• David Woodhouse's avatar
    iommu/vt-d: Fix ATSR handling for Root-Complex integrated endpoints · d14053b3
    David Woodhouse authored
    The VT-d specification says that "Software must enable ATS on endpoint
    devices behind a Root Port only if the Root Port is reported as
    supporting ATS transactions."
    
    We walk up the tree to find a Root Port, but for integrated devices we
    don't find one — we get to the host bridge. In that case we *should*
    allow ATS. Currently we don't, which means that we are incorrectly
    failing to use ATS for the integrated graphics. Fix that.
    
    We should never break out of this loop "naturally" with bus==NULL,
    since we'll always find bridge==NULL in that case (and now return 1).
    
    So remove the check for (!bridge) after the loop, since it can never
    happen. If it did, it would be worthy of a BUG_ON(!bridge). But since
    it'll oops anyway in that case, that'll do just as well.
    
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
    d14053b3
intel-iommu.c 124 KB