Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 4 Jan 2018 15:33:46 +0100
From:      Stefan Esser <se@freebsd.org>
To:        Darren Reed <darrenr@freebsd.org>, freebsd-current@freebsd.org
Subject:   Re: Intel CPU design flaw - FreeBSD affected?
Message-ID:  <b735d895-342c-9a7b-4aea-acc371f48c7e@freebsd.org>
In-Reply-To: <5A4E165B.6040809@freebsd.org>
References:  <9dda0496-be16-35c6-6c45-63d03b218ccb@protected-networks.net> <CANCZdfra8iS6ptP9Ct401sLum2mZi4dg0KTnkayQjUMbyDc4pQ@mail.gmail.com> <CAGfo=8kDVFvuXVf0572LvBY6e3F0XrxDrj_YE6A9puc3T1S3eQ@mail.gmail.com> <5A4E165B.6040809@freebsd.org>

next in thread | previous in thread | raw e-mail | index | archive | help
Am 04.01.18 um 12:56 schrieb Darren Reed:
> On 4/01/2018 11:51 AM, Mark Heily wrote:
>> On Jan 2, 2018 19:05, "Warner Losh" <imp@bsdimp.com> wrote:
>>
>> The register article says the specifics are under embargo still. That would
>> make it hard for anybody working with Intel to comment publicly on the flaw
>> and any mitigations that may be underway. It would be unwise to assume that
>> all the details are out until the embargo lifts.
>>
>>
>> Details of the flaws are now published at:
>>
>> https://meltdownattack.com
> 
> The web page has both: meltdown and spectre.
> Most people are only talking about meltdown which doesn't hit AMD.
> spectre impacts *both* Intel and AMD.
> 
> SuSE are making available a microcode patch for AMD 17h processors that
> disables branch prediction:
> 
> https://lists.opensuse.org/opensuse-security-announce/2018-01/msg00004.html

Disabling branch prediction will have a very noticeable effect on execution
speed in general (while split page tables only affect programs that perform
system calls at a high frequency).

I have not fully read the Meltdown and Spectre papers, yet, but I do assume,
that the attack at the branch prediction tries to counter KASLR, which we do
not support at all in FreeBSD.

So, I guess, we do not have to bother with disabling of branch prediction in
FreeBSD for the time being?

Regards, STefan



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?b735d895-342c-9a7b-4aea-acc371f48c7e>