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Wed, 4 Jan 2023 14:26:02 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1672838762; h=from:from: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; bh=FH7vooKVlXi8JXPp9/BJ56jjaowYk9mqB61YmVsNKDY=; b=GO4vyVDzHMpJmiYd5Tccuux/3Y1KXg3kwYiY1wBIRAyzCwKt2qAVftie65t8DdJtghsUAj aCRYFqLpilCsMrFEGOxO1woqBtsVpSVaqx66/pS1y92uu79i9mt0ZwD7fYKKN7QnIKx1ma rvuMhDCLs3lRpJl8yxcTTZAFxpVTU9w= Date: Wed, 4 Jan 2023 14:25:57 +0100 From: Borislav Petkov To: "Edgecombe, Rick P" Cc: "akpm@linux-foundation.org" , "tglx@linutronix.de" , "linux-arch@vger.kernel.org" , "kcc@google.com" , "Lutomirski, Andy" , "nadav.amit@gmail.com" , "kirill.shutemov@linux.intel.com" , "Schimpe, Christina" , "peterz@infradead.org" , "corbet@lwn.net" , "linux-kernel@vger.kernel.org" , "jannh@google.com" , "dethoma@microsoft.com" , "x86@kernel.org" , "pavel@ucw.cz" , "rdunlap@infradead.org" , "linux-api@vger.kernel.org" , "john.allen@amd.com" , "arnd@arndb.de" , "jamorris@linux.microsoft.com" , "rppt@kernel.org" , "bsingharora@gmail.com" , "mike.kravetz@oracle.com" , "oleg@redhat.com" , "fweimer@redhat.com" , "keescook@chromium.org" , "gorcunov@gmail.com" , "Yu, Yu-cheng" , "andrew.cooper3@citrix.com" , "hpa@zytor.com" , "mingo@redhat.com" , "hjl.tools@gmail.com" , "linux-mm@kvack.org" , "Syromiatnikov, Eugene" , "Yang, Weijiang" , "linux-doc@vger.kernel.org" , "dave.hansen@linux.intel.com" , "Eranian, Stephane" Subject: Re: [PATCH v4 11/39] x86/mm: Update pte_modify for _PAGE_COW Message-ID: References: <20221203003606.6838-1-rick.p.edgecombe@intel.com> <20221203003606.6838-12-rick.p.edgecombe@intel.com> <060f1009199b09b7f8b9698e9f6f8375d9d1b66d.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <060f1009199b09b7f8b9698e9f6f8375d9d1b66d.camel@intel.com> X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: D4B9F18000B X-Stat-Signature: xj1w1nhdagpaidik6tori8t4wsziwr4q X-HE-Tag: 1672838763-714344 X-HE-Meta: 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 5Z6xjQ+L L3CHOynjIevz1iXEQ5wkiWu856rFP8Isf/GWFCxyJLA8iOoZD99xtHlQ80zqtshnIc2DQ 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 Tue, Dec 27, 2022 at 11:31:37PM +0000, Edgecombe, Rick P wrote: > The comment is referring to the dirty bits possibly coming from > newprot, Ah right, ofc. > but looking at it now I think the code was broken trying to > fix the recent soft dirty test breakage. Now it might lose pre-existing > dirty bits in the pte unessarily... I think. Right, does this code need to be simplified? I.e., match the shadow stack PTE (Write=0,Dirty=1) and handle that in a separate helper? So that the flows are separate. I'm not a mm guy but this function makes my head hurt - dunno about other folks. :) Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette