Re: [PATCH v2 2/9] qemu: Introduced VIR_MIGRATE_TPM_SHARED_STORAGE for TPM migration

On 10/6/22 15:47, Daniel P. Berrangé wrote: > On Wed, Oct 05, 2022 at 10:02:00AM -0400, Stefan Berger wrote: >> Introduced VIR_MIGRATE_TPM_SHARED_STORAGE for migrating a TPM across >> shared storage. >> >> At this point do not support this flag in 'virsh', yet. >> >> Signed-off-by: Stefan Berger <stefanb(a)linux.ibm.com&gt; >> --- >> include/libvirt/libvirt-domain.h | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h >> index 8357aea797..110929039d 100644 >> --- a/include/libvirt/libvirt-domain.h >> +++ b/include/libvirt/libvirt-domain.h >> @@ -1098,6 +1098,14 @@ typedef enum { >> * Since: 8.5.0 >> */ >> VIR_MIGRATE_ZEROCOPY = (1 << 20), >> + >> + /* Support TPM migration across hosts that have shared storage setup for >> + * the directory structure holding the state of TPMs. Typically this would >> + * mean that the directory /var/lib/libvirt/swtpm is shared. >> + * >> + * Since: 8.9.0 >> + */ >> + VIR_MIGRATE_TPM_SHARED_STORAGE = (1 << 21), > > Why do we need this flag at all. We don't require users to set any flag > when dealing with shared storage for disks, we just make sure we detect > shared storage and "do the right thing" with it. That could work. Until the state is stored on a shared FS but not shared across migration hosts. But I guess our disk migration code would fail then too, wouldn't it?