lkml.org 
[lkml]   [2022]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5 3/6] iommu: Add return value rules to attach_dev op and APIs
On Thu, Sep 22, 2022 at 01:54:08AM -0700, Nicolin Chen wrote:
> Cases like VFIO wish to attach a device to an existing domain that was
> not allocated specifically from the device. This raises a condition
> where the IOMMU driver can fail the domain attach because the domain and
> device are incompatible with each other.
>
> This is a soft failure that can be resolved by using a different domain.
>
> Provide a dedicated errno EINVAL from the IOMMU driver during attach that
> the reason why the attach failed is because of domain incompatibility.
>
> VFIO can use this to know that the attach is a soft failure and it should
> continue searching. Otherwise, the attach will be a hard failure and VFIO
> will return the code to userspace.
>
> Update kdocs to add rules of return value to the attach_dev op and APIs.
>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
> drivers/iommu/iommu.c | 24 ++++++++++++++++++++++++
> include/linux/iommu.h | 12 ++++++++++++
> 2 files changed, 36 insertions(+)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

\
 
 \ /
  Last update: 2022-09-22 19:27    [W:0.125 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site