Some users told me that savevm path is behaving oddly wrt kvmclock.
The first oddness is that a guarantee we never made (AFAIK) is being broken:
two consecutive "savevm" operations, with the machine stopped in between
produces different results, due to the call to KVM_GET_CLOCK ioctl.
I believe the assumption that if the vm does not run, its saveable
state won't change is fairly reasonable. Maybe we should formally
guarantee that?
Also, this patch deals with the fact that this happens even if
kvmclock is disabled in cpuid: its savevm section is registered
nevertheless. Here, I try to register it only if it's enabled at
machine start.
v2: improvements suggested by Paolo, and patch reordering.
Glauber Costa (2):
Do not register kvmclock savevm section if kvmclock is disabled.
make kvmclock value idempotent for stopped machine
cpus.c | 3 +++
qemu-kvm-x86.c | 23 +++++++++++++++--------
qemu-kvm.h | 3 +++
target-i386/kvm.c | 7 +++++++
4 files changed, 28 insertions(+), 8 deletions(-)