[libvirt] [PATCH 0/5 v3] Interface pools and passthrough mode

[Daniel P. Berrange]

On Wed, Dec 14, 2011 at 10:47:23AM +0000, Shradha Shah wrote:
> Interface Pools and Passthrough mode:
> 
> Current Method:
> The passthrough mode uses a macvtap direct connection to connect each
> guest to the network. The physical interface to be used is picked from
> among those listed in <interface> sub elements of the <forward> element.
> 
> The current specification for <forward> extends to allow 0 or more
> <interface> sub-elements:
> Example:
> <forward mode='passthrough' dev='eth10'/>
> <interface dev='eth10'/>
> <interface dev='eth12'/>
> <interface dev='eth18'/>
> <interface dev='eth20'/>
> </forward>
> 
> However with an ethernet card with 64 VF's or more, the above method
> gets tedious on the system.
> 
> On the other hand, just parameterizing a string (eth%d) is inadequate,
> eg, when there are multiple non-contiguous ranges.
> 
> Proposed Method:
> The 4 patches provided:
> 
> i) Introduce a new element 'pf' to implicitly create an interface pool
> of all the Virtual Functions attached to the specified Physical
> Function.  
> ii) Modify the networkAllocateActualDevice, networkNotifyActualDevice
> and networkReleaseActualDevice API to use the above mentioned interface
> pool in the passthrough mode.
> iii) Allow virsh net-dumpxml to use an option --inactive to
> differentiate between explicit and implicit interface pools
> 
> Hence Libvirt will now support both the methods mentioned below:
> 
> * Explicit interface list. App inputs:
> 
>     <forward mode='passthrough'>
>      <interface dev='eth10'/>
>      <interface dev='eth11'/>
>      <interface dev='eth12'/>
>      <interface dev='eth13'/>
>     </forward>
> 
>    libvirt does not change XML
> 
> * Automatically interface list from PF. App inputs:
> 
>      <forward mode='passthrough'>
>       <pf dev='eth0'/>
>      </forward>
> 
>    libvirt expands XML to be
> 
>     <forward mode='passthrough'>
>       <pf dev='eth0'/>
>       <interface dev='eth10'/>
>       <interface dev='eth11'/>
>       <interface dev='eth12'/>
>       <interface dev='eth13'/>
>      </forward>
> 
> In the above case we need to differentiate between the implicit and
> explicit interface pool, which can be done by comparing the dumpxml from
> active and inactive domains. 
> This will need the addition of the flag VIR_NETWORK_XML_INACTIVE to
> virNetworkGetXMLDesc().
> 
> This patch series supports the use of option --inactive with virsh
> net-dumpxml.


The design and code all looks good to me. Just some fairly minor
code & style bugs to deal with, which I've replied to inline.

Regards,
Daniel
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