drm/xe: Split TLB invalidation code in frontend and backend

The frontend exposes an API to the driver to send invalidations, handles
sequence number assignment, synchronization (fences), and provides a
timeout mechanism. The backend issues the actual invalidation to the
hardware (or firmware).

The new layering easily allows issuing TLB invalidations to different
hardware or firmware interfaces.

Normalize some naming while here too.

Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://lore.kernel.org/r/20250826182911.392550-10-stuart.summers@intel.com

Author: mbrost05

drivers/gpu/drm/xe/Makefile

@@ -75,6 +75,7 @@ xe-y += xe_bb.o \
 	xe_guc_log.o \
 	xe_guc_pc.o \
 	xe_guc_submit.o \
+	xe_guc_tlb_inval.o \
 	xe_heci_gsc.o \
 	xe_huc.o \
 	xe_hw_engine.o \

drivers/gpu/drm/xe/xe_gt.c

@@ -603,8 +603,6 @@ static void xe_gt_fini(void *arg)
 	struct xe_gt *gt = arg;
 	int i;
 
-	xe_gt_tlb_inval_fini(gt);
-
 	for (i = 0; i < XE_ENGINE_CLASS_MAX; ++i)
 		xe_hw_fence_irq_finish(&gt->fence_irq[i]);
 

drivers/gpu/drm/xe/xe_guc_ct.c

@@ -30,9 +30,9 @@
 #include "xe_guc_log.h"
 #include "xe_guc_relay.h"
 #include "xe_guc_submit.h"
+#include "xe_guc_tlb_inval.h"
 #include "xe_map.h"
 #include "xe_pm.h"
-#include "xe_tlb_inval.h"
 #include "xe_trace_guc.h"
 
 static void receive_g2h(struct xe_guc_ct *ct);

