From f21dd494506ad002a5b6b32e50a5d4ccac6929fe Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Wed, 10 Oct 2018 17:14:38 +0200 Subject: [PATCH] KVM: x86: hyperv: optimize sparse VP set processing Rewrite kvm_hv_flush_tlb()/send_ipi_vcpus_mask() making them cleaner and somewhat more optimal. hv_vcpu_in_sparse_set() is converted to sparse_set_to_vcpu_mask() which copies sparse banks u64-at-a-time and then, depending on the num_mismatched_vp_indexes value, returns immediately or does vp index to vcpu index conversion by walking all vCPUs. To support the change and make kvm_hv_send_ipi() look similar to kvm_hv_flush_tlb() send_ipi_vcpus_mask() is introduced. Suggested-by: Roman Kagan Signed-off-by: Vitaly Kuznetsov Reviewed-by: Roman Kagan Signed-off-by: Paolo Bonzini --- arch/x86/kvm/hyperv.c | 167 +++++++++++++++++------------------------- 1 file changed, 68 insertions(+), 99 deletions(-) diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index f1ae1777519c..df9ef8f1d2c8 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -36,6 +36,8 @@ #include "trace.h" +#define KVM_HV_MAX_SPARSE_VCPU_SET_BITS DIV_ROUND_UP(KVM_MAX_VCPUS, 64) + static inline u64 synic_read_sint(struct kvm_vcpu_hv_synic *synic, int sint) { return atomic64_read(&synic->sint[sint]); @@ -1277,37 +1279,47 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata, bool host) return kvm_hv_get_msr(vcpu, msr, pdata, host); } -static __always_inline bool hv_vcpu_in_sparse_set(struct kvm_vcpu_hv *hv_vcpu, - u64 sparse_banks[], - u64 valid_bank_mask) +static __always_inline unsigned long *sparse_set_to_vcpu_mask( + struct kvm *kvm, u64 *sparse_banks, u64 valid_bank_mask, + u64 *vp_bitmap, unsigned long *vcpu_bitmap) { - int bank = hv_vcpu->vp_index / 64, sbank; + struct kvm_hv *hv = &kvm->arch.hyperv; + struct kvm_vcpu *vcpu; + int i, bank, sbank = 0; - if (bank >= 64) - return false; + memset(vp_bitmap, 0, + KVM_HV_MAX_SPARSE_VCPU_SET_BITS * sizeof(*vp_bitmap)); + for_each_set_bit(bank, (unsigned long *)&valid_bank_mask, + KVM_HV_MAX_SPARSE_VCPU_SET_BITS) + vp_bitmap[bank] = sparse_banks[sbank++]; - if (!(valid_bank_mask & BIT_ULL(bank))) - return false; + if (likely(!atomic_read(&hv->num_mismatched_vp_indexes))) { + /* for all vcpus vp_index == vcpu_idx */ + return (unsigned long *)vp_bitmap; + } - /* Sparse bank number equals to the number of set bits before it */ - sbank = bitmap_weight((unsigned long *)&valid_bank_mask, bank); - - return !!(sparse_banks[sbank] & BIT_ULL(hv_vcpu->vp_index % 64)); + bitmap_zero(vcpu_bitmap, KVM_MAX_VCPUS); + kvm_for_each_vcpu(i, vcpu, kvm) { + if (test_bit(vcpu_to_hv_vcpu(vcpu)->vp_index, + (unsigned long *)vp_bitmap)) + __set_bit(i, vcpu_bitmap); + } + return vcpu_bitmap; } static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa, u16 rep_cnt, bool ex) { struct kvm *kvm = current_vcpu->kvm; - struct kvm_hv *hv = &kvm->arch.hyperv; struct kvm_vcpu_hv *hv_vcpu = ¤t_vcpu->arch.hyperv; struct hv_tlb_flush_ex flush_ex; struct hv_tlb_flush flush; - struct kvm_vcpu *vcpu; - unsigned long vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)] = {0}; + u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; + DECLARE_BITMAP(vcpu_bitmap, KVM_MAX_VCPUS); + unsigned long *vcpu_mask; u64 valid_bank_mask; u64 sparse_banks[64]; - int sparse_banks_len, i, bank, sbank; + int sparse_banks_len; bool all_cpus; if (!ex) { @@ -1350,54 +1362,19 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa, return HV_STATUS_INVALID_HYPERCALL_INPUT; } + cpumask_clear(&hv_vcpu->tlb_flush); + + vcpu_mask = all_cpus ? NULL : + sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, + vp_bitmap, vcpu_bitmap); + /* * vcpu->arch.cr3 may not be up-to-date for running vCPUs so we can't * analyze it here, flush TLB regardless of the specified address space. */ - cpumask_clear(&hv_vcpu->tlb_flush); - - if (all_cpus) { - kvm_make_vcpus_request_mask(kvm, - KVM_REQ_TLB_FLUSH | KVM_REQUEST_NO_WAKEUP, - NULL, &hv_vcpu->tlb_flush); - goto ret_success; - } - - if (atomic_read(&hv->num_mismatched_vp_indexes)) { - kvm_for_each_vcpu(i, vcpu, kvm) { - if (hv_vcpu_in_sparse_set(&vcpu->arch.hyperv, - sparse_banks, - valid_bank_mask)) - __set_bit(i, vcpu_bitmap); - } - goto flush_request; - } - - /* - * num_mismatched_vp_indexes