Sean Christopherson <seanjc@xxxxxxxxxx> writes: > On Tue, Apr 29, 2025, Ackerley Tng wrote: >> >> Would like to add an agenda item for 2025-04-30's PUCK meeting: KVM >> memory attributes vs guest_memfd shareability. > > Does next week work for you? I.e. May 7th. I won't be able to make tomorrow's > PUCK (about to send a cancelation mail). > >> 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. > > Has the proposal been posted on-list anywhere? I haven't been following the > guest_memfd threads very closely (understatement). We managed to get it discussed at the guest_memfd upstream call. Here are the slides, updated with discussion notes: https://lpc.events/event/18/contributions/1764/attachments/1409/3708/2025-05-01-kvm-memory-attributes-vs-guest_memfd-shareability.pdf Please remove the topic from the next PUCK! Thanks.
