Currently, when a migration of a VM with an encrypted vTPM fails on the destination host (e.g., due to a mismatch in secret values), the error message displayed on the source host is generic and unhelpful.
For example, a typical error looks like this: "operation failed: job 'migration out' failed: Sibling indicated error 1. operation failed: job 'migration in' failed: load of migration failed: Input/output error" This message does not provide any specific indication of a vTPM failure. Such generic errors are logged using error_report(), which prints to the console/monitor but does not make the detailed error accessible via the QMP query-migrate command. This series addresses the issue, by ensuring that specific TPM error messages are propagated via the QEMU Error object. To make this possible, - A set of functions in the call stack is changed to incorporate an Error object as an additional parameter. - Also, the TPM backend makes use of a new hook called post_load_with_error() that explicitly passes an Error object. While this series focuses specifically on TPM error reporting during live migration, it lays the groundwork for broader improvements. Most methods in savevm.c that previously returned an integer now capture errors in the Error object, enabling other modules to adopt the post_load_with_error hook in the future. One such change previously attempted: https://lists.gnu.org/archive/html/qemu-devel/2021-02/msg01727.html The series does not necessarily have to be applied in 1 go. Each patch can be compiled and tested separately. Resolves: https://issues.redhat.com/browse/RHEL-82826 Signed-off-by: Arun Menon <arme...@redhat.com> --- Changes in v2: - Combine the first two changes into one, focusing on passing the Error object (errp) consistently through functions involved in loading the VM's state. Other functions are not yet changed. - As suggested in the review comment, add null checks for errp before adding error messages, preventing crashes. We also now correctly set errors when post-copy migration fails. - In process_incoming_migration_co(), switch to error_prepend instead of error_setg. This means we now null-check local_err in the "fail" section before using it, preventing dereferencing issues. - Link to v1: https://lore.kernel.org/qemu-devel/20250624-propagate_tpm_error-v1-0-2171487a5...@redhat.com --- Arun Menon (2): migration: Pass Error object errp into vm state loading functions backends/tpm: Propagate vTPM error on migration failure backends/tpm/tpm_emulator.c | 39 +++++++------ hw/display/virtio-gpu.c | 2 +- hw/pci/pci.c | 2 +- hw/s390x/virtio-ccw.c | 2 +- hw/scsi/spapr_vscsi.c | 2 +- hw/vfio/pci.c | 2 +- hw/virtio/virtio-mmio.c | 2 +- hw/virtio/virtio-pci.c | 2 +- hw/virtio/virtio.c | 4 +- include/migration/vmstate.h | 3 +- migration/colo.c | 13 +++-- migration/cpr.c | 2 +- migration/migration.c | 19 ++++-- migration/savevm.c | 137 +++++++++++++++++++++++++++----------------- migration/savevm.h | 7 ++- migration/vmstate-types.c | 10 ++-- migration/vmstate.c | 44 ++++++++------ tests/unit/test-vmstate.c | 18 +++--- 18 files changed, 182 insertions(+), 128 deletions(-) --- base-commit: 43ba160cb4bbb193560eb0d2d7decc4b5fc599fe change-id: 20250624-propagate_tpm_error-bf4ae6c23d30 Best regards, -- Arun Menon <arme...@redhat.com>
