> -----Original Message-----
> From: linux-kernel-ow...@vger.kernel.org
> [mailto:linux-kernel-ow...@vger.kernel.org] On Behalf Of
> sathyanarayanan.kuppusw...@linux.intel.com
> Sent: Monday, May 6, 2019 12:20 PM
> To: bhelg...@google.com
> Cc: linux-...@vger.kernel.org; linux-kernel@vger.kernel.org;
> ashok....@intel.com;
> keith.bu...@intel.com; sathyanarayanan.kuppusw...@linux.intel.com
> Subject: [PATCH v2 3/5] PCI/ATS: Skip VF ATS initialization if PF does not
> implement it
>
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppusw...@linux.intel.com>
>
> If PF does not implement ATS and VF implements/uses it, it might lead to
> runtime issues. Also, as per spec r4.0, sec 9.3.7.8, PF should implement
> ATS if VF implements it. So add additional check to confirm given device
> aligns with the spec.
...
> + /*
> + * Per PCIe r4.0, sec 9.3.7.8, if VF implements Address Translation
> + * Services (ATS) Extended Capability then corresponding PF should
> + * also implement it.
> + */
...
In standardese, "should" means recommended, not required. The PCIe spec uses
"must" for this rule; the comments should match.
