diff options
| author | Zachary Amsden <zamsden@redhat.com> | 2010-08-19 22:07:17 -1000 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-10-24 10:51:22 +0200 |
| commit | 99e3e30aee1a326a98bf3a5f47b8622219c685f3 (patch) | |
| tree | 1b67fc70af33988080784d32725f72b5ce7c07d1 /arch/x86/kvm/x86.c | |
| parent | f4e1b3c8bd2a044cd0ccf80595bfd088a49fe60b (diff) | |
KVM: x86: Move TSC offset writes to common code
Also, ensure that the storing of the offset and the reading of the TSC
are never preempted by taking a spinlock. While the lock is overkill
now, it is useful later in this patch series.
Signed-off-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8b0c51a1adaa..886132b6ef14 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -895,6 +895,22 @@ static void kvm_set_time_scale(uint32_t tsc_khz, struct pvclock_vcpu_time_info * static DEFINE_PER_CPU(unsigned long, cpu_tsc_khz); +void kvm_write_tsc(struct kvm_vcpu *vcpu, u64 data) +{ + struct kvm *kvm = vcpu->kvm; + u64 offset; + unsigned long flags; + + spin_lock_irqsave(&kvm->arch.tsc_write_lock, flags); + offset = data - native_read_tsc(); + kvm_x86_ops->write_tsc_offset(vcpu, offset); + spin_unlock_irqrestore(&kvm->arch.tsc_write_lock, flags); + + /* Reset of TSC must disable overshoot protection below */ + vcpu->arch.hv_clock.tsc_timestamp = 0; +} +EXPORT_SYMBOL_GPL(kvm_write_tsc); + static void kvm_write_guest_time(struct kvm_vcpu *v) { struct timespec ts; @@ -5495,6 +5511,8 @@ struct kvm *kvm_arch_create_vm(void) /* Reserve bit 0 of irq_sources_bitmap for userspace irq source */ set_bit(KVM_USERSPACE_IRQ_SOURCE_ID, &kvm->arch.irq_sources_bitmap); + spin_lock_init(&kvm->arch.tsc_write_lock); + return kvm; } |