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smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=cbuYPLED; arc=none smtp.client-ip=217.70.183.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="cbuYPLED" Received: by mail.gandi.net (Postfix) with ESMTPSA id 2F960432E9; Tue, 25 Feb 2025 11:02:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1740481324; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=OTZveGdwdo+h3hfTN92OPsM+DyaPDfGvt6U7A0Tjx7E=; b=cbuYPLEDB2LNYMmTHPnlN9QT81SoJnA4AOrMR7lmVFIjeVnR1G64h0XJU3nckYQwCCk6cn wAHlBQzEdvVtfwrXzxJ+yV+kcw4u44iFq1nDWtHIOBnY2SLxiic1caDJYyqpH+9tcJCBBk 290oLtZfUyJ44c2ONYFPosSeFdfTfjCtssQkZinQzp+McUwpsrxZzxiHPkswMx5mWMWhEO f/M+ZbuVJ/cXiHAj0EqRMgL+dI/Cqtc1EYXmzGtu9K4R0ztNEb8K1+zaAw3Es0LvxC+KVs 6nYRkXRyHMlLBFOdO6as/ltwEq/s7e+lO/zNkv1hDPSovWJhC+lgQ89n3PO3aQ== Date: Tue, 25 Feb 2025 12:02:02 +0100 From: Louis Chauvet To: =?iso-8859-1?Q?Jos=E9_Exp=F3sito?= Cc: hamohammed.sa@gmail.com, simona@ffwll.ch, melissa.srw@gmail.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 02/16] drm/vkms: Add and remove VKMS instances via configfs Message-ID: Mail-Followup-To: =?iso-8859-1?Q?Jos=E9_Exp=F3sito?= , hamohammed.sa@gmail.com, simona@ffwll.ch, melissa.srw@gmail.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20250218170808.9507-1-jose.exposito89@gmail.com> <20250218170808.9507-3-jose.exposito89@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250218170808.9507-3-jose.exposito89@gmail.com> X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdekudehvdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepfffhvfevuffkfhggtggugfgjsehtkeertddttddunecuhfhrohhmpefnohhuihhsucevhhgruhhvvghtuceolhhouhhishdrtghhrghuvhgvthessghoohhtlhhinhdrtghomheqnecuggftrfgrthhtvghrnhepgfejveetkedvleetudeuudegfeejheeujeefkefgtdeugfetfeeutdevieekvdeknecukfhppeeltddrkeelrdduieefrdduvdejnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepledtrdekledrudeifedruddvjedphhgvlhhopehlohhuihhsqdgthhgruhhvvghtqdhlrghpthhophdpmhgrihhlfhhrohhmpehlohhuihhsrdgthhgruhhvvghtsegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopedutddprhgtphhtthhopehjohhsvgdrvgigphhoshhithhokeelsehgmhgrihhlrdgtohhmpdhrtghpthhtohephhgrmhhohhgrmhhmvggurdhsrgesghhmrghilhdrtghomhdprhgtphhtthhopehsihhmohhnrgesfhhffihllhdrtghhpdhrtghpthhtohepmhgvlhhishhsrgdrshhrfiesghhmrghilhdrtghomhdprhgtphhtthhopehmrggrrhhtvghnrdhlrghnkhhhohhrs hhtsehlihhnuhigrdhinhhtvghlrdgtohhmpdhrtghpthhtohepmhhrihhprghrugeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepthiiihhmmhgvrhhmrghnnhesshhushgvrdguvgdprhgtphhtthhopegrihhrlhhivggusehgmhgrihhlrdgtohhm X-GND-Sasl: louis.chauvet@bootlin.com On 18/02/25 - 18:07, José Expósito wrote: > Allow to create, enable, disable and destroy VKMS instances using > configfs. > > For the moment, it is not possible to add pipeline items, so trying to > enable the device will fail printing an informative error to the log. > > Co-developed-by: Louis Chauvet > Signed-off-by: Louis Chauvet > Signed-off-by: José Expósito Reviewed-by: Louis Chauvet > --- > Documentation/gpu/vkms.rst | 32 +++++ > drivers/gpu/drm/vkms/Kconfig | 1 + > drivers/gpu/drm/vkms/Makefile | 3 +- > drivers/gpu/drm/vkms/vkms_configfs.c | 181 +++++++++++++++++++++++++++ > drivers/gpu/drm/vkms/vkms_configfs.h | 8 ++ > drivers/gpu/drm/vkms/vkms_drv.c | 7 ++ > 6 files changed, 231 insertions(+), 1 deletion(-) > create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.c > create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.h > > diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst > index ba04ac7c2167..423bdf86b5b1 100644 > --- a/Documentation/gpu/vkms.rst > +++ b/Documentation/gpu/vkms.rst > @@ -51,6 +51,38 @@ To disable the driver, use :: > > sudo modprobe -r vkms > > +Configuring With Configfs > +========================= > + > +It is possible