Re: [ANNOUNCE] PUCK Agenda - 2025.04.02 - No Topic

[Sean Christopherson <seanjc@google.com>]

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).