From: Paolo Bonzini <pbonzini@redhat.com> To: "Wu, Feng" <feng.wu@intel.com>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@linux.intel.com>, "x86@kernel.org" <x86@kernel.org>, Gleb Natapov <gleb@kernel.org>, Paolo Bonzini <pbonzini@redhat.com>, "dwmw2@infradead.org" <dwmw2@infradead.org>, "joro@8bytes.org" <joro@8bytes.org>, Alex Williamson <alex.williamson@redhat.com>, jiang.liu-VuQAYsv1563Yd54FQh9/CA@public.gmane.org Cc: "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, KVM list <kvm@vger.kernel.org>, Eric Auger <eric.auger@linaro.org> Subject: Re: [v3 23/26] KVM: Update Posted-Interrupts Descriptor when vCPU is preempted Date: Wed, 17 Dec 2014 18:11:00 +0100 [thread overview] Message-ID: <5491B924.3090200@redhat.com> (raw) In-Reply-To: <1418397300-10870-24-git-send-email-feng.wu@intel.com> On 12/12/2014 16:14, Feng Wu wrote: > + if (irq_remapping_cap(IRQ_POSTING_CAP)) { > + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); > + struct pi_desc old, new; > + unsigned int dest; > + > + memset(&old, 0, sizeof(old)); > + memset(&new, 0, sizeof(new)); This is quite expensive. Just use an u64 for old_control and new_control, instead of a full struct. > > + pi_clear_sn(&new); This can be simply new.sn = 0. It does not need atomic operations. Same in patch 24 (if needed at all there---see the reply there). > > + if (irq_remapping_cap(IRQ_POSTING_CAP)) { > + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); > + struct pi_desc old, new; > + > + memset(&old, 0, sizeof(old)); > + memset(&new, 0, sizeof(new)); > + Here you do not need old/new at all because... > + if (vcpu->preempted) { > + do { > + old.control = new.control = pi_desc->control; > + pi_set_sn(&new); > + } while (cmpxchg(&pi_desc->control, old.control, > + new.control) != old.control); this can do pi_set_sn directly on pi_desc, without the cmpxchg. Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> To: "Wu, Feng" <feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, "H. Peter Anvin" <hpa-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>, "x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" <x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Gleb Natapov <gleb-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Paolo Bonzini <pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org" <dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, "joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org" <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>, Alex Williamson <alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, public-jiang.liu-VuQAYsv1563Yd54FQh9/CA-wOFGN7rlS/M9smdsby/KFg@public.gmane.org Cc: "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" <iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, KVM list <kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Eric Auger <eric.auger-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Subject: Re: [v3 23/26] KVM: Update Posted-Interrupts Descriptor when vCPU is preempted Date: Wed, 17 Dec 2014 18:11:00 +0100 [thread overview] Message-ID: <5491B924.3090200@redhat.com> (raw) In-Reply-To: <1418397300-10870-24-git-send-email-feng.