From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
linux-sgx@vger.kernel.org, x86@kernel.org,
Haitao Huang <haitao.huang@linux.intel.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@amacapital.net>,
Cedric Xing <cedric.xing@intel.com>
Subject: Re: [PATCH] x86/vdso: Remove retpoline from SGX vDSO call
Date: Wed, 30 Sep 2020 08:43:49 -0700 [thread overview]
Message-ID: <20200930154349.GB32672@linux.intel.com> (raw)
In-Reply-To: <20200930152806.GA52739@linux.intel.com>
On Wed, Sep 30, 2020 at 06:28:06PM +0300, Jarkko Sakkinen wrote:
> On Wed, Sep 30, 2020 at 07:33:38AM -0700, Dave Hansen wrote:
> > On 9/30/20 7:20 AM, Jarkko Sakkinen wrote:
> > > I'm not expert on Spectre, or any sort of security researcher, but I've
> > > read a few papers about and understand the general concept. With the
> > > constraints how the callback is used in practice, I'd *guess* it is
> > > fine to drop retpoline but I really need some feedback on this from
> > > people who understand these attacks better.
> >
> > Do you recall why you added it in the first place? What was the
> > motivation for it? Were you responding to a review comment?
>
> Absolutely cannot recall it :-) I even cannot recall the exact time when
> we landed the vDSO in the first place. Too much stuff has happend during
> the long three year upstreaming cycle. I will try to backtrack this
> info.
It originated in a comment from Andy when we were discussing the legitimacy
of the callback. From that point on it got taken as gospel that the indirect
call would be implemented as a retpoline.
https://lkml.kernel.org/r/CALCETrVBR+2HjTqX=W4r9GOq69Xg36v4gmCKqK0wUjzAqBJnrw@mail.gmail.com
next prev parent reply other threads:[~2020-09-30 15:43 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 14:01 [PATCH] x86/vdso: Remove retpoline from SGX vDSO call Jarkko Sakkinen
2020-09-30 14:08 ` Dave Hansen
2020-09-30 14:20 ` Jarkko Sakkinen
2020-09-30 14:33 ` Dave Hansen
2020-09-30 15:28 ` Jarkko Sakkinen
2020-09-30 15:43 ` Sean Christopherson [this message]
2020-09-30 16:28 ` Dave Hansen
2020-09-30 17:01 ` Jethro Beekman
2020-09-30 18:09 ` Andrew Cooper
2020-09-30 19:25 ` Jarkko Sakkinen
2020-09-30 20:45 ` Xing, Cedric
2020-09-30 21:22 ` Jarkko Sakkinen
2020-09-30 21:36 ` Jarkko Sakkinen
2020-09-30 21:46 ` Dave Hansen
2020-09-30 23:41 ` Jarkko Sakkinen
2020-09-30 16:38 ` Jarkko Sakkinen
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