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, 6 insertions, 0 deletions

diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
index c484ba8e05ea..734c3767cfac 100644
--- a/arch/x86/include/asm/kvm_para.h
+++ b/arch/x86/include/asm/kvm_para.h
@@ -192,6 +192,7 @@ void __init kvm_guest_init(void);
 void kvm_async_pf_task_wait(u32 token);
 void kvm_async_pf_task_wake(u32 token);
 u32 kvm_read_and_reset_pf_reason(void);
+extern void kvm_disable_steal_time(void);
 #else
 #define kvm_guest_init() do { } while (0)
 #define kvm_async_pf_task_wait(T) do {} while(0)
@@ -200,6 +201,11 @@ static inline u32 kvm_read_and_reset_pf_reason(void)
 {
         return 0;
 }
+
+static inline void kvm_disable_steal_time(void)
+{
+        return;
+}
 #endif
 
 #endif /* __KERNEL__ */