KVM: x86: Gracefully handle __vmalloc() failure during VM allocation

commit d18b2f43b9 upstream.

Check the result of __vmalloc() to avoid dereferencing a NULL pointer in
the event that allocation failres.

Fixes: d1e5b0e98e ("kvm: Make VM ioctl do valloc for some archs")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/kvm/svm.c

@@ -1917,6 +1917,10 @@ static void __unregister_enc_region_locked(struct kvm *kvm,
 static struct kvm *svm_vm_alloc(void)
 {
 	struct kvm_svm *kvm_svm = vzalloc(sizeof(struct kvm_svm));
+
+	if (!kvm_svm)
+		return NULL;
+
 	return &kvm_svm->kvm;
 }
 

arch/x86/kvm/vmx.c

@@ -10986,6 +10986,10 @@ STACK_FRAME_NON_STANDARD(vmx_vcpu_run);
 static struct kvm *vmx_vm_alloc(void)
 {
 	struct kvm_vmx *kvm_vmx = vzalloc(sizeof(struct kvm_vmx));
+
+	if (!kvm_vmx)
+		return NULL;
+
 	return &kvm_vmx->kvm;
 }