On 2022/5/12 下午7:59, Jason Gunthorpe wrote:
On Thu, May 12, 2022 at 07:57:26PM +0800, zhangfei.gao@xxxxxxxxxxx wrote:
On 2022/5/12 下午7:32, Jason Gunthorpe via iommu wrote:
On Thu, May 12, 2022 at 03:07:09PM +0800, Zhangfei Gao wrote:
I can't help feeling a little wary about removing this until IOMMUFD
can actually offer a functional replacement - is it in the way of
anything upcoming?
From an upstream perspective if someone has a patched kernel to
complete the feature, then they can patch this part in as well, we
should not carry dead code like this in the kernel and in the uapi.
It is not directly in the way, but this needs to get done at some
point, I'd rather just get it out of the way.
We are using this interface for nested mode.
How are you using it? It doesn't do anything. Do you have out of tree
patches as well?
Yes, there are some patches out of tree, since they are pending for almost
one year.
By the way, I am trying to test nesting mode based on iommufd, still
requires iommu_enable_nesting,
which is removed in this patch as well.
This is temporary.
So can we wait for alternative patch then remove them?
Do you see a problem with patching this along with all the other
patches you need?
Not yet.
Currently I am using two workarounds, but it can simply work.
1. Hard code to to enable nesting mode, both in kernel and qemu.
Will consider then.
2. Adding VFIOIOASHwpt *hwpt in VFIOIOMMUFDContainer.
And save hwpt when vfio_device_attach_container.
While currently VFIOIOMMUFDContainer has hwpt_list now.
Have asked Yi in another mail.
Thanks
