linux/include
Glauber Costa afbcf7ab8d KVM: allow userspace to adjust kvmclock offset
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 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. Userspace may also need to trigger
the current data, since from the first migration onwards, it won't be
reflected by a simple call to clock_gettime() anymore.

[marcelo: future-proof abi with a flags field]
[jan: fix KVM_GET_CLOCK by clearing flags field instead of checking it]

Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-12-03 09:32:19 +02:00
..
acpi
asm-generic fcntl: rename F_OWNER_GID to F_OWNER_PGRP 2009-11-17 17:40:33 -08:00
crypto
drm Merge branch 'drm-next' of ../drm-next into drm-linus 2009-10-08 14:03:05 +10:00
keys
linux KVM: allow userspace to adjust kvmclock offset 2009-12-03 09:32:19 +02:00
math-emu
media
mtd
net Merge branch 'security' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2009-11-30 16:47:16 -08:00
pcmcia PM / yenta: Split resume into early and late parts (rev. 4) 2009-11-03 10:54:58 +01:00
rdma
rxrpc
scsi [SCSI] fix async scan add/remove race resulting in an oops 2009-11-26 09:43:39 -06:00
sound
trace
video
xen
Kbuild