svn commit: r289834 - head/sys/x86/x86

[Oliver Pinter]

On Mon, Nov 2, 2015 at 2:44 PM, Oliver Pinter
<oliver.pinter at hardenedbsd.org> wrote:
> On 11/2/15, Roger Pau Monné <royger at freebsd.org> wrote:
>> El 29/10/15 a les 22.48, Oliver Pinter ha escrit:
>>> Yes, at next week I have time for the test.  Please ping me again at
>>> Monday.
>>
>> Ping :).
>
> Pong. :) I now stared a new build with the patch, so I will report
> back 1-2 hours from now.

It's better. :)

root at nyi-01 src# git show | head -30
commit 8f6110bd2e258b3f4224eb580e99fa142bebc727
Author: Roger Pau Monne <roger.pau at citrix.com>
Date:   Thu Oct 29 12:58:23 2015 +0100

    x86/dma_bounce: rework _bus_dmamap_load_ma implementation

    The implementation of bus_dmamap_load_ma_triv currently calls
    _bus_dmamap_load_phys on each page that is part of the passed in buffer.
    Since each page is treated as an individual buffer, the resulting behaviour
    is different from the behaviour of _bus_dmamap_load_buffer. This breaks
    certain drivers, like Xen blkfront.

    If an unmapped buffer of size 4096 that starts at offset 13 into the first
    page is passed to the current _bus_dmamap_load_ma implementation (so the ma
    array contains two pages), the result is that two segments are created, one
    with a size of 4083 and the other with size 13 (because two independant
    calls to _bus_dmamap_load_phys are performed, one for each physical page).
    If the same is done with a mapped buffer and calling _bus_dmamap_load_buffer
    the result is that only one segment is created, with a size of 4096.

    This patch relegates the usage of bus_dmamap_load_ma_triv in x86 bounce
    buffer code to drivers requesting BUS_DMA_KEEP_PG_OFFSET and implements
    _bus_dmamap_load_ma so that it's behaviour is the same as the mapped version
    (_bus_dmamap_load_buffer). This patch only modifies the x86 bounce buffer
    code, other arches are left untouched.

    Reviewed by:                kib, jah
    Differential Revision:      https://reviews.freebsd.org/D888
    Sponsored by:               Citrix Systems R&D

root at nyi-01 src# uname -a
FreeBSD nyi-01.build.hardenedbsd.org 11.0-CURRENT-HBSD FreeBSD
11.0-CURRENT-HBSD #14 8f6110b(jenkins-world-kernel-20151102): Mon Nov
2 09:42:26 EST 2015
root at nyi-01.build.hardenedbsd.org:/usr/obj/usr/src/sys/JENKINS  amd64
root at nyi-01 src# uptime
10:05AM  up 3 mins, 2 users, load averages: 0.46, 1.09, 0.57
root at nyi-01 src#

Now I started a new jenkins build to see the patch under stress.

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