Re: [PATCH 1/2] vhost-user: add VHOST_USER_RESET_DEVICE to reset devices

[Raphael Norwitz]

On Wed, Nov 06, 2019 at 06:36:01AM -0500, Michael S. Tsirkin wrote:
> 
> On Tue, Oct 29, 2019 at 05:38:02PM -0400, Raphael Norwitz wrote:
> > Add a VHOST_USER_RESET_DEVICE message which will reset the vhost user
> > backend. Disabling all rings, and resetting all internal state, ready
> > for the backend to be reinitialized.
> > 
> > A backend has to report it supports this features with the
> > VHOST_USER_PROTOCOL_F_RESET_DEVICE protocol feature bit. If it does
> > so, the new message is used instead of sending a RESET_OWNER which has
> > had inconsistent implementations.
> > 
> > Signed-off-by: David Vrabel <address@hidden>
> > Signed-off-by: Raphael Norwitz <address@hidden>

Ping on this. 

> 
> Looks ok, pls ping me after the release to apply this.
> > ---
> >  docs/interop/vhost-user.rst | 15 +++++++++++++++
> >  hw/virtio/vhost-user.c      |  8 +++++++-
> >  2 files changed, 22 insertions(+), 1 deletion(-)
> > 
> > diff --git a/docs/interop/vhost-user.rst b/docs/interop/vhost-user.rst
> > index 7827b71..d213d4a 100644
> > --- a/docs/interop/vhost-user.rst
> > +++ b/docs/interop/vhost-user.rst
> > @@ -785,6 +785,7 @@ Protocol features
> >    #define VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD  10
> >    #define VHOST_USER_PROTOCOL_F_HOST_NOTIFIER  11
> >    #define VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD 12
> > +  #define VHOST_USER_PROTOCOL_F_RESET_DEVICE   13
> >  
> >  Master message types
> >  --------------------
> > @@ -1190,6 +1191,20 @@ Master message types
> >    ancillary data. The GPU protocol is used to inform the master of
> >    rendering state and updates. See vhost-user-gpu.rst for details.
> >  
> > +``VHOST_USER_RESET_DEVICE``
> > +  :id: 34
> > +  :equivalent ioctl: N/A
> > +  :master payload: N/A
> > +  :slave payload: N/A
> > +
> > +  Ask the vhost user backend to disable all rings and reset all
> > +  internal device state to the initial state, ready to be
> > +  reinitialized. The backend retains ownership of the device
> > +  throughout the reset operation.
> > +
> > +  Only valid if the ``VHOST_USER_PROTOCOL_F_RESET_DEVICE`` protocol
> > +  feature is set by the backend.
> > +
> >  Slave message types
> >  -------------------
> >  
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > index 02a9b25..d27a10f 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -58,6 +58,7 @@ enum VhostUserProtocolFeature {
> >      VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD = 10,
> >      VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11,
> >      VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12,
> > +    VHOST_USER_PROTOCOL_F_RESET_DEVICE = 13,
> >      VHOST_USER_PROTOCOL_F_MAX
> >  };
> >  
> > @@ -98,6 +99,7 @@ typedef enum VhostUserRequest {
> >      VHOST_USER_GET_INFLIGHT_FD = 31,
> >      VHOST_USER_SET_INFLIGHT_FD = 32,
> >      VHOST_USER_GPU_SET_SOCKET = 33,
> > +    VHOST_USER_RESET_DEVICE = 34,
> >      VHOST_USER_MAX
> >  } VhostUserRequest;
> >  
> > @@ -890,10 +892,14 @@ static int vhost_user_set_owner(struct vhost_dev *dev)
> >  static int vhost_user_reset_device(struct vhost_dev *dev)
> >  {
> >      VhostUserMsg msg = {
> > -        .hdr.request = VHOST_USER_RESET_OWNER,
> >          .hdr.flags = VHOST_USER_VERSION,
> >      };
> >  
> > +    msg.hdr.request = virtio_has_feature(dev->protocol_features,
> > +                                         
> > VHOST_USER_PROTOCOL_F_RESET_DEVICE)
> > +        ? VHOST_USER_RESET_DEVICE
> > +        : VHOST_USER_RESET_OWNER;
> > +
> >      if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
> >          return -1;
> >      }
> > -- 
> > 1.8.3.1
> 
>