From: Yongji Xie <xieyongji@bytedance.com>
To: Bob Liu <bob.liu@oracle.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
sgarzare@redhat.com, Parav Pandit <parav@nvidia.com>,
akpm@linux-foundation.org, Randy Dunlap <rdunlap@infradead.org>,
Matthew Wilcox <willy@infradead.org>,
viro@zeniv.linux.org.uk, axboe@kernel.dk, bcrl@kvack.org,
corbet@lwn.net, virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, kvm@vger.kernel.org, linux-aio@kvack.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: Re: [RFC v2 06/13] vduse: Introduce VDUSE - vDPA Device in Userspace
Date: Sun, 10 Jan 2021 18:03:52 +0800 [thread overview]
Message-ID: <CACycT3u859hX5ChcxVS2EMmF4-vu5H+io_CcNWSKaN8NFA9cXg@mail.gmail.com> (raw)
In-Reply-To: <f8dcb8d0-0024-1f78-d1a7-e487ca3deda7@oracle.com>
On Fri, Jan 8, 2021 at 9:32 PM Bob Liu <bob.liu@oracle.com> wrote:
>
> On 12/22/20 10:52 PM, Xie Yongji wrote:
> > This VDUSE driver enables implementing vDPA devices in userspace.
> > Both control path and data path of vDPA devices will be able to
> > be handled in userspace.
> >
> > In the control path, the VDUSE driver will make use of message
> > mechnism to forward the config operation from vdpa bus driver
> > to userspace. Userspace can use read()/write() to receive/reply
> > those control messages.
> >
> > In the data path, the VDUSE driver implements a MMU-based on-chip
> > IOMMU driver which supports mapping the kernel dma buffer to a
> > userspace iova region dynamically. Userspace can access those
> > iova region via mmap(). Besides, the eventfd mechanism is used to
> > trigger interrupt callbacks and receive virtqueue kicks in userspace
> >
> > Now we only support virtio-vdpa bus driver with this patch applied.
> >
> > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > ---
> > Documentation/driver-api/vduse.rst | 74 ++
> > Documentation/userspace-api/ioctl/ioctl-number.rst | 1 +
> > drivers/vdpa/Kconfig | 8 +
> > drivers/vdpa/Makefile | 1 +
> > drivers/vdpa/vdpa_user/Makefile | 5 +
> > drivers/vdpa/vdpa_user/eventfd.c | 221 ++++
> > drivers/vdpa/vdpa_user/eventfd.h | 48 +
> > drivers/vdpa/vdpa_user/iova_domain.c | 442 ++++++++
> > drivers/vdpa/vdpa_user/iova_domain.h | 93 ++
> > drivers/vdpa/vdpa_user/vduse.h | 59 ++
> > drivers/vdpa/vdpa_user/vduse_dev.c | 1121 ++++++++++++++++++++
> > include/uapi/linux/vdpa.h | 1 +
> > include/uapi/linux/vduse.h | 99 ++
> > 13 files changed, 2173 insertions(+)
> > create mode 100644 Documentation/driver-api/vduse.rst
> > create mode 100644 drivers/vdpa/vdpa_user/Makefile
> > create mode 100644 drivers/vdpa/vdpa_user/eventfd.c
> > create mode 100644 drivers/vdpa/vdpa_user/eventfd.h
> > create mode 100644 drivers/vdpa/vdpa_user/iova_domain.c
> > create mode 100644 drivers/vdpa/vdpa_user/iova_domain.h
> > create mode 100644 drivers/vdpa/vdpa_user/vduse.h
> > create mode 100644 drivers/vdpa/vdpa_user/vduse_dev.c
> > create mode 100644 include/uapi/linux/vduse.h
> >
> > diff --git a/Documentation/driver-api/vduse.rst b/Documentation/driver-api/vduse.rst
> > new file mode 100644
> > index 000000000000..da9b3040f20a
> > --- /dev/null
> > +++ b/Documentation/driver-api/vduse.rst
> > @@ -0,0 +1,74 @@
> > +==================================
> > +VDUSE - "vDPA Device in Userspace"
> > +==================================
> > +
> > +vDPA (virtio data path acceleration) device is a device that uses a
> > +datapath which complies with the virtio specifications with vendor
> > +specific control path. vDPA devices can be both physically located on
> > +the hardware or emulated by software. VDUSE is a framework that makes it
> > +possible to implement software-emulated vDPA devices in userspace.
> > +
>
> Could you explain a bit more why need a VDUSE framework?
