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| author | Ingo Molnar <mingo@elte.hu> | 2008-10-28 16:26:12 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-10-28 16:26:12 +0100 |
| commit | 7a9787e1eba95a166265e6a260cf30af04ef0a99 (patch) | |
| tree | e730a4565e0318140d2fbd2f0415d18a339d7336 /arch/x86/kernel/kvmclock.c | |
| parent | 41b9eb264c8407655db57b60b4457fe1b2ec9977 (diff) | |
| parent | 0173a3265b228da319ceb9c1ec6a5682fd1b2d92 (diff) | |
| download | linux-7a9787e1eba95a166265e6a260cf30af04ef0a99.tar.bz2 | |
Merge commit 'v2.6.28-rc2' into x86/pci-ioapic-boot-irq-quirks
Diffstat (limited to 'arch/x86/kernel/kvmclock.c')
| -rw-r--r-- | arch/x86/kernel/kvmclock.c | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 87edf1ceb1df..774ac4991568 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -78,6 +78,34 @@ static cycle_t kvm_clock_read(void) return ret; } +/* + * If we don't do that, there is the possibility that the guest + * will calibrate under heavy load - thus, getting a lower lpj - + * and execute the delays themselves without load. This is wrong, + * because no delay loop can finish beforehand. + * Any heuristics is subject to fail, because ultimately, a large + * poll of guests can be running and trouble each other. So we preset + * lpj here + */ +static unsigned long kvm_get_tsc_khz(void) +{ + return preset_lpj; +} + +static void kvm_get_preset_lpj(void) +{ + struct pvclock_vcpu_time_info *src; + unsigned long khz; + u64 lpj; + + src = &per_cpu(hv_clock, 0); + khz = pvclock_tsc_khz(src); + + lpj = ((u64)khz * 1000); + do_div(lpj, HZ); + preset_lpj = lpj; +} + static struct clocksource kvm_clock = { .name = "kvm-clock", .read = kvm_clock_read, @@ -113,7 +141,7 @@ static void kvm_setup_secondary_clock(void) #endif #ifdef CONFIG_SMP -void __init kvm_smp_prepare_boot_cpu(void) +static void __init kvm_smp_prepare_boot_cpu(void) { WARN_ON(kvm_register_clock("primary cpu clock")); native_smp_prepare_boot_cpu(); @@ -153,6 +181,7 @@ void __init kvmclock_init(void) pv_time_ops.get_wallclock = kvm_get_wallclock; pv_time_ops.set_wallclock = kvm_set_wallclock; pv_time_ops.sched_clock = kvm_clock_read; + pv_time_ops.get_tsc_khz = kvm_get_tsc_khz; #ifdef CONFIG_X86_LOCAL_APIC pv_apic_ops.setup_secondary_clock = kvm_setup_secondary_clock; #endif @@ -163,6 +192,7 @@ void __init kvmclock_init(void) #ifdef CONFIG_KEXEC machine_ops.crash_shutdown = kvm_crash_shutdown; #endif + kvm_get_preset_lpj(); clocksource_register(&kvm_clock); } } |