linux-stable/arch
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
..
alpha alpha: Fixup last users of irq_chip->typename 2009-11-30 22:51:31 -05:00
arm Merge branch 'mach-types' 2009-11-25 22:17:55 +00:00
avr32 at91: at91sam9g45 family: identify several chip versions 2009-11-03 18:42:31 +01:00
blackfin Blackfin: fix SMP build error in start_thread() 2009-11-25 02:38:01 -05:00
cris const: constify remaining file_operations 2009-10-01 16:11:11 -07:00
frv frv: fix check on unsigned in do_signal() 2009-10-29 07:39:32 -07:00
h8300 h8300: Cleanup linker script using new linker script macros. 2009-09-24 17:16:22 -07:00
ia64 KVM: Activate Virtualization On Demand 2009-12-03 09:32:10 +02:00
m32r m32r: fix arch/m32r/boot/compressed/Makefile 2009-11-09 09:00:50 +09:00
m68k tty: Mark generic_serial users as BROKEN 2009-10-30 14:43:12 -07:00
m68knommu m68knommu: fix rename of pt_regs offset defines breakage 2009-09-30 10:06:07 +10:00
microblaze microblaze: Clear sticky FSR register after saving it to func parametr 2009-10-05 11:37:47 +02:00
mips MIPS: RB532: Fix devices.c compilation. 2009-12-02 18:09:51 +00:00
mn10300 mn10300: fix kernel build failures when using gcc-4.x 2009-10-01 16:11:12 -07:00
parisc parisc: fix unwind with recent gcc versions 2009-11-30 08:20:24 -08:00
powerpc KVM: Activate Virtualization On Demand 2009-12-03 09:32:10 +02:00
s390 KVM: Activate Virtualization On Demand 2009-12-03 09:32:10 +02:00
score Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next 2009-09-23 15:37:02 -07:00
sh sh: Fixup last users of irq_chip->typename 2009-11-18 10:50:22 +09:00
sparc Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6 2009-11-30 14:02:23 -08:00
um headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
x86 KVM: allow userspace to adjust kvmclock offset 2009-12-03 09:32:19 +02:00
xtensa headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
.gitignore
Kconfig core, x86: Add user return notifiers 2009-10-01 12:12:18 -07:00