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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jason Gunthorpe <jgg@nvidia.com>, Bjorn Helgaas <helgaas@kernel.org>
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>, Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Dan Williams <dan.j.williams@intel.com>,
	rafael@kernel.org, Diana Craciun <diana.craciun@oss.nxp.com>,
	Cornelia Huck <cohuck@redhat.com>,
	Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Stuart Yoder <stuyoder@gmail.com>,
	Laurentiu Tudor <laurentiu.tudor@nxp.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Li Yang <leoyang.li@nxp.com>, Dmitry Osipenko <digetx@gmail.com>,
	iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 01/14] iommu: Add dma ownership management interfaces
Date: Thu, 6 Jan 2022 11:54:06 +0800	[thread overview]
Message-ID: <9486face-0778-b8d0-6989-94c2e876446b@linux.intel.com> (raw)
In-Reply-To: <20220104192348.GK2328285@nvidia.com>

On 1/5/22 3:23 AM, Jason Gunthorpe wrote:
>>>> The device driver oriented interfaces are,
>>>>
>>>> 	int iommu_device_use_dma_api(struct device *dev);
>>>> 	void iommu_device_unuse_dma_api(struct device *dev);
>> Nit, do we care whether it uses the actual DMA API?  Or is it just
>> that iommu_device_use_dma_api() tells us the driver may program the
>> device to do DMA?
> As the main purpose, yes this is all about the DMA API because it
> asserts the group domain is the DMA API's domain.
> 
> There is a secondary purpose that has to do with the user/kernel
> attack you mentioned above. Maintaining the DMA API domain also
> prevents VFIO from allowing userspace to operate any device in the
> group which blocks P2P attacks to MMIO of other devices.
> 
> This is why, even if the driver doesn't use DMA, it should still do a
> iommu_device_use_dma_api(), except in the special cases where we don't
> care about P2P attacks (eg pci-stub, bridges, etc).
> 

By the way, use_dma_api seems hard to read. How about

	iommu_device_use_default_dma()?

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>, Bjorn Helgaas <helgaas@kernel.org>
Cc: Stuart Yoder <stuyoder@gmail.com>,
	rafael@kernel.org, David Airlie <airlied@linux.ie>,
	linux-pci@vger.kernel.org,
	Thierry Reding <thierry.reding@gmail.com>,
	Diana Craciun <diana.craciun@oss.nxp.com>,
	Dmitry Osipenko <digetx@gmail.com>, Will Deacon <will@kernel.org>,
	Ashok Raj <ashok.raj@intel.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Christoph Hellwig <hch@infradead.org>,
	Kevin Tian <kevin.tian@intel.com>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Alex Williamson <alex.williamson@redhat.com>,
	kvm@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Cornelia Huck <cohuck@redhat.com>,
	linux-kernel@vger.kernel.org, Li Yang <leoyang.li@nxp.com>,
	iommu@lists.linux-foundation.org,
	Jacob jun Pan <jacob.jun.pan@intel.com>,
	Daniel Vetter <daniel@ffwll.ch>,
	Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v5 01/14] iommu: Add dma ownership management interfaces
Date: Thu, 6 Jan 2022 11:54:06 +0800	[thread overview]
Message-ID: <9486face-0778-b8d0-6989-94c2e876446b@linux.intel.com> (raw)
In-Reply-To: <20220104192348.GK2328285@nvidia.com>

On 1/5/22 3:23 AM, Jason Gunthorpe wrote:
>>>> The device driver oriented interfaces are,
>>>>
>>>> 	int iommu_device_use_dma_api(struct device *dev);
>>>> 	void iommu_device_unuse_dma_api(struct device *dev);
>> Nit, do we care whether it uses the actual DMA API?  Or is it just
>> that iommu_device_use_dma_api() tells us the driver may program the
>> device to do DMA?
> As the main purpose, yes this is all about the DMA API because it
> asserts the group domain is the DMA API's domain.
> 
> There is a secondary purpose that has to do with the user/kernel
> attack you mentioned above. Maintaining the DMA API domain also
> prevents VFIO from allowing userspace to operate any device in the
> group which blocks P2P attacks to MMIO of other devices.
> 
> This is why, even if the driver doesn't use DMA, it should still do a
> iommu_device_use_dma_api(), except in the special cases where we don't
> care about P2P attacks (eg pci-stub, bridges, etc).
> 

By the way, use_dma_api seems hard to read. How about

	iommu_device_use_default_dma()?

Best regards,
baolu
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  parent reply	other threads:[~2022-01-06  3:54 UTC|newest]

