Re: [RFC PATCH v2 03/21] HostMem: Add private property and associate it with RAM_KVM_GMEM

[Xiaoyao Li]

On 9/20/2023 3:30 PM, Markus Armbruster wrote:
> Xiaoyao Li <xiaoyao.li@intel.com> writes:
>
> > On 9/19/2023 5:46 PM, Markus Armbruster wrote:
> > > Xiaoyao Li <xiaoyao.li@intel.com> writes:
> > >
> > > > From: Isaku Yamahata <isaku.yamahata@intel.com>
> > > >
> > > > Add a new property "private" to memory backends. When it's set to true,
> > > > it indicates the RAMblock of the backend also requires kvm gmem.
> > > Can you add a brief explanation why you need the property?
> >
> > It provides a mechanism for user to specify whether the memory can serve as 
> > private memory (need request kvm gmem).
>
> Yes, but why would a user want such memory?

Because KVM demands it for confidential guest, e.g., TDX guest. KVM 
demands that the mem slot needs to have KVM_MEM_PRIVATE set and has 
valid gmem associated if the guest accesses it as private memory.