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;
MIME-Version: 1.0
References: <20200618210215.23602-1-daniel.gutson@eclypsium.com>
 <589c89ae-620e-36f8-2be5-4afc727c2911@intel.com> <CAFmMkTHNxSN_uWtm63TdkGxj44NXQQKEOmATXhjA=4DSCS92kQ@mail.gmail.com>
 <23babf62-00cb-cb47-bb19-da9508325934@intel.com> <CAD2FfiFbGdf5uKmsc14F4ZuuCUQYFwfnirn=Y0fu2F0=njvWug@mail.gmail.com>
 <80578b72-cb6f-8da9-1043-b4055c75d7f6@intel.com>
In-Reply-To: <80578b72-cb6f-8da9-1043-b4055c75d7f6@intel.com>
From:   Richard Hughes <hughsient@gmail.com>
Date:   Fri, 19 Jun 2020 14:37:38 +0100
Message-ID: <CAD2FfiG1BgYvR6wkeXGro8v6FQtVjKemmAOOf2W14z5KUWLqhw@mail.gmail.com>
Subject: Re: [PATCH] Ability to read the MKTME status from userspace
To:     Dave Hansen <dave.hansen@intel.com>
Cc:     Daniel Gutson <daniel@eclypsium.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "David S. Miller" <davem@davemloft.net>,
        Rob Herring <robh@kernel.org>, Tony Luck <tony.luck@intel.com>,
        Rahul Tanwar <rahul.tanwar@linux.intel.com>,
        Xiaoyao Li <xiaoyao.li@intel.com>,
        Sean Christopherson <sean.j.christopherson@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Fri, 19 Jun 2020 at 14:33, Dave Hansen <dave.hansen@intel.com> wrote:
> On top of that, the kernel can just swap data out to unencrypted storage.

Right, but for the most part you'd agree that a machine with
functioning TME and encrypted swap partition is more secure than a
machine without TME?

> So, I really wonder what folks want from this flag in the first place.
> It really tells you _nothing_.

Can I use TME if the CPU supports it, but the platform has disabled
it? How do I know that my system is actually *using* the benefits the
TME feature provides?

Richard.