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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: shahafs@mellanox.com, wanpengli@tencent.com, parav@mellanox.com,
	kvm@vger.kernel.org, netdev@vger.kernel.org,
	sean.j.christopherson@intel.com,
	virtualization@lists.linux-foundation.org, eli@mellanox.com,
	pbonzini@redhat.com, "Zhu, Lingshan" <lingshan.zhu@intel.com>
Subject: Re: [PATCH V5 1/6] vhost: introduce vhost_vring_call
Date: Mon, 10 Aug 2020 09:37:00 -0400	[thread overview]
Message-ID: <20200810093630-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <14fd2bf1-e9c1-a192-bd6c-f1ee5fd227f6@redhat.com>

On Wed, Aug 05, 2020 at 10:16:16AM +0800, Jason Wang wrote:
> 
> On 2020/8/4 下午5:21, Michael S. Tsirkin wrote:
> > > > > >    +struct vhost_vring_call {
> > > > > > +    struct eventfd_ctx *ctx;
> > > > > > +    struct irq_bypass_producer producer;
> > > > > > +    spinlock_t ctx_lock;
> > > > > It's not clear to me why we need ctx_lock here.
> > > > > 
> > > > > Thanks
> > > > Hi Jason,
> > > > 
> > > > we use this lock to protect the eventfd_ctx and irq from race conditions,
> > > We don't support irq notification from vDPA device driver in this version,
> > > do we still have race condition?
> > > 
> > > Thanks
> > Jason I'm not sure what you are trying to say here.
> 
> 
> I meant we change the API from V4 so driver won't notify us if irq is
> changed.
> 
> Then it looks to me there's no need for the ctx_lock, everyhing could be
> synchronized with vq mutex.
> 
> Thanks

Jason do you want to post a cleanup patch simplifying code along these
lines?

Thanks,


> > 
> > 

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WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: "Zhu, Lingshan" <lingshan.zhu@intel.com>,
	alex.williamson@redhat.com, pbonzini@redhat.com,
	sean.j.christopherson@intel.com, wanpengli@tencent.com,
	virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, kvm@vger.kernel.org, eli@mellanox.com,
	shahafs@mellanox.com, parav@mellanox.com
Subject: Re: [PATCH V5 1/6] vhost: introduce vhost_vring_call
Date: Mon, 10 Aug 2020 09:37:00 -0400	[thread overview]
Message-ID: <20200810093630-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <14fd2bf1-e9c1-a192-bd6c-f1ee5fd227f6@redhat.com>

On Wed, Aug 05, 2020 at 10:16:16AM +0800, Jason Wang wrote:
> 
> On 2020/8/4 下午5:21, Michael S. Tsirkin wrote:
> > > > > >    +struct vhost_vring_call {
> > > > > > +    struct eventfd_ctx *ctx;
> > > > > > +    struct irq_bypass_producer producer;
> > > > > > +    spinlock_t ctx_lock;
> > > > > It's not clear to me why we need ctx_lock here.
> > > > > 
> > > > > Thanks
> > > > Hi Jason,
> > > > 
> > > > we use this lock to protect the eventfd_ctx and irq from race conditions,
> > > We don't support irq notification from vDPA device driver in this version,
> > > do we still have race condition?
> > > 
> > > Thanks
> > Jason I'm not sure what you are trying to say here.
> 
> 
> I meant we change the API from V4 so driver won't notify us if irq is
> changed.
> 
> Then it looks to me there's no need for the ctx_lock, everyhing could be
> synchronized with vq mutex.
> 
> Thanks

Jason do you want to post a cleanup patch simplifying code along these
lines?

Thanks,


> > 
> > 


  parent reply	other threads:[~2020-08-10 13:37 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31  6:55 [PATCH V5 0/6] IRQ offloading for vDPA Zhu Lingshan
2020-07-31  6:55 ` [PATCH V5 1/6] vhost: introduce vhost_vring_call Zhu Lingshan
2020-08-04  8:38   ` Jason Wang
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  8:53         ` Jason Wang
2020-08-04  9:21         ` Michael S. Tsirkin
2020-08-04  9:21           ` Michael S. Tsirkin
2020-08-05  2:16           ` Jason Wang
2020-08-05  2:16             ` Jason Wang
     [not found]             ` <bf10cde9-db86-a1ac-e2a8-363735e49afb@intel.com>
2020-08-05  5:53               ` Jason Wang
2020-08-05  5:53                 ` Jason Wang
2020-08-10 13:37             ` Michael S. Tsirkin [this message]
2020-08-10 13:37               ` Michael S. Tsirkin
2020-08-11  2:53               ` Jason Wang
2020-08-11  2:53                 ` Jason Wang
     [not found]         ` <4605de34-c426-33d4-714b-e03716d0374c@intel.com>
2020-08-05  2:20           ` Jason Wang
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
2020-08-04  8:51     ` Jason Wang
     [not found]     ` <ae5385dc-6637-c5a3-b00a-02f66bb9a85f@intel.com>
2020-08-04  9:36       ` Michael S. Tsirkin
2020-08-04  9:36         ` Michael S. Tsirkin
2020-08-05  2:36       ` Jason Wang
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  5:51             ` Jason Wang
2020-08-05  8:06   ` 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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