linux-kernel - Re: [PATCH] pci: fix bridge 64bit flag setting

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Date:	Tue, 01 Dec 2009 11:15:32 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Bjorn Helgaas <bjorn.helgaas@...com>
CC:	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Alex Williamson <alex.williamson@...com>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	Grant Grundler <grundler@...isc-linux.org>,
	Ivan Kokshaysky <ink@...assic.park.msu.ru>,
	Alex Chiang <achiang@...com>
Subject: Re: [PATCH] pci: fix bridge 64bit flag setting

Yinghai Lu wrote:
> Bjorn Helgaas wrote:
>> On Tuesday 01 December 2009 12:03:57 am Yinghai Lu wrote:
>>> Alex found one system that one pci bridge pref mmio 64 is not set correctly.
>>> aka, the upper32 base/limit is not cleaned.
>>> he found that bridge is supporting 64 bit pref mmio, but device under that
>>> does not support that. so that IORESOURCE_MEM_64 get cleared in pbus_size_mem()
>> I think it's wrong that pbus_size_mem() fiddles with IORESOURCE_MEM_64
>> in bus resources based on where BARs of devices on that bus live.  That
>> feels fragile.
> 
> yes. need more clean up.

other than we should store PCI_PREF_RANGE_TYPE_64, and use it in pci_setup_bridge

others should be ok.


for pcie hot plug, the bridge IORESOURCE_MEM_64 could be set, and MMIO > 4g, and later when plug one device doesn't
support 64bit mmio pref, and 

pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
                resource_size_t size, resource_size_t align,
                resource_size_t min, unsigned int type_mask,
                void (*alignf)(void *, struct resource *, resource_size_t,
                                resource_size_t),
                void *alignf_data)
{       
        int i, ret = -ENOMEM;        
        resource_size_t max = -1;    

        type_mask |= IORESOURCE_IO | IORESOURCE_MEM;
                
        /* don't allocate too high if the pref mem doesn't support 64bit*/
        if (!(res->flags & IORESOURCE_MEM_64))
                max = PCIBIOS_MAX_MEM_32;

will make sure that allocation will fail.

so it will get range freom mmio non pref range. or fail there again.

then we will release the bridge pref mmio...

YH
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