Hi,

If I just considering the pure context switch ovehead, which one has bigger overhead, using HW vmexit/vmentry to do root and non-root mode switch by programming VT-x vetor or using SW hypercall to inject interrupt to switch from ring 1 to ring 0 (or ring 3 to ring 0 for 64bit OS)? Does the switch between ring1 and ring0 has the same overhead as the switch between ring 3 and ring0?

BTW, both root and non-root mode has four rings, if the ring0 and ring3 in non-root mode are used for guest os kernel and user applications, which ring level in root mode will be used when doing vmexit?

Thanks,

Liang