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 X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 7092DC433F5 for ; Fri, 17 Sep 2021 12:31:08 +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 321F2611C3 for ; Fri, 17 Sep 2021 12:31:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 321F2611C3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 96B6F6EC42; Fri, 17 Sep 2021 12:31:07 +0000 (UTC) Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by gabe.freedesktop.org (Postfix) with ESMTPS id CD0086EC41 for ; Fri, 17 Sep 2021 12:31:06 +0000 (UTC) Received: by mail-wr1-x42e.google.com with SMTP id t18so14980243wrb.0 for ; Fri, 17 Sep 2021 05:31:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=o7A57kYyLnLxBk2EpQRgH/I2WuumqcnhiTb054cfE3c=; b=SZbQN8vwwsLhU3kygY95IQ0nezGZSNxMoK/x8YjC4MKKgST3177d41hO/yXqVZWf25 aBKnaQHpklTXzWUOfTO/rjlub9XjiVYBMxFupu1b0Q87A0rnUeOgOOgZbNU+qwdc/U+H dZjclpEkSqRbCuXZZEnet9I5TUEQapPkdx16s= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=o7A57kYyLnLxBk2EpQRgH/I2WuumqcnhiTb054cfE3c=; b=4qPKDJZ3vh1KQmiDyqxU4042FWk4JSH/ZezhlmaxBSAMpiGfjkPaf9evduyU1niyxO mzsqlAo2trdlqfkUtc742xAgMfDoj0j6rgaoAt98TD7dZtd0Uzy1/M5SHccklkfiySQf ec6GHIYuKHyQ1eYjw2teuV3sL1STgXNFvFhxwvaoWuaMHimiBCtx1syhI0tMap3wHpt/ cbBKyVekPAa2m8InuN3kSAr76ErHDGDfQiAZFeoYVRlUV7FYX8DjSWJ2Xas/yAnk0Cuu FVo3boPmqTo6ZqRcIFeWoLAzdTKp01djyoXm2NiMaTWmxYqARLwiLVvnVVACvF8ZvMhU n+rw== X-Gm-Message-State: AOAM531ffRw4vPBE3Kd6KppnO/oeVmagk3gFGTMD3agBqorD8tNcbpR3 WT7nU1gg6IpwPxz4arcbLqHoqohglw0vQA== X-Google-Smtp-Source: ABdhPJxpwEE7l8onXQlLNuW12oGzeMTFB4nKHgxTHgi0OhO/2feZan/noxssuPOPxbbqSqJX+mtukQ== X-Received: by 2002:adf:8170:: with SMTP id 103mr12045762wrm.167.1631881865219; Fri, 17 Sep 2021 05:31:05 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id n26sm10038744wmi.43.2021.09.17.05.31.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Sep 2021 05:31:04 -0700 (PDT) Date: Fri, 17 Sep 2021 14:31:02 +0200 From: Daniel Vetter To: Matthew Brost Cc: Daniel Vetter , Dave Airlie , Intel Graphics Development , dri-devel , john.c.harrison@intel.com Message-ID: References: <20210914044933.22932-1-matthew.brost@intel.com> <20210914044933.22932-2-matthew.brost@intel.com> <20210914153656.GA23874@jons-linux-dev-box> <20210914211022.GA15442@jons-linux-dev-box> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210914211022.GA15442@jons-linux-dev-box> X-Operating-System: Linux phenom 5.10.0-8-amd64 Subject: Re: [Intel-gfx] [PATCH 1/5] drm/i915: Do not define vma on stack 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Sep 14, 2021 at 02:10:22PM -0700, Matthew Brost wrote: > On Tue, Sep 14, 2021 at 10:05:03PM +0200, Daniel Vetter wrote: > > On Tue, Sep 14, 2021 at 08:36:56AM -0700, Matthew Brost wrote: > > > On Tue, Sep 14, 2021 at 03:04:59PM +1000, Dave Airlie wrote: > > > > On Tue, 14 Sept 2021 at 14:55, Matthew Brost wrote: > > > > > > > > > > From: Venkata Sandeep Dhanalakota > > > > > > > > > > Defining vma on stack can cause stack overflow, if > > > > > vma gets populated with new fields. > > > > > > > > Is there some higher level locking stopping that from getting trashed? > > > > or a guarantee that uc_fw_bind_ggtt is only entered by one thread at a > > > > time? > > > > > > > > > > I believe this function is only called during driver load (inherently > > > one thread) or during a GT reset (protected by reset mutex) so at most 1 > > > thread can be executing this code at once, thus it is safe to use a > > > global dummy vma in this function. > > > > This