KVM Archive on lore.kernel.org
 help / color / Atom feed
From: Jason Wang <jasowang@redhat.com>
To: "Zhu, Lingshan" <lingshan.zhu@intel.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
Subject: Re: [PATCH V5 1/6] vhost: introduce vhost_vring_call
Date: Tue, 4 Aug 2020 16:53:39 +0800
Message-ID: <156b8d71-6870-c163-fdfa-35bf4701987d@redhat.com> (raw)
In-Reply-To: <d51dd4e3-7513-c771-104c-b61f9ee70f30@intel.com>


On 2020/8/4 下午4:42, Zhu, Lingshan wrote:
>
>
> On 8/4/2020 4:38 PM, Jason Wang wrote:
>>
>> On 2020/7/31 下午2:55, Zhu Lingshan wrote:
>>> This commit introduces struct vhost_vring_call which replaced
>>> raw struct eventfd_ctx *call_ctx in struct vhost_virtqueue.
>>> Besides eventfd_ctx, it contains a spin lock and an
>>> irq_bypass_producer in its structure.
>>>
>>> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
>>> Suggested-by: Jason Wang <jasowang@redhat.com>
>>> ---
>>>   drivers/vhost/vdpa.c  |  4 ++--
>>>   drivers/vhost/vhost.c | 22 ++++++++++++++++------
>>>   drivers/vhost/vhost.h |  9 ++++++++-
>>>   3 files changed, 26 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>>> index a54b60d6623f..df3cf386b0cd 100644
>>> --- a/drivers/vhost/vdpa.c
>>> +++ b/drivers/vhost/vdpa.c
>>> @@ -96,7 +96,7 @@ static void handle_vq_kick(struct vhost_work *work)
>>>   static irqreturn_t vhost_vdpa_virtqueue_cb(void *private)
>>>   {
>>>       struct vhost_virtqueue *vq = private;
>>> -    struct eventfd_ctx *call_ctx = vq->call_ctx;
>>> +    struct eventfd_ctx *call_ctx = vq->call_ctx.ctx;
>>>         if (call_ctx)
>>>           eventfd_signal(call_ctx, 1);
>>> @@ -382,7 +382,7 @@ static long vhost_vdpa_vring_ioctl(struct 
>>> vhost_vdpa *v, unsigned int cmd,
>>>           break;
>>>         case VHOST_SET_VRING_CALL:
>>> -        if (vq->call_ctx) {
>>> +        if (vq->call_ctx.ctx) {
>>>               cb.callback = vhost_vdpa_virtqueue_cb;
>>>               cb.private = vq;
>>>           } else {
>>> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
>>> index d7b8df3edffc..9f1a845a9302 100644
>>> --- a/drivers/vhost/vhost.c
>>> +++ b/drivers/vhost/vhost.c
>>> @@ -298,6 +298,13 @@ static void vhost_vq_meta_reset(struct 
>>> vhost_dev *d)
>>>           __vhost_vq_meta_reset(d->vqs[i]);
>>>   }
>>>   +static void vhost_vring_call_reset(struct vhost_vring_call 
>>> *call_ctx)
>>> +{
>>> +    call_ctx->ctx = NULL;
>>> +    memset(&call_ctx->producer, 0x0, sizeof(struct 
>>> irq_bypass_producer));
>>> +    spin_lock_init(&call_ctx->ctx_lock);
>>> +}
>>> +
>>>   static void vhost_vq_reset(struct vhost_dev *dev,
>>>                  struct vhost_virtqueue *vq)
>>>   {
>>> @@ -319,13 +326,13 @@ static void vhost_vq_reset(struct vhost_dev *dev,
>>>       vq->log_base = NULL;
>>>       vq->error_ctx = NULL;
>>>       vq->kick = NULL;
>>> -    vq->call_ctx = NULL;
>>>       vq->log_ctx = NULL;
>>>       vhost_reset_is_le(vq);
>>>       vhost_disable_cross_endian(vq);
>>>       vq->busyloop_timeout = 0;
>>>       vq->umem = NULL;
>>>       vq->iotlb = NULL;
>>> +    vhost_vring_call_reset(&vq->call_ctx);
>>>       __vhost_vq_meta_reset(vq);
>>>   }
>>>   @@ -685,8 +692,8 @@ void vhost_dev_cleanup(struct vhost_dev *dev)
>>> eventfd_ctx_put(dev->vqs[i]->error_ctx);
>>>           if (dev->vqs[i]->kick)
>>>               fput(dev->vqs[i]->kick);
>>> -        if (dev->vqs[i]->call_ctx)
>>> - eventfd_ctx_put(dev->vqs[i]->call_ctx);
>>> +        if (dev->vqs[i]->call_ctx.ctx)
>>> + eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx);
>>>           vhost_vq_reset(dev, dev->vqs[i]);
>>>       }
>>>       vhost_dev_free_iovecs(dev);
>>> @@ -1629,7 +1636,10 @@ long vhost_vring_ioctl(struct vhost_dev *d, 
>>> unsigned int ioctl, void __user *arg
>>>               r = PTR_ERR(ctx);
>>>               break;
>>>           }
>>> -        swap(ctx, vq->call_ctx);
>>> +
>>> +        spin_lock(&vq->call_ctx.ctx_lock);
>>> +        swap(ctx, vq->call_ctx.ctx);
>>> +        spin_unlock(&vq->call_ctx.ctx_lock);
>>>           break;
>>>       case VHOST_SET_VRING_ERR:
>>>           if (copy_from_user(&f, argp, sizeof f)) {
>>> @@ -2440,8 +2450,8 @@ static bool vhost_notify(struct vhost_dev 
>>> *dev, struct vhost_virtqueue *vq)
>>>   void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
>>>   {
>>>       /* Signal the Guest tell them we used something up. */
>>> -    if (vq->call_ctx && vhost_notify(dev, vq))
>>> -        eventfd_signal(vq->call_ctx, 1);
>>> +    if (vq->call_ctx.ctx && vhost_notify(dev, vq))
>>> +        eventfd_signal(vq->call_ctx.ctx, 1);
>>>   }
>>>   EXPORT_SYMBOL_GPL(vhost_signal);
>>>   diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
>>> index c8e96a095d3b..38eb1aa3b68d 100644
>>> --- a/drivers/vhost/vhost.h
>>> +++ b/drivers/vhost/vhost.h
>>> @@ -13,6 +13,7 @@
>>>   #include <linux/virtio_ring.h>
>>>   #include <linux/atomic.h>
>>>   #include <linux/vhost_iotlb.h>
>>> +#include <linux/irqbypass.h>
>>>     struct vhost_work;
>>>   typedef void (*vhost_work_fn_t)(struct vhost_work *work);
>>> @@ -60,6 +61,12 @@ enum vhost_uaddr_type {
>>>       VHOST_NUM_ADDRS = 3,
>>>   };
>>>   +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


