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x86: Increase precision of x86_platform.get/set_wallclock()

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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>
This commit is contained in:
David Vrabel 2013-05-13 18:56:06 +01:00 • committed by John Stultz
parent 0a0a7e66fa
commit 3565184ed0
8 changed files with 32 additions and 41 deletions
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4
include/linux/efi.h
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@ -594,8 +594,8 @@ extern u64 efi_mem_attribute (unsigned long phys_addr, unsigned long size);
extern int __init efi_uart_console_only (void);
extern void efi_initialize_iomem_resources(struct resource *code_resource,
struct resource *data_resource, struct resource *bss_resource);
extern unsigned long efi_get_time(void);
extern int efi_set_rtc_mmss(unsigned long nowtime);
extern void efi_get_time(struct timespec *now);
extern int efi_set_rtc_mmss(const struct timespec *now);
extern void efi_reserve_boot_services(void);
extern struct efi_memory_map memmap;