Re: [RFC PATCH 16/42] iommufd: Enable device feature IOPF during device attachment to KVM HWPT

Jason Gunthorpe
2023-12-04T18:36:09Z

On Sat, Dec 02, 2023 at 05:23:11PM +0800, Yan Zhao wrote:
> Enable device feature IOPF during device attachment to KVM HWPT and abort
> the attachment if feature enabling is failed.
>
> "pin" is not done by KVM HWPT. If VMM wants to create KVM HWPT, it must
> know that all devices attached to this HWPT support IOPF so that pin-all
> is skipped.
>
> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
> ---
> drivers/iommu/iommufd/device.c | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> index 83af6b7e2784b..4ea447e052ce1 100644
> --- a/drivers/iommu/iommufd/device.c
> +++ b/drivers/iommu/iommufd/device.c
> @@ -381,10 +381,26 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
> goto err_unresv;
> idev->igroup->hwpt = hwpt;
> }
> + if (hwpt_is_kvm(hwpt)) {
> + /*
> + * Feature IOPF requires ats is enabled which is true only
> + * after device is attached to iommu domain.
> + * So enable dev feature IOPF after iommu_attach_group().
> + * -EBUSY will be returned if feature IOPF is already on.
> + */
> + rc = iommu_dev_enable_feature(idev->dev, IOMMU_DEV_FEAT_IOPF);
> + if (rc && rc != -EBUSY)
> + goto err_detach;

I would like to remove IOMMU_DEV_FEAT_IOPF completely please

Jason