On 10/06/2009 07:24 PM, Glauber Costa wrote:
When we migrate a kvm guest that uses pvclock between two hosts, we may
suffer a large skew. This is because there can be significant differences
between the monotonic clock of the hosts involved. When a new host with
a much larger monotonic time starts running the guest, the view of time
will be significantly impacted.
Situation is much worse when we do the opposite, and migrate to a host with
a smaller monotonic clock.
This new proposed ioctl will allow userspace to inform us what is the monotonic
clock value in the source host, so we can keep the time skew short, and more
importantly, never goes backwards.
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index f8f8900..0cd5ad8 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -546,6 +546,7 @@ struct kvm_irqfd {
#define KVM_CREATE_PIT2 _IOW(KVMIO, 0x77, struct kvm_pit_config)
#define KVM_SET_BOOT_CPU_ID _IO(KVMIO, 0x78)
#define KVM_IOEVENTFD _IOW(KVMIO, 0x79, struct kvm_ioeventfd)
+#define KVM_ADJUST_CLOCK _IOW(KVMIO, 0x7a, __u64)
Please change to a struct with some reserved space.
Do we want an absolute or relative adjustment?
--
error compiling committee.c: too many arguments to function
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