Re: [PATCH 3/5] mmu: don't set the present bit unconditionally

From: Paolo Bonzini
Date: Tue Jul 05 2016 - 06:50:57 EST




On 05/07/2016 07:50, Wanpeng Li wrote:
>> > This needs a comment:
>> >
>> > /*
>> > * There are two cases in which execonly is false: 1) for
>> > * non-EPT page tables, in which case we need to set the
>> > * P bit; 2) for EPT page tables where an X-- page table
> In the scenario of non-EPT shadow page table and non-nested, the
> present bit can't be set any more since
> context->guest_rsvd_check.bad_mt_xwr is always 0.

This will be fixed with a new shadow_present_mask variable.

Paolo