If the guest has offloaded the timer virq, handle the following
hypercalls for programming the timer:
VCPUOP_set_singleshot_timer
VCPUOP_stop_singleshot_timer
set_timer_op(timestamp_ns)
The event channel corresponding to the timer virq is then used to inject
events once timer deadlines are met. For now we back the PV timer with
hrtimer.
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/kvm/irq.c | 11 ++-
arch/x86/kvm/x86.c | 4 +
arch/x86/kvm/xen.c | 185 +++++++++++++++++++++++++++++++++++++++-
arch/x86/kvm/xen.h | 6 ++
5 files changed, 202 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 92b76127eb43..7fcc81dbb688 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -552,6 +552,8 @@ struct kvm_vcpu_xen {
struct kvm_xen_callback cb;
#define KVM_XEN_NR_VIRQS 24
unsigned int virq_to_port[KVM_XEN_NR_VIRQS];
+ struct hrtimer timer;
+ atomic_t timer_pending;
};
struct kvm_vcpu_arch {
diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index cdb1dbfcc9b1..936c31ae019a 100644
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -34,10 +34,14 @@
*/
int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
+ int r = 0;
+
if (lapic_in_kernel(vcpu))
- return apic_has_pending_timer(vcpu);
+ r = apic_has_pending_timer(vcpu);
+ if (kvm_xen_timer_enabled(vcpu))
+ r += kvm_xen_has_pending_timer(vcpu);
- return 0;
+ return r;
}
EXPORT_SYMBOL(kvm_cpu_has_pending_timer);
@@ -172,6 +176,8 @@ void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
{
if (lapic_in_kernel(vcpu))
kvm_inject_apic_timer_irqs(vcpu);
+ if (kvm_xen_timer_enabled(vcpu))
+ kvm_xen_inject_timer_irqs(vcpu);
}
EXPORT_SYMBOL_GPL(kvm_inject_pending_timer_irqs);
@@ -179,4 +185,5 @@ void __kvm_migrate_timers(struct kvm_vcpu *vcpu)
{
__kvm_migrate_apic_timer(vcpu);
__kvm_migrate_pit_timer(vcpu);
+ __kvm_migrate_xen_timer(vcpu);
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 76bd23113ccd..e29cefd2dc6a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9115,6 +9115,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
vcpu->arch.preempted_in_kernel = false;
kvm_hv_vcpu_init(vcpu);
+ kvm_xen_vcpu_init(vcpu);
return 0;
@@ -9566,6 +9567,9 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
if (kvm_hv_has_stimer_pending(vcpu))
return true;
+ if (kvm_xen_has_pending_timer(vcpu))
+ return true;
+
return false;
}
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 42c1fe01600d..ec40cb1de6b6 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -32,6 +32,7 @@ struct evtchnfd {
};
};
+static int kvm_xen_evtchn_send(struct kvm_vcpu *vcpu, int port);
static void *xen_vcpu_info(struct kvm_vcpu *v);
int kvm_xen_has_interrupt(struct kvm_vcpu *vcpu)
@@ -101,6 +102,91 @@ static void kvm_xen_evtchnfd_upcall(struct kvm_vcpu *vcpu, struct evtchnfd *e)
kvm_xen_do_upcall(vcpu->kvm, e->vcpu, vx->cb.via, vx->cb.vector, 0);
}
+int kvm_xen_has_pending_timer(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_xen *vcpu_xen = vcpu_to_xen_vcpu(vcpu);
+
