Re: [PATCH v12 08/18] KVM: guest_memfd: Allow host to map guest_memfd pages

[Sean Christopherson <seanjc@google.com>]

On Fri, Jun 13, 2025, Sean Christopherson wrote:
> On Wed, Jun 11, 2025, Fuad Tabba wrote:

...

> > +static vm_fault_t kvm_gmem_fault_shared(struct vm_fault *vmf)
> 
> And to my point about "shared", this is also very confusing, because there are
> zero checks in here about shared vs. private.

Heh, and amusingly (to me at least), I was the one that suggested this name[*]:

 : >  static vm_fault_t kvm_gmem_fault(struct vm_fault *vmf)
 :
 : This should be something like kvm_gmem_fault_shared() make it abundantly clear
 : what's being done.  Because it too me a few looks to realize this is faulting
 : memory into host userspace, not into the guest.

Though I don't think my two statements are contradictory.  A bare kvm_gmem_fault()
is confusing because it's ambigous.  kvm_gmem_fault_shared() is confusing because
"shared" is (IMO) bad terminology.

E.g. to me, this is much more obvious:

  static vm_fault_t kvm_gmem_fault_user(struct vm_fault *vmf)

or even

  static vm_fault_t kvm_gmem_fault_user_mapping(struct vm_fault *vmf)

if we're worried about "user" getting confused with supervisor vs. user in the
guest.

[*] https://lore.kernel.org/all/Z-3UGmcCwJtaP-yF@google.com