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Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V . Shankar" , Weijiang Yang , "Kirill A . Shutemov" , joao.moreira@intel.com, John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, Yu-cheng Yu Content-Type: text/plain; charset="UTF-8" ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664551010; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=rav/GnxDxXCmb0MWmQJI5rI/wm0ZOCSwNoHHz9z+r7A=; b=25FQuwgig9NWrO6bCBgBWiHwSJMf5+axRYVDUQM4zGZu5dbE755GGYWBLl3ux+c1EkKyvf JOILWPHOw+6hhaY3pmACaigIKY0k3KnzVl1EZwNv9SfHdnR2R5gMlZALpJcMI3PDNapm7V 24PctUkf5bChJpumczwIVBP+/OCzht8= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=YB6CjrLN; spf=pass (imf17.hostedemail.com: domain of jannh@google.com designates 209.85.166.42 as permitted sender) smtp.mailfrom=jannh@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664551010; a=rsa-sha256; cv=none; b=VGUTjp3weRGetP4Ewm3KmeVTHPiLPHutkz0f3YP4+afpjiUESgvvl9+jh1cC+0IitBR7nI wQ4C43oex/gmXmhY/p/4+8fYLgo/djg2vlIQWtnqIM0XABBp4eGWuFs1dHwMr0OTN6YK21 A0ZiknImUihQg5MOCLFVl/af6VzND7s= Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=YB6CjrLN; spf=pass (imf17.hostedemail.com: domain of jannh@google.com designates 209.85.166.42 as permitted sender) smtp.mailfrom=jannh@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspam-User: X-Stat-Signature: 7u3d1cgw8zfunh3jqrwi9npi6tz8n6nx X-Rspamd-Queue-Id: 2B59C40002 X-Rspamd-Server: rspam08 X-HE-Tag: 1664551009-91945 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 Fri, Sep 30, 2022 at 12:30 AM Rick Edgecombe wrote: > The reason it's lightly used is that Dirty=1 is normally set _before_ a > write. A write with a Write=0 PTE would typically only generate a fault, > not set Dirty=1. Hardware can (rarely) both set Write=1 *and* generate the > fault, resulting in a Dirty=0,Write=1 PTE. Hardware which supports shadow > stacks will no longer exhibit this oddity. Stupid question, since I just recently learned that IOMMUv2 is a thing: I assume this also holds for IOMMUs that implement IOMMUv2/SVA, where the IOMMU directly walks the userspace page tables, and not just for the CPU core?