This can be used to implement a userspace I/O (such as storage,
network and so on) solution (virtio-based) for both container and VM.
> Software emulated vDPA devices is more likely used by debugging only when
> don't have real hardware.
I think software emulated vDPA devices should be also useful in other
cases, just like FUSE does.
> Do you think do the emulation in kernel space is not enough?
>
Doing the emulation in userspace should be more flexible.
Thanks,
Yongji
next prev parent reply other threads:[~2021-01-10 10:05 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-22 14:52 [RFC v2 00/13] Introduce VDUSE - vDPA Device in Userspace Xie Yongji
2020-12-22 14:52 ` [RFC v2 01/13] mm: export zap_page_range() for driver use Xie Yongji
2020-12-22 15:44 ` Christoph Hellwig
2020-12-22 14:52 ` [RFC v2 02/13] eventfd: track eventfd_signal() recursion depth separately in different cases Xie Yongji
2020-12-22 14:52 ` [RFC v2 03/13] eventfd: Increase the recursion depth of eventfd_signal() Xie Yongji
2020-12-22 14:52 ` [RFC v2 04/13] vdpa: Remove the restriction that only supports virtio-net devices Xie Yongji
2020-12-22 14:52 ` [RFC v2 05/13] vdpa: Pass the netlink attributes to ops.dev_add() Xie Yongji
2020-12-22 14:52 ` [RFC v2 06/13] vduse: Introduce VDUSE - vDPA Device in Userspace Xie Yongji
2020-12-23 8:08 ` Jason Wang
2020-12-23 14:17 ` Yongji Xie
2020-12-24 3:01 ` Jason Wang
2020-12-24 8:34 ` Yongji Xie
2020-12-25 6:59 ` Jason Wang
2021-01-08 13:32 ` Bob Liu
2021-01-10 10:03 ` Yongji Xie [this message]
2020-12-22 14:52 ` [RFC v2 07/13] vduse: support get/set virtqueue state Xie Yongji
2020-12-22 14:52 ` [RFC v2 08/13] vdpa: Introduce process_iotlb_msg() in vdpa_config_ops Xie Yongji
2020-12-23 8:36 ` Jason Wang
2020-12-23 11:06 ` Yongji Xie
2020-12-24 2:36 ` Jason Wang
2020-12-24 7:24 ` Yongji Xie
2020-12-22 14:52 ` [RFC v2 09/13] vduse: Add support for processing vhost iotlb message Xie Yongji
2020-12-23 9:05 ` Jason Wang
2020-12-23 12:14 ` [External] " Yongji Xie
2020-12-24 2:41 ` Jason Wang
2020-12-24 7:37 ` Yongji Xie
2020-12-25 2:37 ` Yongji Xie
2020-12-25 7:02 ` Jason Wang
2020-12-25 11:36 ` Yongji Xie
2020-12-25 6:57 ` Jason Wang
2020-12-25 10:31 ` Yongji Xie
2020-12-28 7:43 ` Jason Wang
2020-12-28 8:14 ` Yongji Xie
2020-12-28 8:43 ` Jason Wang
2020-12-28 9:12 ` Yongji Xie
2020-12-29 9:11 ` Jason Wang
2020-12-29 10:26 ` Yongji Xie
2020-12-30 6:10 ` Jason Wang
2020-12-30 7:09 ` Yongji Xie
2020-12-30 8:41 ` Jason Wang
2020-12-30 10:12 ` Yongji Xie
2020-12-31 2:49 ` Jason Wang
2020-12-31 5:15 ` Yongji Xie
2020-12-31 5:49 ` Jason Wang
2020-12-31 6:52 ` Yongji Xie
2020-12-31 7:11 ` Jason Wang
2020-12-31 8:00 ` Yongji Xie
2020-12-22 14:52 ` [RFC v2 10/13] vduse: grab the module's references until there is no vduse device Xie Yongji
2020-12-22 14:52 ` [RFC v2 11/13] vduse/iova_domain: Support reclaiming bounce pages Xie Yongji
2020-12-22 14:52 ` [RFC v2 12/13] vduse: Add memory shrinker to reclaim " Xie Yongji
2020-12-22 14:52 ` [RFC v2 13/13] vduse: Introduce a workqueue for irq injection Xie Yongji
2020-12-23 6:38 ` [RFC v2 00/13] Introduce VDUSE - vDPA Device in Userspace Jason Wang
2020-12-23 8:14 ` Jason Wang
2020-12-23 10:59 ` Yongji Xie
2020-12-24 2:24 ` Jason Wang
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