[libvirt] [PATCH v4 11/11] qemu: Add swtpm to emulator cgroup

[Stefan Berger]

On 05/15/2018 11:34 AM, Daniel P. Berrangé wrote:
> On Tue, May 15, 2018 at 11:25:58AM -0400, Stefan Berger wrote:
>> On 05/10/2018 05:57 PM, Stefan Berger wrote:
>>> Add the external swtpm to the emulator cgroup so that upper limits of CPU
>>> usage can be enforced on the emulated TPM.
>> I haven't made any changes to this yet. A possibility would be to put swtpm
>> into its own tpm-emulator cgroup and extend the XML for the TPM to also have
>> 'period' and 'quota':
>>
>>      <tpm model='tpm-tis'>
>>        <backend type='emulator'>
>>          <period>1000</period>
>>          <quota>500</quota>
>>        </backend>
>>      </tpm>
>>
>> Or we add the following to cputune:
>>
>>          <tpm_emulator_period>1000</tpm_emulator_period>
>>          <tpm_emulator_quota>500</tpm_emulator_quota>
>>
>> The latter would be more consistent, though i would prefer the former.
> I'm not really seeing a compelling reason to need to set tunables on
> the swtpm directly. IMHO we should just consider it part of the
> "emulator" tunables - the fact that it is a separate binary/process
> rather than inside QEMU is just a private impl detail.

One reason I could think of is to approximate the real world a little 
closer where a TPM is typically its own chip.

     Stefan