From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE539C433EF for ; Tue, 9 Nov 2021 13:11:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D837361105 for ; Tue, 9 Nov 2021 13:11:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234671AbhKINNx (ORCPT ); Tue, 9 Nov 2021 08:13:53 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:45413 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234696AbhKINNw (ORCPT ); Tue, 9 Nov 2021 08:13:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636463466; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FkGOhx5eenLdT0pj0I1U37NyfCFn4kD6anHY0qhKa3Q=; b=EGpgdFiDhF1jjJe2vAwGIdFEEhaV9yDD2mHNhrOjF0lQdmD8NgOEfR7ImcNQUYifhPqiLn fGD6LKVkOAkMnF9fP+ZgYn9ksaTvxg2tdpvHsbzk5uQGjpXHkOEYOawDxitHRmEJp9pg0B h93Sy4ir8zYZBbDsMgmdzIgzAQSV42Q= Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-358-clyw0feZMQCuyg_DyO8zhw-1; Tue, 09 Nov 2021 08:11:04 -0500 X-MC-Unique: clyw0feZMQCuyg_DyO8zhw-1 Received: by mail-ed1-f69.google.com with SMTP id s6-20020a056402520600b003e2dea4f9b4so14850281edd.12 for ; Tue, 09 Nov 2021 05:11:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=FkGOhx5eenLdT0pj0I1U37NyfCFn4kD6anHY0qhKa3Q=; b=SNngFFlyiYCGtGlHWx9BpaFocuwbuVH2D1hk8wPtwbzNCnzSqExXCBP4arSHVh9nFx tuUCdDCi1NUv1eIy0nugKGh86YL7Rmeirk0bl48HkQcIF4xToEYjZg/QvSDKuaS3kmIY kBbijdEtLK9Wf3Uf4fXJIiFys3WfHeaHIilUzLdD+zuviA/tj1bhOl7f4ZtqLzfL6rU5 Kn4eFIQMESY4GgLLD0G3oxxSz/VIamN+qePnKQ0ZG8LJAGAOIfxFDLOleTlzgtFgy0EK vJjURj+MuUFizECc/KSQ6OTLcyEoRsG4d9bYMUKDal99MNfa6VB/sKjGL26XnHYd/4pq EFwA== X-Gm-Message-State: AOAM532BxOmRODzkAzfjew6tRpkgiKgFSUvdlXIiezj+Zb9j4DzcUAte bKmTmSa4Z/1OSws8zK0Vxh1MPQW+bsnxx6qaCrpdHWnRKKa9/9oPf5ka3HVGdf1YAlukZMGnxm/ ovhlE+mDHs0Kc873RsQjbH2fN X-Received: by 2002:a17:906:b1d8:: with SMTP id bv24mr9540236ejb.226.1636463463532; Tue, 09 Nov 2021 05:11:03 -0800 (PST) X-Google-Smtp-Source: ABdhPJwafTIpzLlFwfQ4ZdK/4EENOrKMZAfE7ZNrWhQMI9KqiIqGY0UHnciowt7VoXLfn67LOvyDQA== X-Received: by 2002:a17:906:b1d8:: with SMTP id bv24mr9540205ejb.226.1636463463317; Tue, 09 Nov 2021 05:11:03 -0800 (PST) Received: from redhat.com ([2.55.133.41]) by smtp.gmail.com with ESMTPSA id t23sm10989515edc.95.2021.11.09.05.11.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Nov 2021 05:11:01 -0800 (PST) Date: Tue, 9 Nov 2021 08:10:58 -0500 From: "Michael S. Tsirkin" To: Stefano Garzarella Cc: Jason Wang , virtualization , Parav Pandit , linux-kernel Subject: Re: [PATCH] vdpa: add driver_override support Message-ID: <20211109081042-mutt-send-email-mst@kernel.org> References: <20211104161729.258294-1-sgarzare@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 08, 2021 at 06:05:29PM +0100, Stefano Garzarella wrote: > On Fri, Nov 5, 2021 at 4:01 AM Jason Wang wrote: > > > > On Fri, Nov 5, 2021 at 12:17 AM Stefano Garzarella wrote: > > > > > > `driver_override` allows to control which of the vDPA bus drivers > > > binds to a vDPA device. > > > > > > If `driver_override` is not set, the previous behaviour is followed: > > > devices use the first vDPA bus driver loaded (unless auto binding > > > is disabled). > > > > > > Tested on Fedora 34 with driverctl(8): > > > $ modprobe virtio-vdpa > > > $ modprobe vhost-vdpa > > > $ modprobe vdpa-sim-net > > > > > > $ vdpa dev add mgmtdev vdpasim_net name dev1 > > > > > > # dev1 is attached to the first vDPA bus driver loaded > > > $ driverctl -b vdpa list-devices > > > dev1 virtio_vdpa > > > > > > $ driverctl -b vdpa set-override dev1 vhost_vdpa > > > > > > $ driverctl -b vdpa list-devices > > > dev1 vhost_vdpa [*] > > > > > > Note: driverctl(8) integrates with udev so the binding is > > > preserved. > > > > > > Suggested-by: Jason Wang > > > Signed-off-by: Stefano Garzarella > > > --- > > > include/linux/vdpa.h | 2 ++ > > > drivers/vdpa/vdpa.c | 74 ++++++++++++++++++++++++++++++++++++++++++++ > > > 2 files changed, 76 