[libvirt] [PATCHv3 1/2] qemu: support vhost in attach-interface

[Laine Stump]

On 03/09/2011 03:42 PM, Eric Blake wrote:
> * src/qemu/qemu_hotplug.c (qemuDomainAttachNetDevice): Honor vhost
> designations, similar to qemu_command code paths.
> * src/qemu/qemu_command.h (qemuOpenVhostNet): New prototype.
> * src/qemu/qemu_command.c (qemuOpenVhostNet): Export.
> ---
>
> Hmm, I just realized that it might be nice to have a --driver-name
> flag in the virsh attach-interface wrapper command.  Oh well, that can
> be a separate patch.
>
>   src/qemu/qemu_command.c |    3 +-
>   src/qemu/qemu_command.h |    4 +++
>   src/qemu/qemu_hotplug.c |   54 ++++++++++++++++++++++++++++++++++++++++++----
>   3 files changed, 54 insertions(+), 7 deletions(-)
>
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index 198a4e2..8cf1737 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -303,12 +303,11 @@ cleanup:
>   }
>
>
> -static int
> +int
>   qemuOpenVhostNet(virDomainNetDefPtr net,
>                    virBitmapPtr qemuCaps,
>                    int *vhostfd)
>   {
> -
>       *vhostfd = -1;   /* assume we won't use vhost */
>
>       /* If the config says explicitly to not use vhost, return now */
> diff --git a/src/qemu/qemu_command.h b/src/qemu/qemu_command.h
> index 1902472..2ae364c 100644
> --- a/src/qemu/qemu_command.h
> +++ b/src/qemu/qemu_command.h
> @@ -129,6 +129,10 @@ int qemuPhysIfaceConnect(virConnectPtr conn,
>                            const unsigned char *vmuuid,
>                            enum virVMOperationType vmop);
>
> +int qemuOpenVhostNet(virDomainNetDefPtr net,
> +                     virBitmapPtr qemuCaps,
> +                     int *vhostfd);
> +
>   int qemudCanonicalizeMachine(struct qemud_driver *driver,
>                                virDomainDefPtr def);
>
> diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
> index 7895062..e8567ad 100644
> --- a/src/qemu/qemu_hotplug.c
> +++ b/src/qemu/qemu_hotplug.c
> @@ -552,6 +552,8 @@ int qemuDomainAttachNetDevice(virConnectPtr conn,
>       qemuDomainObjPrivatePtr priv = vm->privateData;
>       char *tapfd_name = NULL;
>       int tapfd = -1;
> +    char *vhostfd_name = NULL;
> +    int vhostfd = -1;
>       char *nicstr = NULL;
>       char *netstr = NULL;
>       int ret = -1;
> @@ -592,6 +594,24 @@ int qemuDomainAttachNetDevice(virConnectPtr conn,
>               return -1;
>       }
>
> +    if (net->type == VIR_DOMAIN_NET_TYPE_NETWORK ||
> +        net->type == VIR_DOMAIN_NET_TYPE_BRIDGE ||
> +        net->type == VIR_DOMAIN_NET_TYPE_DIRECT) {
> +        /* Attempt to use vhost-net mode for these types of
> +           network device */
> +        if (qemuOpenVhostNet(net, qemuCaps,&vhostfd)<  0)
> +            goto cleanup;
> +
> +        if (vhostfd>= 0&&
> +            priv->monConfig->type != VIR_DOMAIN_CHR_TYPE_UNIX) {
> +            qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                            _("network device type '%s' cannot be attached: "
> +                            "qemu is not using a unix socket monitor"),
> +                            virDomainNetTypeToString(net->type));
> +            goto cleanup;
> +        }


The above check has already been handled by a combination of the checks 
in the if { } else if { } block above, so it's superfluous here.

ACK with this extra check for monConfig-type removed.