[PATCH v5 5/9] x86, paravirt: Add interface to support kvm/xen vcpu preempted check

This is to fix some lock holder preemption issues. Some other locks implementation do a spin loop before acquiring the lock itself. Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It takes the cpu as parameter and return true if the cpu is preempted. Then kernel can break the

[PATCH v5 5/9] x86, paravirt: Add interface to support kvm/xen vcpu preempted check

This is to fix some lock holder preemption issues. Some other locks implementation do a spin loop before acquiring the lock itself. Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It takes the cpu as parameter and return true if the cpu is preempted. Then kernel can break the