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| author | Zachary Amsden <zamsden@redhat.com> | 2009-10-09 16:26:08 -1000 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2009-12-03 09:32:18 +0200 |
| commit | 6b7d7e762b238f908fe4c3345c2c6eb5c3fdbd59 (patch) | |
| tree | ab2a77aec71450ba11c13a8f31e505df173efd78 /arch/x86/kvm | |
| parent | 565d0998ecac8373b9a9ecd5991abe74318cd235 (diff) | |
| download | blackbird-op-linux-6b7d7e762b238f908fe4c3345c2c6eb5c3fdbd59.tar.gz blackbird-op-linux-6b7d7e762b238f908fe4c3345c2c6eb5c3fdbd59.zip | |
KVM: x86: Harden against cpufreq
If cpufreq can't determine the CPU khz, or cpufreq is not compiled in,
we should fallback to the measured TSC khz.
Signed-off-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
| -rw-r--r-- | arch/x86/kvm/x86.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 098e7f886306..3cffa2cac70b 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1348,8 +1348,12 @@ out: void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { kvm_x86_ops->vcpu_load(vcpu, cpu); - if (unlikely(per_cpu(cpu_tsc_khz, cpu) == 0)) - per_cpu(cpu_tsc_khz, cpu) = cpufreq_quick_get(cpu); + if (unlikely(per_cpu(cpu_tsc_khz, cpu) == 0)) { + unsigned long khz = cpufreq_quick_get(cpu); + if (!khz) + khz = tsc_khz; + per_cpu(cpu_tsc_khz, cpu) = khz; + } kvm_request_guest_time_update(vcpu); } @@ -3144,8 +3148,12 @@ static void kvm_timer_init(void) if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) { cpufreq_register_notifier(&kvmclock_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER); - for_each_online_cpu(cpu) - per_cpu(cpu_tsc_khz, cpu) = cpufreq_get(cpu); + for_each_online_cpu(cpu) { + unsigned long khz = cpufreq_get(cpu); + if (!khz) + khz = tsc_khz; + per_cpu(cpu_tsc_khz, cpu) = khz; + } } else { for_each_possible_cpu(cpu) per_cpu(cpu_tsc_khz, cpu) = tsc_khz; |
