Integer overflow and remote code are never a nice mix.
This has existed since commit 56cd414.
* src/libvirt.c (virDomainGetVcpus): Reject overflow up front.
* src/remote/remote_driver.c (remoteDomainGetVcpus): Avoid overflow
on sending rpc.
* daemon/remote.c (remoteDispatchDomainGetVcpus): Avoid overflow on
receiving rpc.