KVM guest: KVM Steal time registration

This patch implements the kvm bits of the steal time infrastructure.
The most important part of it, is the steal time clock. It is an
continuous clock that shows the accumulated amount of steal time
since vcpu creation. It is supposed to survive cpu offlining/onlining.

[marcelo: fix build with CONFIG_KVM_GUEST=n]

Signed-off-by: Glauber Costa <glommer@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Tested-by: Eric B Munson <emunson@mgebm.net>
CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Avi Kivity <avi@redhat.com>
CC: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index fd248a318211..a7225746ed96 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1737,6 +1737,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
         no-kvmapf       [X86,KVM] Disable paravirtualized asynchronous page
                         fault handling.
 
+        no-steal-acc    [X86,KVM] Disable paravirtualized steal time accounting.
+                        steal time is computed, but won't influence scheduler
+                        behaviour
+
         nolapic         [X86-32,APIC] Do not enable or use the local APIC.
 
         nolapic_timer   [X86-32,APIC] Do not use the local APIC timer.