insertions(+) > > > > > > diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h > > > index c3011ccda430..ae34015b37b7 100644 > > > --- a/include/linux/vdpa.h > > > +++ b/include/linux/vdpa.h > > > @@ -64,6 +64,7 @@ struct vdpa_mgmt_dev; > > > * struct vdpa_device - representation of a vDPA device > > > * @dev: underlying device > > > * @dma_dev: the actual device that is performing DMA > > > + * @driver_override: driver name to force a match > > > > This seems useless? > > > > > * @config: the configuration ops for this device. > > > * @cf_mutex: Protects get and set access to configuration layout. > > > * @index: device index > > > @@ -76,6 +77,7 @@ struct vdpa_mgmt_dev; > > > struct vdpa_device { > > > struct device dev; > > > struct device *dma_dev; > > > + const char *driver_override; > > > const struct vdpa_config_ops *config; > > > struct mutex cf_mutex; /* Protects get/set config */ > > > unsigned int index; > > > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c > > > index 7332a74a4b00..659231bbfee8 100644 > > > --- a/drivers/vdpa/vdpa.c > > > +++ b/drivers/vdpa/vdpa.c > > > @@ -52,8 +52,81 @@ static void vdpa_dev_remove(struct device *d) > > > drv->remove(vdev); > > > } > > > > > > +static int vdpa_dev_match(struct device *dev, struct device_driver *drv) > > > +{ > > > + struct vdpa_device *vdev = dev_to_vdpa(dev); > > > + > > > + /* Check override first, and if set, only use the named driver */ > > > + if (vdev->driver_override) > > > + return strcmp(vdev->driver_override, drv->name) == 0; > > > + > > > + /* Currently devices must be supported by all vDPA bus drivers */ > > > + return 1; > > > +} > > > + > > > +static ssize_t driver_override_store(struct device *dev, > > > + struct device_attribute *attr, > > > + const char *buf, size_t count) > > > +{ > > > + struct vdpa_device *vdev = dev_to_vdpa(dev); > > > + const char *driver_override, *old; > > > + char *cp; > > > + > > > + /* We need to keep extra room for a newline */ > > > + if (count >= (PAGE_SIZE - 1)) > > > + return -EINVAL; > > > + > > > + driver_override = kstrndup(buf, count, GFP_KERNEL); > > > + if (!driver_override) > > > + return -ENOMEM; > > > + > > > + cp = strchr(driver_override, '\n'); > > > + if (cp) > > > + *cp = '\0'; > > > + > > > + device_lock(dev); > > > + old = vdev->driver_override; > > > + if (strlen(driver_override)) { > > > + vdev->driver_override = driver_override; > > > + } else { > > > + kfree(driver_override); > > > + vdev->driver_override = NULL; > > > + } > > > + device_unlock(dev); > > > + > > > + kfree(old); > > > + > > > + return count; > > > +} > > > + > > > +static ssize_t driver_override_show(struct device *dev, > > > + struct device_attribute *attr, char *buf) > > > +{ > > > + struct vdpa_device *vdev = dev_to_vdpa(dev); > > > + ssize_t len; > > > + > > > + device_lock(dev); > > > + len = snprintf(buf, PAGE_SIZE, "%s\n", vdev->driver_override); > > > + device_unlock(dev); > > > + > > > + return len; > > > +} > > > +static DEVICE_ATTR_RW(driver_override); > > > + > > > +static struct attribute *vdpa_dev_attrs[] = { > > > + &dev_attr_driver_override.attr, > > > + NULL, > > > +}; > > > + > > > +static const struct attribute_group vdpa_dev_group = { > > > + .attrs = vdpa_dev_attrs, > > > +}; > > > +__ATTRIBUTE_GROUPS(vdpa_dev); > > > + > > > static struct bus_type vdpa_bus = { > > > .name = "vdpa", > > > + .dev_groups = vdpa_dev_groups, > > > > This reminds me that we probably need to document the sysfs interface > > in Documentation/ABI/testing/sysfs-bus-vdpa. > > > > But it's not the fault of this patch which look good. > > Michael, Jason, about Documentation/ABI/testing/sysfs-bus-vdpa, do you > think is better to send a follow up patch/series, maybe including also > others entries (e.g. bind, unbind) or a v2 including the documentation > of `driver_ovveride`? > > Thanks, > Stefano I'd include it as a patch in series. -- MST