[libvirt] [PATCH v3 4/5] qemu: Use predictable file names for memory-backend-file

[Michal Privoznik]

On 11/07/2017 04:57 PM, Daniel P. Berrange wrote:
> On Tue, Nov 07, 2017 at 04:51:03PM +0100, Michal Privoznik wrote:
>> In some cases management application needs to allocate memory for
>> qemu upfront and then just let qemu use that. Since we don't want
>> to expose path for memory-backend-file anywhere in the domain
>> XML, we can generate predictable paths. In this case:
>>
>>   $memoryBackingDir/libvirt/qemu/$shortName/$alias
>>
>> where $shortName is result of virDomainObjGetShortName().
>>
> 
>> diff --git a/tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args b/tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args
>> index 5700c3413..352819429 100644
>> --- a/tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args
>> +++ b/tests/qemuxml2argvdata/qemuxml2argv-cpu-numa-memshared.args
>> @@ -10,10 +10,12 @@ QEMU_AUDIO_DRV=none \
>>  -M pc \
>>  -m 214 \
>>  -smp 16,sockets=2,cores=4,threads=2 \
>> --object memory-backend-file,id=ram-node0,mem-path=/var/lib/libvirt/qemu/ram,\
>> +-object memory-backend-file,id=ram-node0,\
>> +mem-path=/var/lib/libvirt/qemu/ram/libvirt/qemu/-1-QEMUGuest1/ram-node0,\
> 
> Heh, we're getting '-1' in all the paths here. Presumably this is because in
> the test suite we've not bothered to set the 'id' field to any value.
> 
> I can't help thinking that virDomainObjGetShortName ought to return a fatal
> error if 'id' is still -1, as in non-test suite code, this would be indication
> of a significant screw up by someone trying to create names before the VM config
> is updated to reflect running state.  This would of course mean our tests
> should set 'id' to a sensible value too.
> 
> No need to fix for this patch though - just a curiosity to look at a later
> date

Yeah well,

libvirt.git $ git grep "domain.*-1" tests/ | grep args | wc -l
603

I strongly vote for fixing it up separately then.

Michal