[Skiboot] [PATCH] fast-reboot: improve integrity of fast reboots
stewart at linux.vnet.ibm.com
Fri Feb 23 13:06:19 AEDT 2018
Nicholas Piggin <npiggin at gmail.com> writes:
> On Fri, 23 Feb 2018 11:04:51 +1100
> Stewart Smith <stewart at linux.vnet.ibm.com> wrote:
>> Nicholas Piggin <npiggin at gmail.com> writes:
>> > This is a start on some basic checks that might detect firmware
>> > problems that call for a full IPL. The patch is pretty rough at
>> > the moment but it's just for comments.
>> > - Checksum text and most read-only data, and verify that against
>> > checksum taken at IPL.
>> > - Check integrity of memory allocation structures and freelists.
>> Good idea.
>> > - Zeroes most OS memory (should be parallelised).
>> Been meaning to do this for a while. I wonder how much time it really
>> takes on big systems... Could be worth doing in parallel I guess.
> Just tested in userpsace a single CPU can memset about 32GB/s, and
> multiple on the same node can get 4x that. Multiple nodes should
> scale pretty linearly.
> A fully populated AC922 would be 64 seconds vs 8 seconds, so it will
> get noticable.
Yeah, that's worth it.
OPAL Architect, IBM.
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