This series is rebased on top of Fuad's v4 for shared mapping of guest_memfd [1].
Change since v2 [2]: - David/Mike D: Only compile support for the write syscall if CONFIG_KVM_GMEM_SHARED_MEM introduced in [1] is enabled.
In non-CoCo use cases where the host can access guest memory, guest_memfd can be allocated and populated via the write syscall. Even though the same can also be achieved via userspace mapping and memcpy from userspace, write provides a more performant option because it 1) avoids double initialisation as the kernel does not need to zero pages and 2) does not require setting up page tables.
Nikita
[1] https://lore.kernel.org/kvm/20250218172500.807733-4-tabba@google.com/T/ [2] https://lore.kernel.org/kvm/20241129123929.64790-1-kalyazin@amazon.com/T/
Nikita Kalyazin (2): KVM: guest_memfd: add generic population via write KVM: selftests: update guest_memfd write tests
.../testing/selftests/kvm/guest_memfd_test.c | 85 +++++++++++++++-- virt/kvm/guest_memfd.c | 94 ++++++++++++++++++- 2 files changed, 170 insertions(+), 9 deletions(-)
base-commit: 005f6404708d430abab7fab9b422d0daf6e0c2fe