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* [PATCH V4] drm/xe/: Mutual Exclusivity b/w Multi CCS Mode & SRIOV VF Provisioning
@ 2025-10-06  8:45 Nareshkumar Gollakoti
  2025-10-06  8:57 ` ✗ CI.checkpatch: warning for drm/xe/: Mutual Exclusivity b/w Multi CCS Mode & SRIOV VF Provisioning (rev4) Patchwork
                   ` (3 more replies)
  0 siblings, 4 replies; 7+ messages in thread
From: Nareshkumar Gollakoti @ 2025-10-06  8:45 UTC (permalink / raw)
  To: intel-xe; +Cc: naresh.kumar.g, Michal.Wajdeczko, stuart.summers

Due to SLA agreement between PF and VFs, multi CCS mode can't
be enabled when VFs are already enabled.
Similarly, enabling VFs is disabled when multi CCS mode enabled.

---
v2:
- function xe_device_is_vf_enabled has been refactored to
xe_sriov_pf_has_vfs_enabled and moved to xe_sriov_pf_helper.h.
- The code now distinctly checks for SR-IOV VF mode and
SR-IOV PF with VFs enabled.
- Log messages have been updated to explicitly state the current mode.
- The function xe_multi_ccs_mode_enabled is moved to xe_device.h

v3: Described missed arg documentation for xe_sriov_pf_has_vfs_enabled

v4:
- sysfs interface for CCS mode is not initialized
 when operating in SRIOV VF Mode.
- xe_sriov_pf_has_vfs_enabled() check is sufficient while CCS mode
 enablement.
- remove unnecessary comments as flow is self explanatory.

Signed-off-by: Nareshkumar Gollakoti <naresh.kumar.g@intel.com>
---
 drivers/gpu/drm/xe/xe_device.h           |  8 ++++++++
 drivers/gpu/drm/xe/xe_gt_ccs_mode.c      | 10 ++++++----
 drivers/gpu/drm/xe/xe_pci_sriov.c        |  5 +++++
 drivers/gpu/drm/xe/xe_sriov_pf_helpers.h | 13 +++++++++++++
 4 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
index 32cc6323b7f6..986f9cabb897 100644
--- a/drivers/gpu/drm/xe/xe_device.h
+++ b/drivers/gpu/drm/xe/xe_device.h
@@ -172,6 +172,14 @@ static inline bool xe_device_has_lmtt(struct xe_device *xe)
 	return IS_DGFX(xe);
 }
 
+static inline bool xe_multi_ccs_mode_enabled(struct xe_device *xe)
+{
+	/* Multi CCS mode supported exclusively on GT0 */
+	struct xe_gt *gt = xe_device_get_gt(xe, 0);
+
+	return gt->ccs_mode > 1;
+}
+
 u32 xe_device_ccs_bytes(struct xe_device *xe, u64 size);
 
 void xe_device_snapshot_print(struct xe_device *xe, struct drm_printer *p);
diff --git a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
index 50fffc9ebf62..91908faf3768 100644
--- a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
+++ b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
@@ -13,6 +13,7 @@
 #include "xe_gt_sysfs.h"
 #include "xe_mmio.h"
 #include "xe_sriov.h"
+#include "xe_sriov_pf_helpers.h"
 
 static void __xe_gt_apply_ccs_mode(struct xe_gt *gt, u32 num_engines)
 {
@@ -117,9 +118,8 @@ ccs_mode_store(struct device *kdev, struct device_attribute *attr,
 	u32 num_engines, num_slices;
 	int ret;
 
-	if (IS_SRIOV(xe)) {
-		xe_gt_dbg(gt, "Can't change compute mode when running as %s\n",
-			  xe_sriov_mode_to_string(xe_device_sriov_mode(xe)));
+	if (xe_sriov_pf_has_vfs_enabled(xe)) {
+		xe_gt_dbg(gt, "Can't change CCS mode in SR-IOV PF Mode with VFs Enabled\n");
 		return -EOPNOTSUPP;
 	}
 
@@ -184,6 +184,8 @@ static void xe_gt_ccs_mode_sysfs_fini(void *arg)
  * The number of available compute slices is exposed to user through a per-gt
  * 'num_cslices' sysfs interface.
  *
+ * The sysfs interface for CCS mode is not set up in SRIOV VF Mode.
+ *
  * Returns: Returns error value for failure and 0 for success.
  */
 int xe_gt_ccs_mode_sysfs_init(struct xe_gt *gt)
@@ -191,7 +193,7 @@ int xe_gt_ccs_mode_sysfs_init(struct xe_gt *gt)
 	struct xe_device *xe = gt_to_xe(gt);
 	int err;
 
-	if (!xe_gt_ccs_mode_enabled(gt))
+	if (!xe_gt_ccs_mode_enabled(gt) || IS_SRIOV_VF(xe))
 		return 0;
 
 	err = sysfs_create_files(gt->sysfs, gt_ccs_mode_attrs);
diff --git a/drivers/gpu/drm/xe/xe_pci_sriov.c b/drivers/gpu/drm/xe/xe_pci_sriov.c
index af05db07162e..404337692978 100644
--- a/drivers/gpu/drm/xe/xe_pci_sriov.c
+++ b/drivers/gpu/drm/xe/xe_pci_sriov.c
@@ -155,6 +155,11 @@ static int pf_enable_vfs(struct xe_device *xe, int num_vfs)
 	xe_assert(xe, num_vfs <= total_vfs);
 	xe_sriov_dbg(xe, "enabling %u VF%s\n", num_vfs, str_plural(num_vfs));
 
+	if (xe_multi_ccs_mode_enabled(xe)) {
+		xe_sriov_info(xe, "Disable multi-CCS mode before enabling VF's\n");
+		return -ECANCELED;
+	}
+
 	err = xe_sriov_pf_wait_ready(xe);
 	if (err)
 		goto out;
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
index dd1df950b021..e26837091375 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
@@ -43,4 +43,17 @@ static inline struct mutex *xe_sriov_pf_master_mutex(struct xe_device *xe)
 	return &xe->sriov.pf.master_lock;
 }
 
+/**
+ * xe_sriov_pf_has_vfs_enabled() - Determines if the PF has any VFs enabled
+ * @xe: ptr to xe_device
+ *
+ * Return: true if one or more VFs are enabled on the PF, false otherwise.
+ */
+static inline bool xe_sriov_pf_has_vfs_enabled(const struct xe_device *xe)
+{
+	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+
+	return pci_num_vf(pdev) > 0;
+}
+
 #endif
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 7+ messages in thread
* [PATCH V4] drm/xe/: Mutual Exclusivity b/w Multi CCS Mode & SRIOV VF Provisioning
@ 2025-10-06 11:50 Nareshkumar Gollakoti
  2025-10-07 11:29 ` Michal Wajdeczko
  0 siblings, 1 reply; 7+ messages in thread
From: Nareshkumar Gollakoti @ 2025-10-06 11:50 UTC (permalink / raw)
  To: intel-xe; +Cc: naresh.kumar.g, Michal.Wajdeczko, stuart.summers

Due to SLA agreement between PF and VFs, multi CCS mode can't
be enabled when VFs are already enabled.
Similarly, enabling VFs is disabled when multi CCS mode enabled.

v2:
- function xe_device_is_vf_enabled has been refactored to
  xe_sriov_pf_has_vfs_enabled and moved to xe_sriov_pf_helper.h.
- The code now distinctly checks for SR-IOV VF mode and
  SR-IOV PF with VFs enabled.
- Log messages have been updated to explicitly state the current mode.
- The function xe_multi_ccs_mode_enabled is moved to xe_device.h

v3: Described missed arg documentation for xe_sriov_pf_has_vfs_enabled

v4:
- sysfs interface for CCS mode is not initialized
  when operating in SRIOV VF Mode.
- xe_sriov_pf_has_vfs_enabled() check is sufficient while CCS mode
  enablement.
- remove unnecessary comments as flow is self explanatory.

Signed-off-by: Nareshkumar Gollakoti <naresh.kumar.g@intel.com>
---
 drivers/gpu/drm/xe/xe_device.h           |  8 ++++++++
 drivers/gpu/drm/xe/xe_gt_ccs_mode.c      | 10 ++++++----
 drivers/gpu/drm/xe/xe_pci_sriov.c        |  5 +++++
 drivers/gpu/drm/xe/xe_sriov_pf_helpers.h | 13 +++++++++++++
 4 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_device.h b/drivers/gpu/drm/xe/xe_device.h
index 32cc6323b7f6..986f9cabb897 100644
--- a/drivers/gpu/drm/xe/xe_device.h
+++ b/drivers/gpu/drm/xe/xe_device.h
@@ -172,6 +172,14 @@ static inline bool xe_device_has_lmtt(struct xe_device *xe)
 	return IS_DGFX(xe);
 }
 