>   are you suggesting a better name?
>
> Thanks
>>
>>
>>> +};
>>> +
>>>   /* The virtqueue structure describes a queue attached to a device. */
>>>   struct vhost_virtqueue {
>>>       struct vhost_dev *dev;
>>> @@ -72,7 +79,7 @@ struct vhost_virtqueue {
>>>       vring_used_t __user *used;
>>>       const struct vhost_iotlb_map *meta_iotlb[VHOST_NUM_ADDRS];
>>>       struct file *kick;
>>> -    struct eventfd_ctx *call_ctx;
>>> +    struct vhost_vring_call call_ctx;
>>>       struct eventfd_ctx *error_ctx;
>>>       struct eventfd_ctx *log_ctx;
>>


  parent reply index

Thread overview: 21+ 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
     [not found]     ` <d51dd4e3-7513-c771-104c-b61f9ee70f30@intel.com>
2020-08-04  8:53       ` Jason Wang [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=156b8d71-6870-c163-fdfa-35bf4701987d@redhat.com \
    --to=jasowang@redhat.com \
    --cc=alex.williamson@redhat.com \
    --cc=eli@mellanox.com \
    --cc=kvm@vger.kernel.org \
    --cc=lingshan.zhu@intel.com \
    --cc=mst@redhat.com \
    --cc=netdev@vger.kernel.org \
    --cc=parav@mellanox.com \
    --cc=pbonzini@redhat.com \
    --cc=sean.j.christopherson@intel.com \
    --cc=shahafs@mellanox.com \
    --cc=virtualization@lists.linux-foundation.org \
    --cc=wanpengli@tencent.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

KVM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/kvm/0 kvm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 kvm kvm/ https://lore.kernel.org/kvm \
		kvm@vger.kernel.org
	public-inbox-index kvm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.kvm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git