From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: udev PATH_ID for virtio devices Date: Thu, 27 Mar 2014 20:59:02 +0200 Message-ID: <20140327185902.GA4059@redhat.com> References: <20140327173009.GA2593@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Kay Sievers Cc: Tom Gundersen , virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org On Thu, Mar 27, 2014 at 07:43:34PM +0100, Kay Sievers wrote: > On Thu, Mar 27, 2014 at 6:30 PM, Michael S. Tsirkin wrote: > > > If the virtio device is a PCI device, it is really best to > > treat it like you treat any other PCI function (I guess you mean > > function and not device, right? We support multifunction > > devices and some people do pack multiple NICs in a single device).. > > > > At the moment many devices in a single pci function can not happen on a > > PCI system (no multiport) but if we add multiport, we'll follow some > > existing standard to expose this information to the guest. > > This means, that there can currently never multiple devices below one > and the same virtio parent device? > > Kay There's a single virtio device per pci function (you keep saying device but I hope the distinction is clear and this is just slip of the tongue). For net devices under a pci function that is also currently the case, but I can't yet tell you for sure ahead of the time how we'll present multiport devices if we ever implement them. I'm guessing there will be multiple net devices under a single pci device and we'll present a sysfs attribute with the port number in this case. Hmm maybe we should go ahead and add a place-holder attribute so that it's future-proof? I'll write a patch like that and we'll see how it's accepted. -- MST