| Message ID | 20220414132013.1588929-10-vkuznets@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: x86: hyper-v: Fine-grained TLB flush + L2 TLB flush feature | expand |
On Thu, 2022-04-14 at 15:19 +0200, Vitaly Kuznetsov wrote: > Get rid of on-stack allocation of vcpu_mask and optimize kvm_hv_send_ipi() > for a smaller number of vCPUs in the request. When Hyper-V TLB flush > is in use, HvSendSyntheticClusterIpi{,Ex} calls are not commonly used to > send IPIs to a large number of vCPUs (and are rarely used in general). > > Introduce hv_is_vp_in_sparse_set() to directly check if the specified > VP_ID is present in sparse vCPU set. > > Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> > --- > arch/x86/kvm/hyperv.c | 37 ++++++++++++++++++++++++++----------- > 1 file changed, 26 insertions(+), 11 deletions(-) > > diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c > index 3cf68645a2e6..aebbb598ad1d 100644 > --- a/arch/x86/kvm/hyperv.c > +++ b/arch/x86/kvm/hyperv.c > @@ -1746,6 +1746,25 @@ static void sparse_set_to_vcpu_mask(struct kvm *kvm, u64 *sparse_banks, > } > } > > +static bool hv_is_vp_in_sparse_set(u32 vp_id, u64 valid_bank_mask, u64 sparse_banks[]) > +{ > + int bank, sbank = 0; > + > + if (!test_bit(vp_id / HV_VCPUS_PER_SPARSE_BANK, > + (unsigned long *)&valid_bank_mask)) > + return false; > + > + for_each_set_bit(bank, (unsigned long *)&valid_bank_mask, > + KVM_HV_MAX_SPARSE_VCPU_SET_BITS) { > + if (bank == vp_id / HV_VCPUS_PER_SPARSE_BANK) > + break; > + sbank++; > + } > + > + return test_bit(vp_id % HV_VCPUS_PER_SPARSE_BANK, > + (unsigned long *)&sparse_banks[sbank]); > +} > + > struct kvm_hv_hcall { > u64 param; > u64 ingpa; > @@ -2089,8 +2108,8 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > ((u64)hc->rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET); > } > > -static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector, > - unsigned long *vcpu_bitmap) > +static void kvm_hv_send_ipi_to_many(struct kvm *kvm, u32 vector, > + u64 *sparse_banks, u64 valid_bank_mask) I think the indentation is wrong here (was wrong before as well) > { > struct kvm_lapic_irq irq = { > .delivery_mode = APIC_DM_FIXED, > @@ -2100,7 +2119,10 @@ static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector, > unsigned long i; > > kvm_for_each_vcpu(i, vcpu, kvm) { > - if (vcpu_bitmap && !test_bit(i, vcpu_bitmap)) > + if (sparse_banks && > + !hv_is_vp_in_sparse_set(kvm_hv_get_vpindex(vcpu), > + valid_bank_mask, > + sparse_banks)) > continue; > > /* We fail only when APIC is disabled */ > @@ -2113,7 +2135,6 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > struct kvm *kvm = vcpu->kvm; > struct hv_send_ipi_ex send_ipi_ex; > struct hv_send_ipi send_ipi; > - DECLARE_BITMAP(vcpu_mask, KVM_MAX_VCPUS); > unsigned long valid_bank_mask; > u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; > u32 vector; > @@ -2175,13 +2196,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR)) > return HV_STATUS_INVALID_HYPERCALL_INPUT; > > - if (all_cpus) { > - kvm_send_ipi_to_many(kvm, vector, NULL); > - } else { > - sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, vcpu_mask); > - > - kvm_send_ipi_to_many(kvm, vector, vcpu_mask); > - } > + kvm_hv_send_ipi_to_many(kvm, vector, all_cpus ? NULL : sparse_banks, valid_bank_mask); > > ret_success: > return HV_STATUS_SUCCESS; Overall looks good to me, but I might have missed something. Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com> Best regards, Maxim Levitsky
On Wed, May 11, 2022, Maxim Levitsky wrote: > On Thu, 2022-04-14 at 15:19 +0200, Vitaly Kuznetsov wrote: > > @@ -2089,8 +2108,8 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) > > ((u64)hc->rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET); > > } > > > > -static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector, > > - unsigned long *vcpu_bitmap) > > +static void kvm_hv_send_ipi_to_many(struct kvm *kvm, u32 vector, > > + u64 *sparse_banks, u64 valid_bank_mask) > I think the indentation is wrong here (was wrong before as well) It's correct, the "+" from the diff/patch misaligns the first line because there's no tab to eat the extra character. Amusingly, the misaligment just gets worse the more ">" / quotes that get added to the front. I usually end up applying a patch to double check if I suspect indentation is wrong, it's too hard for me to tell based on the raw patch alone unless it's super bad/obvious.
