x86: Increase precision of x86_platform.get/set_wallclock()
All the virtualized platforms (KVM, lguest and Xen) have persistent
wallclocks that have more than one second of precision.
read_persistent_wallclock() and update_persistent_wallclock() allow
for nanosecond precision but their implementation on x86 with
x86_platform.get/set_wallclock() only allows for one second precision.
This means guests may see a wallclock time that is off by up to 1
second.
Make set_wallclock() and get_wallclock() take a struct timespec
parameter (which allows for nanosecond precision) so KVM and Xen
guests may start with a more accurate wallclock time and a Xen dom0
can maintain a more accurate wallclock for guests.
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index d8d9922..828a156 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -142,6 +142,8 @@
void (*fixup_cpu_id)(struct cpuinfo_x86 *c, int node);
};
+struct timespec;
+
/**
* struct x86_platform_ops - platform specific runtime functions
* @calibrate_tsc: calibrate TSC
@@ -156,8 +158,8 @@
*/
struct x86_platform_ops {
unsigned long (*calibrate_tsc)(void);
- unsigned long (*get_wallclock)(void);
- int (*set_wallclock)(unsigned long nowtime);
+ void (*get_wallclock)(struct timespec *ts);
+ int (*set_wallclock)(const struct timespec *ts);
void (*iommu_shutdown)(void);
bool (*is_untracked_pat_range)(u64 start, u64 end);
void (*nmi_init)(void);