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=-13.6 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,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 DA44DC43214 for ; Fri, 23 Jul 2021 07:32:37 +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 A4A0E60EBD for ; Fri, 23 Jul 2021 07:32:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A4A0E60EBD 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 928386EE4C; Fri, 23 Jul 2021 07:32:35 +0000 (UTC) Received: from mail-wr1-x430.google.com (mail-wr1-x430.google.com [IPv6:2a00:1450:4864:20::430]) by gabe.freedesktop.org (Postfix) with ESMTPS id 729B66FA29 for ; Fri, 23 Jul 2021 07:32:34 +0000 (UTC) Received: by mail-wr1-x430.google.com with SMTP id r2so1323576wrl.1 for ; Fri, 23 Jul 2021 00:32:34 -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:content-transfer-encoding:in-reply-to; bh=fTyz1WerCrslfb+YIcYLjSCv4f+ODjk/GZ36i7RUnFY=; b=RAs+KcgQ3S17683/tmEgIKcErbHFISiFS/7zsiIoPw4NgcGGm1xRRPFbZPR8RDpT/2 N6OLuAiG8p9W+GQAE1R+rAmL6P2CtxtdPu7FZV6xSOjop+iOjdYZeK1szsjUj1h7R879 zp8sm/UpnJjoL957iJ3KL8uBh/x5IMzYFgedQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=fTyz1WerCrslfb+YIcYLjSCv4f+ODjk/GZ36i7RUnFY=; b=f9B0WAK0l4kdtxizlZ9BIWj7kI+c3qwCGpI6ssPZbDndBR49jGVgy2XndOJ8saIyqt 0JtlurXp5qyVi8PofrsGlLgk+EaXCUbvosO8+xPf+pvuAj7IT/lGcjeSit0+s2i3Qm/h apJo3szxTjcxj4lKsdpQ3wo6xFRnROJyc8/0/x6sCocvQpIiys9ZN2o8vI/qU6vyUGX7 DebEZPnLmd284bmGcdjuCUrVUJlYUmmZsHjgwt69tPZGtmb7ZsUadbVhg+NenEy/uyXx 7wvAeHnkuvcptow+KYMjV0DV9LRTA3wfmauU0sQtT0z0zrgdP/N/sqlTRAUxPqfsuHTa goTA== X-Gm-Message-State: AOAM533h+zW7NGalOEvTutRMY1crPnWnKF8Gis5O6qZi0CT0tGRa2cHl 9mca8wdfT69L8T8QvXA9LY9R4A== X-Google-Smtp-Source: ABdhPJw2Xs3tC/Qkan89Y+Jn8WvygHy+iodOVM8ye4ufwvQvuuB+vqHmqpjGsROJSFOV7JWM2Y6ZfQ== X-Received: by 2002:a05:6000:1141:: with SMTP id d1mr3906252wrx.396.1627025552995; Fri, 23 Jul 2021 00:32:32 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id j1sm1187580wrm.86.2021.07.23.00.32.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Jul 2021 00:32:32 -0700 (PDT) Date: Fri, 23 Jul 2021 09:32:30 +0200 From: Daniel Vetter To: Thomas Zimmermann Subject: Re: [PATCH v4 2/4] drm/shmem-helper: Switch to vmf_insert_pfn Message-ID: References: <20210713205153.1896059-1-daniel.vetter@ffwll.ch> <20210713205153.1896059-3-daniel.vetter@ffwll.ch> <573242f9-a29e-73d9-3efb-51c436d636fd@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <573242f9-a29e-73d9-3efb-51c436d636fd@suse.de> X-Operating-System: Linux phenom 5.10.0-7-amd64 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Airlie , Daniel Vetter , Intel Graphics Development , DRI Development , Daniel Vetter Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, Jul 22, 2021 at 08:22:43PM +0200, Thomas Zimmermann wrote: > Hi, > > I'm not knowledgeable enougth to give this a full review. If you can just > answer my questions, fell free to add an > > Acked-by: Thomas Zimmermann > > to the patch. :) > > Am 13.07.21 um 22:51 schrieb Daniel Vetter: > > We want to stop gup, which isn't the case if we use vmf_insert_page > > What is gup? get_user_pages. It pins memory wherever it is, which badly wreaks at least ttm and could also cause trouble with cma allocations. In both cases becaue we can't move/reuse these pages anymore. Now get_user_pages fails when the memory isn't considered "normal", like with VM_PFNMAP and using vm_insert_pfn. For consistency across all dma-buf I'm trying (together with Christian König) to roll this out everywhere, for fewer surprises. E.g. for 5.14 iirc we merged a patch to do the same for ttm, where it closes an actual bug (ttm gets really badly confused when there's suddenly pinned pages where it thought it can move them). cma allcoations already use VM_PFNMAP (because that's what dma_mmap is using underneath), as