[PATCH 28/35] KVM: x86: disallow multiple KVM_CREATE_IRQCHIP

Avi Kivity
2009-11-19T13:35:09Z

From: Marcelo Tosatti <mtosatti@redhat.com>

Otherwise kvm will leak memory on multiple KVM_CREATE_IRQCHIP.
Also serialize multiple accesses with kvm->lock.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
---
arch/x86/kvm/irq.h | 6 +++++-
arch/x86/kvm/x86.c | 30 ++++++++++++++++++++++--------
2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/irq.h b/arch/x86/kvm/irq.h
index c025a23..be399e2 100644
--- a/arch/x86/kvm/irq.h
+++ b/arch/x86/kvm/irq.h
@@ -86,7 +86,11 @@ static inline struct kvm_pic *pic_irqchip(struct kvm *kvm)

static inline int irqchip_in_kernel(struct kvm *kvm)
{
- return pic_irqchip(kvm) != NULL;
+ int ret;
+
+ ret = (pic_irqchip(kvm) != NULL);
+ smp_rmb();
+ return ret;
}

void kvm_pic_reset(struct kvm_kpic_state *s);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 719f31e..97f6f95 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2362,25 +2362,39 @@ long kvm_arch_vm_ioctl(struct file *filp,
if (r)
goto out;
break;
- case KVM_CREATE_IRQCHIP:
+ case KVM_CREATE_IRQCHIP: {
+ struct kvm_pic *vpic;
+
+ mutex_lock(&kvm->lock);
+ r = -EEXIST;
+ if (kvm->arch.vpic)
+ goto create_irqchip_unlock;
r = -ENOMEM;
- kvm->arch.vpic = kvm_create_pic(kvm);
- if (kvm->arch.vpic) {
+ vpic = kvm_create_pic(kvm);
+ if (vpic) {
r = kvm_ioapic_init(kvm);
if (r) {
- kfree(kvm->arch.vpic);
- kvm->arch.vpic = NULL;
- goto out;
+ kfree(vpic);
+ goto create_irqchip_unlock;
}
} else
- goto out;
+ goto create_irqchip_unlock;
+ smp_wmb();
+ kvm->arch.vpic = vpic;
+ smp_wmb();
r = kvm_setup_default_irq_routing(kvm);
if (r) {
+ mutex_lock(&kvm->irq_lock);
kfree(kvm->arch.vpic);
kfree(kvm->arch.vioapic);
- goto out;
+ kvm->arch.vpic = NULL;
+ kvm->arch.vioapic = NULL;
+ mutex_unlock(&kvm->irq_lock);
}
+ create_irqchip_unlock:
+ mutex_unlock(&kvm->lock);
break;
+ }
case KVM_CREATE_PIT:
u.pit_config.flags = KVM_PIT_SPEAKER_DUMMY;
goto create_pit;
--
1.6.5.2