drivers/gpu/drm/xe/xe_guc_tlb_inval.c

@@ -0,0 +1,242 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#include "abi/guc_actions_abi.h"
+
+#include "xe_device.h"
+#include "xe_gt_stats.h"
+#include "xe_gt_types.h"
+#include "xe_guc.h"
+#include "xe_guc_ct.h"
+#include "xe_guc_tlb_inval.h"
+#include "xe_force_wake.h"
+#include "xe_mmio.h"
+#include "xe_tlb_inval.h"
+
+#include "regs/xe_guc_regs.h"
+
+/*
+ * XXX: The seqno algorithm relies on TLB invalidation being processed in order
+ * which they currently are by the GuC, if that changes the algorithm will need
+ * to be updated.
+ */
+
+static int send_tlb_inval(struct xe_guc *guc, const u32 *action, int len)
+{
+	struct xe_gt *gt = guc_to_gt(guc);
+
+	xe_gt_assert(gt, action[1]);	/* Seqno */
+
+	xe_gt_stats_incr(gt, XE_GT_STATS_ID_TLB_INVAL, 1);
+	return xe_guc_ct_send(&guc->ct, action, len,
+			      G2H_LEN_DW_TLB_INVALIDATE, 1);
+}
+
+#define MAKE_INVAL_OP(type)	((type << XE_GUC_TLB_INVAL_TYPE_SHIFT) | \
+		XE_GUC_TLB_INVAL_MODE_HEAVY << XE_GUC_TLB_INVAL_MODE_SHIFT | \
+		XE_GUC_TLB_INVAL_FLUSH_CACHE)
+
+static int send_tlb_inval_all(struct xe_tlb_inval *tlb_inval, u32 seqno)
+{
+	struct xe_guc *guc = tlb_inval->private;
+	u32 action[] = {
+		XE_GUC_ACTION_TLB_INVALIDATION_ALL,
+		seqno,
+		MAKE_INVAL_OP(XE_GUC_TLB_INVAL_FULL),
+	};
+
+	return send_tlb_inval(guc, action, ARRAY_SIZE(action));
+}
+
+static int send_tlb_inval_ggtt(struct xe_tlb_inval *tlb_inval, u32 seqno)
+{
+	struct xe_guc *guc = tlb_inval->private;
+	struct xe_gt *gt = guc_to_gt(guc);
+	struct xe_device *xe = guc_to_xe(guc);
+
+	/*
+	 * Returning -ECANCELED in this function is squashed at the caller and
+	 * signals waiters.
+	 */
+
+	if (xe_guc_ct_enabled(&guc->ct) && guc->submission_state.enabled) {
+		u32 action[] = {
+			XE_GUC_ACTION_TLB_INVALIDATION,
+			seqno,
+			MAKE_INVAL_OP(XE_GUC_TLB_INVAL_GUC),
+		};
+
+		return send_tlb_inval(guc, action, ARRAY_SIZE(action));
+	} else if (xe_device_uc_enabled(xe) && !xe_device_wedged(xe)) {
+		struct xe_mmio *mmio = &gt->mmio;
+		unsigned int fw_ref;
+
+		if (IS_SRIOV_VF(xe))
+			return -ECANCELED;
+
+		fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
+		if (xe->info.platform == XE_PVC || GRAPHICS_VER(xe) >= 20) {
+			xe_mmio_write32(mmio, PVC_GUC_TLB_INV_DESC1,
+					PVC_GUC_TLB_INV_DESC1_INVALIDATE);
+			xe_mmio_write32(mmio, PVC_GUC_TLB_INV_DESC0,
+					PVC_GUC_TLB_INV_DESC0_VALID);
+		} else {
+			xe_mmio_write32(mmio, GUC_TLB_INV_CR,
+					GUC_TLB_INV_CR_INVALIDATE);
+		}
+		xe_force_wake_put(gt_to_fw(gt), fw_ref);
+	}
+
+	return -ECANCELED;
+}
+
+/*
+ * Ensure that roundup_pow_of_two(length) doesn't overflow.
+ * Note that roundup_pow_of_two() operates on unsigned long,
+ * not on u64.
+ */
+#define MAX_RANGE_TLB_INVALIDATION_LENGTH (rounddown_pow_of_two(ULONG_MAX))
+
+static int send_tlb_inval_ppgtt(struct xe_tlb_inval *tlb_inval, u32 seqno,
+				u64 start, u64 end, u32 asid)
+{
+#define MAX_TLB_INVALIDATION_LEN	7
+	struct xe_guc *guc = tlb_inval->private;
+	struct xe_gt *gt = guc_to_gt(guc);
+	u32 action[MAX_TLB_INVALIDATION_LEN];
+	u64 length = end - start;
+	int len = 0;
+
+	if (guc_to_xe(guc)->info.force_execlist)
+		return -ECANCELED;
+
+	action[len++] = XE_GUC_ACTION_TLB_INVALIDATION;
+	action[len++] = seqno;
+	if (!gt_to_xe(gt)->info.has_range_tlb_inval ||
+	    length > MAX_RANGE_TLB_INVALIDATION_LENGTH) {
+		action[len++] = MAKE_INVAL_OP(XE_GUC_TLB_INVAL_FULL);
+	} else {
+		u64 orig_start = start;
+		u64 align;
+
+		if (length < SZ_4K)
+			length = SZ_4K;
+
+		/*
+		 * We need to invalidate a higher granularity if start address
+		 * is not aligned to length. When start is not aligned with
