Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 14 Jul 2022 19:03:32 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Josh Poimboeuf <jpoimboe@kernel.org>
Cc:     Thadeu Lima de Souza Cascardo <cascardo@canonical.com>,
        Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org,
        Daniel Sneddon <daniel.sneddon@linux.intel.com>,
        antonio.gomez.iglesias@linux.intel.com
Subject: Re: [PATCH] x86/bugs: Switch to "auto" when "ibrs" selected on
 Enhanced IBRS parts
Message-ID: <YtBMZMaOnA8g8m0a@worktop.programming.kicks-ass.net>
References: <0456b35fb9ef957d9a9138e0913fb1a3fd445dff.1657747493.git.pawan.kumar.gupta@linux.intel.com>
 <Ys/7RiC9Z++38tzq@quatroqueijos>
 <YtABEwRnWrJyIKTY@worktop.programming.kicks-ass.net>
 <20220714160106.c6efowo6ptsu72ne@treble>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220714160106.c6efowo6ptsu72ne@treble>
Precedence: bulk

On Thu, Jul 14, 2022 at 09:01:06AM -0700, Josh Poimboeuf wrote:

> > Yeah this; if the user asks for IBRS, we should give him IBRS. I hate
> > the 'I know better, let me change that for you' mentality.
> 
> eIBRS CPUs don't even have legacy IBRS so I don't see how this is even
> possible.

You can still WRMSR a lot on them. Might not make sense but it 'works'.