to create and configure multiple VKMS instances via configfs. > + > +Start by mounting configfs and loading VKMS:: > + > + sudo mount -t configfs none /config > + sudo modprobe vkms > + > +Once VKMS is loaded, ``/config/vkms`` is created automatically. Each directory > +under ``/config/vkms`` represents a VKMS instance, create a new one:: > + > + sudo mkdir /config/vkms/my-vkms > + > +By default, the instance is disabled:: > + > + cat /config/vkms/my-vkms/enabled > + 0 > + > +Once you are done configuring the VKMS instance, enable it:: > + > + echo "1" | sudo tee /config/vkms/my-vkms/enabled > + > +Finally, you can remove the VKMS instance disabling it:: > + > + echo "0" | sudo tee /config/vkms/my-vkms/enabled > + > +And removing the top level directory:: > + > + sudo rmdir /config/vkms/my-vkms > + > Testing With IGT > ================ > > diff --git a/drivers/gpu/drm/vkms/Kconfig b/drivers/gpu/drm/vkms/Kconfig > index 3c02f928ffe6..3977bbb99f7d 100644 > --- a/drivers/gpu/drm/vkms/Kconfig > +++ b/drivers/gpu/drm/vkms/Kconfig > @@ -7,6 +7,7 @@ config DRM_VKMS > select DRM_KMS_HELPER > select DRM_GEM_SHMEM_HELPER > select CRC32 > + select CONFIGFS_FS > default n > help > Virtual Kernel Mode-Setting (VKMS) is used for testing or for > diff --git a/drivers/gpu/drm/vkms/Makefile b/drivers/gpu/drm/vkms/Makefile > index d657865e573f..939991fc8233 100644 > --- a/drivers/gpu/drm/vkms/Makefile > +++ b/drivers/gpu/drm/vkms/Makefile > @@ -8,7 +8,8 @@ vkms-y := \ > vkms_composer.o \ > vkms_writeback.o \ > vkms_connector.o \ > - vkms_config.o > + vkms_config.o \ > + vkms_configfs.o > > obj-$(CONFIG_DRM_VKMS) += vkms.o > obj-$(CONFIG_DRM_VKMS_KUNIT_TEST) += tests/ > diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c > new file mode 100644 > index 000000000000..306f571559b7 > --- /dev/null > +++ b/drivers/gpu/drm/vkms/vkms_configfs.c > @@ -0,0 +1,181 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +#include > +#include > +#include > + > +#include "vkms_drv.h" > +#include "vkms_config.h" > +#include "vkms_configfs.h" > + > +/* To avoid registering configfs more than once or unregistering on error */ > +static bool is_configfs_registered; > + > +/** > + * struct vkms_configfs_device - Configfs representation of a VKMS device > + * > + * @group: Top level configuration group that represents a VKMS device. > + * Initialized when a new directory is created under "/config/vkms/" > + * @lock: Lock used to project concurrent access to the configuration attributes > + * @config: Protected by @lock. Configuration of the VKMS device > + * @enabled: Protected by @lock. The device is created or destroyed when this > + * option changes > + */ > +struct vkms_configfs_device { > + struct config_group group; > + > + struct mutex lock; > + struct vkms_config *config; > + bool enabled; > +}; > + > +#define device_item_to_vkms_configfs_device(item) \ > + container_of(to_config_group((item)), struct vkms_configfs_device, \ > + group) > + > +static ssize_t device_enabled_show(struct config_item *item, char *page) > +{ > + struct vkms_configfs_device *dev; > + bool enabled; > + > + dev = device_item_to_vkms_configfs_device(item); > + > + mutex_lock(&dev->lock); > + enabled = dev->enabled; > + mutex_unlock(&dev->lock); > + > + return sprintf(page, "%d\n", enabled); > +} > + > +static ssize_t device_enabled_store(struct config_item *item, const char *page, > + size_t count) > +{ > + struct vkms_configfs_device *dev; > + bool enabled; > + int ret = 0; > + > + dev = device_item_to_vkms_configfs_device(item); > + > + if (kstrtobool(page, &enabled)) > + return -EINVAL; > + > + mutex_lock(&dev->lock); > + > + if (!dev->enabled && enabled) { > + if (!vkms_config_is_valid(dev->config)) { > + ret = -EINVAL; > + goto err_unlock; > + } > + > + ret = vkms_create(dev->config); > + } else