Re: [PATCH v3 04/70] HostMem: Add mechanism to opt in kvm guest memfd via MachineState

[Xiaoyao Li]

On 11/16/2023 2:14 AM, David Hildenbrand wrote:
> On 15.11.23 08:14, Xiaoyao Li wrote:
> > Add a new member "require_guest_memfd" to memory backends. When it's set
> > to true, it enables RAM_GUEST_MEMFD in ram_flags, thus private kvm
> > guest_memfd will be allocated during RAMBlock allocation.
> >
> > Memory backend's @require_guest_memfd is wired with @require_guest_memfd
> > field of MachineState. MachineState::require_guest_memfd is supposed to
> > be set by any VMs that requires KVM guest memfd as private memory, e.g.,
> > TDX VM.
> >
> > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
>
> I'm confused, why do we need this if it's going to be the same for all 
> memory backends right now?

I want to provide a elegant (in my sense) way to configure "the need of 
guest memfd" instead of checking x86machinestate->vm_type in physmem.c