PPC/KVM: early validation of vcpu id
The KVM API restricts vcpu ids to be < KVM_CAP_MAX_VCPUS. On PowerPC
targets, depending on the number of threads per core in the host and
in the guest, some topologies do generate higher vcpu ids actually.
When this happens, QEMU bails out with the following error:
kvm_init_vcpu failed: Invalid argument
The KVM_CREATE_VCPU ioctl has several EINVAL return paths, so it is
not possible to fully disambiguate.
This patch adds a check in the code that computes vcpu ids, so that
we can detect the error earlier, and print a friendlier message instead
of calling KVM_CREATE_VCPU with an obviously bogus vcpu id.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
diff --git a/kvm-all.c b/kvm-all.c
index f9ae8f9..e56f385 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1459,6 +1459,12 @@
return (ret) ? ret : kvm_recommended_vcpus(s);
}
+bool kvm_vcpu_id_is_valid(int vcpu_id)
+{
+ KVMState *s = KVM_STATE(current_machine->accelerator);
+ return vcpu_id >= 0 && vcpu_id < kvm_max_vcpus(s);
+}
+
static int kvm_init(MachineState *ms)
{
MachineClass *mc = MACHINE_GET_CLASS(ms);