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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id m3si11252309pgs.8.2019.02.17.11.34.38 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Sun, 17 Feb 2019 11:34:38 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=VGj5f8mT; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Ci4uWoH4MBnwWxuQBmGDuzl0iJ8j/tRWg8gzhD2bYUc=; b=VGj5f8mT/RltwkdWydT6SH9bH gNKHcIOvyeM+xSHUwIM9Hp/tfShzNNxDH+Ab9V4YnIehCrpb8Jzz3XSYOloucbZLIuOyVher4cy4i 6iHA/JHjdYMJ4bzWV7hn89vsXaRIkfsJUJ/MPLGgjHVfNcjPQ4vVQTWvlL6oDKwd20/VhtLfPJQd0 TmMvy/qOjcueJEsO+KtK3x8iltswq2CPwh5kNNvDvukpQLI9JuoG+uvWQh2rCvHt/TI6CbNhoxhV8 blfMuzSfJJHq5YvKjb6gRKSH65PM8XKp/j30nZ+/nSVFwePnmrEaFw4LCzsCGpagcMjJjBf2JEG5j If9vS0R8w==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gvSCw-00060S-U5; Sun, 17 Feb 2019 19:34:34 +0000 Date: Sun, 17 Feb 2019 11:34:34 -0800 From: Matthew Wilcox To: James Bottomley Cc: Balbir Singh , Mike Rapoport , lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org Subject: Re: [LSF/MM TOPIC] Address space isolation inside the kernel Message-ID: <20190217193434.GQ12668@bombadil.infradead.org> References: <20190207072421.GA9120@rapoport-lnx> <20190216121950.GB31125@350D> <1550334616.3131.10.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1550334616.3131.10.camel@HansenPartnership.com> User-Agent: Mutt/1.9.2 (2017-12-15) 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 Sat, Feb 16, 2019 at 08:30:16AM -0800, James Bottomley wrote: > On Sat, 2019-02-16 at 23:19 +1100, Balbir Singh wrote: > > For namespaces, does allocating the right memory protection key > > work? At some point we'll need to recycle the keys > > I don't think anyone mentioned memory keys and namespaces ... I take it > you're thinking of SEV/MKTME? I thought he meant Protection Keys https://en.wikipedia.org/wiki/Memory_protection#Protection_keys > The idea being to shield one container's > execution from another using memory encryption? We've speculated it's > possible but the actual mechanism we were looking at is tagging pages > to namespaces (essentially using the mount namspace and tags on the > page cache) so the kernel would refuse to map a page into the wrong > namespace. This approach doesn't seem to be as promising as the > separated address space one because the security properties are harder > to measure. What do you mean by "tags on the pages cache"? Is that different from the radix tree tags (now renamed to XArray marks), which are search keys.