[PATCH 07/17] drm/amdgpu: Add sysfs interface for running cleaner shader

[Alex Deucher]

From: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>

This patch adds a new sysfs interface for running the cleaner shader on
AMD GPUs. The cleaner shader is used to clear GPU memory before it's
reused, which can help prevent data leakage between different processes.

The new sysfs file is write-only and is named `run_cleaner_shader`.
Write the number of the partition to this file to trigger the cleaner shader
on that partition. There is only one partition on GPUs which do not
support partitioning.

Changes made in this patch:

- Added `amdgpu_set_run_cleaner_shader` function to handle writes to the
  `run_cleaner_shader` sysfs file.
- Added `run_cleaner_shader` to the list of device attributes in
  `amdgpu_device_attrs`.
- Updated `default_attr_update` to handle `run_cleaner_shader`.
- Added `AMDGPU_DEVICE_ATTR_WO` macro to create write-only device
  attributes.

v2: fix error handling (Alex)

Cc: Christian König <christian.koenig at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 134 ++++++++++++++++++++++++
 1 file changed, 134 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
index 2e35fc2577f9..76f77cf562af 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
@@ -24,10 +24,13 @@
  */
 
 #include <linux/firmware.h>
+#include <linux/pm_runtime.h>
+
 #include "amdgpu.h"
 #include "amdgpu_gfx.h"
 #include "amdgpu_rlc.h"
 #include "amdgpu_ras.h"
+#include "amdgpu_reset.h"
 #include "amdgpu_xcp.h"
 #include "amdgpu_xgmi.h"
 
@@ -1391,6 +1394,129 @@ static ssize_t amdgpu_gfx_get_available_compute_partition(struct device *dev,
 	return sysfs_emit(buf, "%s\n", supported_partition);
 }
 
+static int amdgpu_gfx_run_cleaner_shader_job(struct amdgpu_ring *ring)
+{
+	struct amdgpu_device *adev = ring->adev;
+	long timeout = msecs_to_jiffies(1000);
+	struct dma_fence *f = NULL;
+	struct amdgpu_job *job;
+	struct amdgpu_ib *ib;
+	int i, r;
+
+	r = amdgpu_job_alloc_with_ib(adev, NULL, NULL,
+				     64, AMDGPU_IB_POOL_DIRECT,
+				     &job);
+	if (r)
+		goto err;
+
+	job->enforce_isolation = true;
+
+	ib = &job->ibs[0];
+	for (i = 0; i <= ring->funcs->align_mask; ++i)
+		ib->ptr[i] = ring->funcs->nop;
+	ib->length_dw = ring->funcs->align_mask + 1;
+
+	r = amdgpu_job_submit_direct(job, ring, &f);
+	if (r)
+		goto err_free;
+
+	r = dma_fence_wait_timeout(f, false, timeout);
+	if (r == 0)
+		r = -ETIMEDOUT;
+	else if (r > 0)
+		r = 0;
+
+	amdgpu_ib_free(adev, ib, f);
+	dma_fence_put(f);
+
+	return 0;
+
+err_free:
+	amdgpu_job_free(job);
+	amdgpu_ib_free(adev, ib, f);
+err:
+	return r;
+}
+
+static int amdgpu_gfx_run_cleaner_shader(struct amdgpu_device *adev, int xcp_id)
+{
+	int num_xcc = NUM_XCC(adev->gfx.xcc_mask);
+	struct amdgpu_ring *ring;
+	int num_xcc_to_clear;
+	int i, r, xcc_id;
+
+	if (adev->gfx.num_xcc_per_xcp)
+		num_xcc_to_clear = adev->gfx.num_xcc_per_xcp;
+	else
+		num_xcc_to_clear = 1;
+
+	for (xcc_id = 0; xcc_id < num_xcc; xcc_id++) {
+		for (i = 0; i < adev->gfx.num_compute_rings; i++) {
+			ring = &adev->gfx.compute_ring[i + xcc_id * adev->gfx.num_compute_rings];
+			if ((ring->xcp_id == xcp_id) && ring->sched.ready) {
+				r = amdgpu_gfx_run_cleaner_shader_job(ring);
+				if (r)
+					return r;
+				num_xcc_to_clear--;
+				break;
+			}
+		}
+	}
+
+	if (num_xcc_to_clear)
+		return -ENOENT;
+
+	return 0;
+}
+
+static ssize_t amdgpu_gfx_set_run_cleaner_shader(struct device *dev,
+						 struct device_attribute *attr,
+						 const char *buf,
+						 size_t count)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct amdgpu_device *adev = drm_to_adev(ddev);
+	int ret;
+	long value;
+
+	if (amdgpu_in_reset(adev))
+		return -EPERM;
+	if (adev->in_suspend && !adev->in_runpm)
+		return -EPERM;
+
+	ret = kstrtol(buf, 0, &value);
+
+	if (ret)
+		return -EINVAL;
+
+	if (value < 0)
+		return -EINVAL;
+
+	if (adev->xcp_mgr) {
+		if (value >= adev->xcp_mgr->num_xcps)
+			return -EINVAL;
+	} else {
+		if (value > 1)
+			return -EINVAL;
+	}
+
+	ret = pm_runtime_get_sync(ddev->dev);
+	if (ret < 0) {
+		pm_runtime_put_autosuspend(ddev->dev);
+		return ret;
+	}
+
+	ret = amdgpu_gfx_run_cleaner_shader(adev, value);
+
+	pm_runtime_mark_last_busy(ddev->dev);
+	pm_runtime_put_autosuspend(ddev->dev);
+
+	if (ret)
+		return ret;
+
+	return count;
+}
+
 static ssize_t amdgpu_gfx_get_enforce_isolation(struct device *dev,
 						struct device_attribute *attr,
 						char *buf)
@@ -1469,6 +1595,9 @@ static ssize_t amdgpu_gfx_set_enforce_isolation(struct device *dev,
 	return count;
 }
 
+static DEVICE_ATTR(run_cleaner_shader, 0200,
+		   NULL, amdgpu_gfx_set_run_cleaner_shader);
+
 static DEVICE_ATTR(enforce_isolation, 0644,
 		   amdgpu_gfx_get_enforce_isolation,
 		   amdgpu_gfx_set_enforce_isolation);
@@ -1509,6 +1638,10 @@ int amdgpu_gfx_sysfs_isolation_shader_init(struct amdgpu_device *adev)
 			return r;
 	}
 
+	r = device_create_file(adev->dev, &dev_attr_run_cleaner_shader);
+	if (r)
+		return r;
+
 	return 0;
 }
 
@@ -1516,6 +1649,7 @@ void amdgpu_gfx_sysfs_isolation_shader_fini(struct amdgpu_device *adev)
 {
 	if (!amdgpu_sriov_vf(adev))
 		device_remove_file(adev->dev, &dev_attr_enforce_isolation);
+	device_remove_file(adev->dev, &dev_attr_run_cleaner_shader);
 }
 
 int amdgpu_gfx_cleaner_shader_sw_init(struct amdgpu_device *adev,
-- 
2.46.0