Turns out this doesn't actually save any math or locking, name is chosen rather poorly, it doesn't match the existing kernel APIs, and requires kvm-kmod changes.
Signed-off-by: Zachary Amsden <[email protected]> --- arch/x86/kvm/x86.c | 18 ++++++++++++++---- include/linux/time.h | 1 - kernel/time/timekeeping.c | 28 +--------------------------- 3 files changed, 15 insertions(+), 32 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 4014d6c..03605b8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -919,6 +919,16 @@ static inline u64 nsec_to_cycles(u64 nsec) return ret; } +static inline u64 get_kernel_ns(void) +{ + struct timespec ts; + + WARN_ON(preemptible()); + ktime_get_ts(&ts); + monotonic_to_bootbased(&ts); + return timespec_to_ns(&ts); +} + void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) { struct kvm *kvm = vcpu->kvm; @@ -928,7 +938,7 @@ void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); offset = data - native_read_tsc(); - ns = getnsboottime(); + ns = get_kernel_ns(); elapsed = ns - kvm->arch.last_tsc_nsec; sdiff = data - kvm->arch.last_tsc_write; if (sdiff < 0) @@ -981,7 +991,7 @@ static int kvm_write_guest_time(struct kvm_vcpu *v) /* Keep irq disabled to prevent changes to the clock */ local_irq_save(flags); kvm_get_msr(v, MSR_IA32_TSC, &tsc_timestamp); - kernel_ns = getnsboottime(); + kernel_ns = get_kernel_ns(); this_tsc_khz = __get_cpu_var(cpu_tsc_khz); local_irq_restore(flags); @@ -3327,7 +3337,7 @@ long kvm_arch_vm_ioctl(struct file *filp, goto out; r = 0; - now_ns = getnsboottime(); + now_ns = get_kernel_ns(); delta = user_ns.clock - now_ns; kvm->arch.kvmclock_offset = delta; break; @@ -3336,7 +3346,7 @@ long kvm_arch_vm_ioctl(struct file *filp, struct kvm_clock_data user_ns; u64 now_ns; - now_ns = getnsboottime(); + now_ns = get_kernel_ns(); user_ns.clock = kvm->arch.kvmclock_offset + now_ns; user_ns.flags = 0; diff --git a/include/linux/time.h b/include/linux/time.h index 909e62a..9f15ac7 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -160,7 +160,6 @@ extern void getnstimeofday(struct timespec *tv); extern void getrawmonotonic(struct timespec *ts); extern void getboottime(struct timespec *ts); extern void monotonic_to_bootbased(struct timespec *ts); -extern s64 getnsboottime(void); extern struct timespec timespec_trunc(struct timespec t, unsigned gran); extern int timekeeping_valid_for_hres(void); diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 77e930d..dfbe271 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -284,33 +284,6 @@ void ktime_get_ts(struct timespec *ts) } EXPORT_SYMBOL_GPL(ktime_get_ts); - -/** - * getnsboottime - get the bootbased clock in nsec format - * - * The function calculates the bootbased clock from the realtime - * clock and the wall_to_monotonic offset and stores the result - * in normalized timespec format in the variable pointed to by @ts. - */ -s64 getnsboottime(void) -{ - unsigned int seq; - s64 secs, nsecs; - - WARN_ON(timekeeping_suspended); - - do { - seq = read_seqbegin(&xtime_lock); - secs = xtime.tv_sec + wall_to_monotonic.tv_sec; - secs += total_sleep_time.tv_sec; - nsecs = xtime.tv_nsec + wall_to_monotonic.tv_nsec; - nsecs += total_sleep_time.tv_nsec + timekeeping_get_ns(); - - } while (read_seqretry(&xtime_lock, seq)); - return nsecs + (secs * NSEC_PER_SEC); -} -EXPORT_SYMBOL_GPL(getnsboottime); - /** * do_gettimeofday - Returns the time of day in a timeval * @tv: pointer to the timeval to be set @@ -327,6 +300,7 @@ void do_gettimeofday(struct timeval *tv) } EXPORT_SYMBOL(do_gettimeofday); + /** * do_settimeofday - Sets the time of day * @tv: pointer to the timespec variable containing the new time -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
