> Also, shadow walking is not significantly faster than guest page table walking. And if we miss, we have to walk the guest page tables in any case.
>
Um. i think walking guest page table is slower, it needs to walk memslots for many times
and it triggers page fault if the host page is swapped.
And it is hardly missed, since for tdp, it infrequency zaps shadow pages, for soft mmu,
the mmio spte is always unsync, and in guest, the mmio region is always mapped by kernel,
so it is infrequency to be update and lazily flushed.
>> +
>> +static bool quickly_check_mmio_pf(struct kvm_vcpu *vcpu, u64 addr, bool direct)
>> +{
>> + if (direct&& vcpu_match_mmio_gpa(vcpu, addr))
>> + return true;
>> +
>> + if (vcpu_match_mmio_gva(vcpu, addr))
>> + return true;
>> +
>> + return false;
>> +}
>
> There is also the case of nesting - it's not direct and it's not a gva.
>
If it is direct, we only need to compare the pga, and direct=0, we only need to
compare gva, i'll fix the code to make it clear.