Re: [PATCH RFC 00/10] Intel EPT-Based Sub-page Write Protection Support.

[Christoph Hellwig]

> We introduced 2 ioctls to let user application to set/get subpage write protection bitmap per gfn, each gfn corresponds to a bitmap.
> The user application, qemu, or some other security control daemon. will set the protection bitmap via this ioctl.
> the API defined as:
> 	struct kvm_subpage {
> 		__u64 base_gfn;
> 		__u64 npages;
> 		/* sub-page write-access bitmap array */
> 		__u32 access_map[SUBPAGE_MAX_BITMAP];
> 		}sp;
> 	kvm_vm_ioctl(s, KVM_SUBPAGES_SET_ACCESS, &sp)
> 	kvm_vm_ioctl(s, KVM_SUBPAGES_GET_ACCESS, &sp)

What is the use case for this feature?