From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net-next V2 3/3] tun: add eBPF based queue selection method Date: Wed, 8 Nov 2017 14:28:53 +0900 Message-ID: <1e5256e3-72cf-fa6b-b00e-2661e29291b1@redhat.com> References: <1509445938-4345-1-git-send-email-jasowang@redhat.com> <1509445938-4345-4-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Cc: Network Development , LKML , "Michael S. Tsirkin" , Tom Herbert To: Willem de Bruijn Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 2017年11月04日 08:56, Willem de Bruijn wrote: > On Fri, Nov 3, 2017 at 5:56 PM, Willem de Bruijn > wrote: >> On Tue, Oct 31, 2017 at 7:32 PM, Jason Wang wrote: >>> This patch introduces an eBPF based queue selection method based on >>> the flow steering policy ops. Userspace could load an eBPF program >>> through TUNSETSTEERINGEBPF. This gives much more flexibility compare >>> to simple but hard coded policy in kernel. >>> >>> Signed-off-by: Jason Wang >>> --- >>> +static int tun_set_steering_ebpf(struct tun_struct *tun, void __user *data) >>> +{ >>> + struct bpf_prog *prog; >>> + u32 fd; >>> + >>> + if (copy_from_user(&fd, data, sizeof(fd))) >>> + return -EFAULT; >>> + >>> + prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER); >> If the idea is to allow guests to pass BPF programs down to the host, >> you may want to define a new program type that is more restrictive than >> socket filter. >> >> The external functions allowed for socket filters (sk_filter_func_proto) >> are relatively few (compared to, say, clsact), but may still leak host >> information to a guest. More importantly, guest security considerations >> limits how we can extend socket filters later. > Unless the idea is for the hypervisor to prepared the BPF based on a > limited set of well defined modes that the guest can configure. Then > socket filters are fine, as the BPF is prepared by a regular host process. Yes, I think the idea is to let qemu to build a BPF program now. Passing eBPF program from guest to host is interesting, but an obvious issue is how to deal with the accessing of map. Thanks