diff mbox series

[v3,9/9] drm/tegra: Support context isolation

Message ID 20220218113952.3077606-10-mperttunen@nvidia.com
State New
Headers show
Series None | expand

Commit Message

Mikko Perttunen Feb. 18, 2022, 11:39 a.m. UTC 
For engines that support context isolation, allocate a context when
opening a channel, and set up stream ID offset and context fields
when submitting a job.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
---
 drivers/gpu/drm/tegra/drm.h    |  2 ++
 drivers/gpu/drm/tegra/submit.c | 13 ++++++++++++
 drivers/gpu/drm/tegra/uapi.c   | 36 ++++++++++++++++++++++++++++++++--
 3 files changed, 49 insertions(+), 2 deletions(-)

Comments

Dmitry Osipenko Feb. 21, 2022, 8:02 p.m. UTC | #1 
21.02.2022 15:06, Mikko Perttunen пишет:
> On 2/19/22 20:35, Dmitry Osipenko wrote:
>> 18.02.2022 14:39, Mikko Perttunen пишет:
>>> +    if (context->memory_context &&
>>> context->client->ops->get_streamid_offset) {
>>              ^^^
>>> +        int offset =
>>> context->client->ops->get_streamid_offset(context->client);
>>> +
>>> +        if (offset >= 0) {
>>> +            job->context = context->memory_context;
>>> +            job->engine_streamid_offset = offset;
>>> +            host1x_context_get(job->context);
>>> +        }
>>
>> You should bump refcount unconditionally or you'll get refcnt underflow
>> on put, when offset < 0.
> 
> This refcount is intended to be dropped from 'release_job', where it's
> dropped if job->context is set, which it is from this path.
> 
>>
>>> +    }
>>> +
>>>       /*
>>>        * job_data is now part of job reference counting, so don't
>>> release
>>>        * it from here.
>>> diff --git a/drivers/gpu/drm/tegra/uapi.c b/drivers/gpu/drm/tegra/uapi.c
>>> index 9ab9179d2026..be33da54d12c 100644
>>> --- a/drivers/gpu/drm/tegra/uapi.c
>>> +++ b/drivers/gpu/drm/tegra/uapi.c
>>> @@ -33,6 +33,9 @@ static void tegra_drm_channel_context_close(struct
>>> tegra_drm_context *context)
>>>       struct tegra_drm_mapping *mapping;
>>>       unsigned long id;
>>>   +    if (context->memory_context)
>>> +        host1x_context_put(context->memory_context);
>>
>> The "if (context->memory_context &&
>> context->client->ops->get_streamid_offset)" above doesn't match the "if
>> (context->memory_context)". You'll get refcount underflow.
> 
> And this drop is for the refcount implicitly added when allocating the
> memory context through host1x_context_alloc; so these two places should
> be independent.
> 
> Please elaborate if I missed something.

You named context as memory_context and then have
context=context->memory_context. Please try to improve the variable
names, like drm_ctx->host1x_ctx for example.

I'm also not a big fan of the "if (ref) put(ref)" pattern. Won't be
better to move all the "if (!NULL)" checks inside of get()/put() and
make the invocations unconditional?
diff mbox series

Patch

diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index fc0a19554eac..717e9f81ee1f 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -80,6 +80,7 @@  struct tegra_drm_context {
 
 	/* Only used by new UAPI. */
 	struct xarray mappings;
+	struct host1x_context *memory_context;
 };
 
 struct tegra_drm_client_ops {
@@ -91,6 +92,7 @@  struct tegra_drm_client_ops {
 	int (*submit)(struct tegra_drm_context *context,
 		      struct drm_tegra_submit *args, struct drm_device *drm,
 		      struct drm_file *file);
+	int (*get_streamid_offset)(struct tegra_drm_client *client);
 };
 
 int tegra_drm_submit(struct tegra_drm_context *context,
diff --git a/drivers/gpu/drm/tegra/submit.c b/drivers/gpu/drm/tegra/submit.c
index 6d6dd8c35475..8d74b82b83a5 100644
--- a/drivers/gpu/drm/tegra/submit.c
+++ b/drivers/gpu/drm/tegra/submit.c
@@ -498,6 +498,9 @@  static void release_job(struct host1x_job *job)
 	struct tegra_drm_submit_data *job_data = job->user_data;
 	u32 i;
 
+	if (job->context)
+		host1x_context_put(job->context);
+
 	for (i = 0; i < job_data->num_used_mappings; i++)
 		tegra_drm_mapping_put(job_data->used_mappings[i].mapping);
 
@@ -599,6 +602,16 @@  int tegra_drm_ioctl_channel_submit(struct drm_device *drm, void *data,
 	job->release = release_job;
 	job->timeout = 10000;
 
