Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751858AbaJ0GlE (ORCPT ); Mon, 27 Oct 2014 02:41:04 -0400 Received: from ozlabs.org ([103.22.144.67]:45884 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751149AbaJ0GlC (ORCPT ); Mon, 27 Oct 2014 02:41:02 -0400 In-Reply-To: <1414383875-20835-1-git-send-email-imunsie@au.ibm.com> To: Ian Munsie , mpe From: Michael Ellerman Cc: cbe-oss-dev , mikey , arnd , "Aneesh Kumar K.V" , greg , linux-kernel , linuxppc-dev , anton , imunsie , jk Subject: Re: CXL: Fix PSL error due to duplicate segment table entries Message-Id: <20141027064100.D12B514007D@ozlabs.org> Date: Mon, 27 Oct 2014 17:41:00 +1100 (AEDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-27-10 at 04:24:35 UTC, Ian Munsie wrote: > From: Ian Munsie > > In certain circumstances the PSL can send an interrupt for a segment Define PSL before using it please. > miss that the kernel has already handled. This can happen if multiple > translations for the same segment are queued in the PSL before the > kernel has restarted the first translation. > > The CXL driver did not expect this situation and did not check if a does not and does not, you haven't patched it yet. > segment had already been handled. This could cause a duplicate segment > table entry which in turn caused a PSL error taking down the card. > > This patch fixes the issue by checking for existing entries in the > segment table that match the segment it is trying to insert to avoid > inserting duplicate entries. > > Some of the code has been refactored to simplify it - the segment table > hash has been moved from cxl_load_segment to find_free_sste where it is Any reason that's not a separate patch? > used and we have disabled the secondary hash in the segment table to > reduce the number of entries that need to be tested from 16 to 8. Due to > the large segment sizes we use it is extremely unlikely that the > secondary hash would ever have been used in practice, so this should not > have any negative impacts and may even improve performance. Any reason that's not a separate patch? > copro_calculate_slb will now mask the ESID by the correct mask for 1T vs Didn't, but will after this patch? > 256M segments. This has no effect by itself as the extra bits were > ignored, but it makes debugging the segment table entries easier and > means that we can directly compare the ESID values for duplicates > without needing to worry about masking in the comparison. Separate patch? cheers -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/