From: Daniel Vetter <daniel.vetter@ffwll.ch> To: DRI Development <dri-devel@lists.freedesktop.org>, LKML <linux-kernel@vger.kernel.org> Cc: linux-samsung-soc@vger.kernel.org, "Jan Kara" <jack@suse.cz>, "Kees Cook" <keescook@chromium.org>, kvm@vger.kernel.org, "Jason Gunthorpe" <jgg@ziepe.ca>, "Daniel Vetter" <daniel.vetter@ffwll.ch>, linux-pci@vger.kernel.org, "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>, linux-mm@kvack.org, "Jérôme Glisse" <jglisse@redhat.com>, "John Hubbard" <jhubbard@nvidia.com>, "Bjorn Helgaas" <bhelgaas@google.com>, "Daniel Vetter" <daniel.vetter@intel.com>, "Dan Williams" <dan.j.williams@intel.com>, "Andrew Morton" <akpm@linux-foundation.org>, linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org Subject: [PATCH v6 15/17] PCI: Revoke mappings like devmem Date: Thu, 19 Nov 2020 15:41:44 +0100 Message-ID: <20201119144146.1045202-16-daniel.vetter@ffwll.ch> (raw) In-Reply-To: <20201119144146.1045202-1-daniel.vetter@ffwll.ch> Since 3234ac664a87 ("/dev/mem: Revoke mappings when a driver claims the region") /dev/kmem zaps ptes when the kernel requests exclusive acccess to an iomem region. And with CONFIG_IO_STRICT_DEVMEM, this is the default for all driver uses. Except there's two more ways to access PCI BARs: sysfs and proc mmap support. Let's plug that hole. For revoke_devmem() to work we need to link our vma into the same address_space, with consistent vma->vm_pgoff. ->pgoff is already adjusted, because that's how (io_)remap_pfn_range works, but for the mapping we need to adjust vma->vm_file->f_mapping. The cleanest way is to adjust this at at ->open time: - for sysfs this is easy, now that binary attributes support this. We just set bin_attr->mapping when mmap is supported - for procfs it's a bit more tricky, since procfs pci access has only one file per device, and access to a specific resources first needs to be set up with some ioctl calls. But mmap is only supported for the same resources as sysfs exposes with mmap support, and otherwise rejected, so we can set the mapping unconditionally at open time without harm. A special consideration is for arch_can_pci_mmap_io() - we need to make sure that the ->f_mapping doesn't alias between ioport and iomem space. There's only 2 ways in-tree to support mmap of ioports: generic pci mmap (ARCH_GENERIC_PCI_MMAP_RESOURCE), and sparc as the single architecture hand-rolling. Both approach support ioport mmap through a special pfn range and not through magic pte attributes. Aliasing is therefore not a problem. The only difference in access checks left is that sysfs PCI mmap does not check for CAP_RAWIO. I'm not really sure whether that should be added or not. Acked-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kees Cook <keescook@chromium.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: linux-pci@vger.kernel.org Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> -- v2: - Totally new approach: Adjust filp->f_mapping at open time. Note that this now works on all architectures, not just those support ARCH_GENERIC_PCI_MMAP_RESOURCE --- drivers/pci/pci-sysfs.c | 4 ++++ drivers/pci/proc.c | 1 + 2 files changed, 5 insertions(+) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index d15c881e2e7e..3f1c31bc0b7c 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -929,6 +929,7 @@ void pci_create_legacy_files(struct pci_bus *b) b->legacy_io->read = pci_read_legacy_io; b->legacy_io->write = pci_write_legacy_io; b->legacy_io->mmap = pci_mmap_legacy_io; + b->legacy_io->mapping = iomem_get_mapping(); pci_adjust_legacy_attr(b, pci_mmap_io); error = device_create_bin_file(&b->dev, b->legacy_io); if (error) @@ -941,6 +942,7 @@ void pci_create_legacy_files(struct pci_bus *b) b->legacy_mem->size = 1024*1024; b->legacy_mem->attr.mode = 0600; b->legacy_mem->mmap = pci_mmap_legacy_mem; + b->legacy_io->mapping = iomem_get_mapping(); pci_adjust_legacy_attr(b, pci_mmap_mem); error = device_create_bin_file(&b->dev, b->legacy_mem); if (error) @@ -1156,6 +1158,8 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) res_attr->mmap = pci_mmap_resource_uc; } } + if (res_attr->mmap) + res_attr->mapping = iomem_get_mapping(); res_attr->attr.name = res_attr_name; res_attr->attr.mode = 0600; res_attr->size = pci_resource_len(pdev, num); diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c index 3a2f90beb4cb..9bab07302bbf 100644 --- a/drivers/pci/proc.c +++ b/drivers/pci/proc.c @@ -298,6 +298,7 @@ static int proc_bus_pci_open(struct inode *inode, struct file *file) fpriv->write_combine = 0; file->private_data = fpriv; + file->f_mapping = iomem_get_mapping(); return 0; } -- 2.29.2 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply index Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-19 14:41 [PATCH v6 00/17] follow_pfn and other iomap races Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 01/17] drm/exynos: Stop using frame_vector helpers Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 02/17] drm/exynos: Use FOLL_LONGTERM for g2d cmdlists Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 03/17] misc/habana: Stop using frame_vector helpers Daniel Vetter 2020-11-21 12:47 ` Oded Gabbay 2020-11-19 14:41 ` [PATCH v6 04/17] misc/habana: Use FOLL_LONGTERM for userptr Daniel Vetter 2020-11-21 10:15 ` Oded Gabbay 2020-11-19 14:41 ` [PATCH v6 05/17] mm/frame-vector: Use FOLL_LONGTERM Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 06/17] media: videobuf2: Move frame_vector into media subsystem Daniel Vetter 2020-11-20 8:07 ` Hans Verkuil 2020-11-19 14:41 ` [PATCH v6 07/17] mm: Close race in generic_access_phys Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 08/17] mm: Add unsafe_follow_pfn Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 09/17] media/videbuf1|2: Mark follow_pfn usage as unsafe Daniel Vetter 2020-11-20 8:06 ` Hans Verkuil 2020-11-20 8:28 ` Hans Verkuil 2020-11-20 8:32 ` Tomasz Figa 2020-11-20 9:18 ` Daniel Vetter 2020-11-20 10:38 ` Hans Verkuil 2020-11-20 10:51 ` Daniel Vetter 2020-11-20 12:08 ` Hans Verkuil 2020-11-20 12:23 ` Tomasz Figa 2020-11-24 14:16 ` Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 10/17] vfio/type1: Mark follow_pfn " Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 11/17] PCI: Obey iomem restrictions for procfs mmap Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 12/17] /dev/mem: Only set filp->f_mapping Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 13/17] resource: Move devmem revoke code to resource framework Daniel Vetter 2020-11-19 14:41 ` [PATCH v6 14/17] sysfs: Support zapping of binary attr mmaps Daniel Vetter 2020-11-19 14:41 ` Daniel Vetter [this message] 2020-11-19 14:41 ` [PATCH v6 16/17] RFC: kvm: pass kvm argument to follow_pfn callsites Daniel Vetter 2020-11-20 15:33 ` Paolo Bonzini 2020-11-20 15:44 ` Daniel Vetter 2020-11-20 15:55 ` Paolo Bonzini 2020-11-19 14:41 ` [PATCH v6 17/17] RFC: mm: add mmu_notifier argument to follow_pfn Daniel Vetter 2020-11-20 18:30 ` Jason Gunthorpe 2020-11-24 14:28 ` Daniel Vetter 2020-11-24 15:55 ` Jason Gunthorpe 2020-11-25 9:00 ` Daniel Vetter 2020-11-27 13:12 ` [PATCH v6 00/17] follow_pfn and other iomap races Jason Gunthorpe 2020-11-27 15:36 ` Daniel Vetter
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