KVM: x86: Add module parameter for lapic periodic timer limit

[deliverable/linux.git] / arch / x86 / kvm / lapic.c

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 57dcbd4308fa8f69efec6462a52a13b594bfbeb8..2fb20caae5d8b7453efa989ac44e1ba029577b26 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -68,6 +68,9 @@
 #define VEC_POS(v) ((v) & (32 - 1))
 #define REG_POS(v) (((v) >> 5) << 4)
 
+static unsigned int min_timer_period_us = 500;
+module_param(min_timer_period_us, uint, S_IRUGO | S_IWUSR);
+
 static inline u32 apic_get_reg(struct kvm_lapic *apic, int reg_off)
 {
        return *((u32 *) (apic->regs + reg_off));
@@ -316,8 +319,8 @@ int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda)
                        result = 1;
                break;
        default:
-               printk(KERN_WARNING "Bad DFR vcpu %d: %08x\n",
-                      apic->vcpu->vcpu_id, apic_get_reg(apic, APIC_DFR));
+               apic_debug("Bad DFR vcpu %d: %08x\n",
+                          apic->vcpu->vcpu_id, apic_get_reg(apic, APIC_DFR));
                break;
        }
 
@@ -354,8 +357,8 @@ int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
                result = (target != source);
                break;
        default:
-               printk(KERN_WARNING "Bad dest shorthand value %x\n",
-                      short_hand);
+               apic_debug("kvm: apic: Bad dest shorthand value %x\n",
+                          short_hand);
                break;
        }
 
@@ -401,11 +404,11 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
                break;
 
        case APIC_DM_REMRD:
-               printk(KERN_DEBUG "Ignoring delivery mode 3\n");
+               apic_debug("Ignoring delivery mode 3\n");
                break;
 
        case APIC_DM_SMI:
-               printk(KERN_DEBUG "Ignoring guest SMI\n");
+               apic_debug("Ignoring guest SMI\n");
                break;
 
        case APIC_DM_NMI:
@@ -565,8 +568,7 @@ static u32 __apic_read(struct kvm_lapic *apic, unsigned int offset)
                        val = kvm_apic_id(apic) << 24;
                break;
        case APIC_ARBPRI:
-               printk(KERN_WARNING "Access APIC ARBPRI register "
-                      "which is for P6\n");
+               apic_debug("Access APIC ARBPRI register which is for P6\n");
                break;
 
        case APIC_TMCCT:        /* Timer CCR */
@@ -678,8 +680,16 @@ static void start_apic_timer(struct kvm_lapic *apic)
         * scheduler.
         */
        if (apic_lvtt_period(apic)) {
-               if (apic->lapic_timer.period < NSEC_PER_MSEC/2)
-                       apic->lapic_timer.period = NSEC_PER_MSEC/2;
+               s64 min_period = min_timer_period_us * 1000LL;
+
+               if (apic->lapic_timer.period < min_period) {
+                       pr_info_ratelimited(
+                               "kvm: vcpu %i: requested %lld ns "
+                               "lapic timer period limited to %lld ns\n",
+                               apic->vcpu->vcpu_id, apic->lapic_timer.period,
+                               min_period);
+                       apic->lapic_timer.period = min_period;
+               }
        }
 
        hrtimer_start(&apic->lapic_timer.timer,
@@ -804,14 +814,14 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
 
        case APIC_TDCR:
                if (val & 4)
-                       printk(KERN_ERR "KVM_WRITE:TDCR %x\n", val);
+                       apic_debug("KVM_WRITE:TDCR %x\n", val);
                apic_set_reg(apic, APIC_TDCR, val);
                update_divide_count(apic);
                break;
 
        case APIC_ESR:
                if (apic_x2apic_mode(apic) && val != 0) {
-                       printk(KERN_ERR "KVM_WRITE:ESR not zero %x\n", val);
+                       apic_debug("KVM_WRITE:ESR not zero %x\n", val);
                        ret = 1;
                }
                break;
@@ -864,6 +874,15 @@ static int apic_mmio_write(struct kvm_io_device *this,
        return 0;
 }
 
+void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu)
+{
+       struct kvm_lapic *apic = vcpu->arch.apic;
+
+       if (apic)
+               apic_reg_write(vcpu->arch.apic, APIC_EOI, 0);
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_set_eoi);
+
 void kvm_free_lapic(struct kvm_vcpu *vcpu)
 {
        if (!vcpu->arch.apic)