = EXIT_FASTPATH_REENTER_GUEST; > break; > default: > - return EXIT_FASTPATH_NONE; > + ret = EXIT_FASTPATH_NONE; > } > > - if (!ret) { > + if (ret != EXIT_FASTPATH_NONE) { > trace_kvm_msr_write(msr, data); > - return EXIT_FASTPATH_SKIP_EMUL_INS; > + if (ret == EXIT_FASTPATH_REENTER_GUEST) > + kvm_skip_emulated_instruction(vcpu);
> } > > - return EXIT_FASTPATH_NONE; > + return ret; > } > EXPORT_SYMBOL_GPL(handle_fastpath_set_msr_irqoff); > > -- > 2.7.4 </[email protected]></[email protected]></[email protected]></[email protected]></[email protected]>
