Re: [PATCH 4.5 026/238] PCI: Disable IO/MEM decoding for devices with non-compliant BARs

From: Ben Hutchings
Date: Mon Apr 11 2016 - 19:45:30 EST


On Sun, 2016-04-10 at 11:33 -0700, Greg Kroah-Hartman wrote:
> 4.5-stable review patch.ÂÂIf anyone has any objections, please let me know.
>
> ------------------
>
> From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
> commit b84106b4e2290c081cdab521fa832596cdfea246 upstream.
>
> The PCI config header (first 64 bytes of each device's config space) is
> defined by the PCI spec so generic software can identify the device and
> manage its usage of I/O, memory, and IRQ resources.
>
> Some non-spec-compliant devices put registers other than BARs where the
> BARs should be.ÂÂWhen the PCI core sizes these "BARs", the reads and writes
> it does may have unwanted side effects, and the "BAR" may appear to
> describe non-sensical address space.
>
> Add a flag bit to mark non-compliant devices so we don't touch their BARs.
> Turn off IO/MEM decoding to prevent the devices from consuming address
> space, since we can't read the BARs to find out what that address space
> would be.
[...]

No objection, but patch 005/238 seems to depend on this so please
reorder them so bisection will work.

Ben.

--
Ben Hutchings
This sentence contradicts itself - no actually it doesn't.

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