kind of stuff must be documented in kerneldoc comments. Please use > > the inline struct member format. > > > > Forgot to include kerneldoc for this new field, will add. > > > Also please document the other fields in that struct, cant hurt :-) > > I'll see what I can do but I didn't write this code and may not fully > understand all the fields off hand. Yeah sprinkling FIXME and stuff like that in or leaving it blank if it's completely unknown is fine. -Daniel > > Matt > > > -Daniel > > > > > > > > Matt > > > > > > > Dave. > > > > > > > > > > > > > > Cc: Daniele Ceraolo Spurio > > > > > Cc: Tvrtko Ursulin > > > > > Signed-off-by: Venkata Sandeep Dhanalakota > > > > > Signed-off-by: Matthew Brost > > > > > Reviewed-by: Matthew Brost > > > > > --- > > > > > drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 18 +++++++++--------- > > > > > drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h | 2 ++ > > > > > 2 files changed, 11 insertions(+), 9 deletions(-) > > > > > > > > > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c > > > > > index 3a16d08608a5..f632dbd32b42 100644 > > > > > --- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c > > > > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c > > > > > @@ -413,20 +413,20 @@ static void uc_fw_bind_ggtt(struct intel_uc_fw *uc_fw) > > > > > { > > > > > struct drm_i915_gem_object *obj = uc_fw->obj; > > > > > struct i915_ggtt *ggtt = __uc_fw_to_gt(uc_fw)->ggtt; > > > > > - struct i915_vma dummy = { > > > > > - .node.start = uc_fw_ggtt_offset(uc_fw), > > > > > - .node.size = obj->base.size, > > > > > - .pages = obj->mm.pages, > > > > > - .vm = &ggtt->vm, > > > > > - }; > > > > > + struct i915_vma *dummy = &uc_fw->dummy; > > > > > + > > > > > + dummy->node.start = uc_fw_ggtt_offset(uc_fw); > > > > > + dummy->node.size = obj->base.size; > > > > > + dummy->pages = obj->mm.pages; > > > > > + dummy->vm = &ggtt->vm; > > > > > > > > > > GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj)); > > > > > - GEM_BUG_ON(dummy.node.size > ggtt->uc_fw.size); > > > > > + GEM_BUG_ON(dummy->node.size > ggtt->uc_fw.size); > > > > > > > > > > /* uc_fw->obj cache domains were not controlled across suspend */ > > > > > - drm_clflush_sg(dummy.pages); > > > > > + drm_clflush_sg(dummy->pages); > > > > > > > > > > - ggtt->vm.insert_entries(&ggtt->vm, &dummy, I915_CACHE_NONE, 0); > > > > > + ggtt->vm.insert_entries(&ggtt->vm, dummy, I915_CACHE_NONE, 0); > > > > > } > > > > > > > > > > static void uc_fw_unbind_ggtt(struct intel_uc_fw *uc_fw) > > > > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h > > > > > index 99bb1fe1af66..693cc0ebcd63 100644 > > > > > --- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h > > > > > +++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h > > > > > @@ -10,6 +10,7 @@ > > > > > #include "intel_uc_fw_abi.h" > > > > > #include "intel_device_info.h" > > > > > #include "i915_gem.h" > > > > > +#include "i915_vma.h" > > > > > > > > > > struct drm_printer; > > > > > struct drm_i915_private; > > > > > @@ -75,6 +76,7 @@ struct intel_uc_fw { > > > > > bool user_overridden; > > > > > size_t size; > > > > > struct drm_i915_gem_object *obj; > > > > > + struct i915_vma dummy; > > > > > > > > > > /* > > > > > * The firmware build process will generate a version header file with major and > > > > > -- > > > > > 2.32.0 > > > > > > > > > -- > > Daniel Vetter > > Software Engineer, Intel Corporation > > http://blog.ffwll.ch -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch