> -----Original Message----- > From: Bjorn Helgaas [mailto:helg...@kernel.org] > Sent: Tuesday, February 16, 2016 8:46 AM > To: Jake Oshins <ja...@microsoft.com> > Cc: bhelg...@google.com; linux-...@vger.kernel.org; > gre...@linuxfoundation.org; KY Srinivasan <k...@microsoft.com>; linux- > ker...@vger.kernel.org; de...@linuxdriverproject.org; o...@aepfle.de; > a...@canonical.com; vkuzn...@redhat.com; t...@linutronix.de; Haiyang > Zhang <haiya...@microsoft.com>; marc.zyng...@arm.com; Hadden > Hoppert <hadd...@microsoft.com> > Subject: Re: [PATCH RESEND v2 3/3] PCI: hv: New paravirtual PCI front-end > for Hyper-V VMs > > Hi Jake, > > Looks good to me overall; I marked a few nits below. > > The only real question I have is about domain number allocation. See > the note below. > [snip] > > + > > + /* > > + * The PCI bus "domain" is what is called "segment" in > > + * ACPI and other specs. Pull it from the instance ID, > > + * to get something unique. Bytes 8 and 9 are what is used > > + * in Windows guests, so do the same thing for consistency. > > + */ > > + > > + hbus->sysdata.domain = hdev->dev_instance.b[9] | > > + hdev->dev_instance.b[8] << 8; > > How do we know this is unique? We don't have any idea what the > platform will put in _SEG, so I think there's a potential conflict > here. The Intel VMD driver (arch/x86/pci/vmd.c) has a similar > problem, and it looks for unused domain numbers starting at 0x10000 > (see vmd_find_free_domain()). >
Bjorn, thank you for your very thorough reviews. I deeply appreciate it. I checked the Hyper-V code and it currently does guarantee that these values are unique. When I resend the series, I'll add a comment to that effect. I'll also add a comment to Hyper-V that says that it has to stay that way. I'll resend shortly. Thanks again, Jake _______________________________________________ devel mailing list de...@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
