[PATCH v10 18/27] drm/xe: Implement SR-IOV and eudebug exclusivity

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

From: Christoph Manszewski <christoph.manszewski@intel.com>

EU debug functionality relies on access to specific mmio registers.
Since VFs don't have access to those registers and in order to avoid
interference with VFs, make SR-IOV and eudebug functionality exclusive.
I.e. don't allow enabling eudebug in VF mode and don't allow enabling
eudebug when any VFs are enabled. Likewise, don't allow enabling
VFs when eudebug is enabled.

v2: initialize lock early (Sashiko)
v3: say why eudebug was refused (Claude)

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Christoph Manszewski <christoph.manszewski@intel.com>
Signed-off-by: Maciej Patelczyk <maciej.patelczyk@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
---
 drivers/gpu/drm/xe/tests/xe_eudebug_test.c |  3 +++
 drivers/gpu/drm/xe/xe_eudebug.c            | 24 ++++++++++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/tests/xe_eudebug_test.c b/drivers/gpu/drm/xe/tests/xe_eudebug_test.c
index a207840fdb91..0ed2de04ba83 100644
--- a/drivers/gpu/drm/xe/tests/xe_eudebug_test.c
+++ b/drivers/gpu/drm/xe/tests/xe_eudebug_test.c
@@ -160,6 +160,9 @@ static void toggle_reg(struct kunit *test)
 	if (xe->eudebug.cap_state == XE_EUDEBUG_CAP_NOT_SUPPORTED)
 		kunit_skip(test, "eudebug not supported\n");
 
+	if (IS_SRIOV_VF(xe))
+		kunit_skip(test, "eudebug not available in SR-IOV VF mode\n");
+
 	kunit_printk(KERN_DEBUG, test, "Test eudebug WAs for graphics version: %u\n",
 		     GRAPHICS_VERx100(xe));
 
diff --git a/drivers/gpu/drm/xe/xe_eudebug.c b/drivers/gpu/drm/xe/xe_eudebug.c
index 470246af9810..2c8d8fc82898 100644
--- a/drivers/gpu/drm/xe/xe_eudebug.c
+++ b/drivers/gpu/drm/xe/xe_eudebug.c
@@ -26,6 +26,7 @@
 #include "xe_hw_engine.h"
 #include "xe_macros.h"
 #include "xe_pm.h"
+#include "xe_sriov_pf.h"
 #include "xe_sync.h"
 #include "xe_vm.h"
 
@@ -2245,6 +2246,7 @@ bool xe_eudebug_is_enabled(struct xe_device *xe)
 int xe_eudebug_enable(struct xe_device *xe, bool enable)
 {
 	struct xe_gt *gt;
+	int ret;
 	int i;
 	u8 id;
 
@@ -2259,6 +2261,14 @@ int xe_eudebug_enable(struct xe_device *xe, bool enable)
 	if (enable == xe_eudebug_is_enabled(xe))
 		return 0;
 
+	if (enable && IS_SRIOV_PF(xe)) {
+		ret = xe_sriov_pf_lockdown(xe);
+		if (ret) {
+			drm_dbg(&xe->drm, "Can't enable eudebug: VFs are enabled\n");
+			return ret;
+		}
+	}
+
 	xe_pm_runtime_get(xe);
 	for_each_gt(gt, xe, id) {
 		for (i = 0; i < ARRAY_SIZE(gt->hw_engines); i++) {
@@ -2276,10 +2286,14 @@ int xe_eudebug_enable(struct xe_device *xe, bool enable)
 	WRITE_ONCE(xe->eudebug.cap_state, enable ?
 		   XE_EUDEBUG_CAP_ENABLED : XE_EUDEBUG_CAP_DISABLED);
 
-	if (enable)
+	if (enable) {
 		xe_eudebug_attention_poll_start(xe);
-	else
+	} else {
+		if (IS_SRIOV_PF(xe))
+			xe_sriov_pf_end_lockdown(xe);
+
 		xe_eudebug_attention_poll_stop(xe);
+	}
 
 	return 0;
 }
@@ -2359,6 +2373,11 @@ void xe_eudebug_init(struct xe_device *xe)
 	if (xe->eudebug.cap_state == XE_EUDEBUG_CAP_NOT_SUPPORTED)
 		return;
 
+	if (IS_SRIOV_VF(xe)) {
+		drm_info(&xe->drm, "eudebug not available in SR-IOV VF mode\n");
+		goto out_not_supported;
+	}
+
 	wq = drmm_alloc_ordered_workqueue(dev, "xe-eudebug-discovery", 0);
 	if (IS_ERR(wq)) {
 		err = PTR_ERR(wq);
@@ -2404,6 +2423,7 @@ void xe_eudebug_init(struct xe_device *xe)
 out_err:
 	drm_warn(&xe->drm, "eudebug disabled, init fail: %d\n", err);
 
+out_not_supported:
 	WRITE_ONCE(xe->eudebug.cap_state, XE_EUDEBUG_CAP_NOT_SUPPORTED);
 }
 
-- 
2.53.0