Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 15 Jan 2021 13:46:01 -0600
From:   Josh Poimboeuf <jpoimboe@redhat.com>
To:     =?utf-8?B?SsO8cmdlbiBHcm/Dnw==?= <jgross@suse.com>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>,
        Sami Tolvanen <samitolvanen@google.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        clang-built-linux@googlegroups.com,
        Miroslav Benes <mbenes@suse.cz>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH 14/21] x86/xen: Support objtool vmlinux.o validation in
 xen-head.S
Message-ID: <20210115194601.dkilnfkp6xnhai22@treble>
References: <cover.1610652862.git.jpoimboe@redhat.com>
 <02a3b646aa20035c9c700c5b6d7897a9f898ba24.1610652862.git.jpoimboe@redhat.com>
 <43d47af1-6735-6651-db11-4489c86c62a2@suse.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <43d47af1-6735-6651-db11-4489c86c62a2@suse.com>
Precedence: bulk

On Fri, Jan 15, 2021 at 06:17:25AM +0100, Jürgen Groß wrote:
> On 14.01.21 20:40, Josh Poimboeuf wrote:
> > The Xen hypercall page is filled with zeros, causing objtool to fall
> > through all the empty hypercall functions until it reaches a real
> > function, resulting in a stack state mismatch.
> > 
> > The build-time contents of the hypercall page don't matter, since it
> > gets mapped to the hypervisor.
> 
> This sentence is technically wrong: the contents don't matter, as the
> page will be rewritten by the hypervisor.

Thanks, updated for v2.

-- 
Josh