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c index 3cf68645a2e6..aebbb598ad1d 100644 --- a/arch/x86/kvm/hyperv.c +++ b/arch/x86/kvm/hyperv.c @@ -1746,6 +1746,25 @@ static void sparse_set_to_vcpu_mask(struct kvm *kvm, u64 *sparse_banks, } } +static bool hv_is_vp_in_sparse_set(u32 vp_id, u64 valid_bank_mask, u64 sparse_banks[]) +{ + int bank, sbank = 0; + + if (!test_bit(vp_id / HV_VCPUS_PER_SPARSE_BANK, + (unsigned long *)&valid_bank_mask)) + return false; + + for_each_set_bit(bank, (unsigned long *)&valid_bank_mask, + KVM_HV_MAX_SPARSE_VCPU_SET_BITS) { + if (bank == vp_id / HV_VCPUS_PER_SPARSE_BANK) + break; + sbank++; + } + + return test_bit(vp_id % HV_VCPUS_PER_SPARSE_BANK, + (unsigned long *)&sparse_banks[sbank]); +} + struct kvm_hv_hcall { u64 param; u64 ingpa; @@ -2089,8 +2108,8 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) ((u64)hc->rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET); } -static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector, - unsigned long *vcpu_bitmap) +static void kvm_hv_send_ipi_to_many(struct kvm *kvm, u32 vector, + u64 *sparse_banks, u64 valid_bank_mask) { struct kvm_lapic_irq irq = { .delivery_mode = APIC_DM_FIXED, @@ -2100,7 +2119,10 @@ static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector, unsigned long i; kvm_for_each_vcpu(i, vcpu, kvm) { - if (vcpu_bitmap && !test_bit(i, vcpu_bitmap)) + if (sparse_banks && + !hv_is_vp_in_sparse_set(kvm_hv_get_vpindex(vcpu), + valid_bank_mask, + sparse_banks)) continue; /* We fail only when APIC is disabled */ @@ -2113,7 +2135,6 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) struct kvm *kvm = vcpu->kvm; struct hv_send_ipi_ex send_ipi_ex; struct hv_send_ipi send_ipi; - DECLARE_BITMAP(vcpu_mask, KVM_MAX_VCPUS); unsigned long valid_bank_mask; u64 sparse_banks[KVM_HV_MAX_SPARSE_VCPU_SET_BITS]; u32 vector; @@ -2175,13 +2196,7 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc) if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR)) return HV_STATUS_INVALID_HYPERCALL_INPUT; - if (all_cpus) { - kvm_send_ipi_to_many(kvm, vector, NULL); - } else { - sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, vcpu_mask); - - kvm_send_ipi_to_many(kvm, vector, vcpu_mask); - } + kvm_hv_send_ipi_to_many(kvm, vector, all_cpus ? NULL : sparse_banks, valid_bank_mask); ret_success: return HV_STATUS_SUCCESS;
Get rid of on-stack allocation of vcpu_mask and optimize kvm_hv_send_ipi() for a smaller number of vCPUs in the request. When Hyper-V TLB flush is in use, HvSendSyntheticClusterIpi{,Ex} calls are not commonly used to send IPIs to a large number of vCPUs (and are rarely used in general). Introduce hv_is_vp_in_sparse_set() to directly check if the specified VP_ID is present in sparse vCPU set. Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> --- arch/x86/kvm/hyperv.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-)