+	if (context->memory_context && context->client->ops->get_streamid_offset) {
+		int offset = context->client->ops->get_streamid_offset(context->client);
+
+		if (offset >= 0) {
+			job->context = context->memory_context;
+			job->engine_streamid_offset = offset;
+			host1x_context_get(job->context);
+		}
+	}
+
 	/*
 	 * job_data is now part of job reference counting, so don't release
 	 * it from here.
diff --git a/drivers/gpu/drm/tegra/uapi.c b/drivers/gpu/drm/tegra/uapi.c
index 9ab9179d2026..be33da54d12c 100644
--- a/drivers/gpu/drm/tegra/uapi.c
+++ b/drivers/gpu/drm/tegra/uapi.c
@@ -33,6 +33,9 @@  static void tegra_drm_channel_context_close(struct tegra_drm_context *context)
 	struct tegra_drm_mapping *mapping;
 	unsigned long id;
 
+	if (context->memory_context)
+		host1x_context_put(context->memory_context);
+
 	xa_for_each(&context->mappings, id, mapping)
 		tegra_drm_mapping_put(mapping);
 
@@ -72,6 +75,7 @@  static struct tegra_drm_client *tegra_drm_find_client(struct tegra_drm *tegra, u
 
 int tegra_drm_ioctl_channel_open(struct drm_device *drm, void *data, struct drm_file *file)
 {
+	struct host1x *host = tegra_drm_to_host1x(drm->dev_private);
 	struct tegra_drm_file *fpriv = file->driver_priv;
 	struct tegra_drm *tegra = drm->dev_private;
 	struct drm_tegra_channel_open *args = data;
@@ -102,10 +106,29 @@  int tegra_drm_ioctl_channel_open(struct drm_device *drm, void *data, struct drm_
 		}
 	}
 
+	/* Only allocate context if the engine supports context isolation. */
+	if (client->ops->get_streamid_offset &&
+	    client->ops->get_streamid_offset(client) >= 0) {
+		context->memory_context =
+			host1x_context_alloc(host, get_task_pid(current, PIDTYPE_TGID));
+		if (IS_ERR(context->memory_context)) {
+			if (PTR_ERR(context->memory_context) != -EOPNOTSUPP) {
+				err = PTR_ERR(context->memory_context);
+				goto put_channel;
+			} else {
+				/*
+				 * OK, HW does not support contexts or contexts
+				 * are disabled.
+				 */
+				context->memory_context = NULL;
+			}
+		}
+	}
+
 	err = xa_alloc(&fpriv->contexts, &args->context, context, XA_LIMIT(1, U32_MAX),
 		       GFP_KERNEL);
 	if (err < 0)
-		goto put_channel;
+		goto put_memctx;
 
 	context->client = client;
 	xa_init_flags(&context->mappings, XA_FLAGS_ALLOC1);
@@ -118,6 +141,9 @@  int tegra_drm_ioctl_channel_open(struct drm_device *drm, void *data, struct drm_
 
 	return 0;
 
+put_memctx:
+	if (context->memory_context)
+		host1x_context_put(context->memory_context);
 put_channel:
 	host1x_channel_put(context->channel);
 free:
@@ -156,6 +182,7 @@  int tegra_drm_ioctl_channel_map(struct drm_device *drm, void *data, struct drm_f
 	struct tegra_drm_mapping *mapping;
 	struct tegra_drm_context *context;
 	enum dma_data_direction direction;
+	struct device *mapping_dev;
 	int err = 0;
 
 	if (args->flags & ~DRM_TEGRA_CHANNEL_MAP_READ_WRITE)
@@ -177,6 +204,11 @@  int tegra_drm_ioctl_channel_map(struct drm_device *drm, void *data, struct drm_f
 
 	kref_init(&mapping->ref);
 
+	if (context->memory_context)
+		mapping_dev = &context->memory_context->dev;
+	else
+		mapping_dev = context->client->base.dev;
+
 	mapping->bo = tegra_gem_lookup(file, args->handle);
 	if (!mapping->bo) {
 		err = -EINVAL;
@@ -201,7 +233,7 @@  int tegra_drm_ioctl_channel_map(struct drm_device *drm, void *data, struct drm_f
 		goto put_gem;
 	}
 
-	mapping->map = host1x_bo_pin(context->client->base.dev, mapping->bo, direction, NULL);
+	mapping->map = host1x_bo_pin(mapping_dev, mapping->bo, direction, NULL);
 	if (IS_ERR(mapping->map)) {
 		err = PTR_ERR(mapping->map);
 		goto put_gem;