Date: Thu, 23 Apr 2015 18:11:38 +0200
From: Borislav Petkov <bp@alien8.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
        Denys Vlasenko <dvlasenk@redhat.com>, Ingo Molnar <mingo@kernel.org>,
        Brian Gerst <brgerst@gmail.com>, Steven Rostedt <rostedt@goodmis.org>,
        "H. Peter Anvin" <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Alexei Starovoitov <ast@plumgrid.com>, Will Drewry <wad@chromium.org>,
        Kees Cook <keescook@chromium.org>,
        the arch/x86 maintainers <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] x86/asm/entry/32: Restore %ss before SYSRETL if necessary
Message-ID: <20150423161138.GO28327@pd.tnic>
References: <1429792491-5978-1-git-send-email-dvlasenk@redhat.com>
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On Thu, Apr 23, 2015 at 09:05:07AM -0700, Linus Torvalds wrote:
> So it sounds very much like an AMD bug/misfeature. Because sysret
> *should* reset the descriptor cache. Do we know whether this affects
> *all* AMD CPU's or just a subset?

I am being told that this might appear to be the case with at least one
uarch. I could run code on the boxes I have here to check if Andy comes
up with some nice little "exploit".

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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