| Message ID | 20250225175936.7223-3-jose.exposito89@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | drm/vkms: Add configfs support | expand |
Le 25/02/2025 à 18:59, José Expósito a écrit : > 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. > > Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com> > Co-developed-by: Louis Chauvet <louis.chauvet@bootlin.com> > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com> > Signed-off-by: José Expósito <jose.exposito89@gmail.com> > --- > Documentation/gpu/vkms.rst | 32 +++++ > drivers/gpu/drm/vkms/Kconfig | 1 + > drivers/gpu/drm/vkms/Makefile | 3 +- > drivers/gpu/drm/vkms/vkms_configfs.c | 169 +++++++++++++++++++++++++++ > drivers/gpu/drm/vkms/vkms_configfs.h | 8 ++ > drivers/gpu/drm/vkms/vkms_drv.c | 7 ++ > 6 files changed, 219 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..92512d52ddae > --- /dev/null > +++ b/drivers/gpu/drm/vkms/vkms_configfs.c > @@ -0,0 +1,169 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +#include <linux/cleanup.h> > +#include <linux/configfs.h> > +#include <linux/mutex.h> > +#include <linux/slab.h> > + > +#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; > + > + dev = device_item_to_vkms_configfs_device(item); > + > + guard(mutex)(&dev->lock); > + return sprintf(page, "%d\n", dev->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; > + > + guard(mutex)(&dev->lock); > + > + if (!dev->enabled && enabled) { > + if (!vkms_config_is_valid(dev->config)) > + return -EINVAL; > + > + ret = vkms_create(dev->config); > + if (ret) > + return ret; > + } else if (dev->enabled && !enabled) { > + vkms_destroy(dev->config); > + } > + > + dev->enabled = enabled; Sorry, I was maybe not clear enough, and you may hate me: I don't like `guard(mutex)` :‑(. I proposed scoped_guard because it makes very clear when the mutex is taken/released. For me guard(mutex) is almost the same as mutex_lock/unlock. Yes, your mutex is always released, but: - without reading the code carefully, you don't know you have a mutex (even worse than a mutex_lock because you don't have a bunch of mutex_unlock to remind you) - you keep it until the end of the function, which may lock your mutex for too long The scoped_guard solves the two issues: - you are in a dedicated block + indentation, so it is very easy to see that you currently have a mutex - you know exactly when the mutex is released: leaving the block I am very sorry to make you work twice on this > + > + return (ssize_t)count; > +} > + > +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 <drm/drm_vblank.h> > > #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; >
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..92512d52ddae --- /dev/null +++ b/drivers/gpu/drm/vkms/vkms_configfs.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: GPL-2.0+ +#include <linux/cleanup.h> +#include <linux/configfs.h> +#include <linux/mutex.h> +#include <linux/slab.h> + +#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; + + dev = device_item_to_vkms_configfs_device(item); + + guard(mutex)(&dev->lock); + return sprintf(page, "%d\n", dev->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; + + guard(mutex)(&dev->lock); + + if (!dev->enabled && enabled) { + if (!vkms_config_is_valid(dev->config)) + return -EINVAL; + + ret = vkms_create(dev->config); + if (ret) + return ret; + } else if (dev->enabled && !enabled) { + vkms_destroy(dev->config); + } + + dev->enabled = enabled; + + return (ssize_t)count; +} + +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 <drm/drm_vblank.h> #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;