Messages in this thread | | | Subject | Re: [PATCH v6 5/5] vfio/type1: Use mdev bus iommu_ops for IOMMU callbacks | From | Lu Baolu <> | Date | Tue, 3 Nov 2020 13:22:05 +0800 |
| |
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/
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
| |