diff options
| author | Avi Kivity <avi@redhat.com> | 2012-05-09 16:10:42 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-05-12 09:32:20 -0700 |
| commit | 9c895160d25a76c21b65bad141b08e8d4f99afef (patch) | |
| tree | 22d83e7d09ae2ecc67ff7480a27d6b30b6d32b5b | |
| parent | c1cca0b1b79ba339d040793ad70fad254e1af220 (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.c | 5 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 8 | ||||
| -rw-r--r-- | include/linux/kvm_host.h | 7 | ||||
| -rw-r--r-- | virt/kvm/kvm_main.c | 4 |
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; |