Re: [RFC PATCH 02/12] KVM: x86/mmu: Add dedicated API to map guest_memfd pfn into TDP MMU

[Sean Christopherson]

On Thu, Aug 28, 2025, Rick P Edgecombe wrote:
> On Wed, 2025-08-27 at 19:40 -0500, Ira Weiny wrote:
> > > +		.map_writable = true,
> > 
> > Why is map_writable set?  Doesn't this get translated into host_writable?
> 
> I guess it's normally set only if it's a !KVM_MEM_READONLY slot for private
> faults memory. 

map_writable can also be %false on read faults and the host userspace mapping
isn't writable. 

> But that flag is invalid for gmem. So we should only have
> map_writable=true cases for tdx.

Yep.  And not TDX specific, map_writable _must_ be true for write faults.  The
reason there's two separate flags is so that KVM can opportunistically create a
writable mapping on read faults.