Messages in this thread | | | Subject | Re: [PATCH v6 5/5] vfio/type1: Use mdev bus iommu_ops for IOMMU callbacks | From | Lu Baolu <> | Date | Thu, 12 Nov 2020 10:31:55 +0800 |
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Hi Alex,
On 11/3/20 1:22 PM, Lu Baolu wrote: > Hi Alex, > > On 10/31/20 5:06 AM, Alex Williamson wrote: >> On Fri, 30 Oct 2020 06:16:28 +0000 >> "Tian, Kevin" <kevin.tian@intel.com> wrote: >> >>>> From: Lu Baolu <baolu.lu@linux.intel.com> >>>> Sent: Friday, October 30, 2020 12:58 PM >>>> >>>> With the IOMMU driver registering iommu_ops for the mdev_bus, the >>>> IOMMU >>>> operations on an mdev could be done in the same way as any normal >>>> device >>>> (for example, PCI/PCIe). There's no need to distinguish an mdev from >>>> others for iommu operations. Remove the unnecessary code. >>> >>> This is really a nice cleanup as the output of this change! :) >> >> It's easy to remove a bunch of code when the result is breaking >> everyone else. Please share with me how SR-IOV backed mdevs continue >> to work on AMD platforms, or how they might work on ARM platforms, when >> siov_iommu_ops (VT-d only) becomes the one and only provider of >> iommu_ops on the mdev bus. Hard NAK on this series. Thanks, > > I focused too much on a feature and forgot about university. I should > apologize for this. Sorry about it! > > Back to the original intention of this series. The aux domain was > allocated in vfio/mdev, but it's also needed by the vDCM component of a > device driver for mediated callbacks. Currently vfio/mdev or iommu core > has no support for this. > > We had a proposal when we first did aux-domain support. But was not > discussed since there was no consumer at that time. > > https://lore.kernel.org/linux-iommu/20181105073408.21815-7-baolu.lu@linux.intel.com/
Exposing iommu_domain outside of the vfio/iommu abstract seems not a secure idea. I have posted a new proposal. Can you please help to review?
https://lore.kernel.org/linux-iommu/20201112022407.2063896-1-baolu.lu@linux.intel.com/
Best regards. baolu
> > > Does it look good to you? I can send patches of such solution for > discussion if you think it's a right way. > > Extending the iommu core for subdevice passthrough support sounds an > interesting topic, but it will take much time before we reach a > consensus. It sounds a good topic for the next year's LPC/MC :-). > > Best regards, > baolu
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