On Thu, Apr 7, 2022 at 5:44 AM Brendan Jackman <jackmanb@xxxxxxxxxx> wrote: > > On Thu, 7 Apr 2022 at 01:13, Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote: > > > > On Fri, Apr 1, 2022 at 6:59 PM Joanne Koong <joannekoong@xxxxxx> wrote: > > > > > > From: Joanne Koong <joannelkoong@xxxxxxxxx> > > KP, Florent, Brendan, > > > > You always wanted a way to work with runtime-sized BPF ringbuf samples > > without extra copies. This is the way we can finally do this with good > > usability and simplicity. Please take a look and provide feedback. > > Thanks! > > Thanks folks, this looks very cool. Please excuse my ignorance, one > thing that isn't clear to me is does this work for user memory? Or > would we need bpf_copy_from_user_dynptr to avoid an extra copy? Userspace programs will not be able to use or interact with dynptrs directly. If there is data at a user-space address that needs to be copied into the ringbuffer, the address can be passed to the bpf program and then the bpf program can use a helper like bpf_probe_read_user_dynptr (not added in this patchset but will be part of a following one), which will read the contents at that user address into the ringbuf dynptr.
