Re: [Xen-devel] How to register a 64 bit BAR

["Zytaruk, Kelly" <Kelly.Zytaruk@xxxxxxx>]

Thanks Anthony, you have saved me hours of searching through the source code.

I am working with Xen 4.2 qemu-traditional.  I checked the source code for 
upstream xen (qemu-xen-dir) and I didn't even find any support for the 
pci_register_io_region() function.  Apparently BAR remapping callbacks aren't 
supported in this version.  This is most unfortunate :-(

Thanks for the help,
Kelly

> -----Original Message-----
> From: Anthony PERARD [mailto:anthony.perard@xxxxxxxxxx]
> Sent: Wednesday, September 24, 2014 5:53 AM
> To: Zytaruk, Kelly
> Cc: xen-devel@xxxxxxxxxxxxx
> Subject: Re: [Xen-devel] How to register a 64 bit BAR
> 
> On Tue, Sep 23, 2014 at 08:33:08PM +0000, Zytaruk, Kelly wrote:
> > I have used pci_register_io_region() to register 32 bit BARs but how do I
> register a 64 bit BAR?
> >
> > Let's say my region uses BAR 2 and BAR 3 for a 64 bit address.  Do I
> > register them separately as in
> >
> > pci_register_io_region (dev, 2, region_size, PCI_ADDRESS_SPACE_MEM,
> > &my_func); pci_register_io_region (dev, 3, region_size, ???,
> > &my_func);
> 
> No, that would register two different BARs.
> 
> > What would I specify as a region type for BAR 3?
> 
> Nothing, since you don't want two different BARs.
> 
> > Or is QEMU smart enough for me to register just BAR 2 and it will know
> somehow that it is a 64 bit BAR?
> 
> Nop.
> 
> > I also want to call cpu_register_physical_memory() from within the callback
> but the callback only takes a uint32_t as a physical address.
> > I am having difficulty finding an example that uses a 64 bit BAR address.
> 
> Look for where PCI_ADDRESS_SPACE_MEM is define, and you will find how to
> register a 64bit BAR.
> Unless your are speaking about qemu-traditional and I'm not sure that is
> possible.
> 
> After looking in the source code of qemu-traditional, it does not appear to
> support 64bit BAR. Only QEMU upstream handle them (also called qemu-xen).
> 
> --
> Anthony PERARD

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