[libvirt] [PATCH 7/9] qemu: support unmanaged macvtap devices with <interface type='ethernet'>

[Daniel P. Berrangé]

On Tue, Aug 27, 2019 at 09:46:37PM -0400, Laine Stump wrote:
> Traditionally, macvtap devices are supported using <interface
> type='direct'>, but that type requires specifying a source device name
> and macvtap mode which can't be altered after the initial device
> creation (and may not even be available to the management software
> that's creating the XML config to feed to libvirt).
> 
> But the attributes in the <source> are essentially describing how the
> device will be connected to the network, and if libvirt is to be
> supplied with the name of a macvtap device that has already been
> created, that device will also already be connected to the network
> (and the connection can't be changed). Thus it seems more appropriate
> to use type='ethernet', which was created explicitly for this purpose
> - for devices that have already been (or will be) connected to the
> external network by someone/something outside of libvirt. The fact
> that it is a *macv*tap rather than a contentional tap device is just a
> detail.
> 
> This patch supports using an existing macvtap device with <interface
> type='ethernet'> by checking the supplied target dev name to see if it
> is a macvtap device and, when this is the case, calling
> virNetDevMacVLanTapOpen() instead of virNetDevTapCreate(). For
> consistency, this is only done when target managed='no'.
> 
> Resolves: https://bugzilla.redhat.com/1723367 (partially)
> Signed-off-by: Laine Stump <laine at redhat.com>
> ---
>  src/qemu/qemu_interface.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)

Reviewed-by: Daniel P. Berrangé <berrange at redhat.com>


Regards,
Daniel
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