[PATCH] drm/xe/: Mutual Exclusivity b/w Multi CCS Mode & SRIOV VF Provisioning

[Nareshkumar Gollakoti <naresh.kumar.g@intel.com>]

Multi CCS mode can only be enabled when SRIOV is in PF mode with
no VFs provisioned.
Similarly, provisioning VFs is not allowed when Multi CCS mode is active.

Signed-off-by: Nareshkumar Gollakoti <naresh.kumar.g@intel.com>
---
 drivers/gpu/drm/xe/xe_gt_ccs_mode.c |  7 ++++---
 drivers/gpu/drm/xe/xe_gt_ccs_mode.h | 10 ++++++++++
 drivers/gpu/drm/xe/xe_pci_sriov.c   |  7 +++++++
 drivers/gpu/drm/xe/xe_sriov.h       | 12 ++++++++++++
 4 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
index 50fffc9ebf62..39df801e9cd5 100644
--- a/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
+++ b/drivers/gpu/drm/xe/xe_gt_ccs_mode.c
@@ -117,9 +117,10 @@ 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 (IS_SRIOV_VF_ENABLED(xe)) {
+		xe_gt_dbg(gt, "Can't change compute mode when running as %s / %s\n",
+			  xe_sriov_mode_to_string(xe_device_sriov_mode(xe)),
+			  "One or more VFs enabled");
 		return -EOPNOTSUPP;
 	}
 
diff --git a/drivers/gpu/drm/xe/xe_gt_ccs_mode.h b/drivers/gpu/drm/xe/xe_gt_ccs_mode.h
index f8779852cf0d..1a80a293daa2 100644
--- a/drivers/gpu/drm/xe/xe_gt_ccs_mode.h
+++ b/drivers/gpu/drm/xe/xe_gt_ccs_mode.h
@@ -20,5 +20,15 @@ static inline bool xe_gt_ccs_mode_enabled(const struct xe_gt *gt)
 	return hweight32(CCS_MASK(gt)) > 1;
 }
 
+static inline bool xe_is_primary_gt_multi_ccs_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);
+}
+
+#define IS_PRIMARY_GT_MULTI_CCS_ENABLED(xe) xe_is_primary_gt_multi_ccs_enabled(xe)
+
 #endif
 
diff --git a/drivers/gpu/drm/xe/xe_pci_sriov.c b/drivers/gpu/drm/xe/xe_pci_sriov.c
index af05db07162e..96e3fd51b8f5 100644
--- a/drivers/gpu/drm/xe/xe_pci_sriov.c
+++ b/drivers/gpu/drm/xe/xe_pci_sriov.c
@@ -19,6 +19,7 @@
 #include "xe_sriov_pf.h"
 #include "xe_sriov_pf_helpers.h"
 #include "xe_sriov_printk.h"
+#include "xe_gt_ccs_mode.h"
 
 static int pf_needs_provisioning(struct xe_gt *gt, unsigned int num_vfs)
 {
@@ -153,6 +154,12 @@ static int pf_enable_vfs(struct xe_device *xe, int num_vfs)
 	xe_assert(xe, IS_SRIOV_PF(xe));
 	xe_assert(xe, num_vfs > 0);
 	xe_assert(xe, num_vfs <= total_vfs);
+
+	if (IS_PRIMARY_GT_MULTI_CCS_ENABLED(xe)) {
+		xe_sriov_info(xe, "Can't change the number of VFs while multi-CCS mode is enabled.");
+
+		return -EOPNOTSUPP;
+	}
 	xe_sriov_dbg(xe, "enabling %u VF%s\n", num_vfs, str_plural(num_vfs));
 
 	err = xe_sriov_pf_wait_ready(xe);
diff --git a/drivers/gpu/drm/xe/xe_sriov.h b/drivers/gpu/drm/xe/xe_sriov.h
index 6db45df55615..78019cee61fe 100644
--- a/drivers/gpu/drm/xe/xe_sriov.h
+++ b/drivers/gpu/drm/xe/xe_sriov.h
@@ -36,6 +36,16 @@ static inline bool xe_device_is_sriov_vf(const struct xe_device *xe)
 	return xe_device_sriov_mode(xe) == XE_SRIOV_MODE_VF;
 }
 
+static inline bool xe_device_is_vf_enabled(const struct xe_device *xe)
+{
+	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
+
+	if (xe_device_is_sriov_vf(xe))
+		return true;
+
+	return (pci_num_vf(pdev) > 0);
+}
+
 #ifdef CONFIG_PCI_IOV
 #define IS_SRIOV_PF(xe) xe_device_is_sriov_pf(xe)
 #else
@@ -45,4 +55,6 @@ static inline bool xe_device_is_sriov_vf(const struct xe_device *xe)
 
 #define IS_SRIOV(xe) (IS_SRIOV_PF(xe) || IS_SRIOV_VF(xe))
 
+#define IS_SRIOV_VF_ENABLED(xe) xe_device_is_vf_enabled(xe)
+
 #endif
-- 
2.43.0