Would like to add an agenda item for 2025-04-30's PUCK meeting: KVM memory attributes vs guest_memfd shareability. guest_memfd tracks shareability to determine whether a page can be faulted by the host into userspace. pKVM does not use kvm->mem_attr_array for tracking private/shared status of a page, and for Coco VMs like TDX, there seems to be duplicate tracking of private/shared status in guest_memfd's shareability and in KVM's memory attributes. I would like to discuss a proposal for shared/private conversions to be performed through a guest_memfd (not KVM) ioctl instead of using KVM_SET_MEMORY_ATTRIBUTES, where Coco VMs using guest_memfd for both shared and private memory can be able to (with some other changes around KVM memory attributes) skip tracking private/shared in KVM's memory attributes. Thank you!