if (dev->enabled && !enabled) { > + vkms_destroy(dev->config); > + } > + > + if (ret) > + goto err_unlock; > + > + dev->enabled = enabled; > + > + mutex_unlock(&dev->lock); > + > + return (ssize_t)count; > + > +err_unlock: > + mutex_unlock(&dev->lock); > + return ret; > +} > + > +CONFIGFS_ATTR(device_, enabled); > + > +static struct configfs_attribute *device_item_attrs[] = { > + &device_attr_enabled, > + NULL, > +}; > + > +static void device_release(struct config_item *item) > +{ > + struct vkms_configfs_device *dev; > + > + dev = device_item_to_vkms_configfs_device(item); > + > + if (dev->enabled) > + vkms_destroy(dev->config); > + > + mutex_destroy(&dev->lock); > + vkms_config_destroy(dev->config); > + kfree(dev); > +} > + > +static struct configfs_item_operations device_item_operations = { > + .release = &device_release, > +}; > + > +static const struct config_item_type device_item_type = { > + .ct_attrs = device_item_attrs, > + .ct_item_ops = &device_item_operations, > + .ct_owner = THIS_MODULE, > +}; > + > +static struct config_group *make_device_group(struct config_group *group, > + const char *name) > +{ > + struct vkms_configfs_device *dev; > + > + if (strcmp(name, DEFAULT_DEVICE_NAME) == 0) > + return ERR_PTR(-EINVAL); > + > + dev = kzalloc(sizeof(*dev), GFP_KERNEL); > + if (!dev) > + return ERR_PTR(-ENOMEM); > + > + dev->config = vkms_config_create(name); > + if (IS_ERR(dev->config)) { > + kfree(dev); > + return ERR_CAST(dev->config); > + } > + > + config_group_init_type_name(&dev->group, name, &device_item_type); > + mutex_init(&dev->lock); > + > + return &dev->group; > +} > + > +static struct configfs_group_operations device_group_ops = { > + .make_group = &make_device_group, > +}; > + > +static const struct config_item_type device_group_type = { > + .ct_group_ops = &device_group_ops, > + .ct_owner = THIS_MODULE, > +}; > + > +static struct configfs_subsystem vkms_subsys = { > + .su_group = { > + .cg_item = { > + .ci_name = "vkms", > + .ci_type = &device_group_type, > + }, > + }, > + .su_mutex = __MUTEX_INITIALIZER(vkms_subsys.su_mutex), > +}; > + > +int vkms_configfs_register(void) > +{ > + int ret; > + > + if (is_configfs_registered) > + return 0; > + > + config_group_init(&vkms_subsys.su_group); > + ret = configfs_register_subsystem(&vkms_subsys); > + > + is_configfs_registered = ret == 0; > + > + return ret; > +} > + > +void vkms_configfs_unregister(void) > +{ > + if (is_configfs_registered) > + configfs_unregister_subsystem(&vkms_subsys); > +} > diff --git a/drivers/gpu/drm/vkms/vkms_configfs.h b/drivers/gpu/drm/vkms/vkms_configfs.h > new file mode 100644 > index 000000000000..e9020b0043db > --- /dev/null > +++ b/drivers/gpu/drm/vkms/vkms_configfs.h > @@ -0,0 +1,8 @@ > +/* SPDX-License-Identifier: GPL-2.0+ */ > +#ifndef _VKMS_CONFIGFS_H_ > +#define _VKMS_CONFIGFS_H_ > + > +int vkms_configfs_register(void); > +void vkms_configfs_unregister(void); > + > +#endif /* _VKMS_CONFIGFS_H_ */ > diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c > index 23817c7b997e..5bcfbcb6c0c5 100644 > --- a/drivers/gpu/drm/vkms/vkms_drv.c > +++ b/drivers/gpu/drm/vkms/vkms_drv.c > @@ -28,6 +28,7 @@ > #include > > #include "vkms_config.h" > +#include "vkms_configfs.h" > #include "vkms_drv.h" > > #define DRIVER_NAME "vkms" > @@ -214,6 +215,10 @@ static int __init vkms_init(void) > int ret; > struct vkms_config *config; > > + ret = vkms_configfs_register(); > + if (ret) > + return ret; > + > config = vkms_config_default_create(enable_cursor, enable_writeback, enable_overlay); > if (IS_ERR(config)) > return PTR_ERR(config); > @@ -250,6 +255,8 @@ void vkms_destroy(struct vkms_config *config) > > static void __exit vkms_exit(void) > { > + vkms_configfs_unregister(); > + > if (!default_config) > return; > > -- > 2.48.1 >