linux-kernel - [PATCH v2 8/8] drm/tegra: Support context isolation

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Message-Id: <20210916143302.2024933-9-mperttunen@nvidia.com>
Date:   Thu, 16 Sep 2021 17:33:02 +0300
From:   Mikko Perttunen <mperttunen@...dia.com>
To:     thierry.reding@...il.com, jonathanh@...dia.com, joro@...tes.org,
        will@...nel.org, robh+dt@...nel.org, robin.murphy@....com
Cc:     linux-tegra@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Mikko Perttunen <mperttunen@...dia.com>
Subject: [PATCH v2 8/8] drm/tegra: Support context isolation

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@...dia.com>
---
 drivers/gpu/drm/tegra/drm.h    |  2 ++
 drivers/gpu/drm/tegra/submit.c | 13 +++++++++++++
 drivers/gpu/drm/tegra/uapi.c   | 34 ++++++++++++++++++++++++++++++++--
 3 files changed, 47 insertions(+), 2 deletions(-)

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 776f825df52f..b6008246bebe 100644
--- a/drivers/gpu/drm/tegra/submit.c
+++ b/drivers/gpu/drm/tegra/submit.c
@@ -469,6 +469,9 @@ 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);
 
@@ -572,6 +575,16 @@ 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 690a339c52ec..bfded46b974a 100644
--- a/drivers/gpu/drm/tegra/uapi.c
+++ b/drivers/gpu/drm/tegra/uapi.c
@@ -37,6 +37,9 @@ 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);
 
@@ -76,6 +79,7 @@ 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;
@@ -106,10 +110,29 @@ 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);
@@ -122,6 +145,9 @@ 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:
@@ -180,7 +206,11 @@ int tegra_drm_ioctl_channel_map(struct drm_device *drm, void *data, struct drm_f
 
 	kref_init(&mapping->ref);
 
-	mapping->dev = context->client->base.dev;
+	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;
-- 
2.32.0