Fred Griffoul <[email protected]> writes: > From: Fred Griffoul <[email protected]> > > Some drivers manage RAM outside the page allocator: a carve-out, device > memory, or memory that a host component moves between VMs while they > run. This memory often has no struct page. The driver wants to lend > pages to a VM and to its devices, and to take any of them back later. > > David Woodhouse's series "KVM: Allow alternative providers of > guest_memfd backed by PFNMAP memory" lets such a driver back a > guest_memfd through struct kvm_gmem_ops: > > https://lore.kernel.org/kvm/[email protected]/ > > That covers the guest, but not the VM's devices, which his cover > letter left as an open question. This series adds a small interface in > mm: the driver that owns the memory becomes a provider, and the code > that maps it attaches as a consumer. There are two consumers, a > guest_memfd backend and IOMMU_IOAS_MAP_FILE in iommufd. > > The series is on top of David's v2 (base 0e35b9b6ec0f). Patch 1 was > part of the earlier dma-buf RFC. The provider backend depends on it, so > this series carries it. >
I have been working on something similar for confidential computing use cases. There is likely some overlap between this series and what I posted at [1]. I have not reviewed this series in detail yet, but I will compare the two approaches and identify what can be shared between the use cases. Please let me know how you would like to proceed. [1] https://lore.kernel.org/all/[email protected]/ -aneesh
