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authorAvi Kivity <avi@redhat.com>2012-05-09 16:10:42 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-12 09:32:20 -0700
commit9c895160d25a76c21b65bad141b08e8d4f99afef (patch)
tree22d83e7d09ae2ecc67ff7480a27d6b30b6d32b5b
parentc1cca0b1b79ba339d040793ad70fad254e1af220 (diff)
KVM: Ensure all vcpus are consistent with in-kernel irqchip settings
(cherry picked from commit 3e515705a1f46beb1c942bb8043c16f8ac7b1e9e) If some vcpus are created before KVM_CREATE_IRQCHIP, then irqchip_in_kernel() and vcpu->arch.apic will be inconsistent, leading to potential NULL pointer dereferences. Fix by: - ensuring that no vcpus are installed when KVM_CREATE_IRQCHIP is called - ensuring that a vcpu has an apic if it is installed after KVM_CREATE_IRQCHIP This is somewhat long winded because vcpu->arch.apic is created without kvm->lock held. Based on earlier patch by Michael Ellerman. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/ia64/kvm/kvm-ia64.c5
-rw-r--r--arch/x86/kvm/x86.c8
-rw-r--r--include/linux/kvm_host.h7
-rw-r--r--virt/kvm/kvm_main.c4
4 files changed, 24 insertions, 0 deletions
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 405052002493..8c25855f73a8 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1169,6 +1169,11 @@ out:
#define PALE_RESET_ENTRY 0x80000000ffffffb0UL
+bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu)
+{
+ return irqchip_in_kernel(vcpu->kcm) == (vcpu->arch.apic != NULL);
+}
+
int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
struct kvm_vcpu *v;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 410b6b0565ab..8d1c6c6ecc9e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3131,6 +3131,9 @@ long kvm_arch_vm_ioctl(struct file *filp,
r = -EEXIST;
if (kvm->arch.vpic)
goto create_irqchip_unlock;
+ r = -EINVAL;
+ if (atomic_read(&kvm->online_vcpus))
+ goto create_irqchip_unlock;
r = -ENOMEM;
vpic = kvm_create_pic(kvm);
if (vpic) {
@@ -5956,6 +5959,11 @@ void kvm_arch_check_processor_compat(void *rtn)
kvm_x86_ops->check_processor_compatibility(rtn);
}
+bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu)
+{
+ return irqchip_in_kernel(vcpu->kvm) == (vcpu->arch.apic != NULL);
+}
+
int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu)
{
struct page *page;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index bc2172077d9d..4c4e83d22dce 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -775,6 +775,13 @@ static inline bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu)
{
return vcpu->kvm->bsp_vcpu_id == vcpu->vcpu_id;
}
+
+bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu);
+
+#else
+
+static inline bool kvm_vcpu_compatible(struct kvm_vcpu *vcpu) { return true; }
+
#endif
#ifdef __KVM_HAVE_DEVICE_ASSIGNMENT
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4c68c1e875b5..785822896ced 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1720,6 +1720,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
goto vcpu_destroy;
mutex_lock(&kvm->lock);
+ if (!kvm_vcpu_compatible(vcpu)) {
+ r = -EINVAL;
+ goto unlock_vcpu_destroy;
+ }
if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) {
r = -EINVAL;
goto unlock_vcpu_destroy;