+		 * length we need to find the length large enough to create an
+		 * address mask covering the required range.
+		 */
+		align = roundup_pow_of_two(length);
+		start = ALIGN_DOWN(start, align);
+		end = ALIGN(end, align);
+		length = align;
+		while (start + length < end) {
+			length <<= 1;
+			start = ALIGN_DOWN(orig_start, length);
+		}
+
+		/*
+		 * Minimum invalidation size for a 2MB page that the hardware
+		 * expects is 16MB
+		 */
+		if (length >= SZ_2M) {
+			length = max_t(u64, SZ_16M, length);
+			start = ALIGN_DOWN(orig_start, length);
+		}
+
+		xe_gt_assert(gt, length >= SZ_4K);
+		xe_gt_assert(gt, is_power_of_2(length));
+		xe_gt_assert(gt, !(length & GENMASK(ilog2(SZ_16M) - 1,
+						    ilog2(SZ_2M) + 1)));
+		xe_gt_assert(gt, IS_ALIGNED(start, length));
+
+		action[len++] = MAKE_INVAL_OP(XE_GUC_TLB_INVAL_PAGE_SELECTIVE);
+		action[len++] = asid;
+		action[len++] = lower_32_bits(start);
+		action[len++] = upper_32_bits(start);
+		action[len++] = ilog2(length) - ilog2(SZ_4K);
+	}
+
+	xe_gt_assert(gt, len <= MAX_TLB_INVALIDATION_LEN);
+
+	return send_tlb_inval(guc, action, len);
+}
+
+static bool tlb_inval_initialized(struct xe_tlb_inval *tlb_inval)
+{
+	struct xe_guc *guc = tlb_inval->private;
+
+	return xe_guc_ct_initialized(&guc->ct);
+}
+
+static void tlb_inval_flush(struct xe_tlb_inval *tlb_inval)
+{
+	struct xe_guc *guc = tlb_inval->private;
+
+	LNL_FLUSH_WORK(&guc->ct.g2h_worker);
+}
+
+static long tlb_inval_timeout_delay(struct xe_tlb_inval *tlb_inval)
+{
+	struct xe_guc *guc = tlb_inval->private;
+
+	/* this reflects what HW/GuC needs to process TLB inv request */
+	const long hw_tlb_timeout = HZ / 4;
+
+	/* this estimates actual delay caused by the CTB transport */
+	long delay = xe_guc_ct_queue_proc_time_jiffies(&guc->ct);
+
+	return hw_tlb_timeout + 2 * delay;
+}
+
+static const struct xe_tlb_inval_ops guc_tlb_inval_ops = {
+	.all = send_tlb_inval_all,
+	.ggtt = send_tlb_inval_ggtt,
+	.ppgtt = send_tlb_inval_ppgtt,
+	.initialized = tlb_inval_initialized,
+	.flush = tlb_inval_flush,
+	.timeout_delay = tlb_inval_timeout_delay,
+};
+
+/**
+ * xe_guc_tlb_inval_init_early() - Init GuC TLB invalidation early
+ * @guc: GuC object
+ * @tlb_inval: TLB invalidation client
+ *
+ * Inititialize GuC TLB invalidation by setting back pointer in TLB invalidation
+ * client to the GuC and setting GuC backend ops.
+ */
+void xe_guc_tlb_inval_init_early(struct xe_guc *guc,
+				 struct xe_tlb_inval *tlb_inval)
+{
+	tlb_inval->private = guc;
+	tlb_inval->ops = &guc_tlb_inval_ops;
+}
+
+/**
+ * xe_guc_tlb_inval_done_handler() - TLB invalidation done handler
+ * @guc: guc
+ * @msg: message indicating TLB invalidation done
+ * @len: length of message
+ *
+ * Parse seqno of TLB invalidation, wake any waiters for seqno, and signal any
+ * invalidation fences for seqno. Algorithm for this depends on seqno being
+ * received in-order and asserts this assumption.
+ *
+ * Return: 0 on success, -EPROTO for malformed messages.
+ */
+int xe_guc_tlb_inval_done_handler(struct xe_guc *guc, u32 *msg, u32 len)
+{
+	struct xe_gt *gt = guc_to_gt(guc);
+
+	if (unlikely(len != 1))
+		return -EPROTO;
+
+	xe_tlb_inval_done_handler(&gt->tlb_inval, msg[0]);
+
+	return 0;
+}

drivers/gpu/drm/xe/xe_guc_tlb_inval.h

@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2025 Intel Corporation
+ */
+
+#ifndef _XE_GUC_TLB_INVAL_H_
+#define _XE_GUC_TLB_INVAL_H_
+
+#include <linux/types.h>
+
+struct xe_guc;
+struct xe_tlb_inval;
+
+void xe_guc_tlb_inval_init_early(struct xe_guc *guc,
+				 struct xe_tlb_inval *tlb_inval);
+
+int xe_guc_tlb_inval_done_handler(struct xe_guc *guc, u32 *msg, u32 len);
+
+#endif