is zero so every vcpu has - * vp_index == vcpu_idx. - */ - sbank = 0; - for_each_set_bit(bank, (unsigned long *)&valid_bank_mask, - BITS_PER_LONG) { - for_each_set_bit(i, - (unsigned long *)&sparse_banks[sbank], - BITS_PER_LONG) { - u32 vp_index = bank * 64 + i; - - /* A non-existent vCPU was specified */ - if (vp_index >= KVM_MAX_VCPUS) - return HV_STATUS_INVALID_HYPERCALL_INPUT; - - __set_bit(vp_index, vcpu_bitmap); - } - sbank++; - } - -flush_request: kvm_make_vcpus_request_mask(kvm, KVM_REQ_TLB_FLUSH | KVM_REQUEST_NO_WAKEUP, - vcpu_bitmap, &hv_vcpu->tlb_flush); + vcpu_mask, &hv_vcpu->tlb_flush); ret_success: /* We always do full TLB flush, set rep_done = rep_cnt. */ @@ -1405,18 +1382,38 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *current_vcpu, u64 ingpa, ((u64)rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET); } +static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector, + unsigned long *vcpu_bitmap) +{ + struct kvm_lapic_irq irq = { + .delivery_mode = APIC_DM_FIXED, + .vector = vector + }; + struct kvm_vcpu *vcpu; + int i; + + kvm_for_each_vcpu(i, vcpu, kvm) { + if (vcpu_bitmap && !test_bit(i, vcpu_bitmap)) + continue; + + /* We fail only when APIC is disabled */ + kvm_apic_set_irq(vcpu, &irq, NULL); + } +} + static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa, bool ex, bool fast) { struct kvm *kvm = current_vcpu->kvm; - struct kvm_hv *hv = &kvm->arch.hyperv; struct hv_send_ipi_ex send_ipi_ex; struct hv_send_ipi send_ipi; - struct kvm_vcpu *vcpu; + u64 vp_bitmap[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; + DECLARE_BITMAP(vcpu_bitmap, KVM_MAX_VCPUS); + unsigned long *vcpu_mask; unsigned long valid_bank_mask; u64 sparse_banks[64]; - int sparse_banks_len, bank, i, sbank; - struct kvm_lapic_irq irq = {.delivery_mode = APIC_DM_FIXED}; + int sparse_banks_len; + u32 vector; bool all_cpus; if (!ex) { @@ -1425,18 +1422,18 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa, sizeof(send_ipi)))) return HV_STATUS_INVALID_HYPERCALL_INPUT; sparse_banks[0] = send_ipi.cpu_mask; - irq.vector = send_ipi.vector; + vector = send_ipi.vector; } else { /* 'reserved' part of hv_send_ipi should be 0 */ if (unlikely(ingpa >> 32 != 0)) return HV_STATUS_INVALID_HYPERCALL_INPUT; sparse_banks[0] = outgpa; - irq.vector = (u32)ingpa; + vector = (u32)ingpa; } all_cpus = false; valid_bank_mask = BIT_ULL(0); - trace_kvm_hv_send_ipi(irq.vector, sparse_banks[0]); + trace_kvm_hv_send_ipi(vector, sparse_banks[0]); } else { if (unlikely(kvm_read_guest(kvm, ingpa, &send_ipi_ex, sizeof(send_ipi_ex)))) @@ -1446,7 +1443,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa, send_ipi_ex.vp_set.format, send_ipi_ex.vp_set.valid_bank_mask); - irq.vector = send_ipi_ex.vector; + vector = send_ipi_ex.vector; valid_bank_mask = send_ipi_ex.vp_set.valid_bank_mask; sparse_banks_len = bitmap_weight(&valid_bank_mask, 64) * sizeof(sparse_banks[0]); @@ -1465,42 +1462,14 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *current_vcpu, u64 ingpa, u64 outgpa, return HV_STATUS_INVALID_HYPERCALL_INPUT; } - if ((irq.vector < HV_IPI_LOW_VECTOR) || - (irq.vector > HV_IPI_HIGH_VECTOR)) + if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR)) return HV_STATUS_INVALID_HYPERCALL_INPUT; - if (all_cpus || atomic_read(&hv->num_mismatched_vp_indexes)) { - kvm_for_each_vcpu(i, vcpu, kvm) { - if (all_cpus || hv_vcpu_in_sparse_set( - &vcpu->arch.hyperv, sparse_banks, - valid_bank_mask)) { - /* We fail only when APIC is disabled */ - kvm_apic_set_irq(vcpu, &irq, NULL); - } - } - goto ret_success; - } + vcpu_mask = all_cpus ? NULL : + sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, + vp_bitmap, vcpu_bitmap); - /* - * num_mismatched_vp_indexes is zero so every vcpu has - * vp_index == vcpu_idx. - */ - sbank = 0; - for_each_set_bit(bank, (unsigned long *)&valid_bank_mask, 64) { - for_each_set_bit(i, (unsigned long *)&sparse_banks[sbank], 64) { - u32 vp_index = bank * 64 + i; - struct kvm_vcpu *vcpu = - get_vcpu_by_vpidx(kvm, vp_index); - - /* Unknown vCPU specified */ - if (!vcpu) - continue; - - /* We fail only when APIC is disabled */ - kvm_apic_set_irq(vcpu, &irq, NULL); - } - sbank++; - } + kvm_send_ipi_to_many(kvm, vector, vcpu_mask); ret_success: return HV_STATUS_SUCCESS;