[COMMIT master] KVM: convert ioapic lock to spinlock

[Avi Kivity]

From: Marcelo Tosatti <mtosa...@redhat.com>

kvm_set_irq is used from non sleepable contexes, so convert ioapic from
mutex to spinlock.

KVM-Stable-Tag.
Tested-by: Ralf Bonenkamp <ralf.bonenk...@swyx.com>
Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>

diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 03a5eb2..7c79c1d 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -197,7 +197,7 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, 
int level)
        union kvm_ioapic_redirect_entry entry;
        int ret = 1;
 
-       mutex_lock(&ioapic->lock);
+       spin_lock(&ioapic->lock);
        if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
                entry = ioapic->redirtbl[irq];
                level ^= entry.fields.polarity;
@@ -214,7 +214,7 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, 
int level)
                }
                trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
        }
-       mutex_unlock(&ioapic->lock);
+       spin_unlock(&ioapic->lock);
 
        return ret;
 }
@@ -238,9 +238,9 @@ static void __kvm_ioapic_update_eoi(struct kvm_ioapic 
*ioapic, int vector,
                 * is dropped it will be put into irr and will be delivered
                 * after ack notifier returns.
                 */
-               mutex_unlock(&ioapic->lock);
+               spin_unlock(&ioapic->lock);
                kvm_notify_acked_irq(ioapic->kvm, KVM_IRQCHIP_IOAPIC, i);
-               mutex_lock(&ioapic->lock);
+               spin_lock(&ioapic->lock);
 
                if (trigger_mode != IOAPIC_LEVEL_TRIG)
                        continue;
@@ -259,9 +259,9 @@ void kvm_ioapic_update_eoi(struct kvm *kvm, int vector, int 
trigger_mode)
        smp_rmb();
        if (!test_bit(vector, ioapic->handled_vectors))
                return;
-       mutex_lock(&ioapic->lock);
+       spin_lock(&ioapic->lock);
        __kvm_ioapic_update_eoi(ioapic, vector, trigger_mode);
-       mutex_unlock(&ioapic->lock);
+       spin_unlock(&ioapic->lock);
 }
 
 static inline struct kvm_ioapic *to_ioapic(struct kvm_io_device *dev)
@@ -287,7 +287,7 @@ static int ioapic_mmio_read(struct kvm_io_device *this, 
gpa_t addr, int len,
        ASSERT(!(addr & 0xf));  /* check alignment */
 
        addr &= 0xff;
-       mutex_lock(&ioapic->lock);
+       spin_lock(&ioapic->lock);
        switch (addr) {
        case IOAPIC_REG_SELECT:
                result = ioapic->ioregsel;
@@ -301,7 +301,7 @@ static int ioapic_mmio_read(struct kvm_io_device *this, 
gpa_t addr, int len,
                result = 0;
                break;
        }
-       mutex_unlock(&ioapic->lock);
+       spin_unlock(&ioapic->lock);
 
        switch (len) {
        case 8:
@@ -338,7 +338,7 @@ static int ioapic_mmio_write(struct kvm_io_device *this, 
gpa_t addr, int len,
        }
 
        addr &= 0xff;
-       mutex_lock(&ioapic->lock);
+       spin_lock(&ioapic->lock);
        switch (addr) {
        case IOAPIC_REG_SELECT:
                ioapic->ioregsel = data;
@@ -356,7 +356,7 @@ static int ioapic_mmio_write(struct kvm_io_device *this, 
gpa_t addr, int len,
        default:
                break;
        }
-       mutex_unlock(&ioapic->lock);
+       spin_unlock(&ioapic->lock);
        return 0;
 }
 
@@ -386,7 +386,7 @@ int kvm_ioapic_init(struct kvm *kvm)
        ioapic = kzalloc(sizeof(struct kvm_ioapic), GFP_KERNEL);
        if (!ioapic)
                return -ENOMEM;
-       mutex_init(&ioapic->lock);
+       spin_lock_init(&ioapic->lock);
        kvm->arch.vioapic = ioapic;
        kvm_ioapic_reset(ioapic);
        kvm_iodevice_init(&ioapic->dev, &ioapic_mmio_ops);
@@ -419,9 +419,9 @@ int kvm_get_ioapic(struct kvm *kvm, struct kvm_ioapic_state 
*state)
        if (!ioapic)
                return -EINVAL;
 
-       mutex_lock(&ioapic->lock);
+       spin_lock(&ioapic->lock);
        memcpy(state, ioapic, sizeof(struct kvm_ioapic_state));
-       mutex_unlock(&ioapic->lock);
+       spin_unlock(&ioapic->lock);
        return 0;
 }
 
@@ -431,9 +431,9 @@ int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state 
*state)
        if (!ioapic)
                return -EINVAL;
 
-       mutex_lock(&ioapic->lock);
+       spin_lock(&ioapic->lock);
        memcpy(ioapic, state, sizeof(struct kvm_ioapic_state));
        update_handled_vectors(ioapic);
-       mutex_unlock(&ioapic->lock);
+       spin_unlock(&ioapic->lock);
        return 0;
 }
diff --git a/virt/kvm/ioapic.h b/virt/kvm/ioapic.h
index 8a751b7..0b190c3 100644
--- a/virt/kvm/ioapic.h
+++ b/virt/kvm/ioapic.h
@@ -45,7 +45,7 @@ struct kvm_ioapic {
        struct kvm_io_device dev;
        struct kvm *kvm;
        void (*ack_notifier)(void *opaque, int irq);
-       struct mutex lock;
+       spinlock_t lock;
        DECLARE_BITMAP(handled_vectors, 256);
 };
 
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