Re: [PATCH v2 07/20] kvm: x86/mmu: Support zapping SPTEs in the TDP MMU

[Yu Zhang]

On Wed, Oct 21, 2020 at 07:20:15PM +0200, Paolo Bonzini wrote:
> On 21/10/20 17:02, Yu Zhang wrote:
> >>  void kvm_tdp_mmu_free_root(struct kvm *kvm, struct kvm_mmu_page *root)
> >>  {
> >> +	gfn_t max_gfn = 1ULL << (boot_cpu_data.x86_phys_bits - PAGE_SHIFT);
> >> +
> > boot_cpu_data.x86_phys_bits is the host address width. Value of the guest's
> > may vary. So maybe we should just traverse the memslots and zap the gfn ranges
> > in each of them?
> > 
> 
> It must be smaller than the host value for two-dimensional paging, though.

Yes. And using boot_cpu_data.x86_phys_bits works, but won't it be somewhat
overkilling? E.g. for a host with 46 bits and a guest with 39 bits width?

Any concern for doing the zap by going through the memslots? Thanks. :)

B.R.
Yu
> 
> Paolo
>