is anything that's using remap_pfn_range. Worst case we have to revert this patch for shmem helpers if it breaks something, but I hope that's not the case. On the ttm side we've also had some fallout that we needed to paper over with clever tricks. I'll add the above explanation to the commit message. > > > and VM_MIXEDMAP, because that does not set pte_special. > > > > v2: With this shmem gem helpers now definitely need CONFIG_MMU (0day) > > > > v3: add more depends on MMU. For usb drivers this is a bit awkward, > > but really it's correct: To be able to provide a contig mapping of > > buffers to userspace on !MMU platforms we'd need to use the cma > > helpers for these drivers on those platforms. As-is this wont work. > > > > Also not exactly sure why vm_insert_page doesn't go boom, because that > > definitely wont fly in practice since the pages are non-contig to > > begin with. > > > > Signed-off-by: Daniel Vetter > > Cc: Maarten Lankhorst > > Cc: Maxime Ripard > > Cc: Thomas Zimmermann > > Cc: David Airlie > > Cc: Daniel Vetter > > --- > > drivers/gpu/drm/Kconfig | 2 +- > > drivers/gpu/drm/drm_gem_shmem_helper.c | 4 ++-- > > drivers/gpu/drm/gud/Kconfig | 2 +- > > drivers/gpu/drm/tiny/Kconfig | 4 ++-- > > drivers/gpu/drm/udl/Kconfig | 1 + > > 5 files changed, 7 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > > index 0d372354c2d0..314eefa39892 100644 > > --- a/drivers/gpu/drm/Kconfig > > +++ b/drivers/gpu/drm/Kconfig > > @@ -211,7 +211,7 @@ config DRM_KMS_CMA_HELPER > > config DRM_GEM_SHMEM_HELPER > > bool > > - depends on DRM > > + depends on DRM && MMU > > help > > Choose this if you need the GEM shmem helper functions > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > > index d5e6d4568f99..296ab1b7c07f 100644 > > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > > @@ -542,7 +542,7 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) > > } else { > > page = shmem->pages[page_offset]; > > - ret = vmf_insert_page(vma, vmf->address, page); > > + ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page)); > > } > > mutex_unlock(&shmem->pages_lock); > > @@ -612,7 +612,7 @@ int drm_gem_shmem_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma) > > return ret; > > } > > - vma->vm_flags |= VM_MIXEDMAP | VM_DONTEXPAND; > > + vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND; > > vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); > > if (shmem->map_wc) > > vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot); > > diff --git a/drivers/gpu/drm/gud/Kconfig b/drivers/gpu/drm/gud/Kconfig > > index 1c8601bf4d91..9c1e61f9eec3 100644 > > --- a/drivers/gpu/drm/gud/Kconfig > > +++ b/drivers/gpu/drm/gud/Kconfig > > @@ -2,7 +2,7 @@ > > config DRM_GUD > > tristate "GUD USB Display" > > - depends on DRM && USB > > + depends on DRM && USB && MMU > > select LZ4_COMPRESS > > select DRM_KMS_HELPER > > select DRM_GEM_SHMEM_HELPER > > I'm a kconfig noob, so this is rather a question than a review comment: > > > > If DRM_GEM_SHMEM_HELPER already depends on MMU, this select will fail on > non-MMU platforms? Why does the driver also depend on MMU? Simply to make > the item disappear in menuconfig? > > Best regards > Thomas > > > diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig > > index 5593128eeff9..c11fb5be7d09 100644 > > --- a/drivers/gpu/drm/tiny/Kconfig > > +++ b/drivers/gpu/drm/tiny/Kconfig > > @@ -44,7 +44,7 @@ config DRM_CIRRUS_QEMU > > config DRM_GM12U320 > > tristate "GM12U320 driver for USB projectors" > > - depends on DRM && USB > > + depends on DRM && USB && MMU > > select DRM_KMS_HELPER > > select DRM_GEM_SHMEM_HELPER > > help > > @@ -53,7 +53,7 @@ config DRM_GM12U320 > > config DRM_SIMPLEDRM > > tristate "Simple framebuffer driver" > > - depends on DRM > > + depends on DRM && MMU > > select DRM_GEM_SHMEM_HELPER > > select DRM_KMS_HELPER > > help > > diff --git a/drivers/gpu/drm/udl/Kconfig b/drivers/gpu/drm/udl/Kconfig > > index 1f497d8f1ae5..c744175c6992 100644 > > --- a/drivers/gpu/drm/udl/Kconfig > > +++ b/drivers/gpu/drm/udl/Kconfig > > @@ -4,6 +4,7 @@ config DRM_UDL > > depends on DRM > > depends on USB > > depends on USB_ARCH_HAS_HCD > > + depends on MMU > > select DRM_GEM_SHMEM_HELPER > > select DRM_KMS_HELPER > > help > > > > -- > Thomas Zimmermann > Graphics Driver Developer > SUSE Software Solutions Germany GmbH > Maxfeldstr. 5, 90409 Nürnberg, Germany > (HRB 36809, AG Nürnberg) > Geschäftsführer: Felix Imendörffer > -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch 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=-13.6 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,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 648C4C19F32 for ; 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Fri, 23 Jul 2021 00:32:32 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id j1sm1187580wrm.86.2021.07.23.00.32.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Jul 2021 00:32:32 -0700 (PDT) Date: Fri, 23 Jul 2021 09:32:30 +0200 From: Daniel Vetter To: Thomas Zimmermann Message-ID: References: <20210713205153.1896059-1-daniel.vetter@ffwll.ch> <20210713205153.1896059-3-daniel.vetter@ffwll.ch> <573242f9-a29e-73d9-3efb-51c436d636fd@suse.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <573242f9-a29e-73d9-3efb-51c436d636fd@suse.de> X-Operating-System: Linux phenom 5.10.0-7-amd64 Subject: Re: [Intel-gfx] [PATCH v4 2/4] drm/shmem-helper: Switch to vmf_insert_pfn 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: David Airlie , Daniel Vetter , Intel Graphics Development , DRI Development , Daniel Vetter Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Jul 22, 2021 at 08:22:43PM +0200, Thomas Zimmermann wrote: > Hi, > = > I'm not knowledgeable enougth to give this a full review. If you can just > answer my questions, fell free to add an > = > Acked-by: Thomas Zimmermann > = > to the patch. :) > = > Am 13.07.21 um 22:51 schrieb Daniel Vetter: > > We want to stop gup, which isn't the case if we use vmf_insert_page > = > What is gup? get_user_pages. It pins memory wherever it is, which badly wreaks at least ttm and could also cause trouble with cma allocations. In both cases becaue we can't move/reuse these pages anymore. Now get_user_pages fails when the memory isn't considered "normal", like with VM_PFNMAP and using vm_insert_pfn. For consistency across all dma-buf I'm trying (together with Christian K=F6nig) to roll this out everywhere, for fewer surprises. E.g. for 5.14 iirc we merged a patch to do the same for ttm, where it closes an actual bug (ttm gets really badly confused when there's suddenly pinned pages where it thought it can move them). cma allcoations already use VM_PFNMAP (because that's what dma_mmap is using underneath), as is anything that's using remap_pfn_range. Worst case we have to revert this patch for shmem helpers if it breaks something, but I hope that's not the case. On the ttm side we've also had some fallout that we needed to paper over with clever tricks. I'll add the above explanation to the commit message. > = > > and VM_MIXEDMAP, because that does not set pte_special. > > = > > v2: With this shmem gem helpers now definitely need CONFIG_MMU (0day) > > = > > v3: add more depends on MMU. For usb drivers this is a bit awkward, > > but really it's correct: To be able to provide a contig mapping of > > buffers to userspace on !MMU platforms we'd need to use the cma > > helpers for these drivers on those platforms. As-is this wont work. > > = > > Also not exactly sure why vm_insert_page doesn't go boom, because that > > definitely wont fly