On Fri, Dec 18, 2015 at 5:57 AM, Hannes Reinecke <hare@xxxxxxx> wrote: > 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? If you take a look at the F0 functions what they do is bypass the VPD of the functions other than function 0. As such setting the size to 0 should really have no effect since the VPD of the function isn't actually read if the F0 flag is set. - Alex -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