+ if (kvm_xen_hypercall_enabled(vcpu->kvm) && kvm_xen_timer_enabled(vcpu))
+ return atomic_read(&vcpu_xen->timer_pending);
+
+ return 0;
+}
+
+void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_xen *vcpu_xen = vcpu_to_xen_vcpu(vcpu);
+
+ if (atomic_read(&vcpu_xen->timer_pending) > 0) {
+ kvm_xen_evtchn_send(vcpu, vcpu_xen->virq_to_port[VIRQ_TIMER]);
+
+ atomic_set(&vcpu_xen->timer_pending, 0);
+ }
+}
+
+static enum hrtimer_restart xen_timer_callback(struct hrtimer *timer)
+{
+ struct kvm_vcpu_xen *vcpu_xen =
+ container_of(timer, struct kvm_vcpu_xen, timer);
+ struct kvm_vcpu *vcpu = xen_vcpu_to_vcpu(vcpu_xen);
+ struct swait_queue_head *wq = &vcpu->wq;
+
+ if (atomic_read(&vcpu_xen->timer_pending))
+ return HRTIMER_NORESTART;
+
+ atomic_inc(&vcpu_xen->timer_pending);
+ kvm_set_pending_timer(vcpu);
+
+ if (swait_active(wq))
+ swake_up_one(wq);
+
+ return HRTIMER_NORESTART;
+}
+
+void __kvm_migrate_xen_timer(struct kvm_vcpu *vcpu)
+{
+ struct hrtimer *timer;
+
+ if (!kvm_xen_timer_enabled(vcpu))
+ return;
+
+ timer = &vcpu->arch.xen.timer;
+ if (hrtimer_cancel(timer))
+ hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
+}
+
+static void kvm_xen_start_timer(struct kvm_vcpu *vcpu, u64 delta_ns)
+{
+ struct kvm_vcpu_xen *vcpu_xen = vcpu_to_xen_vcpu(vcpu);
+ struct hrtimer *timer = &vcpu_xen->timer;
+ ktime_t ktime_now;
+
+ atomic_set(&vcpu_xen->timer_pending, 0);
+ ktime_now = ktime_get();
+ hrtimer_start(timer, ktime_add_ns(ktime_now, delta_ns),
+ HRTIMER_MODE_ABS_PINNED);
+}
+
+static void kvm_xen_stop_timer(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_xen *vcpu_xen = vcpu_to_xen_vcpu(vcpu);
+
+ hrtimer_cancel(&vcpu_xen->timer);
+}
+
+void kvm_xen_init_timer(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_xen *vcpu_xen = vcpu_to_xen_vcpu(vcpu);
+
+ hrtimer_init(&vcpu_xen->timer, CLOCK_MONOTONIC,
+ HRTIMER_MODE_ABS_PINNED);
+ vcpu_xen->timer.function = xen_timer_callback;
+}
+
+bool kvm_xen_timer_enabled(struct kvm_vcpu *vcpu)
+{
+ return !!vcpu->arch.xen.virq_to_port[VIRQ_TIMER];
+}
+
void kvm_xen_set_virq(struct kvm *kvm, struct evtchnfd *evt)
{
int virq = evt->virq.type;
@@ -111,6 +197,9 @@ void kvm_xen_set_virq(struct kvm *kvm, struct evtchnfd *evt)
if (!vcpu)
return;
+ if (virq == VIRQ_TIMER)
+ kvm_xen_init_timer(vcpu);
+
vcpu_xen = vcpu_to_xen_vcpu(vcpu);
vcpu_xen->virq_to_port[virq] = evt->port;
}
@@ -514,6 +603,71 @@ static int kvm_xen_hcall_evtchn_send(struct kvm_vcpu *vcpu, int cmd, u64 param)
return kvm_xen_evtchn_send(vcpu, send.port);
}
+static int kvm_xen_hcall_vcpu_op(struct kvm_vcpu *vcpu, int cmd, int vcpu_id,
+ u64 param)
+{
+ struct vcpu_set_singleshot_timer oneshot;
+ int ret = -EINVAL;
+ long delta;
+ gpa_t gpa;
+ int idx;
+
+ /* Only process timer ops with commands 6 to 9 */
+ if (cmd < VCPUOP_set_periodic_timer ||
+ cmd > VCPUOP_stop_singleshot_timer)
+ return ret;
+
+ if (!kvm_xen_timer_enabled(vcpu))
+ return ret;
+
+ idx = srcu_read_lock(&vcpu->kvm->srcu);
+ gpa = kvm_mmu_gva_to_gpa_system(vcpu, param, NULL);
