KVM: ia64: Fix halt emulation logic

Common halt logic was changed by x86 and did not update ia64.  This patch
updates halt for ia64.

Fixes a regression causing guests to hang with more than 2 vcpus.

Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

4 files changed, 46 insertions, 40 deletions

diff --git a/arch/ia64/include/asm/kvm_host.h b/arch/ia64/include/asm/kvm_host.h
index 04c0b88f7b3a..c60d324da540 100644
--- a/arch/ia64/include/asm/kvm_host.h
+++ b/arch/ia64/include/asm/kvm_host.h
@@ -365,7 +365,8 @@ struct kvm_vcpu_arch {
         long itc_offset;
         unsigned long itc_check;
         unsigned long timer_check;
-        unsigned long timer_pending;
+        unsigned int timer_pending;
+        unsigned int timer_fired;
 
         unsigned long vrr[8];
         unsigned long ibr[8];
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 8a2b13ff0aff..3caac477de9e 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -385,6 +385,7 @@ static int handle_global_purge(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         struct kvm *kvm = vcpu->kvm;
         struct call_data call_data;
         int i;
+
         call_data.ptc_g_data = p->u.ptc_g_data;
 
         for (i = 0; i < KVM_MAX_VCPUS; i++) {
@@ -418,33 +419,41 @@ int kvm_emulate_halt(struct kvm_vcpu *vcpu)
         ktime_t kt;
         long itc_diff;
         unsigned long vcpu_now_itc;
-
         unsigned long expires;
         struct hrtimer *p_ht = &vcpu->arch.hlt_timer;
         unsigned long cyc_per_usec = local_cpu_data->cyc_per_usec;
         struct vpd *vpd = to_host(vcpu->kvm, vcpu->arch.vpd);
 
-        vcpu_now_itc = ia64_getreg(_IA64_REG_AR_ITC) + vcpu->arch.itc_offset;
+        if (irqchip_in_kernel(vcpu->kvm)) {
 
-        if (time_after(vcpu_now_itc, vpd->itm)) {
-                vcpu->arch.timer_check = 1;
-                return 1;
-        }
-        itc_diff = vpd->itm - vcpu_now_itc;
-        if (itc_diff < 0)
-                itc_diff = -itc_diff;
+                vcpu_now_itc = ia64_getreg(_IA64_REG_AR_ITC) + vcpu->arch.itc_offset;
 
-        expires = div64_u64(itc_diff, cyc_per_usec);
-        kt = ktime_set(0, 1000 * expires);
-        vcpu->arch.ht_active = 1;
-        hrtimer_start(p_ht, kt, HRTIMER_MODE_ABS);
+                if (time_after(vcpu_now_itc, vpd->itm)) {
+                        vcpu->arch.timer_check = 1;
+                        return 1;
+                }
+                itc_diff = vpd->itm - vcpu_now_itc;
+                if (itc_diff < 0)
+                        itc_diff = -itc_diff;
+
+                expires = div64_u64(itc_diff, cyc_per_usec);
+                kt = ktime_set(0, 1000 * expires);
+
+                down_read(&vcpu->kvm->slots_lock);
+                vcpu->arch.ht_active = 1;
+                hrtimer_start(p_ht, kt, HRTIMER_MODE_ABS);
 
-        if (irqchip_in_kernel(vcpu->kvm)) {
                 vcpu->arch.mp_state = KVM_MP_STATE_HALTED;
                 kvm_vcpu_block(vcpu);
                 hrtimer_cancel(p_ht);
                 vcpu->arch.ht_active = 0;
 
+                if (test_and_clear_bit(KVM_REQ_UNHALT, &vcpu->requests))
+                        if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED)
+                                vcpu->arch.mp_state =
+                                        KVM_MP_STATE_RUNNABLE;
+                up_read(&vcpu->kvm->slots_lock);
+
                 if (vcpu->arch.mp_state != KVM_MP_STATE_RUNNABLE)
                         return -EINTR;
                 return 1;
@@ -484,10 +493,6 @@ static int (*kvm_vti_exit_handlers[])(struct kvm_vcpu *vcpu,
 static const int kvm_vti_max_exit_handlers =
                 sizeof(kvm_vti_exit_handlers)/sizeof(*kvm_vti_exit_handlers);
 
