Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965642AbbLPBzq (ORCPT ); Tue, 15 Dec 2015 20:55:46 -0500 Received: from mga14.intel.com ([192.55.52.115]:49875 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932784AbbLPBzf (ORCPT ); Tue, 15 Dec 2015 20:55:35 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,435,1444719600"; d="scan'208";a="872356132" From: Feng Wu To: pbonzini@redhat.com, rkrcmar@redhat.com Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Feng Wu Subject: [PATCH v2 1/2] KVM: x86: Use vector-hashing to deliver lowest-priority interrupts Date: Wed, 16 Dec 2015 09:37:32 +0800 Message-Id: <1450229853-3886-2-git-send-email-feng.wu@intel.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1450229853-3886-1-git-send-email-feng.wu@intel.com> References: <1450229853-3886-1-git-send-email-feng.wu@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6470 Lines: 210 Use vector-hashing to deliver lowest-priority interrupts, As an example, modern Intel CPUs in server platform use this method to handle lowest-priority interrupts. Signed-off-by: Feng Wu --- arch/x86/kvm/irq_comm.c | 27 ++++++++++++++++++----- arch/x86/kvm/lapic.c | 57 ++++++++++++++++++++++++++++++++++++++++--------- arch/x86/kvm/lapic.h | 2 ++ arch/x86/kvm/x86.c | 9 ++++++++ arch/x86/kvm/x86.h | 1 + 5 files changed, 81 insertions(+), 15 deletions(-) diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c index 84b96d3..c8c5f61 100644 --- a/arch/x86/kvm/irq_comm.c +++ b/arch/x86/kvm/irq_comm.c @@ -32,6 +32,7 @@ #include "ioapic.h" #include "lapic.h" +#include "x86.h" static int kvm_set_pic_irq(struct kvm_kernel_irq_routing_entry *e, struct kvm *kvm, int irq_source_id, int level, @@ -53,8 +54,10 @@ static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e, int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, struct kvm_lapic_irq *irq, unsigned long *dest_map) { - int i, r = -1; + int i, r = -1, idx = 0; struct kvm_vcpu *vcpu, *lowest = NULL; + unsigned long dest_vcpu_bitmap[BITS_TO_LONGS(KVM_MAX_VCPUS)]; + unsigned int dest_vcpus = 0; if (irq->dest_mode == 0 && irq->dest_id == 0xff && kvm_lowest_prio_delivery(irq)) { @@ -65,6 +68,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r, dest_map)) return r; + memset(dest_vcpu_bitmap, 0, sizeof(dest_vcpu_bitmap)); + kvm_for_each_vcpu(i, vcpu, kvm) { if (!kvm_apic_present(vcpu)) continue; @@ -78,13 +83,25 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src, r = 0; r += kvm_apic_set_irq(vcpu, irq, dest_map); } else if (kvm_lapic_enabled(vcpu)) { - if (!lowest) - lowest = vcpu; - else if (kvm_apic_compare_prio(vcpu, lowest) < 0) - lowest = vcpu; + if (!kvm_vector_hashing_enabled()) { + if (!lowest) + lowest = vcpu; + else if (kvm_apic_compare_prio(vcpu, lowest) < 0) + lowest = vcpu; + } else { + __set_bit(vcpu->vcpu_id, dest_vcpu_bitmap); + dest_vcpus++; + } } } + if (dest_vcpus != 0) { + idx = kvm_vector_2_index(irq->vector, dest_vcpus, + dest_vcpu_bitmap, KVM_MAX_VCPUS); + + lowest = kvm_get_vcpu(kvm, idx - 1); + } + if (lowest) r = kvm_apic_set_irq(lowest, irq, dest_map); diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index ecd4ea1..e29001f 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -678,6 +678,22 @@ bool kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source, } } +int kvm_vector_2_index(u32 vector, u32 dest_vcpus, + const unsigned long *bitmap, u32 bitmap_size) +{ + u32 mod; + int i, idx = 0; + + mod = vector % dest_vcpus; + + for (i = 0; i <= mod; i++) { + idx = find_next_bit(bitmap, bitmap_size, idx) + 1; + BUG_ON(idx > bitmap_size); + } + + return idx; +} + bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src, struct kvm_lapic_irq *irq, int *r, unsigned long *dest_map) { @@ -731,17 +747,38 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src, dst = map->logical_map[cid]; if (kvm_lowest_prio_delivery(irq)) { - int l = -1; - for_each_set_bit(i, &bitmap, 16) { - if (!dst[i]) - continue; - if (l < 0) - l = i; - else if (kvm_apic_compare_prio(dst[i]->vcpu, dst[l]->vcpu) < 0) - l = i; + if (!kvm_vector_hashing_enabled()) { + int l = -1; + for_each_set_bit(i, &bitmap, 16) { + if (!dst[i]) + continue; + if (l < 0) + l = i; + else if (kvm_apic_compare_prio(dst[i]->vcpu, dst[l]->vcpu) < 0) + l = i; + } + bitmap = (l >= 0) ? 1 << l : 0; + } else { + int idx = 0; + unsigned int dest_vcpus = 0; + + for_each_set_bit(i, &bitmap, 16) { + if (!dst[i] && !kvm_lapic_enabled(dst[i]->vcpu)) { + __clear_bit(i, &bitmap); + continue; + } + } + + dest_vcpus = hweight16(bitmap); + + if (dest_vcpus != 0) { + idx = kvm_vector_2_index(irq->vector, + dest_vcpus, &bitmap, 16); + + bitmap = 0; + __set_bit(idx-1, &bitmap); + } } - - bitmap = (l >= 0) ? 1 << l : 0; } } diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index fde8e35d..6890ef0 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -170,4 +170,6 @@ void wait_lapic_expire(struct kvm_vcpu *vcpu); bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq, struct kvm_vcpu **dest_vcpu); +int kvm_vector_2_index(u32 vector, u32 dest_vcpus, + const unsigned long *bitmap, u32 bitmap_size); #endif diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4a6eff1..fb47730 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -118,6 +118,9 @@ module_param(tsc_tolerance_ppm, uint, S_IRUGO | S_IWUSR); unsigned int lapic_timer_advance_ns = 0; module_param(lapic_timer_advance_ns, uint, S_IRUGO | S_IWUSR); +bool __read_mostly enable_vector_hashing = 1; +module_param(enable_vector_hashing, bool, S_IRUGO); + static bool backwards_tsc_observed = false; #define KVM_NR_SHARED_MSRS 16 @@ -8165,6 +8168,12 @@ int kvm_arch_update_irqfd_routing(struct kvm *kvm, unsigned int host_irq, return kvm_x86_ops->update_pi_irte(kvm, host_irq, guest_irq, set); } +bool kvm_vector_hashing_enabled(void) +{ + return enable_vector_hashing; +} +EXPORT_SYMBOL_GPL(kvm_vector_hashing_enabled); + EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_fast_mmio); EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq); diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index f2afa5f..04bd0f9 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -179,6 +179,7 @@ int kvm_mtrr_set_msr(struct kvm_vcpu *vcpu, u32 msr, u64 data); int kvm_mtrr_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata); bool kvm_mtrr_check_gfn_range_consistency(struct kvm_vcpu *vcpu, gfn_t gfn, int page_num); +bool kvm_vector_hashing_enabled(void); #define KVM_SUPPORTED_XCR0 (XFEATURE_MASK_FP | XFEATURE_MASK_SSE \ | XFEATURE_MASK_YMM | XFEATURE_MASK_BNDREGS \ -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/