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> On 12/12/2014 16:14, Feng Wu wrote: > + if (irq_remapping_cap(IRQ_POSTING_CAP)) { > + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); > + struct pi_desc old, new; > + unsigned int dest; > + > + memset(&old, 0, sizeof(old)); > + memset(&new, 0, sizeof(new)); This is quite expensive. Just use an u64 for old_control and new_control, instead of a full struct. > > + pi_clear_sn(&new); This can be simply new.sn = 0. It does not need atomic operations. Same in patch 24 (if needed at all there---see the reply there). > > + if (irq_remapping_cap(IRQ_POSTING_CAP)) { > + struct pi_desc *pi_desc = vcpu_to_pi_desc(vcpu); > + struct pi_desc old, new; > + > + memset(&old, 0, sizeof(old)); > + memset(&new, 0, sizeof(new)); > + Here you do not need old/new at all because... > + if (vcpu->preempted) { > + do { > + old.control = new.control = pi_desc->control; > + pi_set_sn(&new); > + } while (cmpxchg(&pi_desc->control, old.control, > + new.control) != old.control); this can do pi_set_sn directly on pi_desc, without the cmpxchg. Paolo
next prev parent reply other threads:[~2014-12-17 17:11 UTC|newest] Thread overview: 267+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-12-12 15:14 [v3 00/26] Add VT-d Posted-Interrupts support Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 01/26] genirq: Introduce irq_set_vcpu_affinity() to target an interrupt to a VCPU Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 02/26] iommu: Add new member capability to struct irq_remap_ops Feng Wu 2015-01-28 15:22 ` David Woodhouse 2015-01-28 15:22 ` David Woodhouse 2015-01-29 8:34 ` Wu, Feng 2015-01-29 8:34 ` Wu, Feng 2014-12-12 15:14 ` [v3 03/26] iommu, x86: Define new irte structure for VT-d Posted-Interrupts Feng Wu 2014-12-12 15:14 ` Feng Wu 2015-01-28 15:26 ` David Woodhouse 2015-01-28 15:26 ` David Woodhouse 2014-12-12 15:14 ` [v3 04/26] iommu, x86: Implement irq_set_vcpu_affinity for intel_ir_chip Feng Wu 2014-12-12 15:14 ` Feng Wu 2015-01-28 15:26 ` David Woodhouse 2015-01-28 15:26 ` David Woodhouse 2015-01-29 7:55 ` Wu, Feng 2015-01-29 7:55 ` Wu, Feng 2014-12-12 15:14 ` [v3 05/26] x86, irq: Implement irq_set_vcpu_affinity for pci_msi_ir_controller Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 06/26] iommu, x86: No need to migrating irq for VT-d Posted-Interrupts Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-18 14:26 ` Zhang, Yang Z 2014-12-18 14:26 ` Zhang, Yang Z 2014-12-19 1:40 ` Wu, Feng 2014-12-19 1:40 ` Wu, Feng 2014-12-19 1:46 ` Zhang, Yang Z 2014-12-19 1:46 ` Zhang, Yang Z 2014-12-19 11:59 ` Paolo Bonzini 2014-12-19 11:59 ` Paolo Bonzini 2014-12-23 0:37 ` Zhang, Yang Z 2014-12-23 0:37 ` Zhang, Yang Z 2014-12-23 8:47 ` Paolo Bonzini 2014-12-23 8:47 ` Paolo Bonzini 2014-12-23 9:07 ` Wu, Feng 2014-12-23 9:07 ` Wu, Feng 2014-12-23 9:34 ` Paolo Bonzini 2014-12-23 9:34 ` Paolo Bonzini 2014-12-24 1:38 ` Zhang, Yang Z 2014-12-24 1:38 ` Zhang, Yang Z 2014-12-24 2:12 ` Jiang Liu 2014-12-24 2:12 ` Jiang Liu 2014-12-24 2:32 ` Zhang, Yang Z 2014-12-24 2:32 ` Zhang, Yang Z 2014-12-24 3:08 ` Wu, Feng 2014-12-24 3:08 ` Wu, Feng 2014-12-24 4:04 ` Zhang, Yang Z 2014-12-24 4:04 ` Zhang, Yang Z 2014-12-24 4:54 ` Jiang Liu 2014-12-24 4:54 ` Jiang Liu 2015-01-28 15:29 ` David Woodhouse 2015-01-28 15:29 ` David Woodhouse 2014-12-12 15:14 ` [v3 07/26] iommu, x86: Add cap_pi_support() to detect VT-d PI capability Feng Wu 2015-01-28 15:32 ` David Woodhouse 2015-01-28 15:32 ` David Woodhouse 2014-12-12 15:14 ` [v3 08/26] iommu, x86: Add intel_irq_remapping_capability() for Intel Feng Wu 2015-01-28 15:37 ` David Woodhouse 2015-01-28 15:37 ` David Woodhouse 2015-01-29 8:57 ` Wu, Feng 2015-01-29 8:57 ` Wu, Feng 2014-12-12 15:14 ` [v3 09/26] iommu, x86: define irq_remapping_cap() Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 10/26] KVM: change struct pi_desc for VT-d Posted-Interrupts Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 11/26] KVM: Add some helper functions for Posted-Interrupts Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 12/26] KVM: Initialize VT-d Posted-Interrupts Descriptor Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-18 15:19 ` Zhang, Yang Z 2014-12-18 15:19 ` Zhang, Yang Z 2014-12-12 15:14 ` [v3 13/26] KVM: Define a new interface kvm_find_dest_vcpu() for VT-d PI Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-18 14:49 ` Zhang, Yang Z 2014-12-18 14:49 ` Zhang, Yang Z 2014-12-18 16:58 ` Paolo Bonzini 2014-12-18 16:58 ` Paolo Bonzini 2014-12-19 1:13 ` Zhang, Yang Z 2014-12-19 1:30 ` Wu, Feng 2014-12-19 1:30 ` Wu, Feng 2014-12-19 1:30 ` Wu, Feng 2014-12-19 1:30 ` Wu, Feng 2014-12-19 1:47 ` Zhang, Yang Z 2014-12-19 1:47 ` Zhang, Yang Z 2014-12-19 11:59 ` Paolo Bonzini 2014-12-19 11:59 ` Paolo Bonzini 2014-12-19 23:48 ` Wu, Feng 2014-12-19 23:48 ` Wu, Feng 2014-12-20 13:16 ` Paolo Bonzini 2014-12-20 13:16 ` Paolo Bonzini 2014-12-22 4:48 ` Wu, Feng 2014-12-22 4:48 ` Wu, Feng 2014-12-22 9:27 ` Paolo Bonzini 2014-12-22 9:27 ` Paolo Bonzini 2014-12-22 11:04 ` Wu, Feng 2014-12-22 11:04 ` Wu, Feng 2014-12-22 11:06 ` Paolo Bonzini 2014-12-22 11:06 ` Paolo Bonzini 2014-12-22 11:17 ` Wu, Feng 2014-12-22 11:17 ` Wu, Feng 2014-12-22 11:23 ` Paolo Bonzini 2014-12-22 11:23 ` Paolo Bonzini 2014-12-22 14:13 ` Yong Wang 2014-12-22 14:13 ` Yong Wang 2015-01-09 14:54 ` Radim Krčmář 2015-01-09 14:56 ` Paolo Bonzini 2015-01-09 15:12 ` Radim Krčmář 2015-01-09 15:18 ` Paolo Bonzini 2015-01-09 15:47 ` Radim Krčmář 2015-01-13 0:27 ` Wu, Feng 2015-01-13 0:27 ` Wu, Feng 2015-01-13 16:17 ` Radim Kr?má? 2015-01-14 1:27 ` Wu, Feng 2015-01-14 1:27 ` Wu, Feng 2015-01-14 13:02 ` Paolo Bonzini 2015-01-14 13:02 ` Paolo Bonzini 2015-01-14 16:59 ` Radim Kr?má? 2015-01-14 16:59 ` Radim Kr?má? 2015-01-20 21:04 ` Nadav Amit 2015-01-20 21:04 ` Nadav Amit 2015-01-21 21:16 ` Radim Kr?má? 2015-01-21 21:16 ` Radim Kr?má? 2014-12-12 15:14 ` [v3 14/26] KVM: Get Posted-Interrupts descriptor address from struct kvm_vcpu Feng Wu 2014-12-12 15:14 ` [v3 15/26] KVM: add interfaces to control PI outside vmx Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 16/26] KVM: Make struct kvm_irq_routing_table accessible Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-17 16:17 ` Paolo Bonzini 2014-12-17 16:17 ` Paolo Bonzini 2014-12-19 2:19 ` Wu, Feng 2014-12-19 2:19 ` Wu, Feng 2014-12-19 11:59 ` Paolo Bonzini 2014-12-19 11:59 ` Paolo Bonzini 2014-12-19 23:39 ` Wu, Feng 2014-12-19 23:39 ` Wu, Feng 2014-12-12 15:14 ` [v3 17/26] KVM: make kvm_set_msi_irq() public Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-17 17:32 ` Paolo Bonzini 2014-12-17 17:32 ` Paolo Bonzini 2014-12-12 15:14 ` [v3 18/26] KVM: kvm-vfio: User API for VT-d Posted-Interrupts Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 19/26] KVM: kvm-vfio: implement the VFIO skeleton " Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 20/26] KVM: x86: kvm-vfio: VT-d posted-interrupts setup Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 21/26] x86, irq: Define a global vector for VT-d Posted-Interrupts Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-18 14:54 ` Zhang, Yang Z 2014-12-18 14:54 ` Zhang, Yang Z 2014-12-19 0:52 ` Wu, Feng 2014-12-19 0:52 ` Wu, Feng 2015-01-30 18:18 ` H. Peter Anvin 2015-01-30 18:18 ` H. Peter Anvin 2015-02-02 1:06 ` Wu, Feng 2015-02-02 1:06 ` Wu, Feng 2015-02-23 22:04 ` Marcelo Tosatti 2015-02-23 22:04 ` Marcelo Tosatti 2014-12-12 15:14 ` [v3 22/26] KVM: Define a wakeup worker thread for vCPU Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-12 15:14 ` [v3 23/26] KVM: Update Posted-Interrupts Descriptor when vCPU is preempted Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-17 17:11 ` Paolo Bonzini [this message] 2014-12-17 17:11 ` Paolo Bonzini 2014-12-18 3:15 ` Wu, Feng 2014-12-18 3:15 ` Wu, Feng 2014-12-18 8:32 ` Paolo Bonzini 2014-12-18 8:32 ` Paolo Bonzini 2014-12-19 2:09 ` Wu, Feng 2014-12-19 2:09 ` Wu, Feng 2014-12-19 2:09 ` Wu, Feng 2015-02-23 22:21 ` Marcelo Tosatti 2015-02-23 22:21 ` Marcelo Tosatti 2015-03-02 9:12 ` Wu, Feng 2015-03-02 9:12 ` Wu, Feng 2014-12-12 15:14 ` [v3 24/26] KVM: Update Posted-Interrupts Descriptor when vCPU is blocked Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-17 17:09 ` Paolo Bonzini 2014-12-17 17:09 ` Paolo Bonzini 2014-12-18 3:16 ` Wu, Feng 