From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Lendacky Subject: Re: [RFC PATCH v1 09/28] x86/efi: Access EFI data as encrypted when SEV is active Date: Thu, 22 Sep 2016 14:04:27 -0500 Message-ID: <1a22afee-a146-414c-6f58-66a942f7aab9@amd.com> References: <147190820782.9523.4967724730957229273.stgit@brijesh-build-machine> <147190832511.9523.10850626471583956499.stgit@brijesh-build-machine> <20160922143545.3kl7khff6vqk7b2t@pd.tnic> <464461b7-1efb-0af1-dd3e-eb919a2578e9@redhat.com> <20160922145947.52v42l7p7dl7u3r4@pd.tnic> <938ee0cf-85e6-eefa-7df9-9d5e09ed7a9d@redhat.com> <20160922170718.34d4ppockeurrg25@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160922170718.34d4ppockeurrg25@pd.tnic> Sender: owner-linux-mm@kvack.org To: Borislav Petkov , Paolo Bonzini Cc: Brijesh Singh , simon.guinot@sequanux.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, rkrcmar@redhat.com, matt@codeblueprint.co.uk, linus.walleij@linaro.org, linux-mm@kvack.org, paul.gortmaker@windriver.com, hpa@zytor.com, dan.j.williams@intel.com, aarcange@redhat.com, sfr@canb.auug.org.au, andriy.shevchenko@linux.intel.com, herbert@gondor.apana.org.au, bhe@redhat.com, xemul@parallels.com, joro@8bytes.org, x86@kernel.org, mingo@redhat.com, msalter@redhat.com, ross.zwisler@linux.intel.com, dyoung@redhat.com, jroedel@suse.de, keescook@chromium.org, toshi.kani@hpe.com, mathieu.desnoyers@efficios.com, devel@linuxdriverproject.org, tglx@linutronix.de, mchehab@kernel.org, iamjoonsoo.kim@lge.com, labbott@fedoraproject.org, tony.luck@intel.com, alexandre.bounine@idt.com, kuleshovmail@gm List-Id: linux-efi@vger.kernel.org On 09/22/2016 12:07 PM, Borislav Petkov wrote: > On Thu, Sep 22, 2016 at 05:05:54PM +0200, Paolo Bonzini wrote: >> Which paragraph? > > "Linux relies on BIOS to set this bit if BIOS has determined that the > reduction in the physical address space as a result of enabling memory > encryption..." > > Basically, you can enable SME in the BIOS and you're all set. That's not what I mean here. If the BIOS sets the SMEE bit in the SYS_CFG msr then, even if the encryption bit is never used, there is still a reduction in physical address space. Transparent SME (TSME) will be a BIOS option that will result in the memory controller performing encryption no matter what. In this case all data will be encrypted without a reduction in physical address space. Thanks, Tom > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org