On Mon, Jun 03, 2019 at 14:52:40 +0200, Ján Tomko wrote: > On Mon, Jun 03, 2019 at 02:27:58PM +0200, Jiri Denemark wrote: > >When migrating a domain with invtsc CPU feature enabled, the TSC > >frequency of the destination host must match the frequency used when the > >domain was started on the source host or the destination host has to > >support TSC scaling. > > > >If the frequencies do not match and the destination host does not > >support TSC scaling, QEMU will fail to set the right TSC frequency when > >starting vCPUs on the destination and thus migration will fail. However, > >this is quite late since both host might have spent significant time > >transferring memory and perhaps even storage data. > > > >By adding the check to libvirt we can let migration fail before any data > >starts to be sent over. If for some reason libvirt is unable to detect > >the host's TSC frequency or scaling support, we'll just let QEMU try and > >the migration will either succeed or fail later. > > > >Luckily, we mandate TSC frequency to be explicitly set in the domain XML > >to even allow migration of domains with invtsc. We can just check > >whether the requested frequency is compatible with the current host > >before starting QEMU. > > > >https://bugzilla.redhat.com/show_bug.cgi?id=1641702 > > > >Signed-off-by: Jiri Denemark <jdenemar@xxxxxxxxxx> > >--- > > src/qemu/qemu_process.c | 53 +++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 53 insertions(+) > > > > Reviewed-by: Ján Tomko <jtomko@xxxxxxxxxx> Thanks for the review and I'm sorry for forgetting to add the Reviewed-by line into the commits before pushing. Jirka -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
