Re: [PATCH 02/22] kvm: mmu: Introduce tdp_iter

[Paolo Bonzini]

On 01/10/20 01:20, Eric van Tassell wrote:
>>
>> +int is_shadow_present_pte(u64 pte)
>>   {
>>       return (pte != 0) && !is_mmio_spte(pte);
> From <Figure 28-1: Formats of EPTP and EPT Paging-Structure Entries" of
> the manual I don't have at my fingertips right now, I believe you should
> only check the low 3 bits(mask = 0x7). Since the upper bits are ignored,
> might that not mean they're not guaranteed to be 0?

No, this a property of the KVM MMU (and how it builds its PTEs) rather
than the hardware present check.

Paolo