-static void kvm_prepare_guest_switch(struct kvm_vcpu *vcpu)
-{
-}
-
 static uint32_t kvm_get_exit_reason(struct kvm_vcpu *vcpu)
 {
         struct exit_ctl_data *p_exit_data;
@@ -600,8 +605,6 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 
 again:
         preempt_disable();
-
-        kvm_prepare_guest_switch(vcpu);
         local_irq_disable();
 
         if (signal_pending(current)) {
@@ -614,7 +617,7 @@ again:
 
         vcpu->guest_mode = 1;
         kvm_guest_enter();
-
+        down_read(&vcpu->kvm->slots_lock);
         r = vti_vcpu_run(vcpu, kvm_run);
         if (r < 0) {
                 local_irq_enable();
@@ -634,9 +637,8 @@ again:
          * But we need to prevent reordering, hence this barrier():
          */
         barrier();
-
         kvm_guest_exit();
-
+        up_read(&vcpu->kvm->slots_lock);
         preempt_enable();
 
         r = kvm_handle_exit(kvm_run, vcpu);
@@ -673,6 +675,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 
         if (unlikely(vcpu->arch.mp_state == KVM_MP_STATE_UNINITIALIZED)) {
                 kvm_vcpu_block(vcpu);
+                clear_bit(KVM_REQ_UNHALT, &vcpu->requests);
                 vcpu_put(vcpu);
                 return -EAGAIN;
         }
@@ -1125,15 +1128,16 @@ static enum hrtimer_restart hlt_timer_fn(struct hrtimer *data)
         wait_queue_head_t *q;
 
         vcpu  = container_of(data, struct kvm_vcpu, arch.hlt_timer);
+        q = &vcpu->wq;
+
         if (vcpu->arch.mp_state != KVM_MP_STATE_HALTED)
                 goto out;
 
-        q = &vcpu->wq;
-        if (waitqueue_active(q)) {
-                vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
+        if (waitqueue_active(q))
                 wake_up_interruptible(q);
-        }
+
 out:
+        vcpu->arch.timer_fired = 1;
         vcpu->arch.timer_check = 1;
         return HRTIMER_NORESTART;
 }
@@ -1702,12 +1706,14 @@ static void vcpu_kick_intr(void *info)
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 {
         int ipi_pcpu = vcpu->cpu;
+        int cpu = get_cpu();
 
         if (waitqueue_active(&vcpu->wq))
                 wake_up_interruptible(&vcpu->wq);
 
-        if (vcpu->guest_mode)
+        if (vcpu->guest_mode && cpu != ipi_pcpu)
                 smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0);
+        put_cpu();
 }
 
 int kvm_apic_set_irq(struct kvm_vcpu *vcpu, u8 vec, u8 trig)
@@ -1717,13 +1723,7 @@ int kvm_apic_set_irq(struct kvm_vcpu *vcpu, u8 vec, u8 trig)
 
         if (!test_and_set_bit(vec, &vpd->irr[0])) {
                 vcpu->arch.irq_new_pending = 1;
-                 if (vcpu->arch.mp_state == KVM_MP_STATE_RUNNABLE)
-                        kvm_vcpu_kick(vcpu);
-                else if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED) {
-                        vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
-                        if (waitqueue_active(&vcpu->wq))
-                                wake_up_interruptible(&vcpu->wq);
-                }
+                kvm_vcpu_kick(vcpu);
                 return 1;
         }
         return 0;
@@ -1793,7 +1793,7 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu)
 
 int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
 {
-        return 0;
+        return vcpu->arch.timer_fired;
 }
 
 gfn_t unalias_gfn(struct kvm *kvm, gfn_t gfn)
diff --git a/arch/ia64/kvm/kvm_fw.c b/arch/ia64/kvm/kvm_fw.c
index 0c69d9ec92d4..cb7600bdff9d 100644
--- a/arch/ia64/kvm/kvm_fw.c
+++ b/arch/ia64/kvm/kvm_fw.c
@@ -286,6 +286,12 @@ static  u64 kvm_get_pal_call_index(struct kvm_vcpu *vcpu)
         return index;
 }
 
+static void prepare_for_halt(struct kvm_vcpu *vcpu)
+{
+        vcpu->arch.timer_pending = 1;
+        vcpu->arch.timer_fired = 0;
+}
+
 int kvm_pal_emul(struct kvm_vcpu *vcpu, struct kvm_run *run)
 {
 
@@ -304,11 +310,10 @@ int kvm_pal_emul(struct kvm_vcpu *vcpu, struct kvm_run *run)
                 break;
         case PAL_HALT_LIGHT:
         {
-                vcpu->arch.timer_pending = 1;
                 INIT_PAL_STATUS_SUCCESS(result);
+                prepare_for_halt(vcpu);
                 if (kvm_highest_pending_irq(vcpu) == -1)
                         ret = kvm_emulate_halt(vcpu);
-
         }
                 break;
 
diff --git a/arch/ia64/kvm/process.c b/arch/ia64/kvm/process.c
index 3417783ae164..800817307b7b 100644
--- a/arch/ia64/kvm/process.c
+++ b/arch/ia64/kvm/process.c
@@ -713,7 +713,7 @@ void leave_hypervisor_tail(void)
                                 if (!(VCPU(v, itv) & (1 << 16))) {
                                         vcpu_pend_interrupt(v, VCPU(v, itv)
                                                         & 0xff);
-                                VMX(v, itc_check) = 0;
+                                        VMX(v, itc_check) = 0;
                                 } else {
                                         v->arch.timer_pending = 1;
                                 }