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[192.55.52.93]) by mx.google.com with ESMTPS id q2si1948860plh.56.2019.06.13.07.19.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Jun 2019 07:19:05 -0700 (PDT) Received-SPF: pass (google.com: domain of dave.hansen@intel.com designates 192.55.52.93 as permitted sender) client-ip=192.55.52.93; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dave.hansen@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=dave.hansen@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 13 Jun 2019 07:19:04 -0700 X-ExtLoop1: 1 Received: from enagarix-mobl.amr.corp.intel.com (HELO [10.251.15.213]) ([10.251.15.213]) by orsmga004.jf.intel.com with ESMTP; 13 Jun 2019 07:19:02 -0700 Subject: Re: [RFC 00/10] Process-local memory allocations for hiding KVM secrets To: Alexander Graf , Marius Hillenbrand , kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, Alexander Graf , David Woodhouse , the arch/x86 maintainers , Andy Lutomirski , Peter Zijlstra References: <20190612170834.14855-1-mhillenb@amazon.de> <54a4d14c-b19b-339e-5a15-adb10297cb30@amazon.com> From: Dave Hansen Openpgp: preference=signencrypt Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <54a4d14c-b19b-339e-5a15-adb10297cb30@amazon.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 6/13/19 12:27 AM, Alexander Graf wrote: >> Where's the context-switching code?  Did I just miss it? > > I'm not sure I understand the question. With this mechanism, the global > linear map pages are just not present anymore, so there is no context > switching needed. For the process local memory, the page table is > already mm local, so we don't need to do anything special during context > switch, no? Thanks for explaining, I was just confused. Andy reminded me when comparing it to the LDT area: since this area is per-mm/pgd and we context switch that *obviously* there's no extra work to do at context switch time, as long as the area is marked non-Global.