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Message-Id: <20200722094910.218014-1-lingshan.zhu@live.com>
Date: Wed, 22 Jul 2020 17:49:04 +0800
From: Zhu Lingshan <lingshan.zhu@...e.com>
To: jasowang@...hat.com, alex.williamson@...hat.com, mst@...hat.com,
pbonzini@...hat.com, sean.j.christopherson@...el.com,
wanpengli@...cent.com
Cc: virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org,
kvm@...r.kernel.org, Zhu Lingshan <lingshan.zhu@...e.com>
Subject: [PATCH V3 0/6] IRQ offloading for vDPA
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 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_update_vq_irq()
(6)minor improvements
Zhu Lingshan (6):
vhost: introduce vhost_vring_call
kvm: detect assigned device via irqbypass manager
vDPA: implement vq IRQ allocate/free helpers in vDPA core
vhost_vdpa: implement IRQ offloading in vhost_vdpa
ifcvf: replace irq_request/free with vDPA helpers
irqbypass: do not start cons/prod when failed connect
arch/x86/kvm/x86.c | 11 +++++-
drivers/vdpa/ifcvf/ifcvf_main.c | 14 ++++---
drivers/vdpa/vdpa.c | 49 +++++++++++++++++++++++
drivers/vhost/Kconfig | 1 +
drivers/vhost/vdpa.c | 70 +++++++++++++++++++++++++++++++--
drivers/vhost/vhost.c | 22 ++++++++---
drivers/vhost/vhost.h | 9 ++++-
include/linux/vdpa.h | 13 ++++++
virt/lib/irqbypass.c | 16 +++++---
9 files changed, 182 insertions(+), 23 deletions(-)
--
2.18.4
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