From: Lu Baolu <baolu.lu@linux.intel.com> To: Jason Gunthorpe <jgg@nvidia.com> Cc: baolu.lu@linux.intel.com, Christoph Hellwig <hch@infradead.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Joerg Roedel <joro@8bytes.org>, Alex Williamson <alex.williamson@redhat.com>, Bjorn Helgaas <bhelgaas@google.com>, Kevin Tian <kevin.tian@intel.com>, Ashok Raj <ashok.raj@intel.com>, Chaitanya Kulkarni <kch@nvidia.com>, kvm@vger.kernel.org, rafael@kernel.org, linux-pci@vger.kernel.org, Cornelia Huck <cohuck@redhat.com>, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Jacob jun Pan <jacob.jun.pan@intel.com>, Diana Craciun <diana.craciun@oss.nxp.com>, Will Deacon <will@kernel.org> Subject: Re: [PATCH 01/11] iommu: Add device dma ownership set/release interfaces Date: Thu, 18 Nov 2021 09:12:41 +0800 [thread overview] Message-ID: <5901c54b-a6eb-b060-aa52-15de7708d703@linux.intel.com> (raw) In-Reply-To: <20211117133517.GJ2105516@nvidia.com> On 11/17/21 9:35 PM, Jason Gunthorpe wrote: > On Wed, Nov 17, 2021 at 01:22:19PM +0800, Lu Baolu wrote: >> Hi Jason, >> >> On 11/16/21 9:46 PM, Jason Gunthorpe wrote: >>> On Tue, Nov 16, 2021 at 09:57:30AM +0800, Lu Baolu wrote: >>>> Hi Christoph, >>>> >>>> On 11/15/21 9:14 PM, Christoph Hellwig wrote: >>>>> On Mon, Nov 15, 2021 at 10:05:42AM +0800, Lu Baolu wrote: >>>>>> +enum iommu_dma_owner { >>>>>> + DMA_OWNER_NONE, >>>>>> + DMA_OWNER_KERNEL, >>>>>> + DMA_OWNER_USER, >>>>>> +}; >>>>>> + >>>>> >>>>>> + enum iommu_dma_owner dma_owner; >>>>>> + refcount_t owner_cnt; >>>>>> + struct file *owner_user_file; >>>>> >>>>> I'd just overload the ownership into owner_user_file, >>>>> >>>>> NULL -> no owner >>>>> (struct file *)1UL) -> kernel >>>>> real pointer -> user >>>>> >>>>> Which could simplify a lot of the code dealing with the owner. >>>>> >>>> >>>> Yeah! Sounds reasonable. I will make this in the next version. >>> >>> It would be good to figure out how to make iommu_attach_device() >>> enforce no other driver binding as a kernel user without a file *, as >>> Robin pointed to, before optimizing this. >>> >>> This fixes an existing bug where iommu_attach_device() only checks the >>> group size and is vunerable to a hot plug increasing the group size >>> after it returns. That check should be replaced by this series's logic >>> instead. >> >> As my my understanding, the essence of this problem is that only the >> user owner of the iommu_group could attach an UNMANAGED domain to it. >> If I understand it right, how about introducing a new interface to >> allocate a user managed domain and storing the user file pointer in it. > > For iommu_attach_device() the semantic is simple non-sharing, so there > is no need for the file * at all, it can just be NULL. The file * being NULL means the device is only owned by the kernel driver. Perhaps we can check this pointer in iommu_attach_device() to avoid using it for user domain attachment. > >> Does above help here? > > No, iommu_attach_device() is kernel only and should not interact with > userspace. The existing iommu_attach_device() allows only for singleton group. As we have added group ownership attribute, we can enforce this interface only for kernel domain usage. > > I'm also going to see if I can learn what Tegra is doing with > iommu_attach_group() Okay! Thank you! > > Jason > Best regards, baolu
WARNING: multiple messages have this Message-ID (diff)
From: Lu Baolu <baolu.lu@linux.intel.com> To: Jason Gunthorpe <jgg@nvidia.com> Cc: Kevin Tian <kevin.tian@intel.com>, Chaitanya Kulkarni <kch@nvidia.com>, Ashok Raj <ashok.raj@intel.com>, kvm@vger.kernel.org, rafael@kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Cornelia Huck <cohuck@redhat.com>, Will Deacon <will@kernel.org>, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Christoph Hellwig <hch@infradead.org>, Alex Williamson <alex.williamson@redhat.com>, Jacob jun Pan <jacob.jun.pan@intel.com>, linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>, Diana Craciun <diana.craciun@oss.nxp.com> Subject: Re: [PATCH 01/11] iommu: Add device dma ownership