Re: [PATCH v8 4/4] iommu/vt-d: Fail probe on ATS configuration failure

[Jason Gunthorpe]

On Thu, Jun 04, 2026 at 06:21:16PM +0000, Pranjal Shrivastava wrote:
> Update the Intel VT-d driver to handle ATS configuration and enablement
> more strictly. Specifically, update the device probe to fail if
> pci_prepare_ats() returns an error. This ensures that any ATS-capable
> master reaching the attach phase is guaranteed to have a valid config.
> 
> Additionally, update iommu_enable_pci_ats() to WARN() if pci_enable_ats
> fails. Since earlier checks in the probe phase preclude config-related
> failures, any failure during hardware enablement is considered a kernel
> bug.
> 
> Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Signed-off-by: Pranjal Shrivastava <praan@xxxxxxxxxx>
> ---
>  drivers/iommu/intel/iommu.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>

Jason