2014-12-18 3:16 ` Wu, Feng 2014-12-18 8:37 ` Paolo Bonzini 2014-12-18 8:37 ` Paolo Bonzini 2014-12-19 2:51 ` Wu, Feng 2014-12-19 2:51 ` Wu, Feng 2014-12-19 2:51 ` Wu, Feng 2015-02-25 21:50 ` Marcelo Tosatti 2015-02-26 8:08 ` Wu, Feng 2015-02-26 23:41 ` Marcelo Tosatti 2015-02-26 23:41 ` Marcelo Tosatti 2015-02-26 23:40 ` Marcelo Tosatti 2015-02-26 23:40 ` Marcelo Tosatti 2015-03-02 13:36 ` Wu, Feng 2015-03-02 13:36 ` Wu, Feng 2015-03-04 12:06 ` Marcelo Tosatti 2015-03-06 6:51 ` Wu, Feng 2015-03-06 6:51 ` Wu, Feng 2015-03-12 1:15 ` Marcelo Tosatti 2015-03-16 11:42 ` Wu, Feng 2015-03-16 11:42 ` Wu, Feng 2015-03-25 23:17 ` Marcelo Tosatti 2015-03-25 23:17 ` Marcelo Tosatti 2015-03-27 6:34 ` Wu, Feng 2015-03-27 6:34 ` Wu, Feng 2015-03-27 19:30 ` Marcelo Tosatti 2015-03-30 4:46 ` Wu, Feng 2015-03-30 4:46 ` Wu, Feng 2015-03-30 23:55 ` Marcelo Tosatti 2015-03-31 1:13 ` Wu, Feng 2015-04-14 7:37 ` Wu, Feng 2015-06-05 21:59 ` Marcelo Tosatti 2015-06-08 1:43 ` Wu, Feng 2014-12-12 15:14 ` [v3 25/26] KVM: Suppress posted-interrupt when 'SN' is set Feng Wu 2014-12-12 15:14 ` Feng Wu 2014-12-17 17:42 ` Paolo Bonzini 2014-12-17 17:42 ` Paolo Bonzini 2014-12-17 17:42 ` Paolo Bonzini 2014-12-17 17:42 ` Paolo Bonzini 2014-12-18 3:14 ` Wu, Feng 2014-12-18 3:14 ` Wu, Feng 2014-12-18 8:38 ` Paolo Bonzini 2014-12-18 8:38 ` Paolo Bonzini 2014-12-18 15:09 ` Zhang, Yang Z 2014-12-18 15:09 ` Zhang, Yang Z 2014-12-19 2:58 ` Wu, Feng 2014-12-19 2:58 ` Wu, Feng 2014-12-19 2:58 ` Wu, Feng 2014-12-19 3:32 ` Zhang, Yang Z 2014-12-19 3:32 ` Zhang, Yang Z 2014-12-19 3:32 ` Zhang, Yang Z 2014-12-19 4:34 ` Wu, Feng 2014-12-19 4:34 ` Wu, Feng 2014-12-19 4:34 ` Wu, Feng 2014-12-19 4:44 ` Zhang, Yang Z 2014-12-19 4:44 ` Zhang, Yang Z 2014-12-19 4:44 ` Zhang, Yang Z 2014-12-19 4:49 ` Wu, Feng 2014-12-19 4:49 ` Wu, Feng 2014-12-19 4:49 ` Wu, Feng 2014-12-19 5:25 ` Zhang, Yang Z 2014-12-19 5:25 ` Zhang, Yang Z 2014-12-19 5:25 ` Zhang, Yang Z 2014-12-19 5:46 ` Wu, Feng 2014-12-19 5:46 ` Wu, Feng 2014-12-19 5:46 ` Wu, Feng 2014-12-19 7:04 ` Zhang, Yang Z 2014-12-19 7:04 ` Zhang, Yang Z 2014-12-19 12:00 ` Paolo Bonzini 2014-12-19 12:00 ` Paolo Bonzini 2014-12-19 23:34 ` Wu, Feng 2014-12-19 23:34 ` Wu, Feng 2014-12-12 15:15 ` [v3 26/26] iommu/vt-d: Add a command line parameter for VT-d posted-interrupts Feng Wu 2014-12-12 15:15 ` Feng Wu 2015-01-28 15:39 ` David Woodhouse 2015-01-28 15:39 ` David Woodhouse 2014-12-16 9:04 ` [v3 00/26] Add VT-d Posted-Interrupts support Wu, Feng 2015-01-06 1:10 ` Wu, Feng 2015-01-06 1:10 ` Wu, Feng 2015-01-09 12:46 ` joro 2015-01-09 13:58 ` Wu, Feng 2015-01-21 2:25 ` Wu, Feng 2015-01-21 2:25 ` Wu, Feng 2015-01-28 3:01 ` Wu, Feng 2015-01-28 3:01 ` Wu, Feng 2015-01-28 3:44 ` Alex Williamson 2015-01-28 3:44 ` Alex Williamson 2015-01-28 4:44 ` Wu, Feng 2015-01-28 4:44 ` Wu, Feng
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