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Date:   Mon, 14 Jan 2019 14:06:19 +0100 (CET)
From:   Jiri Kosina <jikos@kernel.org>
To:     Pavel Machek <pavel@ucw.cz>
cc:     Tim Chen <tim.c.chen@linux.intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        David Woodhouse <dwmw@amazon.co.uk>,
        Andi Kleen <ak@linux.intel.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Asit Mallick <asit.k.mallick@intel.com>,
        Arjan van de Ven <arjan@linux.intel.com>,
        Jon Masters <jcm@redhat.com>,
        Waiman Long <longman9394@gmail.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        Borislav Petkov <bp@alien8.de>, linux-kernel@vger.kernel.org,
        x86@kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] x86/speculation: Add document to describe Spectre and
 its mitigations
In-Reply-To: <20190114130153.GC21544@amd>
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On Mon, 14 Jan 2019, Pavel Machek wrote:

> Frankly I'd not call it Meltdown, as it works only on data in the cache, 
> so the defense is completely different. Seems more like a l1tf
> :-).

Meltdown on x86 also seems to work only for data in L1D, but the pipeline 
could be constructed in a way that data are actually fetched into L1D 
before speculation gives up, which is not the case on ppc (speculation 
aborts on L2->L1 propagation IIRC). That's why flushing L1D on ppc is 
sufficient, but on x86 it's not.

-- 
Jiri Kosina
SUSE Labs