What were you trying to do that didn't work?

When migrate a VM with encrypted vtpm to a target host with different secret value, the error message does not show exact error.

Request from RHEL-7041. 

What is the impact of this issue to you?

Please provide the package NVR for which the bug is seen:

qemu-kvm-9.1.0-15.el10.x86_64

libvirt-11.1.0-1.el10.x86_64:
swtpm-0.9.0-5.el10.x86_64
libtpms-0.9.6-10.el10.x86_64
kernel-6.12.0-55.el10.x86_64

How reproducible is this bug?:

100%

Steps to reproduce

1. Create vtpm secret with same uuid but different values on both hosts.

refer to https://libvirt.org/formatsecret.html#usage-type-vtpm

2. Start guest with encrypted vtpm on source host.
<tpm model='tpm-crb'>
<backend type='emulator' version='2.0'>
<encryption secret='1498c26a-fead-4b2f-8071-94f2aa6ca0c0'/>
</backend>
<alias name='tpm0'/>
</tpm>

3. Migrate guest to target host.

Even with the new qemu feature:
# grep exit-on-error  /var/cache/libvirt/qemu/capabilities/ -Rin
/var/cache/libvirt/qemu/capabilities/3c76bc41d59c0c7314b1ae8e63f4f765d2cf16abaeea081b3ca1f5d8732f7bb1.xml:174:  <flag name='migrate-incoming.exit-on-error'/>

Error msg is still not as expected:
# virsh migrate rhel10-0 qemu+ssh://target_host/system --live --verboseMigration: [100.00 %]error: operation failed: migration failed. Message from the source host: operation failed: job 'migration out' failed: Sibling indicated error 1. Message from the destination host: operation failed: job 'migration in' failed: load of migration failed: Input/output error

In target virtqemud log, qemu-kvm apparently knows the exact error: "TPM error 0x21 decryption error".

2025-03-05T03:46:45.040350Z qemu-kvm: error while loading state for instance 0x0 of device 'tpm-emulator'
2025-03-05T03:46:45.043988Z qemu-kvm: load of migration failed: Input/output error
2025-03-05 03:46:45.044+0000: 42291: debug : qemuMonitorIO:517 : Error on monitor internal error: QEMU unexpectedly closed the monitor (vm='rhel10-0'): 2025-03-05T03:46:45.040299Z qemu-kvm: tpm-emulator: Setting the stateblob (type 1) failed with a TPM error 0x21 decryption error
2025-03-05T03:46:45.040350Z qemu-kvm: error while loading state for instance 0x0 of device 'tpm-emulator'
2025-03-05T03:46:45.043988Z qemu-kvm: load of migration failed: Input/output error mon=0x7f8a5402c430 vm=0x7f8a5400af70 name=rhel10-0

Expected results

Following exact error should also be propagated:

0'): 2025-03-05T03:46:45.040299Z qemu-kvm: tpm-emulator: Setting the stateblob (type 1) failed with a TPM error 0x21 decryption error 2025-03-05T03:46:45.040350Z qemu-kvm: error while loading state for instance 0x0 of device 'tpm-emulator'

Actual results