From patchwork Wed Jun 9 04:36:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Ekstrand X-Patchwork-Id: 12308933 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 904F5C47095 for ; Wed, 9 Jun 2021 04:37:24 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 5BE9A60E0C for ; Wed, 9 Jun 2021 04:37:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5BE9A60E0C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=jlekstrand.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7D4636ECD3; Wed, 9 Jun 2021 04:37:07 +0000 (UTC) Received: from mail-pg1-x532.google.com (mail-pg1-x532.google.com [IPv6:2607:f8b0:4864:20::532]) by gabe.freedesktop.org (Postfix) with ESMTPS id C58D96ECCB for ; Wed, 9 Jun 2021 04:37:05 +0000 (UTC) Received: by mail-pg1-x532.google.com with SMTP id q15so18373564pgg.12 for ; Tue, 08 Jun 2021 21:37:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jlekstrand-net.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=9GkdfaE3t13R9T72eqm82POqsmg3dw3tDZsRQFXSYNE=; b=lywyJRD2X5n/yCt/BWKP3QILwC/7IxkK2LA91yb5FMKIRY2DtpFJMvwHvh9HvGNT1x /HncopfvjSUf09ZnEgDi2yIb7Rov4hld2aX+7lSNk13VTombjk7Umt6rH6MK++3kdw9X /6/Do7KlwcSPx9R5Cj2Wmm5/6fqs3EETLkMPJBrMw03DaECEfSaZ6tJvzOQ1yko9Q/kx fJPUmOVlIWU8FMDRb+XtaiGs+ttGG6DQ6qCay/1qO0l2MxDe39ZjryF0mw806hh+93SU oCNRDS43zpv2/KhmXXDF2QoxQuuQtHQAbUirGQh6JUBebHwTSyKZGLWBER07HOJ/0OwK 1HsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=9GkdfaE3t13R9T72eqm82POqsmg3dw3tDZsRQFXSYNE=; b=KlFULxZ/5luNdpgILYXtn/jeIDqCdpUwIBgOCHI6XMCIU8j4NL4S79/ih9XRSqSmKu Vt2fGwO6ab9qs91F9aCO73YcgYtr/hoi8/Qfr7TW3eRiGGO/xbZzdCTbXsKfoRb5vQqN e+OtY5FPuSAGEg1RT23RWedV89Y1OfcoDeAlgvzJRo0NTr+Ccoze8XOv1wrzEPQ1l3GF CwWEY9u2xBjSKg6oHKzAQy9A14zqiDZnm4dw1aVq1cAqiiOExckal6UrCl7rwtJJQaVO ktchoElZrPQDYiAHpzI4P8335+htzdjmfeppJjq2XZ4d5fDegxTqef2tWbKXYNKazw+7 BK2A== X-Gm-Message-State: AOAM533ZWlIpjNQU2GV1Gr58MC2Uhmcg/V1FQA/YZ6VH54pydE/4TQ3w BCu1b72gBPdAanSigJXZCt8eww== X-Google-Smtp-Source: ABdhPJwndcTWdmhMhdGHQXZM6tuaNbgsQmGaGdexJwVBQi3YeTPCkD23SfjEEPX5yWUsked0CHX+GA== X-Received: by 2002:a63:d47:: with SMTP id 7mr1824065pgn.339.1623213425213; Tue, 08 Jun 2021 21:37:05 -0700 (PDT) Received: from omlet.com (jfdmzpr06-ext.jf.intel.com. [134.134.137.75]) by smtp.gmail.com with ESMTPSA id t5sm11991612pfe.116.2021.06.08.21.37.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 08 Jun 2021 21:37:04 -0700 (PDT) From: Jason Ekstrand To: dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Date: Tue, 8 Jun 2021 23:36:08 -0500 Message-Id: <20210609043613.102962-27-jason@jlekstrand.net> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210609043613.102962-1-jason@jlekstrand.net> References: <20210609043613.102962-1-jason@jlekstrand.net> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 26/31] drm/i915/gem: Don't allow changing the engine set on running contexts (v2) X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Vetter Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" When the APIs were added to manage the engine set on a GEM context directly from userspace, the questionable choice was made to allow changing the engine set on a context at any time. This is horribly racy and there's absolutely no reason why any userspace would want to do this outside of trying to exercise interesting race conditions. By removing support for CONTEXT_PARAM_ENGINES from ctx_setparam, we make it impossible to change the engine set after the context has been fully created. This doesn't yet let us delete all the deferred engine clean-up code as that's still used for handling the case where the client dies or calls GEM_CONTEXT_DESTROY while work is in flight. However, moving to an API where the engine set is effectively immutable gives us more options to potentially clean that code up a bit going forward. It also removes a whole class of ways in which a client can hurt itself or try to get around kernel context banning. v2 (Jason Ekstrand): - Expand the commit mesage Signed-off-by: Jason Ekstrand Reviewed-by: Daniel Vetter --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 