+static inline bool xe_multi_ccs_mode_enabled(struct xe_device *xe)
+{
+	/* Multi CCS mode supported exclusively on GT0 */
+	struct xe_gt *gt = xe_device_get_gt(xe, 0);
+
+	return gt->ccs_mode > 1;
+}
+
 u32 xe_device_ccs_bytes(struct xe_device *xe, u64 size);
 
 void xe_device_snapshot_print(struct xe_device *xe, struct drm_printer *p);
diff --git a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
index 50fffc9ebf62..91908faf3768 100644
--- a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
+++ b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
@@ -13,6 +13,7 @@
 #include "xe_gt_sysfs.h"
 #include "xe_mmio.h"
 #include "xe_sriov.h"
+#include "xe_sriov_pf_helpers.h"
 
 static void __xe_gt_apply_ccs_mode(struct xe_gt *gt, u32 num_engines)
 {
@@ -117,9 +118,8 @@ ccs_mode_store(struct device *kdev, struct device_attribute *attr,
 	u32 num_engines, num_slices;
 	int ret;
 
-	if (IS_SRIOV(xe)) {
-		xe_gt_dbg(gt, "Can't change compute mode when running as %s\n",
-			  xe_sriov_mode_to_string(xe_device_sriov_mode(xe)));
+	if (xe_sriov_pf_has_vfs_enabled(xe)) {
+		xe_gt_dbg(gt, "Can't change CCS mode in SR-IOV PF Mode with VFs Enabled\n");
 		return -EOPNOTSUPP;
 	}
 
@@ -184,6 +184,8 @@ static void xe_gt_ccs_mode_sysfs_fini(void *arg)
  * The number of available compute slices is exposed to user through a per-gt
  * 'num_cslices' sysfs interface.
  *
+ * The sysfs interface for CCS mode is not set up in SRIOV VF Mode.
+ *
  * Returns: Returns error value for failure and 0 for success.
  */
 int xe_gt_ccs_mode_sysfs_init(struct xe_gt *gt)
@@ -191,7 +193,7 @@ int xe_gt_ccs_mode_sysfs_init(struct xe_gt *gt)
 	struct xe_device *xe = gt_to_xe(gt);
 	int err;
 
-	if (!xe_gt_ccs_mode_enabled(gt))
+	if (!xe_gt_ccs_mode_enabled(gt) || IS_SRIOV_VF(xe))
 		return 0;
 
 	err = sysfs_create_files(gt->sysfs, gt_ccs_mode_attrs);
diff --git a/drivers/gpu/drm/xe/xe_pci_sriov.c b/drivers/gpu/drm/xe/xe_pci_sriov.c
index 9c1c9e669b04..0715f87a5ecc 100644
--- a/drivers/gpu/drm/xe/xe_pci_sriov.c
+++ b/drivers/gpu/drm/xe/xe_pci_sriov.c
@@ -153,6 +153,11 @@ static int pf_enable_vfs(struct xe_device *xe, int num_vfs)
 	xe_assert(xe, num_vfs <= total_vfs);
 	xe_sriov_dbg(xe, "enabling %u VF%s\n", num_vfs, str_plural(num_vfs));
 
+	if (xe_multi_ccs_mode_enabled(xe)) {
+		xe_sriov_info(xe, "Disable multi-CCS mode before enabling VF's\n");
+		return -ECANCELED;
+	}
+
 	err = xe_sriov_pf_wait_ready(xe);
 	if (err)
 		goto out;
diff --git a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
index dd1df950b021..e26837091375 100644
--- a/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
+++ b/drivers/gpu/drm/xe/xe_sriov_pf_helpers.h
@@ -43,4 +43,17 @@ static inline struct mutex *xe_sriov_pf_master_mutex(struct xe_device *xe)
 	return &xe->sriov.pf.master_lock;
 }
 
+/**
+ * xe_sriov_pf_has_vfs_enabled() - Determines if the PF has any VFs enabled
+ * @xe: ptr to xe_device
+ *
+ * Return: true if one or more VFs are enabled on the PF, false otherwise.
+ */
+static inline bool xe_sriov_pf_has_vfs_enabled(const struct xe_device *xe)
+{
+	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+
+	return pci_num_vf(pdev) > 0;
+}
+
 #endif
-- 
2.43.0


^ permalink raw reply related	[flat|nested] 7+ messages in thread
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2025-10-06  8:45 [PATCH V4] drm/xe/: Mutual Exclusivity b/w Multi CCS Mode & SRIOV VF Provisioning Nareshkumar Gollakoti
2025-10-06  8:57 ` ✗ CI.checkpatch: warning for drm/xe/: Mutual Exclusivity b/w Multi CCS Mode & SRIOV VF Provisioning (rev4) Patchwork
2025-10-06  8:59 ` ✓ CI.KUnit: success " Patchwork
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2025-10-06 11:50 [PATCH V4] drm/xe/: Mutual Exclusivity b/w Multi CCS Mode & SRIOV VF Provisioning Nareshkumar Gollakoti
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