From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CD671C61DC2 for ; Wed, 26 Aug 2026 13:52:23 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8851D10ED50; Wed, 26 Aug 2026 13:52:23 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="BKuQxJre"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.14]) by gabe.freedesktop.org (Postfix) with ESMTPS id E40EC10ED4C for ; Wed, 26 Aug 2026 13:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1787752341; x=1819288341; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=3ddEOyaNhwc8gpWbnIGBt/DiMKx8TJgAqNgisBWlO28=; b=BKuQxJrew274TcUozX0Vz6xb4oHw/DC87Qjaa9vayDRx5XDuv7zIyxb8 OGUXaEtpHZW9Cq6RTP4gp2wJMKgNnZXuP5m/tEMtUbyvbtWYYWBLf8bvw 9BqxkxTo/J07pq6P7GZO3ZjjcsaSSVRLHqsyPBUmNDz8jOenv1Vsg1Ess tr+lNOvK7U1N/WqlukX8bqCiv0H+NR5cPWzyEHWmZOhfDg2nzysHLD3ac WjE1qMXmcDSb3xh3iit8oFNbonnUgPQDos8DLH3we7I0n4e6pob9miyw4 2WLxIl9w9+GGJo9SDzSTh6Uu8d0FReDJIJV//lDlb+qGoQmblSt54xvih A==; X-CSE-ConnectionGUID: 5EZP5UTgSlGWhwAZC1Sp2A== X-CSE-MsgGUID: YxZgDkSWTe+ui4XVJPTeRg== X-IronPort-AV: E=McAfee;i="6800,10657,11886"; a="88251054" X-IronPort-AV: E=Sophos;i="6.25,244,1779174000"; d="scan'208";a="88251054" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2026 06:52:21 -0700 X-CSE-ConnectionGUID: 10W6H2CWR4etf0aVBzLk0Q== X-CSE-MsgGUID: Hgvt2vTiQeKwaMKIGyfv3g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,244,1779174000"; d="scan'208";a="269533535" Received: from tejasupa-desk.iind.intel.com (HELO tejasupa-desk) ([10.190.239.37]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2026 06:52:19 -0700 From: Tejas Upadhyay To: intel-xe@lists.freedesktop.org Cc: himal.prasad.ghimiray@intel.com, rodrigo.vivi@intel.com, michal.wajdeczko@intel.com, Tejas Upadhyay Subject: [PATCH V18 14/14] drm/xe: Add fault-inject based VRAM page offline injection Date: Wed, 26 Aug 2026 19:21:49 +0530 Message-ID: <20260826135136.204044-30-tejas.upadhyay@intel.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260826135136.204044-16-tejas.upadhyay@intel.com> References: <20260826135136.204044-16-tejas.upadhyay@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" Add a fault-inject based debugfs interface for testing VRAM page offlining. This replaces the previous standalone debugfs approach with the standard kernel fault-inject infrastructure. Two debugfs entries are created under the xe debugfs root for CRI platforms: - inject_mempage_offline/: Standard fault-inject knobs (probability, times, interval, etc.) created by fault_create_debugfs_attr(). Without CONFIG_FAULT_INJECTION_DEBUG_FS, the stub returns ERR_PTR(-ENODEV) and no knobs are created, making the trigger effectively a no-op. - inject_mempage_offline_trigger: Write a PFN value to inject a specific page, or write "0" to auto-pick the last unallocated VRAM page The trigger accepts: - "0" : auto-pick last unallocated page - "0xPFN" : inject fault at a specific PFN address Usage: echo 100 > inject_mempage_offline/probability echo 1 > inject_mempage_offline/times echo 0 > inject_mempage_offline_trigger probability: likelihood of should_fail() returning true (0-100) times: number of times injection is allowed (-1 for unlimited) v5(Sashiko): - exclude SRIOV and remove dpa_base addition, already absolute dpa v4(Himal): - Use xe_fault_mempage_offline() instead of IS_ENABLED() + direct should_fail(). CONFIG_FAULT_INJECTION_DEBUG_FS is now an implicit requirement for the trigger to function. v3(Himal): - Use FAULT_ACTION v2(sashiko): - use cond_resched() - validate input first and fix addr < 0 case - validate vr, move block, found var as local to scope_guard Signed-off-by: Tejas Upadhyay --- drivers/gpu/drm/xe/xe_debugfs.c | 47 +++++++++++++++++++++++++ drivers/gpu/drm/xe/xe_debugfs.h | 2 ++ drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 52 ++++++++++++++++++++++++++++ drivers/gpu/drm/xe/xe_ttm_vram_mgr.h | 1 + 4 files changed, 102 insertions(+) diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c index e19eafffbb08..003abf4af2e3 100644 --- a/drivers/gpu/drm/xe/xe_debugfs.c +++ b/drivers/gpu/drm/xe/xe_debugfs.c @@ -45,12 +45,18 @@ DECLARE_FAULT_ATTR(gt_reset_failure); DECLARE_FAULT_ATTR(inject_csc_hw_error); DECLARE_FAULT_ATTR(wedge_cold_reset); +DECLARE_FAULT_ATTR(inject_mempage_offline); static bool csc_hw_error_available(struct xe_device *xe) { return !IS_SRIOV_VF(xe) && xe->info.platform == XE_BATTLEMAGE; } +static bool is_crescent_island_pf(struct xe_device *xe) +{ + return !IS_SRIOV_VF(xe) && xe->info.platform == XE_CRESCENTISLAND; +} + /* * Fault injection table. Each entry registers a debugfs attribute; add a * matching FAULT_ACTION() below for every entry added here. @@ -67,6 +73,9 @@ static struct { .is_visible = csc_hw_error_available }, { .name = "wedge_cold_reset", .attr = &wedge_cold_reset }, + { .name = "inject_mempage_offline", + .attr = &inject_mempage_offline, + .is_visible = is_crescent_island_pf }, }; /* @@ -82,6 +91,39 @@ bool xe_fault_##name(void) \ FAULT_ACTION(gt_reset, gt_reset_failure) FAULT_ACTION(csc_hw_error, inject_csc_hw_error) FAULT_ACTION(wedge_cold_reset, wedge_cold_reset) +FAULT_ACTION(mempage_offline, inject_mempage_offline) + +static ssize_t inject_mempage_offline_trigger(struct file *f, + const char __user *ubuf, + size_t size, loff_t *pos) +{ + struct xe_device *xe = file_inode(f)->i_private; + struct xe_tile *tile = xe_device_get_root_tile(xe); + struct xe_vram_region *vr = tile->mem.vram; + u64 pfn; + int ret; + + if (!vr) + return -ENODEV; + + ret = kstrtou64_from_user(ubuf, size, 0, &pfn); + if (ret) + return ret; + + if (!xe_fault_mempage_offline()) + return size; + + if (pfn == 0) + return xe_ttm_vram_inject_fault(xe) ?: size; + + /* User provided PFN - convert to DPA and inject */ + return xe_ttm_vram_handle_addr_fault(xe, pfn << PAGE_SHIFT) ?: size; +} + +static const struct file_operations inject_mempage_offline_fops = { + .owner = THIS_MODULE, + .write = inject_mempage_offline_trigger, +}; static void xe_fault_inject_debugfs_register(struct xe_device *xe, struct dentry *root) @@ -96,6 +138,11 @@ static void xe_fault_inject_debugfs_register(struct xe_device *xe, fault_create_debugfs_attr(xe_fault_inject_entry[i].name, root, xe_fault_inject_entry[i].attr); } + + if (is_crescent_island_pf(xe)) { + debugfs_create_file("inject_mempage_offline_trigger", 0200, + root, xe, &inject_mempage_offline_fops); + } } static void read_residency_counter(struct xe_device *xe, struct xe_mmio *mmio, diff --git a/drivers/gpu/drm/xe/xe_debugfs.h b/drivers/gpu/drm/xe/xe_debugfs.h index 0dcd28fd7dc0..88d91c78036b 100644 --- a/drivers/gpu/drm/xe/xe_debugfs.h +++ b/drivers/gpu/drm/xe/xe_debugfs.h @@ -14,11 +14,13 @@ struct xe_device; bool xe_fault_gt_reset(void); bool xe_fault_csc_hw_error(void); bool xe_fault_wedge_cold_reset(void); +bool xe_fault_mempage_offline(void); void xe_debugfs_register(struct xe_device *xe); #else static inline bool xe_fault_gt_reset(void) { return false; } static inline bool xe_fault_csc_hw_error(void) { return false; } static inline bool xe_fault_wedge_cold_reset(void) { return false; } +static inline bool xe_fault_mempage_offline(void) { return false; } static inline void xe_debugfs_register(struct xe_device *xe) { } #endif diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c index 8f583f1631bf..c54ad017725f 100644 --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c @@ -895,6 +895,58 @@ int xe_ttm_vram_handle_addr_fault(struct xe_device *xe, u64 addr) } EXPORT_SYMBOL(xe_ttm_vram_handle_addr_fault); +/** + * xe_ttm_vram_inject_fault - Inject a VRAM page fault for testing + * @xe: xe device instance + * + * Picks the last unallocated VRAM page and reports it as faulted + * via xe_ttm_vram_handle_addr_fault(). Used by the fault-inject + * debugfs interface for testing page offlining. + * + * Return: 0 on success, negative error code on failure. + */ +int xe_ttm_vram_inject_fault(struct xe_device *xe) +{ + struct xe_tile *tile = xe_device_get_root_tile(xe); + struct xe_vram_region *vr = tile->mem.vram; + struct xe_ttm_vram_mgr *vram_mgr = &vr->ttm; + struct gpu_buddy *mm = &vram_mgr->mm; + u64 addr; + + if (vr->actual_physical_size < SZ_4K) + return -ENOSPC; + + addr = vr->actual_physical_size - SZ_4K; + while (addr < vr->actual_physical_size) { + struct gpu_buddy_block *block; + bool found = false; + + scoped_guard(mutex, &vram_mgr->lock) { + block = gpu_buddy_allocated_addr_to_block(mm, addr); + if (!block) + found = true; + } + + /* + * Intentional race window: xe_ttm_vram_handle_addr_fault() + * re-acquires vram_mgr->lock internally, so we cannot hold + * it here. A concurrent allocation claiming this page between + * the two calls is an acceptable false negative for this + * test-only path. + */ + if (found) + return xe_ttm_vram_handle_addr_fault(xe, addr + vr->dpa_base); + + cond_resched(); + if (addr == 0) + break; + addr -= SZ_4K; + } + + return -ENOSPC; +} +EXPORT_SYMBOL(xe_ttm_vram_inject_fault); + static int vram_bad_pages_show(struct seq_file *m, void *unused) { struct xe_device *xe = m->private; diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h index f354c26c4257..8878e36292b2 100644 --- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h +++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h @@ -33,6 +33,7 @@ void xe_ttm_vram_get_used(struct ttm_resource_manager *man, u64 *used, u64 *used_visible); int xe_ttm_vram_handle_addr_fault(struct xe_device *xe, u64 addr); +int xe_ttm_vram_inject_fault(struct xe_device *xe); void xe_ttm_vram_debugfs_init(struct xe_device *xe, struct dentry *root); static inline struct xe_ttm_vram_mgr_resource * to_xe_ttm_vram_mgr_resource(struct ttm_resource *res) -- 2.52.0