Thread overview: 112+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-04  1:56 [PATCH v5 00/14] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu
2022-01-04  1:56 ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 01/14] iommu: Add dma ownership management interfaces Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04 10:08   ` Christoph Hellwig
2022-01-04 10:08     ` Christoph Hellwig
2022-01-04 16:41     ` Bjorn Helgaas
2022-01-04 16:41       ` Bjorn Helgaas
2022-01-04 19:23       ` Jason Gunthorpe
2022-01-04 19:23         ` Jason Gunthorpe via iommu
2022-01-06  3:18         ` Lu Baolu
2022-01-06  3:18           ` Lu Baolu
2022-01-06  3:54         ` Lu Baolu [this message]
2022-01-06  3:54           ` Lu Baolu
2022-01-06 15:46           ` Jason Gunthorpe
2022-01-06 15:46             ` Jason Gunthorpe via iommu
2022-01-07  1:50             ` Lu Baolu
2022-01-07  1:50               ` Lu Baolu
2022-01-06  3:43       ` Lu Baolu
2022-01-06  3:43         ` Lu Baolu
2022-01-06  3:47       ` Lu Baolu
2022-01-06  3:47         ` Lu Baolu
2022-01-06  3:51       ` Lu Baolu
2022-01-06  3:51         ` Lu Baolu
2022-01-05  6:57     ` Lu Baolu
2022-01-05  6:57       ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 02/14] driver core: Add dma_cleanup callback in bus_type Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04 10:08   ` Christoph Hellwig
2022-01-04 10:08     ` Christoph Hellwig
2022-01-04 12:39     ` Jason Gunthorpe
2022-01-04 12:39       ` Jason Gunthorpe via iommu
2022-01-04 13:04       ` Greg Kroah-Hartman
2022-01-04 13:04         ` Greg Kroah-Hartman
2022-02-08  5:55         ` Lu Baolu
2022-02-08  5:55           ` Lu Baolu
2022-02-08 11:35           ` Greg Kroah-Hartman
2022-02-08 11:35             ` Greg Kroah-Hartman
2022-02-14 10:01     ` Greg Kroah-Hartman
2022-02-14 10:01       ` Greg Kroah-Hartman
2022-02-14 10:02   ` Greg Kroah-Hartman
2022-02-14 10:02     ` Greg Kroah-Hartman
2022-01-04  1:56 ` [PATCH v5 03/14] amba: Stop sharing platform_dma_configure() Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 04/14] driver core: platform: Add driver dma ownership management Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-02-14  9:59   ` Greg Kroah-Hartman
2022-02-14  9:59     ` Greg Kroah-Hartman
2022-02-14 13:18     ` Jason Gunthorpe
2022-02-14 13:18       ` Jason Gunthorpe via iommu
2022-02-14 13:37       ` Greg Kroah-Hartman
2022-02-14 13:37         ` Greg Kroah-Hartman
2022-02-14 13:43         ` Jason Gunthorpe
2022-02-14 13:43           ` Jason Gunthorpe via iommu
2022-01-04  1:56 ` [PATCH v5 05/14] amba: " Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 06/14] bus: fsl-mc: " Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 07/14] PCI: " Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-02-14 10:03   ` Greg Kroah-Hartman
2022-02-14 10:03     ` Greg Kroah-Hartman
2022-02-14 12:38     ` Jason Gunthorpe
2022-02-14 12:38       ` Jason Gunthorpe via iommu
2022-02-14 12:51       ` Greg Kroah-Hartman
2022-02-14 12:51         ` Greg Kroah-Hartman
2022-02-14 13:11         ` Jason Gunthorpe
2022-02-14 13:11           ` Jason Gunthorpe via iommu
2022-02-14 13:39           ` Greg Kroah-Hartman
2022-02-14 13:39             ` Greg Kroah-Hartman
2022-02-14 13:43             ` Jason Gunthorpe
2022-02-14 13:43               ` Jason Gunthorpe via iommu
2022-02-15  3:06               ` Lu Baolu
2022-02-15  3:06                 ` Lu Baolu
2022-02-23 18:00   ` Bjorn Helgaas
2022-02-23 18:00     ` Bjorn Helgaas
2022-02-23 18:07     ` Jason Gunthorpe
2022-02-23 18:07       ` Jason Gunthorpe via iommu
2022-01-04  1:56 ` [PATCH v5 08/14] PCI: pci_stub: Suppress kernel DMA ownership auto-claiming Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 09/14] PCI: portdrv: " Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04 17:06   ` Bjorn Helgaas
2022-01-04 17:06     ` Bjorn Helgaas
2022-01-04 19:26     ` Jason Gunthorpe
2022-01-04 19:26       ` Jason Gunthorpe via iommu
2022-01-04 19:51       ` Bjorn Helgaas
2022-01-04 19:51         ` Bjorn Helgaas
2022-01-05  0:35         ` Jason Gunthorpe
2022-01-05  0:35           ` Jason Gunthorpe via iommu
2022-01-06  4:12     ` Lu Baolu
2022-01-06  4:12       ` Lu Baolu
2022-01-06 18:32       ` Bjorn Helgaas
2022-01-06 18:32         ` Bjorn Helgaas
2022-01-07  1:53         ` Lu Baolu
2022-01-07  1:53           ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 10/14] vfio: Set DMA ownership for VFIO devices Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 11/14] vfio: Remove use of vfio_group_viable() Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 12/14] vfio: Delete the unbound_list Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 13/14] vfio: Remove iommu group notifier Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04  1:56 ` [PATCH v5 14/14] iommu: Remove iommu group changes notifier Lu Baolu
2022-01-04  1:56   ` Lu Baolu
2022-01-04 12:48 ` [PATCH v5 00/14] Fix BUG_ON in vfio_iommu_group_notifier() Jason Gunthorpe
2022-01-04 12:48   ` Jason Gunthorpe via iommu
2022-01-05  6:52   ` Lu Baolu
2022-01-05  6:52     ` Lu Baolu
2022-02-18  1:07 ` Lu Baolu
2022-02-18  1:07   ` Lu Baolu

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