By measuring time between a vcpu_put and a vcpu_load, we can estimate how much time did the guest stay out of the cpu. This is exported to the guest at every clock update.
Signed-off-by: Glauber Costa <[email protected]> --- arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kvm/x86.c | 12 +++++++++++- 2 files changed, 13 insertions(+), 1 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 502e53f..bc28aff 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -364,6 +364,8 @@ struct kvm_vcpu_arch { u64 hv_vapic; cpumask_var_t wbinvd_dirty_mask; + u64 time_out; + u64 last_time_out; }; struct kvm_arch { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e7e3b50..680feaa 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -925,8 +925,9 @@ static void kvm_write_guest_time(struct kvm_vcpu *v) vcpu->hv_clock.system_time = ts.tv_nsec + (NSEC_PER_SEC * (u64)ts.tv_sec) + v->kvm->arch.kvmclock_offset; - vcpu->hv_clock.flags = 0; + vcpu->hv_clock.flags = PVCLOCK_STEAL_BIT; + vcpu->hv_clock.steal_time = vcpu->time_out / 1000000; /* * The interface expects us to write an even number signaling that the * update is finished. Since the guest won't see the intermediate @@ -1798,6 +1799,8 @@ static bool need_emulate_wbinvd(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) { + s64 now; + /* Address WBINVD may be executed by guest */ if (need_emulate_wbinvd(vcpu)) { if (kvm_x86_ops->has_wbinvd_exit()) @@ -1815,12 +1818,19 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu) per_cpu(cpu_tsc_khz, cpu) = khz; } kvm_request_guest_time_update(vcpu); + + now = getnsboottime(); + + if (vcpu->arch.last_time_out != 0) + vcpu->arch.time_out += now - vcpu->arch.last_time_out; } void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu) { kvm_x86_ops->vcpu_put(vcpu); kvm_put_guest_fpu(vcpu); + + vcpu->arch.last_time_out = getnsboottime(); } static int is_efer_nx(void) -- 1.6.2.2 -- 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
