Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965679AbbLPBzs (ORCPT ); Tue, 15 Dec 2015 20:55:48 -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 S933938AbbLPBzh (ORCPT ); Tue, 15 Dec 2015 20:55:37 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,435,1444719600"; d="scan'208";a="872356154" 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 2/2] KVM: x86: Add lowest-priority support for vt-d posted-interrupts Date: Wed, 16 Dec 2015 09:37:33 +0800 Message-Id: <1450229853-3886-3-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: 3677 Lines: 130 Use vector-hashing to deliver lowest-priority interrupts for VT-d posted-interrupts. Signed-off-by: Feng Wu --- arch/x86/kvm/lapic.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/lapic.h | 2 ++ arch/x86/kvm/vmx.c | 12 ++++++++-- 3 files changed, 79 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index e29001f..d4f2c8f 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -854,6 +854,73 @@ out: } /* + * This routine handles lowest-priority interrupts using vector-hashing + * mechanism. As an example, modern Intel CPUs use this method to handle + * lowest-priority interrupts. + * + * Here is the details about the vector-hashing mechanism: + * 1. For lowest-priority interrupts, store all the possible destination + * vCPUs in an array. + * 2. Use "guest vector % max number of destination vCPUs" to find the right + * destination vCPU in the array for the lowest-priority interrupt. + */ +struct kvm_vcpu *kvm_intr_vector_hashing_dest(struct kvm *kvm, + struct kvm_lapic_irq *irq) +{ + struct kvm_apic_map *map; + struct kvm_vcpu *vcpu = NULL; + + if (irq->shorthand) + return NULL; + + rcu_read_lock(); + map = rcu_dereference(kvm->arch.apic_map); + + if (!map) + goto out; + + if ((irq->dest_mode != APIC_DEST_PHYSICAL) && + kvm_lowest_prio_delivery(irq)) { + u16 cid; + int i, idx = 0; + unsigned long bitmap = 1; + unsigned int dest_vcpus = 0; + struct kvm_lapic **dst = NULL; + + + if (!kvm_apic_logical_map_valid(map)) + goto out; + + apic_logical_id(map, irq->dest_id, &cid, (u16 *)&bitmap); + + if (cid >= ARRAY_SIZE(map->logical_map)) + goto out; + + dst = map->logical_map[cid]; + + 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); + vcpu = dst[idx-1]->vcpu; + } + } + +out: + rcu_read_unlock(); + return vcpu; +} +EXPORT_SYMBOL_GPL(kvm_intr_vector_hashing_dest); + +/* * Add a pending IRQ into lapic. * Return 1 if successfully added and 0 if discarded. */ diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h index 6890ef0..52bffce 100644 --- a/arch/x86/kvm/lapic.h +++ b/arch/x86/kvm/lapic.h @@ -172,4 +172,6 @@ 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); +struct kvm_vcpu *kvm_intr_vector_hashing_dest(struct kvm *kvm, + struct kvm_lapic_irq *irq); #endif diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 5eb56ed..3f89189 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -10702,8 +10702,16 @@ static int vmx_update_pi_irte(struct kvm *kvm, unsigned int host_irq, */ kvm_set_msi_irq(e, &irq); - if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) - continue; + + if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) { + if (!kvm_vector_hashing_enabled() || + irq.delivery_mode != APIC_DM_LOWEST) + continue; + + vcpu = kvm_intr_vector_hashing_dest(kvm, &irq); + if (!vcpu) + continue; + } vcpu_info.pi_desc_addr = __pa(vcpu_to_pi_desc(vcpu)); vcpu_info.vector = irq.vector; -- 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/