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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB1F0C47422 for ; Wed, 24 Jan 2024 07:29:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3B4B36B007E; Wed, 24 Jan 2024 02:29:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 33F1D6B0080; Wed, 24 Jan 2024 02:29:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 191A96B0082; Wed, 24 Jan 2024 02:29:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 009A46B007E for ; Wed, 24 Jan 2024 02:29:21 -0500 (EST) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id C72FC80305 for ; Wed, 24 Jan 2024 07:29:21 +0000 (UTC) X-FDA: 81713378922.24.272EE3B Received: from mail-wm1-f51.google.com (mail-wm1-f51.google.com [209.85.128.51]) by imf12.hostedemail.com (Postfix) with ESMTP id AF80E4000F for ; Wed, 24 Jan 2024 07:29:19 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=jKpyvAYz; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf12.hostedemail.com: domain of ckoenig.leichtzumerken@gmail.com designates 209.85.128.51 as permitted sender) smtp.mailfrom=ckoenig.leichtzumerken@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1706081359; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=9DRGXaVxKMFHx2hiT7iy2bNi9Kyy1UbBqRbOG7bk9EA=; b=ZYEM6efWMOfc1wH5cI9J5/MiXQx7Ik6ZFJLJdD7e9ROj1BA9KDLbuoTprumkH2PCreqXQm CAv65lwVJy4+JHFgMBRLr1HY3FkXg/v8CA1fxh0S9DIHZgyKCzoaxnnJu+pbxj3TCqOa/D d1waqFYVlHD+ITS9rWlguVFm9m+pAz4= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=jKpyvAYz; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf12.hostedemail.com: domain of ckoenig.leichtzumerken@gmail.com designates 209.85.128.51 as permitted sender) smtp.mailfrom=ckoenig.leichtzumerken@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1706081359; a=rsa-sha256; cv=none; b=YfVxfkR8eq9RmI88szvi4iTrEqmLRV6gc4Gfg6BPjmtaxzM7FM+lKMeiPEvBiB4vLslxWW fsF7Mb34IKH6axfS4LQKpXBeSRdYC69jj92TMiRiXRD9LybUgdFonZuQGTTphP2jGLZh2C qVuWR9LF9RRA8aZsXnjMymRTZ8Vp6ZU= Received: by mail-wm1-f51.google.com with SMTP id 5b1f17b1804b1-40e7065b7bdso61044135e9.3 for ; Tue, 23 Jan 2024 23:29:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1706081358; x=1706686158; darn=kvack.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=9DRGXaVxKMFHx2hiT7iy2bNi9Kyy1UbBqRbOG7bk9EA=; b=jKpyvAYz6djVDh5t6t0Jw1ULyU1AwldM/3WgyWDtHYHOMzSs3h56KlW8WXkD8xCfIM aJXolll9vrpeMNNhAx6KKo+c1Y8U1QVyYyZK7qnZPpkgGBVi2cv98QNPRVlQwQVENKV2 geQ2LGIkzrlYkrn9T6TJzP9Ga7fb3Q3sF1ayuzKDC1SEfaEgYVFRTvEr7zcS872XBt32 OVyIXRLOvBMTOkMpCVS+a8RBnIHmo8LoHcONEv+vO4Pb6ky5wA6gz6vdme4S9GaxtqYJ UCFgQrNeBPC2O6vzkf95haOyWenAonaZub6BYSvv6Cx21XUaXYt+9B3tZc92cw5Skur1 Y7Vw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706081358; x=1706686158; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=9DRGXaVxKMFHx2hiT7iy2bNi9Kyy1UbBqRbOG7bk9EA=; b=v4BUC9/4YauU2S0ugXZnHFpKGcPemfVdKk7FBiGBsEAXg4bEpa8/IUDxBnTELVF20J I0Geo7TVeqqA7UZB52MqskSoUh9ibiKiBqs+CD9aCxY66YnwDAvjCw/IR0Yu7yQZFzVG U2gLL3lZdIyiRX3WZ2aKDqzbHfL++1lLUwJ0Y6yGUXs+wsMXvwkCrMqEULu4Sy5URz81 Se1dY6jEM3NrNjwF0ecR8tPqO9EE/4a29tEpkw1TWcT3gWju8VMs6d/1gZRTqHw3qb2f nMhTNjRM9ZkbvcpbUxcfa2yWvMm8ZarjoIIPUoEPN7BVPH6q9KG4ZRTtGI0SeP3LIdu4 glHA== X-Gm-Message-State: AOJu0YzsqLVPnPB+X4yoLDcYIBHOzp0riuqeYX+h8098zFDu5TbFyDSl ntzMPbOM+kc8QEdNLy5o7DRAGCccj8GjswCodPei4/Ks+6TB9wtN X-Google-Smtp-Source: AGHT+IHyzerc8ODlelT9LcIwOXuNITuEKHKrpG9psQo5pdYryIcUoR+iK8dwa6wgUjXdTp7WS5B1lg== X-Received: by 2002:a05:600c:33a5:b0:40e:43e4:d9ca with SMTP id o37-20020a05600c33a500b0040e43e4d9camr560010wmp.179.1706081357705; Tue, 23 Jan 2024 23:29:17 -0800 (PST) Received: from [10.254.108.81] (munvpn.amd.com. [165.204.72.6]) by smtp.gmail.com with ESMTPSA id h7-20020a05600c350700b0040e63226f6dsm303045wmq.1.2024.01.23.23.29.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 23 Jan 2024 23:29:17 -0800 (PST) Message-ID: Date: Wed, 24 Jan 2024 08:29:14 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: Remove double faults once write a device pfn Content-Language: en-US To: "Zhou, Xianrong" , "Koenig, Christian" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Cc: "lee@kernel.org" , "kherbst@redhat.com" , "nouveau@lists.freedesktop.org" , "dave.hansen@linux.intel.com" , "dri-devel@lists.freedesktop.org" , "Huang, Ray" , "hpa@zytor.com" , "zack.rusin@broadcom.com" , "airlied@gmail.com" , "Zhang, GuoQing (Sam)" , "Li, Huazeng" , "x86@kernel.org" , "amd-gfx@lists.freedesktop.org" , "Xu, Colin" , "mingo@redhat.com" , "dakr@redhat.com" , "matthew.auld@intel.com" , "bcm-kernel-feedback-list@broadcom.com" , "Yang, Philip" , "joonas.lahtinen@linux.intel.com" , "tzimmermann@suse.de" , "intel-gfx@lists.freedesktop.org" , "maarten.lankhorst@linux.intel.com" , "jani.nikula@linux.intel.com" , "bp@alien8.de" , "mripard@kernel.org" , "luto@kernel.org" , "rodrigo.vivi@intel.com" , "tglx@linutronix.de" , "Zhu, James" , "surenb@google.com" , "Liu, Monk" , "tvrtko.ursulin@linux.intel.com" , "Kuehling, Felix" , "Pan, Xinhui" , "daniel@ffwll.ch" , "Deucher, Alexander" , "akpm@linux-foundation.org" , "SHANMUGAM, SRINIVASAN" , "nirmoy.das@intel.com" References: <20240122033210.713530-1-Xianrong.Zhou@amd.com> <5ed7d46b-ae26-43f2-81e0-91e3cfc0218a@amd.com> <76c3658d-2256-49c6-8e4c-49555c0a350a@amd.com> From: =?UTF-8?Q?Christian_K=C3=B6nig?= In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: AF80E4000F X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: t7zynmkikdkba8uo3o7ma3nabsgat8r1 X-HE-Tag: 1706081359-195687 X-HE-Meta: U2FsdGVkX19LI5GWYlWm8JhphWnv+ZUoC7kuinekViRajWv3awUomX3McPOn7xjRAyYr5E03ahU0AnS1OY7Nmfp/CBeYGkyrJLD17PWeqQ/LUnZVD0axwoSaugG010FnHFibIPYg8BA0yNLKrXgeYIOsEH9Zt5H/etbPAzbqVYp0SVUTL+xRlbRDOnElp+uumeAJAdKUe4GVCMRIstnhwAQPCiT+8b4EYO/jLCceR1hKyeShCtyLtZuP5bpjd3XpVAg6xc/yZ2MMrwBYhUhNeErqm00DOUO2OLLeTwn4AFxyZpymjnSPIU9d6DKKzWpDe6HPAHcOQqQ2+ZLpeMi5b2jsxXAp6n/vJeYysds3JBRNFK648qKMIyywdCpPihX1R8egZ91Zeh72mH+P4kNASCA+B8VtHY0KiiHARjff6hFG0X8tpdjuHIhX2bOgwA4fAcThW+7tsycYMdLoqQDYOJ0gp7wFW2eBKYPQ1klBsRkL6YKnBzENcMT0f9yGOfgmKBQ9apaaabYNGesKd5wLi8XbELIh3ayaG8zs2Oz/9nsenBHQRC75C5Frlz0otisFfNEtIronL6tH7mX1C/iyXBQc0kW0+CkWhFnjPKLVy6l53LXnMIYf2qSjcF0MHlsXafB80xyBjUr8O6MxgU1pH/HImqzenWKkB4FTJgA+yfQDzt4VHCpQO2q8ruGej5p4q6Sy6OSNPr/2p2uzfa/qZewwLKQBMrenEW1pDd2GjBKc1op2hVNv9pVef3xKUC5+djcBo2BeNgcSZQlNMjfPrY3Be/ewxY/u+vRTuRuUg9k9vdsue6RlvChoLZm9sTizcrmXQjkg5BTPJh8JH+i67tHUcJO5+0xi+MiaLG9iujEVLehCbIE/BnckgiUUjO7mZ40+sEMUyCwCWVNN73AWwuUqMhb8LmXiUzBtzp5V2tAVfvfIBTcg3If8yVNz/Zt4TDvzHfhmvcLTFvyBsh8 2ElgpxPB 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Am 24.01.24 um 03:43 schrieb Zhou, Xianrong: > [AMD Official Use Only - General] > >>>>> The vmf_insert_pfn_prot could cause unnecessary double faults on a >>>>> device pfn. Because currently the vmf_insert_pfn_prot does not make >>>>> the pfn writable so the pte entry is normally read-only or dirty >>>>> catching. >>>> What? How do you got to this conclusion? >>> Sorry. I did not mention that this problem only exists on arm64 platform. >> Ok, that makes at least a little bit more sense. >> >>> Because on arm64 platform the PTE_RDONLY is automatically attached to >>> the userspace pte entries even through VM_WRITE + VM_SHARE. >>> The PTE_RDONLY needs to be cleared in vmf_insert_pfn_prot. However >>> vmf_insert_pfn_prot do not make the pte writable passing false >>> @mkwrite to insert_pfn. >> Question is why is arm64 doing this? As far as I can see they must have some >> hardware reason for that. >> >> The mkwrite parameter to insert_pfn() was added by commit >> b2770da642540 to make insert_pfn() look more like insert_pfn_pmd() so that >> the DAX code can insert PTEs which are writable and dirty at the same time. >> > This is one scenario to do so. In fact on arm64 there are many scenarios could > be to do so. So we can let vmf_insert_pfn_prot supporting @mkwrite for drivers > at core layer and let drivers to decide whether or not to make writable and dirty > at one time. The patch did this. Otherwise double faults on arm64 when call > vmf_insert_pfn_prot. Well, that doesn't answer my question why arm64 is double faulting in the first place,. So as long as this isn't sorted out I'm going to reject this patch. Regards, Christian. > >> This is a completely different use case to what you try to use it here for and >> that looks extremely fishy to me. >> >> Regards, >> Christian. >> >>>>> The first fault only sets up the pte entry which actually is dirty >>>>> catching. And the second immediate fault to the pfn due to first >>>>> dirty catching when the cpu re-execute the store instruction. >>>> It could be that this is done to work around some hw behavior, but >>>> not because of dirty catching. >>>> >>>>> Normally if the drivers call vmf_insert_pfn_prot and also supply >>>>> 'pfn_mkwrite' callback within vm_operations_struct which requires >>>>> the pte to be dirty catching then the vmf_insert_pfn_prot and the >>>>> double fault are reasonable. It is not a problem. >>>> Well, as far as I can see that behavior absolutely doesn't make sense. >>>> >>>> When pfn_mkwrite is requested then the driver should use PAGE_COPY, >>>> which is exactly what VMWGFX (the only driver using dirty tracking) is >> doing. >>>> Everybody else uses PAGE_SHARED which should make the pte writeable >>>> immediately. >>>> >>>> Regards, >>>> Christian. >>>> >>>>> However the most of drivers calling vmf_insert_pfn_prot do not >>>>> supply the 'pfn_mkwrite' callback so that the second fault is unnecessary. >>>>> >>>>> So just like vmf_insert_mixed and vmf_insert_mixed_mkwrite pair, we >>>>> should also supply vmf_insert_pfn_mkwrite for drivers as well. >>>>> >>>>> Signed-off-by: Xianrong Zhou >>>>> --- >>>>> arch/x86/entry/vdso/vma.c | 3 ++- >>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 2 +- >>>>> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 2 +- >>>>> drivers/gpu/drm/nouveau/nouveau_gem.c | 2 +- >>>>> drivers/gpu/drm/radeon/radeon_gem.c | 2 +- >>>>> drivers/gpu/drm/ttm/ttm_bo_vm.c | 8 +++++--- >>>>> drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c | 8 +++++--- >>>>> include/drm/ttm/ttm_bo.h | 3 ++- >>>>> include/linux/mm.h | 2 +- >>>>> mm/memory.c | 14 +++++++++++--- >>>>> 10 files changed, 30 insertions(+), 16 deletions(-) >>>>> >>>>> diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c >>>>> index 7645730dc228..dd2431c2975f 100644 >>>>> --- a/arch/x86/entry/vdso/vma.c >>>>> +++ b/arch/x86/entry/vdso/vma.c >>>>> @@ -185,7 +185,8 @@ static vm_fault_t vvar_fault(const struct >>>> vm_special_mapping *sm, >>>>> if (pvti && vclock_was_used(VDSO_CLOCKMODE_PVCLOCK)) >>>> { >>>>> return vmf_insert_pfn_prot(vma, vmf->address, >>>>> __pa(pvti) >> PAGE_SHIFT, >>>>> - pgprot_decrypted(vma- >>>>> vm_page_prot)); >>>>> + pgprot_decrypted(vma- >>>>> vm_page_prot), >>>>> + true); >>>>> } >>>>> } else if (sym_offset == image->sym_hvclock_page) { >>>>> pfn = hv_get_tsc_pfn(); diff --git >>>>> a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c >>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c >>>>> index 49a5f1c73b3e..adcb20d9e624 100644 >>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c >>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c >>>>> @@ -64,7 +64,7 @@ static vm_fault_t amdgpu_gem_fault(struct >> vm_fault >>>> *vmf) >>>>> } >>>>> >>>>> ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma- >>>>> vm_page_prot, >>>>> - TTM_BO_VM_NUM_PREFAULT); >>>>> + TTM_BO_VM_NUM_PREFAULT, >>>> true); >>>>> drm_dev_exit(idx); >>>>> } else { >>>>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c >>>>> b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c >>>>> index 9227f8146a58..c6f13ae6c308 100644 >>>>> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c >>>>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c >>>>> @@ -1114,7 +1114,7 @@ static vm_fault_t vm_fault_ttm(struct vm_fault >>>>> *vmf) >>>>> >>>>> if (drm_dev_enter(dev, &idx)) { >>>>> ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma- >>>>> vm_page_prot, >>>>> - TTM_BO_VM_NUM_PREFAULT); >>>>> + TTM_BO_VM_NUM_PREFAULT, >>>> true); >>>>> drm_dev_exit(idx); >>>>> } else { >>>>> ret = ttm_bo_vm_dummy_page(vmf, vmf->vma- >>>>> vm_page_prot); diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c >>>>> b/drivers/gpu/drm/nouveau/nouveau_gem.c >>>>> index 49c2bcbef129..7e1453762ec9 100644 >>>>> --- a/drivers/gpu/drm/nouveau/nouveau_gem.c >>>>> +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c >>>>> @@ -56,7 +56,7 @@ static vm_fault_t nouveau_ttm_fault(struct >>>>> vm_fault >>>>> *vmf) >>>>> >>>>> nouveau_bo_del_io_reserve_lru(bo); >>>>> prot = vm_get_page_prot(vma->vm_flags); >>>>> - ret = ttm_bo_vm_fault_reserved(vmf, prot, >>>> TTM_BO_VM_NUM_PREFAULT); >>>>> + ret = ttm_bo_vm_fault_reserved(vmf, prot, >>>> TTM_BO_VM_NUM_PREFAULT, >>>>> +true); >>>>> nouveau_bo_add_io_reserve_lru(bo); >>>>> if (ret == VM_FAULT_RETRY && !(vmf->flags & >>>> FAULT_FLAG_RETRY_NOWAIT)) >>>>> return ret; >>>>> diff --git a/drivers/gpu/drm/radeon/radeon_gem.c >>>>> b/drivers/gpu/drm/radeon/radeon_gem.c >>>>> index 3fec3acdaf28..b21cf00ae162 100644 >>>>> --- a/drivers/gpu/drm/radeon/radeon_gem.c >>>>> +++ b/drivers/gpu/drm/radeon/radeon_gem.c >>>>> @@ -62,7 +62,7 @@ static vm_fault_t radeon_gem_fault(struct vm_fault >>>> *vmf) >>>>> goto unlock_resv; >>>>> >>>>> ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot, >>>>> - TTM_BO_VM_NUM_PREFAULT); >>>>> + TTM_BO_VM_NUM_PREFAULT, true); >>>>> if (ret == VM_FAULT_RETRY && !(vmf->flags & >>>> FAULT_FLAG_RETRY_NOWAIT)) >>>>> goto unlock_mclk; >>>>> >>>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c >>>>> b/drivers/gpu/drm/ttm/ttm_bo_vm.c index >>>> 4212b8c91dd4..7d14a7d267aa >>>>> 100644 >>>>> --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c >>>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c >>>>> @@ -167,6 +167,7 @@ EXPORT_SYMBOL(ttm_bo_vm_reserve); >>>>> * @num_prefault: Maximum number of prefault pages. The caller >>>>> may >>>> want to >>>>> * specify this based on madvice settings and the size of the GPU object >>>>> * backed by the memory. >>>>> + * @mkwrite: make the pfn or page writable >>>>> * >>>>> * This function inserts one or more page table entries pointing to the >>>>> * memory backing the buffer object, and then returns a return >>>>> code @@ -180,7 +181,8 @@ EXPORT_SYMBOL(ttm_bo_vm_reserve); >>>>> */ >>>>> vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, >>>>> pgprot_t prot, >>>>> - pgoff_t num_prefault) >>>>> + pgoff_t num_prefault, >>>>> + bool mkwrite) >>>>> { >>>>> struct vm_area_struct *vma = vmf->vma; >>>>> struct ttm_buffer_object *bo = vma->vm_private_data; @@ -263,7 >>>>> +265,7 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, >>>>> * at arbitrary times while the data is mmap'ed. >>>>> * See vmf_insert_pfn_prot() for a discussion. >>>>> */ >>>>> - ret = vmf_insert_pfn_prot(vma, address, pfn, prot); >>>>> + ret = vmf_insert_pfn_prot(vma, address, pfn, prot, >>>>> + mkwrite); >>>>> >>>>> /* Never error on prefaulted PTEs */ >>>>> if (unlikely((ret & VM_FAULT_ERROR))) { @@ -312,7 >>>>> +314,7 >>>> @@ >>>>> vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t >> prot) >>>>> /* Prefault the entire VMA range right away to avoid further faults */ >>>>> for (address = vma->vm_start; address < vma->vm_end; >>>>> address += PAGE_SIZE) >>>>> - ret = vmf_insert_pfn_prot(vma, address, pfn, prot); >>>>> + ret = vmf_insert_pfn_prot(vma, address, pfn, prot, >>>>> + true); >>>>> >>>>> return ret; >>>>> } >>>>> diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c >>>>> b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c >>>>> index 74ff2812d66a..bb8e4b641681 100644 >>>>> --- a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c >>>>> +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c >>>>> @@ -452,12 +452,14 @@ vm_fault_t vmw_bo_vm_fault(struct vm_fault >>>> *vmf) >>>>> * sure the page protection is write-enabled so we don't get >>>>> * a lot of unnecessary write faults. >>>>> */ >>>>> - if (vbo->dirty && vbo->dirty->method == VMW_BO_DIRTY_MKWRITE) >>>>> + if (vbo->dirty && vbo->dirty->method == VMW_BO_DIRTY_MKWRITE) >>>> { >>>>> prot = vm_get_page_prot(vma->vm_flags & ~VM_SHARED); >>>>> - else >>>>> + ret = ttm_bo_vm_fault_reserved(vmf, prot, num_prefault, >>>> false); >>>>> + } else { >>>>> prot = vm_get_page_prot(vma->vm_flags); >>>>> + ret = ttm_bo_vm_fault_reserved(vmf, prot, num_prefault, >>>> true); >>>>> + } >>>>> >>>>> - ret = ttm_bo_vm_fault_reserved(vmf, prot, num_prefault); >>>>> if (ret == VM_FAULT_RETRY && !(vmf->flags & >>>> FAULT_FLAG_RETRY_NOWAIT)) >>>>> return ret; >>>>> >>>>> diff --git a/include/drm/ttm/ttm_bo.h b/include/drm/ttm/ttm_bo.h >>>>> index 0223a41a64b2..66e293db69ee 100644 >>>>> --- a/include/drm/ttm/ttm_bo.h >>>>> +++ b/include/drm/ttm/ttm_bo.h >>>>> @@ -386,7 +386,8 @@ vm_fault_t ttm_bo_vm_reserve(struct >>>> ttm_buffer_object *bo, >>>>> struct vm_fault *vmf); >>>>> vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, >>>>> pgprot_t prot, >>>>> - pgoff_t num_prefault); >>>>> + pgoff_t num_prefault, >>>>> + bool mkwrite); >>>>> vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf); >>>>> void ttm_bo_vm_open(struct vm_area_struct *vma); >>>>> void ttm_bo_vm_close(struct vm_area_struct *vma); diff --git >>>>> a/include/linux/mm.h b/include/linux/mm.h index >>>>> f5a97dec5169..f8868e28ea04 100644 >>>>> --- a/include/linux/mm.h >>>>> +++ b/include/linux/mm.h >>>>> @@ -3553,7 +3553,7 @@ int vm_map_pages_zero(struct >> vm_area_struct >>>> *vma, struct page **pages, >>>>> vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned >>>>> long >>>> addr, >>>>> unsigned long pfn); >>>>> vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, >>>>> unsigned >>>> long addr, >>>>> - unsigned long pfn, pgprot_t pgprot); >>>>> + unsigned long pfn, pgprot_t pgprot, bool >>>>> + mkwrite); >>>>> vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned >>>>> long >>>> addr, >>>>> pfn_t pfn); >>>>> vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma, >>>>> diff --git a/mm/memory.c b/mm/memory.c index >>>>> 7e1f4849463a..2c28f1a349ff >>>>> 100644 >>>>> --- a/mm/memory.c >>>>> +++ b/mm/memory.c >>>>> @@ -2195,6 +2195,7 @@ static vm_fault_t insert_pfn(struct >>>> vm_area_struct *vma, unsigned long addr, >>>>> * @addr: target user address of this page >>>>> * @pfn: source kernel pfn >>>>> * @pgprot: pgprot flags for the inserted page >>>>> + * @mkwrite: make the pfn writable >>>>> * >>>>> * This is exactly like vmf_insert_pfn(), except that it allows drivers >>>>> * to override pgprot on a per-page basis. >>>>> @@ -2223,7 +2224,7 @@ static vm_fault_t insert_pfn(struct >>>> vm_area_struct *vma, unsigned long addr, >>>>> * Return: vm_fault_t value. >>>>> */ >>>>> vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, >>>>> unsigned >>>> long addr, >>>>> - unsigned long pfn, pgprot_t pgprot) >>>>> + unsigned long pfn, pgprot_t pgprot, bool >>>>> + mkwrite) >>>>> { >>>>> /* >>>>> * Technically, architectures with pte_special can avoid all >>>>> these @@ -2246,7 +2247,7 @@ vm_fault_t vmf_insert_pfn_prot(struct >>>> vm_area_struct *vma, unsigned long addr, >>>>> track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV)); >>>>> >>>>> return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot, >>>>> - false); >>>>> + mkwrite); >>>>> } >>>>> EXPORT_SYMBOL(vmf_insert_pfn_prot); >>>>> >>>>> @@ -2273,10 +2274,17 @@ EXPORT_SYMBOL(vmf_insert_pfn_prot); >>>>> vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned >>>>> long >>>> addr, >>>>> unsigned long pfn) >>>>> { >>>>> - return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); >>>>> + return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot, >>>>> +false); >>>>> } >>>>> EXPORT_SYMBOL(vmf_insert_pfn); >>>>> >>>>> +vm_fault_t vmf_insert_pfn_mkwrite(struct vm_area_struct *vma, >>>>> +unsigned >>>> long addr, >>>>> + unsigned long pfn) { >>>>> + return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot, >>>> true); >>>>> +} EXPORT_SYMBOL(vmf_insert_pfn_mkwrite); >>>>> + >>>>> static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn) >>>>> { >>>>> /* these checks mirror the abort conditions in vm_normal_page >>>>> */