From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:39199) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tkirm-0007bC-Jo for qemu-devel@nongnu.org; Mon, 17 Dec 2012 17:08:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Tkirl-0004NW-BE for qemu-devel@nongnu.org; Mon, 17 Dec 2012 17:08:54 -0500 Received: from cantor2.suse.de ([195.135.220.15]:48710 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tkirl-0004NR-1L for qemu-devel@nongnu.org; Mon, 17 Dec 2012 17:08:53 -0500 Message-ID: <50CF97EB.9070200@suse.de> Date: Mon, 17 Dec 2012 23:08:43 +0100 From: =?ISO-8859-1?Q?Andreas_F=E4rber?= MIME-Version: 1.0 References: <20121217154521.GA28674@redhat.com> <50CF5CA2.7060800@suse.de> <50CF629A.4090005@redhat.com> <50CF6384.9040809@suse.de> <20121217204811.GB30842@redhat.com> <50CF8AE7.1090803@suse.de> <20121217211831.GA11153@redhat.com> In-Reply-To: <20121217211831.GA11153@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH] virtio: make bindings typesafe List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Anthony Liguori , Jan Kiszka , qemu-devel@nongnu.org, Alexander Graf , Christian Borntraeger , Paolo Bonzini , fred.konrad@greensocs.com Am 17.12.2012 22:18, schrieb Michael S. Tsirkin: > On Mon, Dec 17, 2012 at 10:13:11PM +0100, Andreas F=E4rber wrote: >> Am 17.12.2012 21:48, schrieb Michael S. Tsirkin: >>> On Mon, Dec 17, 2012 at 07:25:08PM +0100, Andreas F=E4rber wrote: >>>> Am 17.12.2012 19:21, schrieb Paolo Bonzini: >>>>> Il 17/12/2012 18:55, Andreas F=E4rber ha scritto: >>>>>> Am 17.12.2012 16:45, schrieb Michael S. Tsirkin: >>>>>>> diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c >>>>>>> index 3ea4140..63ae888 100644 >>>>>>> --- a/hw/virtio-pci.c >>>>>>> +++ b/hw/virtio-pci.c >>>>>>> @@ -98,34 +98,34 @@ bool virtio_is_big_endian(void); >>>>>>> =20 >>>>>>> /* virtio device */ >>>>>>> =20 >>>>>>> -static void virtio_pci_notify(void *opaque, uint16_t vector) >>>>>>> +static void virtio_pci_notify(DeviceState *d, uint16_t vector) >>>>>>> { >>>>>>> - VirtIOPCIProxy *proxy =3D opaque; >>>>>>> + VirtIOPCIProxy *proxy =3D container_of(d, VirtIOPCIProxy, pc= i_dev.qdev); >>>>>> >>>>>> Nack. This is going the wrong direction QOM-wise and you among all >>>>>> others know that from PCI host bridges! >>>>> >>>>> Well, that's just a difference of VIRTIO_PCI_PROXY(d) vs. container= _of. >>>> >>>> VIRTIO_PCI_PROXY(d) would be acceptable, sure. But as-is this patch = just >>>> pushes unnecessary work on Fred, me, you or anyone else who works wi= th QOM. >>> >>> What's VIRTIO_PCI_PROXY? Note this is data path we do not want extra >>> code. >> >> My complaint is the direct access of pci_dev, qdev, etc. parent fields >> in many places as the main change of this patch. Those mean more place= s >> to touch in a future patch. >> >> Use of any new-style macro hiding these - wherever the particular one >> suggested may be defined or whether it needs to be added - is better. >> >> If performance of dynamic_cast is an issue - something I'd leave you t= o >> discuss with Anthony - you can just do a C cast directly. Just don't >> spread this qdev paradigm further please. >=20 > OK so just >=20 > #define VIRTIO_PCI_PROXY(d) container_of(d, VirtIOPCIProxy, pci_dev.qde= v) >=20 > is OK with you? Well, at least it's better than inlining it... I would've expected to see VIRTIO_PCI_PROXY(obj) defined as OBJECT_CHECK(VirtIOPCIProxy, (obj), TYPE_something) somewhere. If, as you imply with "data path", this were a problem, you could just do VirtIOPCIProxy *proxy =3D (VirtIOPCIProxy *)d inline to allow for VIRTIO_PCI_PROXY() to be used in the QOM sense elsewhere. Andreas --=20 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 N=FCrnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imend=F6rffer; HRB 16746 AG N=FCrnbe= rg