[PATCH 1/4] drm/xe: Introduce a simple wedged state

* [PATCH 1/4] drm/xe: Introduce a simple wedged state
@ 2024-04-09 22:15 Rodrigo Vivi
  2024-04-09 22:15 ` [PATCH 2/4] drm/xe: declare wedged upon GuC load failure Rodrigo Vivi
                   ` (12 more replies)
  0 siblings, 13 replies; 32+ messages in thread
From: Rodrigo Vivi @ 2024-04-09 22:15 UTC (permalink / raw)
  To: intel-xe
  Cc: Rodrigo Vivi, Ashutosh Dixit, Tvrtko Ursulin,
	Thomas Hellström, Lucas De Marchi, Anshuman Gupta,
	Himal Prasad Ghimiray

Introduce a very simple 'wedged' state where any attempt
to access the GPU is entirely blocked.

On some critical cases, like on gt_reset failure, we need to
block any other attempt to use the GPU. Otherwise we are at
a risk of reaching cases that would force us to reboot the machine.

So, when this cases are identified we corner and block any GPU
access. No IOCTL and not even another GT reset should be attempted.

The 'wedged' state in Xe is an end state with no way back.
Only a device "re-probe" (unbind + bind) can restore the GPU access.

v2: - s/wedged/busted (Lucas)
    - use unbind+bind instead of module reload (Lucas)
    - added more info on unbind operations and instruction on bug report
    - only print the message once.

v3: - s/busted/wedged (Ashutosh, Tvrtko, Thomas)
    - don't assume user has sudo and tee available (Lucas)

v4: - remove unnecessary cases around ct communication or migration.

Cc: Ashutosh Dixit <ashutosh.dixit@intel.com>
Cc: Tvrtko Ursulin <tursulin@ursulin.net>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com> #v2
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com> #v2
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
 drivers/gpu/drm/xe/xe_device.c       |  6 ++++++
 drivers/gpu/drm/xe/xe_device.h       | 20 ++++++++++++++++++++
 drivers/gpu/drm/xe/xe_device_types.h |  3 +++
 drivers/gpu/drm/xe/xe_gt.c           |  5 ++++-
 drivers/gpu/drm/xe/xe_guc_pc.c       |  3 +++
 5 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 9083f5e02dd9..67de795e43b3 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -142,6 +142,9 @@ static long xe_drm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	struct xe_device *xe = to_xe_device(file_priv->minor->dev);
 	long ret;
 
+	if (xe_device_wedged(xe))
+		return -ECANCELED;
+
 	ret = xe_pm_runtime_get_ioctl(xe);
 	if (ret >= 0)
 		ret = drm_ioctl(file, cmd, arg);
@@ -157,6 +160,9 @@ static long xe_drm_compat_ioctl(struct file *file, unsigned int cmd, unsigned lo
 	struct xe_device *xe = to_xe_device(file_priv->minor->dev);
 	long ret;
 
+	if (xe_device_wedged(xe))
+		return -ECANCELED;
+
 	ret = xe_pm_runtime_get_ioctl(xe);
 	if (ret >= 0)
 		ret = drm_compat_ioctl(file, cmd, arg);
diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
index d413bc2c6be5..c532209c5bbd 100644
--- a/drivers/gpu/drm/xe/xe_device.h
+++ b/drivers/gpu/drm/xe/xe_device.h
@@ -176,4 +176,24 @@ void xe_device_snapshot_print(struct xe_device *xe, struct drm_printer *p);
 u64 xe_device_canonicalize_addr(struct xe_device *xe, u64 address);
 u64 xe_device_uncanonicalize_addr(struct xe_device *xe, u64 address);
 
+static inline bool xe_device_wedged(struct xe_device *xe)
+{
+	return atomic_read(&xe->wedged);
+}
+
+static inline void xe_device_declare_wedged(struct xe_device *xe)
+{
+	if (!atomic_xchg(&xe->wedged, 1)) {
+		xe->needs_flr_on_fini = true;
+		drm_err(&xe->drm,
+			"CRITICAL: Xe has declared device %s as wedged.\n"
+			"IOCTLs and executions are blocked until device is probed again with unbind and bind operations:\n"
+			"echo '%s' > /sys/bus/pci/drivers/xe/unbind\n"
+			"echo '%s' > /sys/bus/pci/drivers/xe/bind\n"
+			"Please file a _new_ bug report at https://gitlab.freedesktop.org/drm/xe/kernel/issues/new\n",
+			dev_name(xe->drm.dev), dev_name(xe->drm.dev),
+			dev_name(xe->drm.dev));
+	}
+}
+
 #endif
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index faa32407efa5..b9ef60f21750 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -458,6 +458,9 @@ struct xe_device {
 	/** @needs_flr_on_fini: requests function-reset on fini */
 	bool needs_flr_on_fini;
 
+	/** @wedged: Xe device faced a critical error and is now blocked. */
+	atomic_t wedged;
+
 	/* private: */
 
 #if IS_ENABLED(CONFIG_DRM_XE_DISPLAY)
diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
index cfa5da900461..0844081b88ef 100644
--- a/drivers/gpu/drm/xe/xe_gt.c
+++ b/drivers/gpu/drm/xe/xe_gt.c
@@ -633,6 +633,9 @@ static int gt_reset(struct xe_gt *gt)
 {
 	int err;
 
+	if (xe_device_wedged(gt_to_xe(gt)))
+		return -ECANCELED;
+
 	/* We only support GT resets with GuC submission */
 	if (!xe_device_uc_enabled(gt_to_xe(gt)))
 		return -ENODEV;
@@ -685,7 +688,7 @@ static int gt_reset(struct xe_gt *gt)
 err_fail:
 	xe_gt_err(gt, "reset failed (%pe)\n", ERR_PTR(err));
 
-	gt_to_xe(gt)->needs_flr_on_fini = true;
+	xe_device_declare_wedged(gt_to_xe(gt));
 
 	return err;
 }
diff --git a/drivers/gpu/drm/xe/xe_guc_pc.c b/drivers/gpu/drm/xe/xe_guc_pc.c
index 521ae24f2314..f4663f1b0a80 100644
--- a/drivers/gpu/drm/xe/xe_guc_pc.c
+++ b/drivers/gpu/drm/xe/xe_guc_pc.c
@@ -902,6 +902,9 @@ static void xe_guc_pc_fini(struct drm_device *drm, void *arg)
 		return;
 	}
 
+	if (xe_device_wedged(xe))
+		return;
+
 	XE_WARN_ON(xe_force_wake_get(gt_to_fw(pc_to_gt(pc)), XE_FORCEWAKE_ALL));
 	XE_WARN_ON(xe_guc_pc_gucrc_disable(pc));
 	XE_WARN_ON(xe_guc_pc_stop(pc));
-- 
2.44.0


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