Add VMEXIT sampling

This patch add VMEXIT sampling when KVM_RECORD. vcpu->nr_vmexit records total VMEXIT
and vcpu->nr_sync records synchronization VMEXIT.

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
Bypass the first log quantum of each vcpu

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
Add conflict detection function to tm_unsync_commit

Now UNSYNC_PREEMPTION with HARD_MMU can support conflict detection and some basic
data analyse (e.g. conflict ratio).

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
Add __mmu_walk_spt_fast and optimize code routine

Add __mmu_walk_spt_fast (though not faster) and optimize code routine of mmu_walk_spt.

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
Add simulator to SOFTWARE logging mode

Change SOFT mode to fit for simulator.

Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>