Re: [Xen-devel] [PATCH v3 1/2] xen-pciback: return proper values during BAR sizing
From: David Vrabel
Date: Fri Jun 24 2016 - 10:08:31 EST
On 24/06/16 10:13, Jan Beulich wrote:
> Reads following writes with all address bits set to 1 should return all
> changeable address bits as one, not the BAR size (nor, as was the case
> for the upper half of 64-bit BARs, the high half of the region's end
> address). Presumably this didn't cause any problems so far because
> consumers use the value to calculate the size (usually via val & -val),
> and do nothing else with it.
>
> But also consider the exception here: Unimplemented BARs should always
> return all zeroes.
>
> And finally, the check for whether to return the sizing address on read
> for the ROM BAR should ignore all non-address bits, not just the ROM
> Enable one.
Applied to for-linus-4.7b, thanks.
David