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From: Zhu Lingshan <lingshan.zhu@intel.com>
To: jasowang@redhat.com, alex.williamson@redhat.com, mst@redhat.com,
	pbonzini@redhat.com, sean.j.christopherson@intel.com,
	wanpengli@tencent.com
Cc: virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, kvm@vger.kernel.org, eli@mellanox.com,
	shahafs@mellanox.com, parav@mellanox.com,
	Zhu Lingshan <lingshan.zhu@intel.com>
Subject: [PATCH V5 0/6] IRQ offloading for vDPA
Date: Fri, 31 Jul 2020 14:55:27 +0800
Message-ID: <20200731065533.4144-1-lingshan.zhu@intel.com> (raw)

This series intends to implement IRQ offloading for
vhost_vdpa.

By the feat of irq forwarding facilities like posted
interrupt on X86, irq bypass can  help deliver
interrupts to vCPU directly.

vDPA devices have dedicated hardware backends like VFIO
pass-throughed devices. So it would be possible to setup
irq offloading(irq bypass) for vDPA devices and gain
performance improvements.

In my testing, with this feature, we can save 0.1ms
in a ping between two VFs on average.
changes from V4:
(1)in vhost_vdpa, setup irq offloading after config_ops->set_status.
(2)minor improvements

changes from V3:
(1)removed vDPA irq allocate/free helpers in vDPA core.
(2)add a new function get_vq_irq() in struct vdpa_config_ops,
upper layer driver can use this function to: A. query the
irq numbner of a vq. B. detect whether a vq is enabled.
(3)implement get_vq_irq() in ifcvf driver.
(4)in vhost_vdpa, set_status() will setup irq offloading when
setting DRIVER_OK, and unsetup when receive !DRIVER_OK.
(5)minor improvements.

changes from V2:
(1)rename struct vhost_call_ctx to vhost_vring_call
(2)add kvm_arch_end_assignment() in del_producer()
code path
(3)rename vDPA helpers to vdpa_devm_request_irq()
and vdpa_devm_free_irq(). Add better comments
for them.
(4)better comments for setup_vq_irq() and
unsetup_vq_irq()
(5)In vDPA VHOST_SET_VRING_CALL, will call vhost_vdpa_update_vq_irq()
without checking producer.irq, move this check into
vhost_vdpa_update_vq_irq(), so that get advantage of the spinlock.
(6)Add a function vhost_vdpa_clean_irq(), this function will unregister
the producer of vqs when vhost_vdpa_release(). This is safe
for control vq.
(7) minor improvements

changes from V1:
(1)dropped vfio changes.
(3)removed KVM_HVAE_IRQ_BYPASS checks
(4)locking fixes
(5)simplified vhost_vdpa_updat

Zhu Lingshan (6):
  vhost: introduce vhost_vring_call
  kvm: detect assigned device via irqbypass manager
  vDPA: add get_vq_irq() in vdpa_config_ops
  vhost_vdpa: implement IRQ offloading in vhost_vdpa
  ifcvf: implement vdpa_config_ops.get_vq_irq()
  irqbypass: do not start cons/prod when failed connect

 arch/x86/kvm/x86.c              | 12 ++++-
 drivers/vdpa/ifcvf/ifcvf_main.c | 18 ++++++-
 drivers/vhost/Kconfig           |  1 +
 drivers/vhost/vdpa.c            | 83 +++++++++++++++++++++++++++++++--
 drivers/vhost/vhost.c           | 22 ++++++---
 drivers/vhost/vhost.h           |  9 +++-
 include/linux/vdpa.h            |  6 +++
 virt/lib/irqbypass.c            | 16 ++++---
 8 files changed, 147 insertions(+), 20 deletions(-)

-- 
2.18.4


             reply index

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31  6:55 Zhu Lingshan [this message]
2020-07-31  6:55 ` [PATCH V5 1/6] vhost: introduce vhost_vring_call Zhu Lingshan
2020-08-04  8:38   ` Jason Wang
     [not found]     ` <d51dd4e3-7513-c771-104c-b61f9ee70f30@intel.com>
2020-08-04  8:53       ` Jason Wang
2020-08-04  9:21         ` Michael S. Tsirkin
2020-08-05  2:16           ` Jason Wang
     [not found]             ` <bf10cde9-db86-a1ac-e2a8-363735e49afb@intel.com>
2020-08-05  5:53               ` Jason Wang
2020-08-10 13:37             ` Michael S. Tsirkin
2020-08-11  2:53               ` Jason Wang
     [not found]         ` <4605de34-c426-33d4-714b-e03716d0374c@intel.com>
2020-08-05  2:20           ` Jason Wang
2020-07-31  6:55 ` [PATCH V5 2/6] kvm: detect assigned device via irqbypass manager Zhu Lingshan
2020-07-31  6:55 ` [PATCH V5 3/6] vDPA: add get_vq_irq() in vdpa_config_ops Zhu Lingshan
2020-07-31  6:55 ` [PATCH V5 4/6] vhost_vdpa: implement IRQ offloading in vhost_vdpa Zhu Lingshan
2020-08-04  8:51   ` Jason Wang
     [not found]     ` <ae5385dc-6637-c5a3-b00a-02f66bb9a85f@intel.com>
2020-08-04  9:36       ` Michael S. Tsirkin
2020-08-05  2:36       ` Jason Wang
     [not found]         ` <cb01a490-e9e6-42f5-b6c3-caefa2d91b9f@intel.com>
2020-08-05  5:51           ` Jason Wang
2020-08-05  8:06   ` Jason Wang
2020-08-05  8:12     ` Zhu, Lingshan
2020-07-31  6:55 ` [PATCH V5 5/6] ifcvf: implement vdpa_config_ops.get_vq_irq() Zhu Lingshan
2020-07-31  6:55 ` [PATCH V5 6/6] irqbypass: do not start cons/prod when failed connect Zhu Lingshan

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