On 9/11/2026 7:55 AM, Ackerley Tng via B4 Relay wrote:
> From: Sean Christopherson <[email protected]>
>
> Add and use kvm_arch_has_gmem_convert() to guard guest_memfd's invocation
> of arch hooks related to converting memory between private and shared, as
> only one half of the x86 CoCo duo needs the runtime hooks (any pre-work is
> pure overhead for TDX). At this exact moment, the overhead is negligible,
> but that will change when in-place conversion comes along, at which point
> to-shared conversions will "need" to find all affected folios prior to
> calling into arch code. In quotes because very technically that work could
> be pushed to arch code, but that would bleed guest_memfd details into arch
> code and would be far worse than adding yet another kvm_arch_has... hook.
>
> Opportunistically provide the kvm_arch_gmem_make_private() declaration, and
> rely on dead-code elimination to eliminate the call to non-existent code
> when CONFIG_HAVE_KVM_ARCH_GMEM_CONVERT=n.
>
> Reported-by: Binbin Wu <[email protected]>
> Closes:
> https://lore.kernel.org/all/[email protected]
> Suggested-by: Ackerley Tng <[email protected]>
> Signed-off-by: Sean Christopherson <[email protected]>
> Signed-off-by: Ackerley Tng <[email protected]>
> Reviewed-by: Fuad Tabba <[email protected]>
> Reviewed-by: Binbin Wu <[email protected]>
> Reviewed-by: David Hildenbrand (Arm) <[email protected]>
Reviewed-by: Xiaoyao Li <[email protected]>
