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 A4687CDB474 for ; Mon, 23 Oct 2023 08:49:53 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 1A93810E194; Mon, 23 Oct 2023 08:49:53 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 43FCD10E194 for ; Mon, 23 Oct 2023 08:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1698050991; x=1729586991; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=Ru8CKOBHyiJPuiwY3OoJs+n0mrP+BkAcjvw2CJtlFIk=; b=L3KzDKETS3t5+4e+q2zFo85J+9bRFMSsJMXe/xV1+LFTI/O0uYsj+epA 8MaEDJQ7tUU7F4+fFbzoStfBlCIa9YwVs2Oyi4ODDG6iezwRBIVb2XpH2 XtQVBKUQDcz6g0GVZo9oc395CimhrGQ9XJvkJj3dUQWgSsnEyCtlB4kfB sfQtxSpxyfbgVfPnRUZzgcxlKJmcYq+EKRH1Uaci4+F2LMlA+HF5EXT94 1lJEKxarXnBnJWrOitRnCkkg5AAYFL3zowm9GbVnbecR6rBwCAbPPkMyN YdQqtfuWKokRrrcTRve3xr1usjQDRF4c/VpRNt7ACD3i2sZEB3TNqO2jV w==; X-IronPort-AV: E=McAfee;i="6600,9927,10871"; a="389642687" X-IronPort-AV: E=Sophos;i="6.03,244,1694761200"; d="scan'208";a="389642687" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2023 01:49:50 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10871"; a="1005239682" X-IronPort-AV: E=Sophos;i="6.03,244,1694761200"; d="scan'208";a="1005239682" Received: from nirmoyda-mobl.ger.corp.intel.com (HELO [10.249.40.234]) ([10.249.40.234]) by fmsmga006-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Oct 2023 01:49:48 -0700 Message-ID: <6090c205-04e3-84f9-bbf3-cc6318de4445@linux.intel.com> Date: Mon, 23 Oct 2023 10:49:46 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Content-Language: en-US To: Andrzej Hajda , intel-gfx@lists.freedesktop.org References: <20231023-wabb-v3-0-1a4fbc632440@intel.com> <20231023-wabb-v3-2-1a4fbc632440@intel.com> From: Nirmoy Das In-Reply-To: <20231023-wabb-v3-2-1a4fbc632440@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Intel-gfx] [PATCH v3 2/4] drm/i915: Reserve some kernel space per vm 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: Chris Wilson , Jonathan Cavitt Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Hi Andrzej, On 10/23/2023 9:41 AM, Andrzej Hajda wrote: > Reserve two pages in each vm for kernel space to use for things > such as workarounds. > > v2: use real memory, do not decrease vm.total > > Suggested-by: Chris Wilson > Signed-off-by: Andrzej Hajda > Reviewed-by: Jonathan Cavitt > --- > drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 38 ++++++++++++++++++++++++++++++++++++ > drivers/gpu/drm/i915/gt/intel_gtt.h | 1 + > 2 files changed, 39 insertions(+) > > diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c > index 84aa29715e0aca..c25e1d4cceeb17 100644 > --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c > +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c > @@ -5,6 +5,7 @@ > > #include > > +#include "gem/i915_gem_internal.h" > #include "gem/i915_gem_lmem.h" > > #include "gen8_ppgtt.h" > @@ -953,6 +954,39 @@ gen8_alloc_top_pd(struct i915_address_space *vm) > return ERR_PTR(err); > } > > +static int gen8_init_rsvd(struct i915_address_space *vm) > +{ > + const resource_size_t size = 2 * PAGE_SIZE; > + struct drm_i915_private *i915 = vm->i915; > + struct drm_i915_gem_object *obj; > + struct i915_vma *vma; > + int ret; > + > + obj = i915_gem_object_create_lmem(i915, size, > + I915_BO_ALLOC_VOLATILE | > + I915_BO_ALLOC_GPU_ONLY); Please add a comment why GPU_ONLY flag is used. It makes sense to me now but good to have a comment for the future. Also why 2 pages are reserved ? Regards, Nirmoy > + if (IS_ERR(obj)) > + obj = i915_gem_object_create_internal(i915, size); > + if (IS_ERR(obj)) > + return PTR_ERR(obj); > + > + vma = i915_vma_instance(obj, vm, NULL); > + if (IS_ERR(vma)) { > + ret = PTR_ERR(vma); > + goto unref; > + } > + > + ret = i915_vma_pin(vma, 0, 0, PIN_USER | PIN_HIGH); > + if (ret) > + goto unref; > + > + vm->rsvd = i915_vma_make_unshrinkable(vma); > + > +unref: > + i915_gem_object_put(obj); > + return ret; > +} > + > /* > * GEN8 legacy ppgtt programming is accomplished through a max 4 PDP registers > * with a net effect resembling a 2-level page table in normal x86 terms. Each > @@ -1034,6 +1068,10 @@ struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt, > if (intel_vgpu_active(gt->i915)) > gen8_ppgtt_notify_vgt(ppgtt, true); > > + err = gen8_init_rsvd(&ppgtt->vm); > + if (err) > + goto err_put; > + > return ppgtt; > > err_put: > diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h > index 15c71da14d1d27..4a35ef24501b5f 100644 > --- a/drivers/gpu/drm/i915/gt/intel_gtt.h > +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h > @@ -250,6 +250,7 @@ struct i915_address_space { > struct work_struct release_work; > > struct drm_mm mm; > + struct i915_vma *rsvd; > struct intel_gt *gt; > struct drm_i915_private *i915; > struct device *dma; >