in practice since the pages are non-contig to > > begin with. > > = > > Signed-off-by: Daniel Vetter > > Cc: Maarten Lankhorst > > Cc: Maxime Ripard > > Cc: Thomas Zimmermann > > Cc: David Airlie > > Cc: Daniel Vetter > > --- > > drivers/gpu/drm/Kconfig | 2 +- > > drivers/gpu/drm/drm_gem_shmem_helper.c | 4 ++-- > > drivers/gpu/drm/gud/Kconfig | 2 +- > > drivers/gpu/drm/tiny/Kconfig | 4 ++-- > > drivers/gpu/drm/udl/Kconfig | 1 + > > 5 files changed, 7 insertions(+), 6 deletions(-) > > = > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig > > index 0d372354c2d0..314eefa39892 100644 > > --- a/drivers/gpu/drm/Kconfig > > +++ b/drivers/gpu/drm/Kconfig > > @@ -211,7 +211,7 @@ config DRM_KMS_CMA_HELPER > > config DRM_GEM_SHMEM_HELPER > > bool > > - depends on DRM > > + depends on DRM && MMU > > help > > Choose this if you need the GEM shmem helper functions > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/d= rm_gem_shmem_helper.c > > index d5e6d4568f99..296ab1b7c07f 100644 > > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > > @@ -542,7 +542,7 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fau= lt *vmf) > > } else { > > page =3D shmem->pages[page_offset]; > > - ret =3D vmf_insert_page(vma, vmf->address, page); > > + ret =3D vmf_insert_pfn(vma, vmf->address, page_to_pfn(page)); > > } > > mutex_unlock(&shmem->pages_lock); > > @@ -612,7 +612,7 @@ int drm_gem_shmem_mmap(struct drm_gem_object *obj, = struct vm_area_struct *vma) > > return ret; > > } > > - vma->vm_flags |=3D VM_MIXEDMAP | VM_DONTEXPAND; > > + vma->vm_flags |=3D VM_PFNMAP | VM_DONTEXPAND; > > vma->vm_page_prot =3D vm_get_page_prot(vma->vm_flags); > > if (shmem->map_wc) > > vma->vm_page_prot =3D pgprot_writecombine(vma->vm_page_prot); > > diff --git a/drivers/gpu/drm/gud/Kconfig b/drivers/gpu/drm/gud/Kconfig > > index 1c8601bf4d91..9c1e61f9eec3 100644 > > --- a/drivers/gpu/drm/gud/Kconfig > > +++ b/drivers/gpu/drm/gud/Kconfig > > @@ -2,7 +2,7 @@ > > config DRM_GUD > > tristate "GUD USB Display" > > - depends on DRM && USB > > + depends on DRM && USB && MMU > > select LZ4_COMPRESS > > select DRM_KMS_HELPER > > select DRM_GEM_SHMEM_HELPER > = > I'm a kconfig noob, so this is rather a question than a review comment: > = > = > = > If DRM_GEM_SHMEM_HELPER already depends on MMU, this select will fail on > non-MMU platforms? Why does the driver also depend on MMU? Simply to make > the item disappear in menuconfig? > = > Best regards > Thomas > = > > diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig > > index 5593128eeff9..c11fb5be7d09 100644 > > --- a/drivers/gpu/drm/tiny/Kconfig > > +++ b/drivers/gpu/drm/tiny/Kconfig > > @@ -44,7 +44,7 @@ config DRM_CIRRUS_QEMU > > config DRM_GM12U320 > > tristate "GM12U320 driver for USB projectors" > > - depends on DRM && USB > > + depends on DRM && USB && MMU > > select DRM_KMS_HELPER > > select DRM_GEM_SHMEM_HELPER > > help > > @@ -53,7 +53,7 @@ config DRM_GM12U320 > > config DRM_SIMPLEDRM > > tristate "Simple framebuffer driver" > > - depends on DRM > > + depends on DRM && MMU > > select DRM_GEM_SHMEM_HELPER > > select DRM_KMS_HELPER > > help > > diff --git a/drivers/gpu/drm/udl/Kconfig b/drivers/gpu/drm/udl/Kconfig > > index 1f497d8f1ae5..c744175c6992 100644 > > --- a/drivers/gpu/drm/udl/Kconfig > > +++ b/drivers/gpu/drm/udl/Kconfig > > @@ -4,6 +4,7 @@ config DRM_UDL > > depends on DRM > > depends on USB > > depends on USB_ARCH_HAS_HCD > > + depends on MMU > > select DRM_GEM_SHMEM_HELPER > > select DRM_KMS_HELPER > > help > > = > = > -- = > Thomas Zimmermann > Graphics Driver Developer > SUSE Software Solutions Germany GmbH > Maxfeldstr. 5, 90409 N=FCrnberg, Germany > (HRB 36809, AG N=FCrnberg) > Gesch=E4ftsf=FChrer: Felix Imend=F6rffer > = -- = Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx