kernel: KVM: Explicitly verify target vCPU is online in kvm_get_vcpu()

In the Linux kernel, the following vulnerability has been resolved: KVM: Explicitly verify target vCPU is online in kvmgetvcpu Explicitly verify the target vCPU is fully online prior to clamping the index in kvmgetvcpu. If the index is "bad", the nospec clamping will generate '0', i.e. KVM will...