Messages in this thread | | | From | "Elliott, Robert (Servers)" <> | Subject | RE: [PATCH v2 3/5] PCI/ATS: Skip VF ATS initialization if PF does not implement it | Date | Mon, 6 May 2019 22:35:38 +0000 |
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> -----Original Message----- > From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-owner@vger.kernel.org] On Behalf Of > sathyanarayanan.kuppuswamy@linux.intel.com > Sent: Monday, May 6, 2019 12:20 PM > To: bhelgaas@google.com > Cc: linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org; ashok.raj@intel.com; > keith.busch@intel.com; sathyanarayanan.kuppuswamy@linux.intel.com > Subject: [PATCH v2 3/5] PCI/ATS: Skip VF ATS initialization if PF does not implement it > > From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@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.
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