drm/xe/pf: Introduce mutex to protect VFs configurations

PF driver will maintain configurations and resources for every VF
and this data could span multiple tiles and/or GTs.  Prepare mutex
to protect data that we will add in upcoming patches.
Reviewed-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240410170338.1199-2-michal.wajdeczko@intel.com

drivers/gpu/drm/xe/xe_sriov.c

@@ -94,6 +94,13 @@ int xe_sriov_init(struct xe_device *xe)
 	if (!IS_SRIOV(xe))
 		return 0;
 
+	if (IS_SRIOV_PF(xe)) {
+		int err = xe_sriov_pf_init_early(xe);
+
+		if (err)
+			return err;
+	}
+
 	xe_assert(xe, !xe->sriov.wq);
 	xe->sriov.wq = alloc_workqueue("xe-sriov-wq", 0, 0);
 	if (!xe->sriov.wq)

drivers/gpu/drm/xe/xe_sriov_pf.c

@@ -3,6 +3,8 @@
  * Copyright © 2023-2024 Intel Corporation
  */
 
+#include <drm/drm_managed.h>
+
 #include "xe_assert.h"
 #include "xe_device.h"
 #include "xe_module.h"
@@ -70,6 +72,19 @@ bool xe_sriov_pf_readiness(struct xe_device *xe)
 	return true;
 }
 
+/**
+ * xe_sriov_pf_init_early - Initialize SR-IOV PF specific data.
+ * @xe: the &xe_device to initialize
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int xe_sriov_pf_init_early(struct xe_device *xe)
+{
+	xe_assert(xe, IS_SRIOV_PF(xe));
+
+	return drmm_mutex_init(&xe->drm, &xe->sriov.pf.master_lock);
+}
+
 /**
  * xe_sriov_pf_print_vfs_summary - Print SR-IOV PF information.
  * @xe: the &xe_device to print info from

drivers/gpu/drm/xe/xe_sriov_pf.h

@@ -13,12 +13,18 @@ struct xe_device;
 
 #ifdef CONFIG_PCI_IOV
 bool xe_sriov_pf_readiness(struct xe_device *xe);
+int xe_sriov_pf_init_early(struct xe_device *xe);
 void xe_sriov_pf_print_vfs_summary(struct xe_device *xe, struct drm_printer *p);
 #else
 static inline bool xe_sriov_pf_readiness(struct xe_device *xe)
 {
 	return false;
 }
+
+static inline int xe_sriov_pf_init_early(struct xe_device *xe)
+{
+	return 0;
+}
 #endif
 
 #endif

drivers/gpu/drm/xe/xe_sriov_types.h

@@ -7,6 +7,7 @@
 #define _XE_SRIOV_TYPES_H_
 
 #include <linux/build_bug.h>
+#include <linux/mutex.h>
 #include <linux/types.h>
 
 /**
@@ -50,6 +51,9 @@ struct xe_device_pf {
 
 	/** @driver_max_vfs: Maximum number of VFs supported by the driver. */
 	u16 driver_max_vfs;
+
+	/** @master_lock: protects all VFs configurations across GTs */
+	struct mutex master_lock;
 };
 
 #endif