303 -------------------- 1 file changed, 303 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 2f3d92224d2fe..574451e744583 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -1819,305 +1819,6 @@ static int set_sseu(struct i915_gem_context *ctx, return ret; } -struct set_engines { - struct i915_gem_context *ctx; - struct i915_gem_engines *engines; -}; - -static int -set_engines__load_balance(struct i915_user_extension __user *base, void *data) -{ - struct i915_context_engines_load_balance __user *ext = - container_of_user(base, typeof(*ext), base); - const struct set_engines *set = data; - struct drm_i915_private *i915 = set->ctx->i915; - struct intel_engine_cs *stack[16]; - struct intel_engine_cs **siblings; - struct intel_context *ce; - struct intel_sseu null_sseu = {}; - u16 num_siblings, idx; - unsigned int n; - int err; - - if (!HAS_EXECLISTS(i915)) - return -ENODEV; - - if (intel_uc_uses_guc_submission(&i915->gt.uc)) - return -ENODEV; /* not implement yet */ - - if (get_user(idx, &ext->engine_index)) - return -EFAULT; - - if (idx >= set->engines->num_engines) { - drm_dbg(&i915->drm, "Invalid placement value, %d >= %d\n", - idx, set->engines->num_engines); - return -EINVAL; - } - - idx = array_index_nospec(idx, set->engines->num_engines); - if (set->engines->engines[idx]) { - drm_dbg(&i915->drm, - "Invalid placement[%d], already occupied\n", idx); - return -EEXIST; - } - - if (get_user(num_siblings, &ext->num_siblings)) - return -EFAULT; - - err = check_user_mbz(&ext->flags); - if (err) - return err; - - err = check_user_mbz(&ext->mbz64); - if (err) - return err; - - siblings = stack; - if (num_siblings > ARRAY_SIZE(stack)) { - siblings = kmalloc_array(num_siblings, - sizeof(*siblings), - GFP_KERNEL); - if (!siblings) - return -ENOMEM; - } - - for (n = 0; n < num_siblings; n++) { - struct i915_engine_class_instance ci; - - if (copy_from_user(&ci, &ext->engines[n], sizeof(ci))) { - err = -EFAULT; - goto out_siblings; - } - - siblings[n] = intel_engine_lookup_user(i915, - ci.engine_class, - ci.engine_instance); - if (!siblings[n]) { - drm_dbg(&i915->drm, - "Invalid sibling[%d]: { class:%d, inst:%d }\n", - n, ci.engine_class, ci.engine_instance); - err = -EINVAL; - goto out_siblings; - } - } - - ce = intel_execlists_create_virtual(siblings, n); - if (IS_ERR(ce)) { - err = PTR_ERR(ce); - goto out_siblings; - } - - intel_context_set_gem(ce, set->ctx, null_sseu); - - if (cmpxchg(&set->engines->engines[idx], NULL, ce)) { - intel_context_put(ce); - err = -EEXIST; - goto out_siblings; - } - -out_siblings: - if (siblings != stack) - kfree(siblings); - - return err; -} - -static int -set_engines__bond(struct i915_user_extension __user *base, void *data) -{ - struct i915_context_engines_bond __user *ext = - container_of_user(base, typeof(*ext), base); - const struct set_engines *set = data; - struct drm_i915_private *i915 = set->ctx->i915; - struct i915_engine_class_instance ci; - struct intel_engine_cs *virtual; - struct intel_engine_cs *master; - u16 idx, num_bonds; - int err, n; - - if (get_user(idx, &ext->virtual_index)) - return -EFAULT; - - if (idx >= set->engines->num_engines) { - drm_dbg(&i915->drm, - "Invalid index for virtual engine: %d >= %d\n", - idx, set->engines->num_engines); - return -EINVAL; - } - - idx = array_index_nospec(idx, set->engines->num_engines); - if (!set->engines->engines[idx]) { - drm_dbg(&i915->drm, "Invalid engine at %d\n", idx); - return -EINVAL; - } - virtual = set->engines->engines[idx]->engine; - - if (intel_engine_is_virtual(virtual)) { - drm_dbg(&i915->drm, - "Bonding with virtual engines not allowed\n"); - return -EINVAL; - } - - err = check_user_mbz(&ext->flags); - if (err) - return err; - - for (n = 0; n < ARRAY_SIZE(ext->mbz64); n++) { - err = check_user_mbz(&ext->mbz64[n]); - if (err) - return err; - } - - if (copy_from_user(&ci, &ext->master, sizeof(ci))) - return -EFAULT; - - master = intel_engine_lookup_user(i915, - ci.engine_class, ci.engine_instance); - if (!master) { - drm_dbg(&i915->drm, - "Unrecognised