+ srcu_read_unlock(&vcpu->kvm->srcu, idx);
+
+ if (!gpa)
+ return ret;
+
+ switch (cmd) {
+ case VCPUOP_set_singleshot_timer:
+ if (kvm_vcpu_read_guest(vcpu, gpa, &oneshot,
+ sizeof(oneshot)))
+ return -EFAULT;
+
+ delta = oneshot.timeout_abs_ns - get_kvmclock_ns(vcpu->kvm);
+ kvm_xen_start_timer(vcpu, delta);
+ ret = 0;
+ break;
+ case VCPUOP_stop_singleshot_timer:
+ kvm_xen_stop_timer(vcpu);
+ ret = 0;
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+static int kvm_xen_hcall_set_timer_op(struct kvm_vcpu *vcpu, uint64_t timeout)
+{
+ ktime_t ktime_now = ktime_get();
+ long delta = timeout - get_kvmclock_ns(vcpu->kvm);
+
+ if (!kvm_xen_timer_enabled(vcpu))
+ return -EINVAL;
+
+ if (timeout == 0) {
+ kvm_xen_stop_timer(vcpu);
+ } else if (unlikely(timeout < ktime_now) ||
+ ((uint32_t) (delta >> 50) != 0)) {
+ kvm_xen_start_timer(vcpu, 50000000);
+ } else {
+ kvm_xen_start_timer(vcpu, delta);
+ }
+
+ return 0;
+}
+
int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
{
bool longmode;
@@ -546,10 +700,20 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
case __HYPERVISOR_event_channel_op:
r = kvm_xen_hcall_evtchn_send(vcpu, params[0],
params[1]);
- if (!r) {
- kvm_xen_hypercall_set_result(vcpu, r);
- return kvm_skip_emulated_instruction(vcpu);
- }
+ if (!r)
+ goto hcall_success;
+ break;
+ case __HYPERVISOR_vcpu_op:
+ r = kvm_xen_hcall_vcpu_op(vcpu, params[0], params[1],
+ params[2]);
+ if (!r)
+ goto hcall_success;
+ break;
+ case __HYPERVISOR_set_timer_op:
+ r = kvm_xen_hcall_set_timer_op(vcpu, params[0]);
+ if (!r)
+ goto hcall_success;
+ break;
/* fallthrough */
default:
break;
@@ -567,6 +731,14 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
kvm_xen_hypercall_complete_userspace;
return 0;
+
+hcall_success:
+ kvm_xen_hypercall_set_result(vcpu, r);
+ return kvm_skip_emulated_instruction(vcpu);
+}
+
+void kvm_xen_vcpu_init(struct kvm_vcpu *vcpu)
+{
}
void kvm_xen_vcpu_uninit(struct kvm_vcpu *vcpu)
@@ -579,6 +751,11 @@ void kvm_xen_vcpu_uninit(struct kvm_vcpu *vcpu)
put_page(virt_to_page(vcpu_xen->pv_time));
if (vcpu_xen->steal_time)
put_page(virt_to_page(vcpu_xen->steal_time));
+
+ if (!kvm_xen_timer_enabled(vcpu))
+ return;
+
+ kvm_xen_stop_timer(vcpu);
}
void kvm_xen_init_vm(struct kvm *kvm)
diff --git a/arch/x86/kvm/xen.h b/arch/x86/kvm/xen.h
index 8f26625564c8..f82b8b5b3345 100644
--- a/arch/x86/kvm/xen.h
+++ b/arch/x86/kvm/xen.h
@@ -37,6 +37,12 @@ int kvm_xen_setup_evtchn(struct kvm *kvm,
void kvm_xen_init_vm(struct kvm *kvm);
void kvm_xen_destroy_vm(struct kvm *kvm);
int kvm_vm_ioctl_xen_eventfd(struct kvm *kvm, struct kvm_xen_eventfd *args);
+void kvm_xen_vcpu_init(struct kvm_vcpu *vcpu);
void kvm_xen_vcpu_uninit(struct kvm_vcpu *vcpu);
+void __kvm_migrate_xen_timer(struct kvm_vcpu *vcpu);
+int kvm_xen_has_pending_timer(struct kvm_vcpu *vcpu);
+void kvm_xen_inject_timer_irqs(struct kvm_vcpu *vcpu);
+bool kvm_xen_timer_enabled(struct kvm_vcpu *vcpu);
+
#endif
--
2.11.0
