Commit 1919d168 authored by Matthew Brost's avatar Matthew Brost
Browse files

drm/xe: Implement xe_pagefault_init 



Create pagefault queues and initialize them.

v2:
 - Fix kernel doc + add comment for number PF queue (Francois)
v4:
 - Move init after GT init (CI, Francois)

Signed-off-by: default avatarMatthew Brost <matthew.brost@intel.com>
Reviewed-by: default avatarFrancois Dugast <francois.dugast@intel.com>
Tested-by: default avatarFrancois Dugast <francois.dugast@intel.com>
Link: https://patch.msgid.link/20251031165416.2871503-3-matthew.brost@intel.com
parent 620a09fb

drivers/gpu/drm/xe/xe_device.c

+5 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ 
#include "xe_nvm.h"

#include "xe_oa.h"

#include "xe_observation.h"

#include "xe_pagefault.h"

#include "xe_pat.h"

#include "xe_pcode.h"

#include "xe_pm.h"
@@ -896,6 +897,10 @@ int xe_device_probe(struct xe_device *xe) 
			return err;

	}



	err = xe_pagefault_init(xe);

	if (err)

		return err;



	if (xe->tiles->media_gt &&

	    XE_GT_WA(xe->tiles->media_gt, 15015404425_disable))

		XE_DEVICE_WA_DISABLE(xe, 15015404425);

drivers/gpu/drm/xe/xe_device_types.h

+11 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include "xe_lmtt_types.h"

#include "xe_memirq_types.h"

#include "xe_oa_types.h"

#include "xe_pagefault_types.h"

#include "xe_platform_types.h"

#include "xe_pmu_types.h"

#include "xe_pt_types.h"
@@ -413,6 +414,16 @@ struct xe_device { 
		u32 next_asid;

		/** @usm.lock: protects UM state */

		struct rw_semaphore lock;

		/** @usm.pf_wq: page fault work queue, unbound, high priority */

		struct workqueue_struct *pf_wq;

		/*

		 * We pick 4 here because, in the current implementation, it

		 * yields the best bandwidth utilization of the kernel paging

		 * engine.

		 */

#define XE_PAGEFAULT_QUEUE_COUNT	4

		/** @usm.pf_queue: Page fault queues */

		struct xe_pagefault_queue pf_queue[XE_PAGEFAULT_QUEUE_COUNT];

	} usm;



	/** @pinned: pinned BO state */

drivers/gpu/drm/xe/xe_pagefault.c

+96 −2
Original line number Diff line number Diff line
@@ -3,6 +3,10 @@ 
 * Copyright © 2025 Intel Corporation

 */



#include <drm/drm_managed.h>



#include "xe_device.h"

#include "xe_gt_types.h"

#include "xe_pagefault.h"

#include "xe_pagefault_types.h"
@@ -21,6 +25,76 @@ 
 * xe_pagefault.c implements the consumer layer.

 */



static int xe_pagefault_entry_size(void)

{

	/*

	 * Power of two alignment is not a hardware requirement, rather a

	 * software restriction which makes the math for page fault queue

	 * management simplier.

	 */

	return roundup_pow_of_two(sizeof(struct xe_pagefault));

}



static void xe_pagefault_queue_work(struct work_struct *w)

{

	/* TODO: Implement */

}



static int xe_pagefault_queue_init(struct xe_device *xe,

				   struct xe_pagefault_queue *pf_queue)

{

	struct xe_gt *gt;

	int total_num_eus = 0;

	u8 id;



	for_each_gt(gt, xe, id) {

		xe_dss_mask_t all_dss;

		int num_dss, num_eus;



		bitmap_or(all_dss, gt->fuse_topo.g_dss_mask,

			  gt->fuse_topo.c_dss_mask, XE_MAX_DSS_FUSE_BITS);



		num_dss = bitmap_weight(all_dss, XE_MAX_DSS_FUSE_BITS);

		num_eus = bitmap_weight(gt->fuse_topo.eu_mask_per_dss,

					XE_MAX_EU_FUSE_BITS) * num_dss;



		total_num_eus += num_eus;

	}



	xe_assert(xe, total_num_eus);



	/*

	 * user can issue separate page faults per EU and per CS

	 *

	 * XXX: Multiplier required as compute UMD are getting PF queue errors

	 * without it. Follow on why this multiplier is required.

	 */

#define PF_MULTIPLIER	8

	pf_queue->size = (total_num_eus + XE_NUM_HW_ENGINES) *

		xe_pagefault_entry_size() * PF_MULTIPLIER;

	pf_queue->size = roundup_pow_of_two(pf_queue->size);

#undef PF_MULTIPLIER



	drm_dbg(&xe->drm, "xe_pagefault_entry_size=%d, total_num_eus=%d, pf_queue->size=%u",

		xe_pagefault_entry_size(), total_num_eus, pf_queue->size);



	spin_lock_init(&pf_queue->lock);

	INIT_WORK(&pf_queue->worker, xe_pagefault_queue_work);



	pf_queue->data = drmm_kzalloc(&xe->drm, pf_queue->size, GFP_KERNEL);

	if (!pf_queue->data)

		return -ENOMEM;



	return 0;

}



static void xe_pagefault_fini(void *arg)

{

	struct xe_device *xe = arg;



	destroy_workqueue(xe->usm.pf_wq);

}



/**

 * xe_pagefault_init() - Page fault init

 * @xe: xe device instance
@@ -31,8 +105,28 @@ 
 */

int xe_pagefault_init(struct xe_device *xe)

{

	/* TODO - implement */

	int err, i;



	if (!xe->info.has_usm)

		return 0;



	xe->usm.pf_wq = alloc_workqueue("xe_page_fault_work_queue",

					WQ_UNBOUND | WQ_HIGHPRI,

					XE_PAGEFAULT_QUEUE_COUNT);

	if (!xe->usm.pf_wq)

		return -ENOMEM;



	for (i = 0; i < XE_PAGEFAULT_QUEUE_COUNT; ++i) {

		err = xe_pagefault_queue_init(xe, xe->usm.pf_queue + i);

		if (err)

			goto err_out;

	}



	return devm_add_action_or_reset(xe->drm.dev, xe_pagefault_fini, xe);



err_out:

	destroy_workqueue(xe->usm.pf_wq);

	return err;

}



/**