master engine: { class:%u, instance:%u }\n", - ci.engine_class, ci.engine_instance); - return -EINVAL; - } - - if (get_user(num_bonds, &ext->num_bonds)) - return -EFAULT; - - for (n = 0; n < num_bonds; n++) { - struct intel_engine_cs *bond; - - if (copy_from_user(&ci, &ext->engines[n], sizeof(ci))) - return -EFAULT; - - bond = intel_engine_lookup_user(i915, - ci.engine_class, - ci.engine_instance); - if (!bond) { - drm_dbg(&i915->drm, - "Unrecognised engine[%d] for bonding: { class:%d, instance: %d }\n", - n, ci.engine_class, ci.engine_instance); - return -EINVAL; - } - } - - return 0; -} - -static const i915_user_extension_fn set_engines__extensions[] = { - [I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE] = set_engines__load_balance, - [I915_CONTEXT_ENGINES_EXT_BOND] = set_engines__bond, -}; - -static int -set_engines(struct i915_gem_context *ctx, - const struct drm_i915_gem_context_param *args) -{ - struct drm_i915_private *i915 = ctx->i915; - struct i915_context_param_engines __user *user = - u64_to_user_ptr(args->value); - struct intel_sseu null_sseu = {}; - struct set_engines set = { .ctx = ctx }; - unsigned int num_engines, n; - u64 extensions; - int err; - - if (!args->size) { /* switch back to legacy user_ring_map */ - if (!i915_gem_context_user_engines(ctx)) - return 0; - - set.engines = default_engines(ctx, null_sseu); - if (IS_ERR(set.engines)) - return PTR_ERR(set.engines); - - goto replace; - } - - if (args->size < sizeof(*user) || - !IS_ALIGNED(args->size - sizeof(*user), sizeof(*user->engines))) { - drm_dbg(&i915->drm, "Invalid size for engine array: %d\n", - args->size); - return -EINVAL; - } - - num_engines = (args->size - sizeof(*user)) / sizeof(*user->engines); - /* RING_MASK has no shift so we can use it directly here */ - if (num_engines > I915_EXEC_RING_MASK + 1) - return -EINVAL; - - set.engines = alloc_engines(num_engines); - if (!set.engines) - return -ENOMEM; - - for (n = 0; n < num_engines; n++) { - struct i915_engine_class_instance ci; - struct intel_engine_cs *engine; - struct intel_context *ce; - - if (copy_from_user(&ci, &user->engines[n], sizeof(ci))) { - __free_engines(set.engines, n); - return -EFAULT; - } - - if (ci.engine_class == (u16)I915_ENGINE_CLASS_INVALID && - ci.engine_instance == (u16)I915_ENGINE_CLASS_INVALID_NONE) { - set.engines->engines[n] = NULL; - continue; - } - - engine = intel_engine_lookup_user(ctx->i915, - ci.engine_class, - ci.engine_instance); - if (!engine) { - drm_dbg(&i915->drm, - "Invalid engine[%d]: { class:%d, instance:%d }\n", - n, ci.engine_class, ci.engine_instance); - __free_engines(set.engines, n); - return -ENOENT; - } - - ce = intel_context_create(engine); - if (IS_ERR(ce)) { - __free_engines(set.engines, n); - return PTR_ERR(ce); - } - - intel_context_set_gem(ce, ctx, null_sseu); - - set.engines->engines[n] = ce; - } - set.engines->num_engines = num_engines; - - err = -EFAULT; - if (!get_user(extensions, &user->extensions)) - err = i915_user_extensions(u64_to_user_ptr(extensions), - set_engines__extensions, - ARRAY_SIZE(set_engines__extensions), - &set); - if (err) { - free_engines(set.engines); - return err; - } - -replace: - mutex_lock(&ctx->engines_mutex); - if (i915_gem_context_is_closed(ctx)) { - mutex_unlock(&ctx->engines_mutex); - free_engines(set.engines); - return -ENOENT; - } - if (args->size) - i915_gem_context_set_user_engines(ctx); - else - i915_gem_context_clear_user_engines(ctx); - set.engines = rcu_replace_pointer(ctx->engines, set.engines, 1); - mutex_unlock(&ctx->engines_mutex); - - /* Keep track of old engine sets for kill_context() */ - engines_idle_release(ctx, set.engines); - - return 0; -} - static int set_persistence(struct i915_gem_context *ctx, const struct drm_i915_gem_context_param *args) @@ -2200,10 +1901,6 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv, ret = set_sseu(ctx, args); break; - case I915_CONTEXT_PARAM_ENGINES: - ret = set_engines(ctx, args); - break; - case I915_CONTEXT_PARAM_PERSISTENCE: ret = set_persistence(ctx, args); break;