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>
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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
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