On 25/09/2017 06:44, Wei Wang wrote:

Passthrough the MSR_IA32_DEBUGCTLMSR to the guest, and take advantage of
the hardware VT-x feature to auto switch the msr upon VMExit and VMEntry.

I think most bits in the MSR should not be passed through (for example
FREEZE_WHILE_SMM_EN, FREEZE_LBRS_ON_PMI etc.).  Using auto-switch of
course is fine instead.

Paolo