Messages in this thread | | | Date | Fri, 29 Oct 2021 09:44:52 -0300 | From | Jason Gunthorpe <> | Subject | Re: [RFC 20/20] Doc: Add documentation for /dev/iommu |
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On Fri, Oct 29, 2021 at 11:15:31AM +1100, David Gibson wrote:
> > +Device must be bound to an iommufd before the attach operation can > > +be conducted. The binding operation builds the connection between > > +the devicefd (opened via device-passthrough framework) and IOMMUFD. > > +IOMMU-protected security context is esbliashed when the binding > > +operation is completed. > > This can't be quite right. You can't establish a safe security > context until all devices in the groun are bound, but you can only > bind them one at a time.
When any device is bound the entire group is implicitly adopted to this iommufd and the whole group enters a safe-for-userspace state.
It is symmetrical with the kernel side which is also device focused, when any struct device is bound to a kernel driver the entire group is implicitly adopted to kernel mode.
Lu should send a patch series soon that harmonize how this works, it is a very nice cleanup.
Jason
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