| Message ID | 1617785588-18722-1-git-send-email-wanpengli@tencent.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/kvm: Don't alloc __pv_cpu_mask when !CONFIG_SMP | expand |
On Wed, Apr 07, 2021, Wanpeng Li wrote: > From: Wanpeng Li <wanpengli@tencent.com> > > Enable PV TLB shootdown when !CONFIG_SMP doesn't make sense. Let's move > it inside CONFIG_SMP. In addition, we can avoid alloc __pv_cpu_mask when > !CONFIG_SMP and get rid of 'alloc' variable in kvm_alloc_cpumask. ... > +static bool pv_tlb_flush_supported(void) { return false; } > +static bool pv_ipi_supported(void) { return false; } > +static void kvm_flush_tlb_others(const struct cpumask *cpumask, > + const struct flush_tlb_info *info) { } > +static void kvm_setup_pv_ipi(void) { } If you shuffle things around a bit more, you can avoid these stubs, and hide the definition of __pv_cpu_mask behind CONFIG_SMP, too. diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 5e78e01ca3b4..13c6b1c7c01b 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -451,6 +451,8 @@ static void __init sev_map_percpu_data(void) } } +#ifdef CONFIG_SMP + static bool pv_tlb_flush_supported(void) { return (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) && @@ -460,8 +462,6 @@ static bool pv_tlb_flush_supported(void) static DEFINE_PER_CPU(cpumask_var_t, __pv_cpu_mask); -#ifdef CONFIG_SMP - static bool pv_ipi_supported(void) { return kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI); @@ -574,45 +574,6 @@ static void kvm_smp_send_call_func_ipi(const struct cpumask *mask) } } -static void __init kvm_smp_prepare_boot_cpu(void) -{ - /* - * Map the per-cpu variables as decrypted before kvm_guest_cpu_init() - * shares the guest physical address with the hypervisor. - */ - sev_map_percpu_data(); - - kvm_guest_cpu_init(); - native_smp_prepare_boot_cpu(); - kvm_spinlock_init(); -} - -static void kvm_guest_cpu_offline(void) -{ - kvm_disable_steal_time(); - if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) - wrmsrl(MSR_KVM_PV_EOI_EN, 0); - kvm_pv_disable_apf(); - apf_task_wake_all(); -} - -static int kvm_cpu_online(unsigned int cpu) -{ - local_irq_disable(); - kvm_guest_cpu_init(); - local_irq_enable(); - return 0; -} - -static int kvm_cpu_down_prepare(unsigned int cpu) -{ - local_irq_disable(); - kvm_guest_cpu_offline(); - local_irq_enable(); - return 0; -} -#endif - static void kvm_flush_tlb_others(const struct cpumask *cpumask, const struct flush_tlb_info *info) { @@ -639,6 +600,63 @@ static void kvm_flush_tlb_others(const struct cpumask *cpumask, native_flush_tlb_others(flushmask, info); } +static void __init kvm_smp_prepare_boot_cpu(void) +{ + /* + * Map the per-cpu variables as decrypted before kvm_guest_cpu_init() + * shares the guest physical address with the hypervisor. + */ + sev_map_percpu_data(); + + kvm_guest_cpu_init(); + native_smp_prepare_boot_cpu(); + kvm_spinlock_init(); +} + +static void kvm_guest_cpu_offline(void) +{ + kvm_disable_steal_time(); + if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) + wrmsrl(MSR_KVM_PV_EOI_EN, 0); + kvm_pv_disable_apf(); + apf_task_wake_all(); +} + +static int kvm_cpu_online(unsigned int cpu) +{ + local_irq_disable(); + kvm_guest_cpu_init(); + local_irq_enable(); + return 0; +} + +static int kvm_cpu_down_prepare(unsigned int cpu) +{ + local_irq_disable(); + kvm_guest_cpu_offline(); + local_irq_enable(); + return 0; +} + +static __init int kvm_alloc_cpumask(void) +{ + int cpu; + + if (!kvm_para_available() || nopv) + return 0; + + if (pv_tlb_flush_supported() || pv_ipi_supported()) + for_each_possible_cpu(cpu) { + zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, cpu), + GFP_KERNEL, cpu_to_node(cpu)); + } + + return 0; +} +arch_initcall(kvm_alloc_cpumask); + +#endif + static void __init kvm_guest_init(void) { int i; @@ -653,21 +671,21 @@ static void __init kvm_guest_init(void) pv_ops.time.steal_clock = kvm_steal_clock; } + if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) + apic_set_eoi_write(kvm_guest_apic_eoi_write); + + if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) { + static_branch_enable(&kvm_async_pf_enabled); + alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt); + } + +#ifdef CONFIG_SMP if (pv_tlb_flush_supported()) { pv_ops.mmu.flush_tlb_others = kvm_flush_tlb_others; pv_ops.mmu.tlb_remove_table = tlb_remove_table; pr_info("KVM setup pv remote TLB flush\n"); } - if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) - apic_set_eoi_write(kvm_guest_apic_eoi_write); - - if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_INT) && kvmapf) { - static_branch_enable(&kvm_async_pf_enabled); - alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_kvm_asyncpf_interrupt); - } - -#ifdef CONFIG_SMP smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu; if (pv_sched_yield_supported()) { smp_ops.send_call_func_ipi = kvm_smp_send_call_func_ipi; @@ -734,7 +752,7 @@ static uint32_t __init kvm_detect(void) static void __init kvm_apic_init(void) { -#if defined(CONFIG_SMP) +#ifdef CONFIG_SMP if (pv_ipi_supported()) kvm_setup_pv_ipi(); #endif @@ -794,31 +812,6 @@ static __init int activate_jump_labels(void) } arch_initcall(activate_jump_labels); -static __init int kvm_alloc_cpumask(void) -{ - int cpu; - bool alloc = false; - - if (!kvm_para_available() || nopv) - return 0; - - if (pv_tlb_flush_supported()) - alloc = true; - -#if defined(CONFIG_SMP) - if (pv_ipi_supported()) - alloc = true; -#endif - - if (alloc) - for_each_possible_cpu(cpu) { - zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, cpu), - GFP_KERNEL, cpu_to_node(cpu)); - } - - return 0; -} -arch_initcall(kvm_alloc_cpumask); #ifdef CONFIG_PARAVIRT_SPINLOCKS
On Fri, 9 Apr 2021 at 04:20, Sean Christopherson <seanjc@google.com> wrote: > > On Wed, Apr 07, 2021, Wanpeng Li wrote: > > From: Wanpeng Li <wanpengli@tencent.com> > > > > Enable PV TLB shootdown when !CONFIG_SMP doesn't make sense. Let's move > > it inside CONFIG_SMP. In addition, we can avoid alloc __pv_cpu_mask when > > !CONFIG_SMP and get rid of 'alloc' variable in kvm_alloc_cpumask. > > ... > > > +static bool pv_tlb_flush_supported(void) { return false; } > > +static bool pv_ipi_supported(void) { return false; } > > +static void kvm_flush_tlb_others(const struct cpumask *cpumask, > > + const struct flush_tlb_info *info) { } > > +static void kvm_setup_pv_ipi(void) { } > > If you shuffle things around a bit more, you can avoid these stubs, and hide the > definition of __pv_cpu_mask behind CONFIG_SMP, too. Thanks, I will move around. Wanpeng
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 5e78e01..202e1f0 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -451,6 +451,11 @@ static void __init sev_map_percpu_data(void) } } + +static DEFINE_PER_CPU(cpumask_var_t, __pv_cpu_mask); + +#ifdef CONFIG_SMP + static bool pv_tlb_flush_supported(void) { return (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) && @@ -458,10 +463,6 @@ static bool pv_tlb_flush_supported(void) kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)); } -static DEFINE_PER_CPU(cpumask_var_t, __pv_cpu_mask); - -#ifdef CONFIG_SMP - static bool pv_ipi_supported(void) { return kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI); @@ -574,6 +575,32 @@ static void kvm_smp_send_call_func_ipi(const struct cpumask *mask) } } +static void kvm_flush_tlb_others(const struct cpumask *cpumask, + const struct flush_tlb_info *info) +{ + u8 state; + int cpu; + struct kvm_steal_time *src; + struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask); + + cpumask_copy(flushmask, cpumask); + /* + * We have to call flush only on online vCPUs. And + * queue flush_on_enter for pre-empted vCPUs + */ + for_each_cpu(cpu, flushmask) { + src = &per_cpu(steal_time, cpu); + state = READ_ONCE(src->preempted); + if ((state & KVM_VCPU_PREEMPTED)) { + if (try_cmpxchg(&src->preempted, &state, + state | KVM_VCPU_FLUSH_TLB)) + __cpumask_clear_cpu(cpu, flushmask); + } + } + + native_flush_tlb_others(flushmask, info); +} + static void __init kvm_smp_prepare_boot_cpu(void) { /* @@ -611,33 +638,16 @@ static int kvm_cpu_down_prepare(unsigned int cpu) local_irq_enable(); return 0; } -#endif -static void kvm_flush_tlb_others(const struct cpumask *cpumask, - const struct flush_tlb_info *info) -{ - u8 state; - int cpu; - struct kvm_steal_time *src; - struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_cpu_mask); +#else - cpumask_copy(flushmask, cpumask); - /* - * We have to call flush only on online vCPUs. And - * queue flush_on_enter for pre-empted vCPUs - */ - for_each_cpu(cpu, flushmask) { - src = &per_cpu(steal_time, cpu); - state = READ_ONCE(src->preempted); - if ((state & KVM_VCPU_PREEMPTED)) { - if (try_cmpxchg(&src->preempted, &state, - state | KVM_VCPU_FLUSH_TLB)) - __cpumask_clear_cpu(cpu, flushmask); - } - } +static bool pv_tlb_flush_supported(void) { return false; } +static bool pv_ipi_supported(void) { return false; } +static void kvm_flush_tlb_others(const struct cpumask *cpumask, + const struct flush_tlb_info *info) { } +static void kvm_setup_pv_ipi(void) { } - native_flush_tlb_others(flushmask, info); -} +#endif static void __init kvm_guest_init(void) { @@ -734,10 +744,8 @@ static uint32_t __init kvm_detect(void) static void __init kvm_apic_init(void) { -#if defined(CONFIG_SMP) if (pv_ipi_supported()) kvm_setup_pv_ipi(); -#endif } static bool __init kvm_msi_ext_dest_id(void) @@ -797,20 +805,11 @@ arch_initcall(activate_jump_labels); static __init int kvm_alloc_cpumask(void) { int cpu; - bool alloc = false; if (!kvm_para_available() || nopv) return 0; - if (pv_tlb_flush_supported()) - alloc = true; - -#if defined(CONFIG_SMP) - if (pv_ipi_supported()) - alloc = true; -#endif - - if (alloc) + if (pv_tlb_flush_supported() || pv_ipi_supported()) for_each_possible_cpu(cpu) { zalloc_cpumask_var_node(per_cpu_ptr(&__pv_cpu_mask, cpu), GFP_KERNEL, cpu_to_node(cpu));