Re: [RFCv2 13/13] KVM: unmap guest memory using poisoned pages

[Xiaoyao Li]

On 4/17/2021 1:30 AM, Sean Christopherson wrote:
> On Fri, Apr 16, 2021, Kirill A. Shutemov wrote:
[...]
> > index fadaccb95a4c..cd2374802702 100644
> > --- a/include/linux/kvm_host.h
> > +++ b/include/linux/kvm_host.h
> > @@ -436,6 +436,8 @@ static inline int kvm_arch_vcpu_memslots_id(struct kvm_vcpu *vcpu)
> >   }
> >   #endif
> >   
> > +#define KVM_NR_SHARED_RANGES 32
> > +
> >   /*
> >    * Note:
> >    * memslots are not sorted by id anymore, please use id_to_memslot()
> > @@ -513,6 +515,10 @@ struct kvm {
> >   	pid_t userspace_pid;
> >   	unsigned int max_halt_poll_ns;
> >   	u32 dirty_ring_size;
> > +	bool mem_protected;
> > +	void *id;
> > +	int nr_shared_ranges;
> > +	struct range shared_ranges[KVM_NR_SHARED_RANGES];
>
> Hard no for me.  IMO, anything that requires KVM to track shared/pinned pages in
> a separate tree/array is non-starter.  More specific to TDX #MCs, KVM should not
> be the canonical reference for the state of a page.

Do you mean something in struct page to track if the page is shared or 
private?