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[209.85.220.65]) by mx.google.com with SMTPS id 38sor15343832pln.23.2019.04.02.07.37.20 for (Google Transport Security); Tue, 02 Apr 2019 07:37:20 -0700 (PDT) Received-SPF: pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=E28SvG5d; spf=pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=andreyknvl@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=AZM0NDA8LlxUlUA4BDtBxMo35ithERuB831S3MqOTmk=; b=E28SvG5dm9izC+3mjpy3q8xFCHxoyu+qey1rLW7qQ0QxP93/QB6H4RCTfH6Qq90+Fc orupXRcR0c3gINBCpcAOPxJR7br/HOCpLjgZnpaJg0WHNcYmMLmxi/Z1L+tKanLn2KD/ ovnRH/9UehjTF2zWXtRxF22eU5Vncrq1418ZpW8MIeX7PAIMlcXLBHAZMMGRVUlY+MED vN0LHoR53v7gw96/OO7JXdVlVy2J0duEFGYNyFt+3+k0NQSXc/i795xNrUYCY1xogcu6 11b5Hoo1RME/5GD8UJu2JhSPQgRVBKE1OsXLA0Cz/pVkhpxJM80aiPOsjTvgQOulf00G v8Rg== X-Google-Smtp-Source: APXvYqwf7ZfG3H65SinFpQJ6JCmP2a3SknI4Skw41NmgVRrjGVTTmaDiRJSBca6KdRWZXn45jyVCd0IkeB1uda+7vj0= X-Received: by 2002:a17:902:586:: with SMTP id f6mr69482466plf.68.1554215839809; Tue, 02 Apr 2019 07:37:19 -0700 (PDT) MIME-Version: 1.0 References: <017804b2198a906463d634f84777b6087c9b4a40.1553093421.git.andreyknvl@google.com> <574648a3-3a05-bea7-3f4e-7d71adedf1dc@amd.com> In-Reply-To: <574648a3-3a05-bea7-3f4e-7d71adedf1dc@amd.com> From: Andrey Konovalov Date: Tue, 2 Apr 2019 16:37:08 +0200 Message-ID: Subject: Re: [PATCH v13 14/20] drm/amdgpu, arm64: untag user pointers in amdgpu_ttm_tt_get_user_pages To: "Kuehling, Felix" Cc: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Vincenzo Frascino , Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , "Deucher, Alexander" , "Koenig, Christian" , "Zhou, David(ChunMing)" , Yishai Hadas , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , "linux-arm-kernel@lists.infradead.org" , "linux-mm@kvack.org" , "linux-arch@vger.kernel.org" , "netdev@vger.kernel.org" , "bpf@vger.kernel.org" , "amd-gfx@lists.freedesktop.org" , "dri-devel@lists.freedesktop.org" , "linux-rdma@vger.kernel.org" , "linux-media@vger.kernel.org" , "kvm@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Kevin Brodsky , Chintan Pandya , Jacob Bramley , Ruben Ayrapetyan , Szabolcs Nagy , Lee Smith , Kostya Serebryany , Dmitry Vyukov , Ramana Radhakrishnan , Luc Van Oostenryck , Dave Martin , Evgeniy Stepanov Content-Type: text/plain; charset="UTF-8" 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: On Mon, Mar 25, 2019 at 11:21 PM Kuehling, Felix wrote: > > On 2019-03-20 10:51 a.m., Andrey Konovalov wrote: > > This patch is a part of a series that extends arm64 kernel ABI to allow to > > pass tagged user pointers (with the top byte set to something else other > > than 0x00) as syscall arguments. > > > > amdgpu_ttm_tt_get_user_pages() uses provided user pointers for vma > > lookups, which can only by done with untagged pointers. > > > > Untag user pointers in this function. > > > > Signed-off-by: Andrey Konovalov > > --- > > drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > > index 73e71e61dc99..891b027fa33b 100644 > > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c > > @@ -751,10 +751,11 @@ int amdgpu_ttm_tt_get_user_pages(struct ttm_tt *ttm, struct page **pages) > > * check that we only use anonymous memory to prevent problems > > * with writeback > > */ > > - unsigned long end = gtt->userptr + ttm->num_pages * PAGE_SIZE; > > + unsigned long userptr = untagged_addr(gtt->userptr); > > + unsigned long end = userptr + ttm->num_pages * PAGE_SIZE; > > struct vm_area_struct *vma; > > > > - vma = find_vma(mm, gtt->userptr); > > + vma = find_vma(mm, userptr); > > if (!vma || vma->vm_file || vma->vm_end < end) { > > up_read(&mm->mmap_sem); > > return -EPERM; > > We'll need to be careful that we don't break your change when the > following commit gets applied through drm-next for Linux 5.2: > > https://cgit.freedesktop.org/~agd5f/linux/commit/?h=drm-next-5.2-wip&id=915d3eecfa23693bac9e54cdacf84fb4efdcc5c4 > > Would it make sense to apply the untagging in amdgpu_ttm_tt_set_userptr > instead? That would avoid this conflict and I think it would clearly put > the untagging into the user mode code path where the tagged pointer > originates. > > In amdgpu_gem_userptr_ioctl and amdgpu_amdkfd_gpuvm.c (init_user_pages) > we also set up an MMU notifier with the (tagged) pointer from user mode. > That should probably also use the untagged address so that MMU notifiers > for the untagged address get correctly matched up with the right BO. I'd > move the untagging further up the call stack to cover that. For the GEM > case I think amdgpu_gem_userptr_ioctl would be the right place. For the > KFD case, I'd do this in amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu. Will do in v14, thanks a lot for looking at this! Is this applicable to the radeon driver (drivers/gpu/drm/radeon) as well? It seems to be using very similar structure. > > Regards, > Felix >