Re: [PATCH v4 13/18] KVM: guest_memfd: Pass GPA, not GFN, to prepare() hook

[Ackerley Tng]

Sean Christopherson <seanjc@xxxxxxxxxx> writes:

> Pass a GPA instead of a GFN to kvm_arch_gmem_prepare() so that the GFN/GPA
> can be made optional in the future, i.e. so that guest_memfd can pass
> INVALID_GPA.  This will allow reworking the hook into a general .convert()

How about defining a INVALID_GFN instead of using gpa just so
INVALID_GPA can be passed? The SNP side takes a gfn, so it seems like
the 2 PAGE_SHIFTs are extra work.

Reviewed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>

> hook, i.e. so that it can be used for both "make private" and "make shared"
> operations, at which point guest_memfd may not have a corresponding GFN,
> e.g. when converting memory back to a shared state when a folio is freed.
>
> Opportunistically swap the ordering of @pfn and @gpa params for
> kvm_x86_ops.gmem_prepare() to match that of kvm_arch_gmem_prepare().
>
> No functional change intended.
>
>
> [...snip...]
>