set/release interfaces Date: Thu, 18 Nov 2021 09:12:41 +0800 [thread overview] Message-ID: <5901c54b-a6eb-b060-aa52-15de7708d703@linux.intel.com> (raw) In-Reply-To: <20211117133517.GJ2105516@nvidia.com> On 11/17/21 9:35 PM, Jason Gunthorpe wrote: > On Wed, Nov 17, 2021 at 01:22:19PM +0800, Lu Baolu wrote: >> Hi Jason, >> >> On 11/16/21 9:46 PM, Jason Gunthorpe wrote: >>> On Tue, Nov 16, 2021 at 09:57:30AM +0800, Lu Baolu wrote: >>>> Hi Christoph, >>>> >>>> On 11/15/21 9:14 PM, Christoph Hellwig wrote: >>>>> On Mon, Nov 15, 2021 at 10:05:42AM +0800, Lu Baolu wrote: >>>>>> +enum iommu_dma_owner { >>>>>> + DMA_OWNER_NONE, >>>>>> + DMA_OWNER_KERNEL, >>>>>> + DMA_OWNER_USER, >>>>>> +}; >>>>>> + >>>>> >>>>>> + enum iommu_dma_owner dma_owner; >>>>>> + refcount_t owner_cnt; >>>>>> + struct file *owner_user_file; >>>>> >>>>> I'd just overload the ownership into owner_user_file, >>>>> >>>>> NULL -> no owner >>>>> (struct file *)1UL) -> kernel >>>>> real pointer -> user >>>>> >>>>> Which could simplify a lot of the code dealing with the owner. >>>>> >>>> >>>> Yeah! Sounds reasonable. I will make this in the next version. >>> >>> It would be good to figure out how to make iommu_attach_device() >>> enforce no other driver binding as a kernel user without a file *, as >>> Robin pointed to, before optimizing this. >>> >>> This fixes an existing bug where iommu_attach_device() only checks the >>> group size and is vunerable to a hot plug increasing the group size >>> after it returns. That check should be replaced by this series's logic >>> instead. >> >> As my my understanding, the essence of this problem is that only the >> user owner of the iommu_group could attach an UNMANAGED domain to it. >> If I understand it right, how about introducing a new interface to >> allocate a user managed domain and storing the user file pointer in it. > > For iommu_attach_device() the semantic is simple non-sharing, so there > is no need for the file * at all, it can just be NULL. The file * being NULL means the device is only owned by the kernel driver. Perhaps we can check this pointer in iommu_attach_device() to avoid using it for user domain attachment. > >> Does above help here? > > No, iommu_attach_device() is kernel only and should not interact with > userspace. The existing iommu_attach_device() allows only for singleton group. As we have added group ownership attribute, we can enforce this interface only for kernel domain usage. > > I'm also going to see if I can learn what Tegra is doing with > iommu_attach_group() Okay! Thank you! > > Jason > Best regards, baolu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2021-11-18 1:17 UTC|newest] Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-15 2:05 [PATCH 00/11] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 01/11] iommu: Add device dma ownership set/release interfaces Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 13:14 ` Christoph Hellwig 2021-11-15 13:14 ` Christoph Hellwig 2021-11-16 1:57 ` Lu Baolu 2021-11-16 1:57 ` Lu Baolu 2021-11-16 13:46 ` Jason Gunthorpe 2021-11-16 13:46 ` Jason Gunthorpe via iommu 2021-11-17 5:22 ` Lu Baolu 2021-11-17 5:22 ` Lu Baolu 2021-11-17 13:35 ` Jason Gunthorpe 2021-11-17 13:35 ` Jason Gunthorpe via iommu 2021-11-18 1:12 ` Lu Baolu [this message] 2021-11-18 1:12 ` Lu Baolu 2021-11-18 14:10 ` Jason Gunthorpe 2021-11-18 14:10 ` Jason Gunthorpe via iommu 2021-11-18 2:39 ` Tian, Kevin 2021-11-18 2:39 ` Tian, Kevin 2021-11-18 13:33 ` Jason Gunthorpe 2021-11-18 13:33 ` Jason Gunthorpe via iommu 2021-11-19 5:44 ` Tian, Kevin 2021-11-19 5:44 ` Tian, Kevin 2021-11-19 11:14 ` Lu Baolu 2021-11-19 11:14 ` Lu Baolu 2021-11-19 15:06 ` Jörg Rödel 2021-11-19 15:06 ` Jörg Rödel 2021-11-19 15:43 ` Jason Gunthorpe 2021-11-19 15:43 ` Jason Gunthorpe via iommu 2021-11-20 11:16 ` Lu Baolu 2021-11-20 11:16 ` Lu Baolu 2021-11-19 12:56 ` Jason Gunthorpe 2021-11-19 12:56 ` Jason Gunthorpe via iommu 2021-11-15 20:38 ` Bjorn Helgaas 2021-11-15 20:38 ` Bjorn Helgaas 2021-11-16 1:52 ` Lu Baolu 2021-11-16 1:52 