KVM: Convert kvm->requests_lock to raw_spinlock_t

The code relies on kvm->requests_lock inhibiting preemption.

Noted by Jan Kiszka.

Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 3145b28..a3fd0f9 100644 (file)
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -161,7 +161,7 @@ struct kvm_memslots {
 
 struct kvm {
        spinlock_t mmu_lock;
-       spinlock_t requests_lock;
+       raw_spinlock_t requests_lock;
        struct mutex slots_lock;
        struct mm_struct *mm; /* userspace tied to this vm */
        struct kvm_memslots *memslots;

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0a360c2..548f925 100644 (file)
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -138,7 +138,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
 
        zalloc_cpumask_var(&cpus, GFP_ATOMIC);
 
-       spin_lock(&kvm->requests_lock);
+       raw_spin_lock(&kvm->requests_lock);
        me = smp_processor_id();
        kvm_for_each_vcpu(i, vcpu, kvm) {
                if (test_and_set_bit(req, &vcpu->requests))
@@ -153,7 +153,7 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req)
                smp_call_function_many(cpus, ack_flush, NULL, 1);
        else
                called = false;
-       spin_unlock(&kvm->requests_lock);
+       raw_spin_unlock(&kvm->requests_lock);
        free_cpumask_var(cpus);
        return called;
 }
@@ -409,7 +409,7 @@ static struct kvm *kvm_create_vm(void)
        kvm->mm = current->mm;
        atomic_inc(&kvm->mm->mm_count);
        spin_lock_init(&kvm->mmu_lock);
-       spin_lock_init(&kvm->requests_lock);
+       raw_spin_lock_init(&kvm->requests_lock);
        kvm_eventfd_init(kvm);
        mutex_init(&kvm->lock);
        mutex_init(&kvm->irq_lock);