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Re: [Qemu-devel] [PATCH v6 2/2] vhost-user: new protocol feature for mul
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v6 2/2] vhost-user: new protocol feature for multi queue |
Date: |
Tue, 1 Sep 2015 13:09:15 +0300 |
On Tue, Sep 01, 2015 at 05:16:31PM +0800, Yuanhan Liu wrote:
> On Thu, Aug 13, 2015 at 12:22:50PM +0300, Michael S. Tsirkin wrote:
> > On Wed, Aug 12, 2015 at 02:25:42PM +0800, Ouyang Changchun wrote:
> > > This patch is based on top of "vhost-user: protocol updates" series
> > > proposed earlier by Michael S. Tsirkin.
> > >
> > > Use new message VHOST_USER_SET_VRING_FLAG to enable and disable an
> > > actual virt queue, which is similar to attach/detach queue for tap device.
> > > virtio driver on guest doesn't have to use max virt queue pair, it could
> > > enable any number of virt queue ranging from 1 to max virt queue pair.
> > >
> > > It requires that VHOST_USER_F_PROTOCOL_FEATURES is present.
> > >
> > > Signed-off-by: Changchun Ouyang <address@hidden>
> > > ---
> > > This is added since v5
> > >
> > > docs/specs/vhost-user.txt | 17 +++++++++++++++++
> > > hw/net/vhost_net.c | 18 ++++++++++++++++++
> > > hw/net/virtio-net.c | 2 ++
> > > hw/virtio/vhost-user.c | 35
> > > +++++++++++++++++++++++++++++++++--
> > > include/hw/virtio/vhost-backend.h | 2 ++
> > > include/net/vhost_net.h | 1 +
> > > 6 files changed, 73 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> > > index 9390f89..cca3e5b 100644
> > > --- a/docs/specs/vhost-user.txt
> > > +++ b/docs/specs/vhost-user.txt
> > > @@ -135,6 +135,10 @@ As older slaves don't support negotiating protocol
> > > features,
> > > a feature bit was dedicated for this purpose:
> > > #define VHOST_USER_F_PROTOCOL_FEATURES 30
> > >
> > > +The Slave uses vring flag to notify the vhost-user whether one virtq is
> > > enabled
> > > +or not. This request doesn't require replies:
> > > +#define VHOST_USER_PROTOCOL_F_VRING_FLAG 2
> > > +
> > > Multi queue support
> > > -------------------
> > > The protocol supports multiple queues by setting all index fields in the
> > > sent
> > > @@ -306,3 +310,16 @@ Message types
> > > Bits (0-7) of the payload contain the vring index. Bit 8 is the
> > > invalid FD flag. This flag is set when there is no file descriptor
> > > in the ancillary data.
> > > +
> > > + * VHOST_USER_SET_VRING_FLAG
> > > +
> > > + Id: 18
> > > + Equivalent ioctl: N/A
> > > + Master payload: vring state description
> > > +
> > > + Set the flag(enable or disable) in the vring, the vhost user
> > > backend
> > > + enable or disable the vring according to state.num. Olny legal if
> > > feature
> > > + bit VHOST_USER_F_PROTOCOL_FEATURES is present in
> > > VHOST_USER_GET_FEATURE
> > > + and feature bit VHOST_USER_PROTOCOL_F_VRING_FLAG is present in
> > > + VHOST_USER_GET_PROTOCOL_FEATURES. The vring is enabled when
> > > state.num is
> > > + 1, otherwise, the vring is disabled.
> > > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> > > index 9cd6c05..5fa341c 100644
> > > --- a/hw/net/vhost_net.c
> > > +++ b/hw/net/vhost_net.c
> > > @@ -405,6 +405,19 @@ VHostNetState *get_vhost_net(NetClientState *nc)
> > >
> > > return vhost_net;
> > > }
> > > +
> > > +int vhost_set_vring_flag(NetClientState *nc, unsigned int enable)
> > > +{
> > > + if (nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER) {
> > > + struct vhost_net *net = get_vhost_net(nc);
> > > + const VhostOps *vhost_ops = net->dev.vhost_ops;
> > > + if (vhost_ops->vhost_backend_mq_set_vring_flag)
> > > + return vhost_ops->vhost_backend_mq_set_vring_flag(&net->dev,
> > > enable);
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > #else
> > > struct vhost_net *vhost_net_init(VhostNetOptions *options)
> > > {
> > > @@ -455,4 +468,9 @@ VHostNetState *get_vhost_net(NetClientState *nc)
> > > {
> > > return 0;
> > > }
> > > +
> > > +int vhost_set_vring_flag(NetClientState *nc, unsigned int enable)
> > > +{
> > > + return 0;
> > > +}
> > > #endif
> > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > > index 3af6faf..272b77d 100644
> > > --- a/hw/net/virtio-net.c
> > > +++ b/hw/net/virtio-net.c
> > > @@ -396,6 +396,7 @@ static int peer_attach(VirtIONet *n, int index)
> > > }
> > >
> > > if (nc->peer->info->type != NET_CLIENT_OPTIONS_KIND_TAP) {
> > > + vhost_set_vring_flag(nc->peer, 1);
> > > return 0;
> > > }
> > >
> > > @@ -411,6 +412,7 @@ static int peer_detach(VirtIONet *n, int index)
> > > }
> > >
> > > if (nc->peer->info->type != NET_CLIENT_OPTIONS_KIND_TAP) {
> > > + vhost_set_vring_flag(nc->peer, 0);
> > > return 0;
> > > }
> > >
> > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> > > index fb11d4c..d806ce2 100644
> > > --- a/hw/virtio/vhost-user.c
> > > +++ b/hw/virtio/vhost-user.c
> > > @@ -25,7 +25,8 @@
> > >
> > > #define VHOST_MEMORY_MAX_NREGIONS 8
> > > #define VHOST_USER_F_PROTOCOL_FEATURES 30
> > > -#define VHOST_USER_PROTOCOL_FEATURE_MASK 0x0ULL
> > > +#define VHOST_USER_PROTOCOL_F_VRING_FLAG 2
> > > +#define VHOST_USER_PROTOCOL_FEATURE_MASK 0x7ULL
> > >
> > > typedef enum VhostUserRequest {
> > > VHOST_USER_NONE = 0,
> > > @@ -45,6 +46,7 @@ typedef enum VhostUserRequest {
> > > VHOST_USER_SET_VRING_ERR = 14,
> > > VHOST_USER_GET_PROTOCOL_FEATURES = 15,
> > > VHOST_USER_SET_PROTOCOL_FEATURES = 16,
> > > + VHOST_USER_SET_VRING_FLAG = 18,
> > > VHOST_USER_MAX
> > > } VhostUserRequest;
> > >
> > > @@ -399,6 +401,34 @@ static int vhost_user_init(struct vhost_dev *dev,
> > > void *opaque)
> > > return 0;
> > > }
> > >
> > > +static int vhost_user_set_vring_flag(struct vhost_dev *dev, unsigned int
> > > enable)
> > > +{
> > > + VhostUserMsg msg = { 0 };
> > > + int err;
> > > +
> > > + assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
> > > +
> > > + if ((dev->backend_features & ( 1ULL <<
> > > VHOST_USER_F_PROTOCOL_FEATURES)) == 0)
> > > + return -1;
> > > +
> > > + if ((dev->protocol_features & (1ULL <<
> > > VHOST_USER_PROTOCOL_F_VRING_FLAG)) == 0)
> > > + return -1;
> > > +
> > > + msg.request = VHOST_USER_SET_VRING_FLAG;
> > > + msg.flags = VHOST_USER_VERSION;
> > > + /* Set the virt queue pair index */
> > > + msg.state.index = dev->vq_index / 2;
> >
> > Thinking about this, this means that the index value is specific to virtio
> > net.
> > This seems wrong.
>
> How about adding a new field queue_index to vhost_dev structure? So that
> we could get rid of it.
>
> --yliu
don't we have it already?
/* the first virtqueue which would be used by this vhost dev */
int vq_index;
> >
> > > + msg.state.num = enable;
> > > + msg.size = sizeof msg.state;
> > > +
> > > + err = vhost_user_write(dev, &msg, NULL, 0);
> > > + if (err < 0) {
> > > + return err;
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > static int vhost_user_cleanup(struct vhost_dev *dev)
> > > {
> > > assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
> > > @@ -412,5 +442,6 @@ const VhostOps user_ops = {
> > > .backend_type = VHOST_BACKEND_TYPE_USER,
> > > .vhost_call = vhost_user_call,
> > > .vhost_backend_init = vhost_user_init,
> > > - .vhost_backend_cleanup = vhost_user_cleanup
> > > + .vhost_backend_cleanup = vhost_user_cleanup,
> > > + .vhost_backend_mq_set_vring_flag = vhost_user_set_vring_flag,
> > > };
> > > diff --git a/include/hw/virtio/vhost-backend.h
> > > b/include/hw/virtio/vhost-backend.h
> > > index e472f29..c394147 100644
> > > --- a/include/hw/virtio/vhost-backend.h
> > > +++ b/include/hw/virtio/vhost-backend.h
> > > @@ -24,12 +24,14 @@ typedef int (*vhost_call)(struct vhost_dev *dev,
> > > unsigned long int request,
> > > void *arg);
> > > typedef int (*vhost_backend_init)(struct vhost_dev *dev, void *opaque);
> > > typedef int (*vhost_backend_cleanup)(struct vhost_dev *dev);
> > > +typedef int (*vhost_backend_mq_set_vring_flag)(struct vhost_dev *dev,
> > > unsigned int enable);
> > >
> > > typedef struct VhostOps {
> > > VhostBackendType backend_type;
> > > vhost_call vhost_call;
> > > vhost_backend_init vhost_backend_init;
> > > vhost_backend_cleanup vhost_backend_cleanup;
> > > + vhost_backend_mq_set_vring_flag vhost_backend_mq_set_vring_flag;
> > > } VhostOps;
> > >
> > > extern const VhostOps user_ops;
> > > diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
> > > index b1c18a3..9b76548 100644
> > > --- a/include/net/vhost_net.h
> > > +++ b/include/net/vhost_net.h
> > > @@ -29,4 +29,5 @@ bool vhost_net_virtqueue_pending(VHostNetState *net,
> > > int n);
> > > void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
> > > int idx, bool mask);
> > > VHostNetState *get_vhost_net(NetClientState *nc);
> > > +int vhost_set_vring_flag(NetClientState * nc, unsigned int enable);
> > > #endif
> > > --
> > > 1.8.4.2
> > >