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 02/11] driver core: Set DMA ownership during driver bind/unbind Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 6:59 ` Greg Kroah-Hartman 2021-11-15 6:59 ` Greg Kroah-Hartman 2021-11-15 13:20 ` Christoph Hellwig 2021-11-15 13:20 ` Christoph Hellwig 2021-11-15 13:38 ` Jason Gunthorpe via iommu 2021-11-15 13:38 ` Jason Gunthorpe 2021-11-15 13:19 ` Christoph Hellwig 2021-11-15 13:19 ` Christoph Hellwig 2021-11-15 13:24 ` Jason Gunthorpe 2021-11-15 13:24 ` Jason Gunthorpe via iommu 2021-11-15 15:37 ` Robin Murphy 2021-11-15 15:37 ` Robin Murphy 2021-11-15 15:56 ` Jason Gunthorpe 2021-11-15 15:56 ` Jason Gunthorpe via iommu 2021-11-15 18:15 ` Christoph Hellwig 2021-11-15 18:15 ` Christoph Hellwig 2021-11-15 18:35 ` Robin Murphy 2021-11-15 18:35 ` Robin Murphy 2021-11-15 19:39 ` Jason Gunthorpe via iommu 2021-11-15 19:39 ` Jason Gunthorpe 2021-11-15 2:05 ` [PATCH 03/11] PCI: pci_stub: Suppress kernel DMA ownership auto-claiming Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 13:21 ` Christoph Hellwig 2021-11-15 13:21 ` Christoph Hellwig 2021-11-15 13:31 ` Jason Gunthorpe via iommu 2021-11-15 13:31 ` Jason Gunthorpe 2021-11-15 15:14 ` Robin Murphy 2021-11-15 15:14 ` Robin Murphy 2021-11-15 16:17 ` Jason Gunthorpe 2021-11-15 16:17 ` Jason Gunthorpe via iommu 2021-11-15 17:54 ` Robin Murphy 2021-11-15 17:54 ` Robin Murphy 2021-11-15 18:19 ` Christoph Hellwig 2021-11-15 18:19 ` Christoph Hellwig 2021-11-15 18:44 ` Robin Murphy 2021-11-15 18:44 ` Robin Murphy 2021-11-15 19:22 ` Jason Gunthorpe via iommu 2021-11-15 19:22 ` Jason Gunthorpe 2021-11-15 20:58 ` Robin Murphy 2021-11-15 20:58 ` Robin Murphy 2021-11-15 21:19 ` Jason Gunthorpe via iommu 2021-11-15 21:19 ` Jason Gunthorpe 2021-11-15 20:48 ` Bjorn Helgaas 2021-11-15 20:48 ` Bjorn Helgaas 2021-11-15 22:17 ` Bjorn Helgaas 2021-11-15 22:17 ` Bjorn Helgaas 2021-11-16 6:05 ` Lu Baolu 2021-11-16 6:05 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 04/11] PCI: portdrv: " Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 20:44 ` Bjorn Helgaas 2021-11-15 20:44 ` Bjorn Helgaas 2021-11-16 7:24 ` Lu Baolu 2021-11-16 7:24 ` Lu Baolu 2021-11-16 20:22 ` Bjorn Helgaas 2021-11-16 20:22 ` Bjorn Helgaas 2021-11-16 20:48 ` Jason Gunthorpe 2021-11-16 20:48 ` Jason Gunthorpe via iommu 2021-11-15 2:05 ` [PATCH 05/11] iommu: Add security context management for assigned devices Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 13:22 ` Christoph Hellwig 2021-11-15 13:22 ` Christoph Hellwig 2021-11-16 7:25 ` Lu Baolu 2021-11-16 7:25 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 06/11] iommu: Expose group variants of dma ownership interfaces Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 13:27 ` Christoph Hellwig 2021-11-15 13:27 ` Christoph Hellwig 2021-11-16 9:42 ` Lu Baolu 2021-11-16 9:42 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 07/11] vfio: Use DMA_OWNER_USER to declaim passthrough devices Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 08/11] vfio: Remove use of vfio_group_viable() Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 09/11] vfio: Delete the unbound_list Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 10/11] vfio: Remove iommu group notifier Lu Baolu 2021-11-15 2:05 ` Lu Baolu 2021-11-15 2:05 ` [PATCH 11/11] iommu: Remove iommu group changes notifier Lu Baolu 2021-11-15 2:05 ` Lu Baolu
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=5901c54b-a6eb-b060-aa52-15de7708d703@linux.intel.com \ --to=baolu.lu@linux.intel.com \ --cc=alex.williamson@redhat.com \ --cc=ashok.raj@intel.com \ --cc=bhelgaas@google.com \ --cc=cohuck@redhat.com \ --cc=diana.craciun@oss.nxp.com \ --cc=gregkh@linuxfoundation.org \ --cc=hch@infradead.org \ --cc=iommu@lists.linux-foundation.org \ --cc=jacob.jun.pan@intel.com \ --cc=jgg@nvidia.com \ --cc=joro@8bytes.org \ --cc=kch@nvidia.com \ --cc=kevin.tian@intel.com \ --cc=kvm@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-pci@vger.kernel.org \ --cc=rafael@kernel.org \ --cc=will@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.