[PATCH 2/2] qemu: tpm: Remove TPM state after successful migration

[Stefan Berger]

On 10/3/22 11:20, Michal Prívozník wrote:
> On 8/23/22 18:28, Stefan Berger wrote:
>> This patch 'fixes' the behavior of the persistent_state TPM domain XML
>> attribute that intends to preserve the state of the TPM but should not
>> keep the state around on all the hosts a VM has been migrated to. It
>> removes the TPM state directory structure from the source host upon
>> successful migration when non-shared storage is used. Similarly, it
>> removes it from the destination host upon migration failure when
>> non-shared storage is used.
>>
>> Signed-off-by: Stefan Berger <stefanb at linux.ibm.com>
>> ---
>>   src/qemu/qemu_migration.c | 14 +++++++++++---
>>   src/qemu/qemu_tpm.h       | 12 ++++++++++++
>>   2 files changed, 23 insertions(+), 3 deletions(-)
>>
>> diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
>> index 7f69991e2b..355a2cb5c7 100644
>> --- a/src/qemu/qemu_migration.c
>> +++ b/src/qemu/qemu_migration.c
>> @@ -38,6 +38,7 @@
>>   #include "qemu_security.h"
>>   #include "qemu_slirp.h"
>>   #include "qemu_block.h"
>> +#include "qemu_tpm.h"
>>   
>>   #include "domain_audit.h"
>>   #include "virlog.h"
>> @@ -4006,6 +4007,7 @@ qemuMigrationSrcConfirm(virQEMUDriver *driver,
>>       qemuMigrationJobPhase phase;
>>       g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
>>       qemuDomainObjPrivate *priv = vm->privateData;
>> +    virDomainUndefineFlagsValues undefFlags = 0;

unsigned int undefFlags = 0; ?

>>       int ret = -1;
>>   
>>       VIR_DEBUG("vm=%p, flags=0x%x, cancelled=%d", vm, flags, cancelled);
>> @@ -4054,7 +4056,9 @@ qemuMigrationSrcConfirm(virQEMUDriver *driver,
>>               virDomainDeleteConfig(cfg->configDir, cfg->autostartDir, vm);
>>               vm->persistent = 0;
>>           }
>> -        qemuDomainRemoveInactive(driver, vm, 0);
>> +        if (!qemuTPMCheckKeepTPMStateMigrationSrcSuccess(vm))
>> +            undefFlags |= VIR_DOMAIN_UNDEFINE_TPM;
>> +        qemuDomainRemoveInactive(driver, vm, undefFlags);
>>       }
>>   
>>    cleanup:
>> @@ -6590,6 +6594,7 @@ qemuMigrationDstFinishActive(virQEMUDriver *driver,
>>       virObjectEvent *event;
>>       bool inPostCopy = false;
>>       bool doKill = priv->job.phase != QEMU_MIGRATION_PHASE_FINISH_RESUME;
>> +    virDomainUndefineFlagsValues undefFlags = 0;
>>       int rc;
>>   
>>       VIR_DEBUG("vm=%p, flags=0x%lx, retcode=%d",
>> @@ -6666,8 +6671,11 @@ qemuMigrationDstFinishActive(virQEMUDriver *driver,
>>                                    jobPriv->migParams, priv->job.apiFlags);
>>       }
>>   
>> -    if (!virDomainObjIsActive(vm))
>> -        qemuDomainRemoveInactive(driver, vm, 0);
>> +    if (!virDomainObjIsActive(vm)) {
>> +        if (!qemuTPMCheckKeepTPMStateMigrationDstFailure(vm))
>> +            undefFlags |= VIR_DOMAIN_UNDEFINE_TPM;
>> +        qemuDomainRemoveInactive(driver, vm, undefFlags);
>> +    }
>>   
>>       virErrorRestore(&orig_err);
>>       return NULL;
>> diff --git a/src/qemu/qemu_tpm.h b/src/qemu/qemu_tpm.h
>> index f068f3ca5a..c5d8774f07 100644
>> --- a/src/qemu/qemu_tpm.h
>> +++ b/src/qemu/qemu_tpm.h
>> @@ -56,3 +56,15 @@ int qemuExtTPMSetupCgroup(virQEMUDriver *driver,
>>                             virCgroup *cgroup)
>>       ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(3)
>>       G_GNUC_WARN_UNUSED_RESULT;
>> +
>> +static inline bool
>> +qemuTPMCheckKeepTPMStateMigrationSrcSuccess(virDomainObj *vm G_GNUC_UNUSED)
>> +{
>> +    return false;
>> +}
>> +
>> +static inline bool
>> +qemuTPMCheckKeepTPMStateMigrationDstFailure(virDomainObj *vm G_GNUC_UNUSED)
>> +{
>> +    return false;
>> +}
> 
> Yeah, I know where you're headed with these two, but G_GNUC_UNUSED
> breaks syntax-check. And they can be added in shared storage state series.

But you agree to the expressive names? I am asking because they will re-appear then?
> 
> Michal
>