Messages in this thread | | | Date | Sun, 30 May 2010 16:13:59 +0300 | From | Avi Kivity <> | Subject | Re: [PATCH] VFIO driver: Non-privileged user level PCI drivers |
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On 05/30/2010 04:03 PM, Michael S. Tsirkin wrote: > > >>>>> IMO this was because this driver does two things: programming iommu and >>>>> handling interrupts. uio does interrupt handling. >>>>> We could have moved iommu / DMA programming to >>>>> a separate driver, and have uio work with it. >>>>> This would solve limitation of the current driver >>>>> that is needs an iommu domain per device. >>>>> >>>>> >>>>> >>>> How do we enforce security then? We need to ensure that unprivileged >>>> users can only use the device with an iommu. >>>> >>>> >>> Force assigning to iommu before we allow any other operation? >>> >>> >> That means the driver must be aware of the iommu. >> > The userspace driver? Yes. And It is a good thing to be explicit > there anyway, since this lets userspace map a non-contigious > virtual address list into a contiguous bus address range. >
No, the kernel driver. It cannot allow userspace to enable bus mastering unless it knows the iommu is enabled for the device and remaps dma to user pages.
-- error compiling committee.c: too many arguments to function
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