Re: [PATCH 2/2] pci: Update VPD size with correct length

[Hannes Reinecke]

On 12/18/2015 02:49 PM, Alexander Duyck wrote:
> On Fri, Dec 18, 2015 at 12:35 AM, Hannes Reinecke <hare@xxxxxxx> wrote:
> > PCI-2.2 VPD entries have a maximum size of 32k, but might actually
> > be smaller than that. To figure out the actual size one has to read
> > the VPD area until the 'end marker' is reached.
> > Trying to read VPD data beyond that marker results in 'interesting'
> > effects, from simple read errors to crashing the card. And to make
> > matters worse not every PCI card implements this properly, leaving
> > us with no 'end' marker or even completely invalid data.
> > This path modifies the size of the VPD attribute to the available
> > size, or set it to '0' if no valid data could be read.
>
> This isn't what I had in mind.  There is no need to add an f0 version
> of the size function.  The size for all functions other than function
> 0 when the F0 flag is set is 0.  We aren't going to be reading their
> VPD, we only read the VPD region of function 0.
Ah. (I'm a bit confused about the proposed action for VPD other than 
function 0).
So the idea here is to _disallow_ access to VPDs from functions 
other than '0' unless these functions have different PCI IDs?

Cheers,

Hannes
--
Dr. Hannes Reinecke		               zSeries & Storage
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