Re: [libvirt] [PATCH] dosc: schema: fix usb source address device attribute format
On 1/26/19 9:16 AM, John Ferlan wrote:
On 1/21/19 3:57 AM, Nikolay Shirokovskiy wrote:
> Device attribute does not have dotted "portAddr" format. Instead it
> has single number format described but "usbAddr" which corresponds
> to device parsing code in virDomainHostdevSubsysUSBDefParseXML.
>
> Looks like [1] mistakenly changed device format for hostdev devices.
> And [2] copy-n-paste this for hostdev network interfaces.
>
> [1] 31710a53 Modify USB port to be defined as a port path
> [2] 3b1c191f conf: parse/format type='hostdev' network interfaces
>
> Signed-off-by: Nikolay Shirokovskiy <nshirokovskiy(a)virtuozzo.com>
> ---
> docs/schemas/domaincommon.rng | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
This a really strange/involved one, but seemingly correct. It also seems
that an <interface type='hostdev'... <source ... where the source is USB
couldn't or doesn't use the startupPolicy that would be present in a
normal <hostdev mode='subsystem' type='usb'...>...
The parser and formatter will parse and format an <interface
type='hostdev'> where the source device is USB, but that isn't supported
by any hypervisor (it would require a standard method of setting the MAC
address of the USB netdev before giving it to the guest, and AFAIK that
doesn't exist). In the original commit I mention that it's allowed by
the parser only for completeness' sake.
Anyway, I'm certainly not the expert there - something Laine
would
perhaps be better suited for, but certainly missing from the interface
RNG, but is processed in virDomainHostdevDefParseXMLSubsys. It also
seems to be a hostdevsubsyspci property as well.
What I was looking for was a way for the <interface...> RNG to perhaps
make use of the hostdevsubsyspci and hostdevsubsysusb, but some of what
goes on in RNG rules is like black magic voodoo ;-)...
In the hypothetical/mythical future where such a thing exists and
support is added, the RNG would presumably be changed. For now it
doesn't exist, so the RNG is fine as-is.