Emulated TPM devices and snapshots of running VMs

[Milan Zamazal]

Peter Krempa <pkrempa at redhat.com> writes:

> On Thu, Jul 09, 2020 at 14:14:32 +0200, Milan Zamazal wrote:
>> Milan Zamazal <mzamazal at redhat.com> writes:
>> 
>
>> > Hi,
>> >
>> > I would like to clarify how to make snapshots of running VMs with
>> > emulated TPM devices.  As far as I understand QEMU documentation, it's
>> > possible to make snapshots of running VMs with TPM, but it's important
>> > to retain the state of swtpm.  Does libvirt assist with that in any way
>> > or is it completely user's responsibility?  libvirt pauses the VM
>> > internally when making a snapshot, which should be the right moment to
>> > copy the swtpm data, but the user doesn't have control over it.  Is
>> > there a way to make a copy of swtpm data that is guaranteed to be
>> > consistent with the snapshot?
>> 
>> No idea?
>
> I can comment only on the fact that libvirt doesn't do anything
> regarding snapshots on a VM with TPM.

Thank you for the confirmation.

Can anybody confirm there is no way to perform custom actions while a VM
is frozen by libvirt when making a memory snapshot, before we start
thinking about workarounds and/or filing a RFE?

Thanks,
Milan