On Tuesday 11 Feb 2025 at 16:34:02 (+0000), Fuad Tabba wrote: > > Sorry, yes, that wasn't clear. I meant that kvm_mem_is_private() calls > > kvm_get_memory_attributes() which indexes kvm->mem_attr_array. The > > comment in struct kvm indicates that this xarray is protected by RCU for > > readers, so I was just checking if we were relying on > > kvm_handle_guest_abort() to take srcu_read_lock(&kvm->srcu) for us, or > > if there was something else more subtle here. > > I was kind of afraid that people would be confused by this, and I > commented on it in the commit message of the earlier patch: > https://lore.kernel.org/all/20250211121128.703390-6-tabba@xxxxxxxxxx/ > > > Note that the word "private" in the name of the function > > kvm_mem_is_private() doesn't necessarily indicate that the memory > > isn't shared, but is due to the history and evolution of > > guest_memfd and the various names it has received. In effect, > > this function is used to multiplex between the path of a normal > > page fault and the path of a guest_memfd backed page fault. > > kvm_mem_is_private() is property of the memslot itself. No xarrays > harmed in the process :) Ah, I see, but could someone enable CONFIG_GENERIC_PRIVATE_MEM and related and get confused? Should KVM_GENERIC_MEMORY_ATTRIBUTES=n depend on !ARM64? Or is it KVM_GMEM_SHARED_MEM that needs to depend on the generic implementation being off? Thanks, Quentin
