linux-kernel - RE: [PATCH 1/2] x86: Set up resources correctly on Hyper-V Generation 2

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Message-ID: <DM2PR21MB0089C6E00631E41BE4221612CB160@DM2PR21MB0089.namprd21.prod.outlook.com>
Date:   Fri, 19 Aug 2016 16:46:36 +0000
From:   Matthew Wilcox <mawilcox@...rosoft.com>
To:     Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Matthew Wilcox <mawilcox@...uxonhyperv.com>
CC:     "x86@...nel.org" <x86@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-nvdimm@...1.01.org" <linux-nvdimm@...1.01.org>
Subject: RE: [PATCH 1/2] x86: Set up resources correctly on Hyper-V Generation
 2

I don't think we need to gate this based on the platform.  If you look at the differences between what is done:

 - The printk is no longer called.  That's fine; we already did the printk modified in patch 2/2.  The user is aware there machine doesn't have PCI :-)

 - We set the cacheline size.  That's copying a value from the cpuinfo to a global __read_mostly variable and emitting a printk.  No big deal.

 - In pcibios_resource_survey, we iterate over three empty lists, call e820_reserve_resources_late() (which is what we want!) and call ioapic_insert_resources() (which I rather think we want too)

In short, not calling these functions is a bug.  We just haven't noticed before now because PCI is so omnipresent.

-----Original Message-----
From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@...cle.com] 
Sent: Friday, August 19, 2016 12:07 PM
To: Matthew Wilcox <mawilcox@...uxonhyperv.com>
Cc: x86@...nel.org; linux-kernel@...r.kernel.org; linux-nvdimm@...1.01.org; Matthew Wilcox <mawilcox@...rosoft.com>
Subject: Re: [PATCH 1/2] x86: Set up resources correctly on Hyper-V Generation 2

On Thu, Aug 18, 2016 at 12:12:54PM -0700, Matthew Wilcox wrote:
> @@ -516,11 +516,6 @@ void __init pcibios_set_cache_line_size(void)
>  
>  int __init pcibios_init(void)
>  {
> -	if (!raw_pci_ops && !raw_pci_ext_ops) {
> -		printk(KERN_WARNING "PCI: System does not support PCI\n");
> -		return 0;
> -	}

So shouldn't this be gated on whether the platform is HyperV?

> -
>  	pcibios_set_cache_line_size();
>  	pcibios_resource_survey();
>  
> --
> 2.8.1
> 
> _______________________________________________
> Linux-nvdimm mailing list
> Linux-nvdimm@...ts.01.org
> https://lists.01.org/mailman/listinfo/linux-nvdimm

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