From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:27378 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389281AbfJYBot (ORCPT ); Thu, 24 Oct 2019 21:44:49 -0400 Subject: Re: [PATCH V5 2/6] modpost: add support for mdev class id References: <20191023130752.18980-1-jasowang@redhat.com> <20191023130752.18980-3-jasowang@redhat.com> <20191023154245.32e4fa49@x1.home> <555a101e-0ed1-2e9d-c1a4-e3b37d76bd18@redhat.com> <20191024135441.160daa56@x1.home> From: Jason Wang Message-ID: <7eb2c515-74a9-7d65-e09c-dee4f952e9c1@redhat.com> Date: Fri, 25 Oct 2019 09:44:05 +0800 MIME-Version: 1.0 In-Reply-To: <20191024135441.160daa56@x1.home> Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Sender: linux-s390-owner@vger.kernel.org List-ID: To: Alex Williamson Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, kwankhede@nvidia.com, mst@redhat.com, tiwei.bie@intel.com, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, cohuck@redhat.com, maxime.coquelin@redhat.com, cunming.liang@intel.com, zhihong.wang@intel.com, rob.miller@broadcom.com, xiao.w.wang@intel.com, haotian.wang@sifive.com, zhenyuw@linux.intel.com, zhi.a.wang@intel.com, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, airlied@linux.ie, daniel@ffwll.ch, farman@linux.ibm.com, pasic@linux.ibm.com, sebott@linux.ibm.com, oberpar@linux.ibm.com, heiko.carstens@de.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, akrowiak@linux.ibm.com, freude@linux.ibm.com, lingshan.zhu@intel.com, idos@mellanox.com, eperezma@redhat.com, lulu@redhat.com, parav@mellanox.com, christophe.de.dinechin@gmail.com, kevin.tian@intel.com, stefanha@redhat.com On 2019/10/25 =E4=B8=8A=E5=8D=883:54, Alex Williamson wrote: > On Thu, 24 Oct 2019 11:31:04 +0800 > Jason Wang wrote: > >> On 2019/10/24 =E4=B8=8A=E5=8D=885:42, Alex Williamson wrote: >>> On Wed, 23 Oct 2019 21:07:48 +0800 >>> Jason Wang wrote: >>> =20 >>>> Add support to parse mdev class id table. >>>> >>>> Reviewed-by: Parav Pandit >>>> Signed-off-by: Jason Wang >>>> --- >>>> drivers/vfio/mdev/vfio_mdev.c | 2 ++ >>>> scripts/mod/devicetable-offsets.c | 3 +++ >>>> scripts/mod/file2alias.c | 10 ++++++++++ >>>> 3 files changed, 15 insertions(+) >>>> >>>> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_md= ev.c >>>> index 7b24ee9cb8dd..cb701cd646f0 100644 >>>> --- a/drivers/vfio/mdev/vfio_mdev.c >>>> +++ b/drivers/vfio/mdev/vfio_mdev.c >>>> @@ -125,6 +125,8 @@ static const struct mdev_class_id id_table[] =3D { >>>> =09{ 0 }, >>>> }; >>>> =20 >>>> +MODULE_DEVICE_TABLE(mdev, id_table); >>>> + >>> Two questions, first we have: >>> >>> #define MODULE_DEVICE_TABLE(type, name) = \ >>> extern typeof(name) __mod_##type##__##name##_device_table = \ >>> __attribute__ ((unused, alias(__stringify(name)))) >>> >>> Therefore we're defining __mod_mdev__id_table_device_table with alias >>> id_table. When the virtio mdev bus driver is added in 5/6 it uses the >>> same name value. I see virtio types all register this way (virtio, >>> id_table), so I assume there's no conflict, but pci types mostly (not >>> entirely) seem to use unique names. Is there a preference to one way >>> or the other or it simply doesn't matter? >> >> It looks to me that those symbol were local, so it doesn't matter. But >> if you wish I can switch to use unique name. > I don't have a strong opinion, I'm just trying to make sure we're not > doing something obviously broken. Yes, to be more safe I will switch to unique names here. > >>>> static struct mdev_driver vfio_mdev_driver =3D { >>>> =09.name=09=3D "vfio_mdev", >>>> =09.probe=09=3D vfio_mdev_probe, >>>> diff --git a/scripts/mod/devicetable-offsets.c b/scripts/mod/devicetab= le-offsets.c >>>> index 054405b90ba4..6cbb1062488a 100644 >>>> --- a/scripts/mod/devicetable-offsets.c >>>> +++ b/scripts/mod/devicetable-offsets.c >>>> @@ -231,5 +231,8 @@ int main(void) >>>> =09DEVID(wmi_device_id); >>>> =09DEVID_FIELD(wmi_device_id, guid_string); >>>> =20 >>>> +=09DEVID(mdev_class_id); >>>> +=09DEVID_FIELD(mdev_class_id, id); >>>> + >>>> =09return 0; >>>> } >>>> diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c >>>> index c91eba751804..d365dfe7c718 100644 >>>> --- a/scripts/mod/file2alias.c >>>> +++ b/scripts/mod/file2alias.c >>>> @@ -1335,6 +1335,15 @@ static int do_wmi_entry(const char *filename, v= oid *symval, char *alias) >>>> =09return 1; >>>> } >>>> =20 >>>> +/* looks like: "mdev:cN" */ >>>> +static int do_mdev_entry(const char *filename, void *symval, char *al= ias) >>>> +{ >>>> +=09DEF_FIELD(symval, mdev_class_id, id); >>>> + >>>> +=09sprintf(alias, "mdev:c%02X", id); >>> A lot of entries call add_wildcard() here, should we? Sorry for the >>> basic questions, I haven't played in this code. Thanks, >> >> It's really good question. My understanding is we won't have a module >> that can deal with all kinds of classes like CLASS_ID_ANY. So there's >> probably no need for the wildcard. > The comment for add_wildcard() indicates future extension, so it's hard > to know what we might need in the future until we do need it. The > majority of modules.alias entries on my laptop (even if I exclude pci > aliases) end with a wildcard. Thanks, Yes, so I will add that for future extension. Thanks > > Alex >