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([2601:646:c200:1ef2:a93f:12ed:b744:bd73]) by smtp.gmail.com with ESMTPSA id x132sm12819152pfc.57.2020.05.12.13.07.51 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 12 May 2020 13:07:51 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Andy Lutomirski Mime-Version: 1.0 (1.0) Subject: Re: [RFC v4][PATCH part-1 0/7] ASI - Part I (ASI Infrastructure and PTI) Date: Tue, 12 May 2020 13:07:28 -0700 Message-Id: <7F322031-034E-4B36-A60F-663EAA4C99C9@amacapital.net> References: Cc: Alexandre Chartre , rkrcmar@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, pbonzini@redhat.com, konrad.wilk@oracle.com, jan.setjeeilers@oracle.com, liran.alon@oracle.com, junaids@google.com, graf@amazon.de, rppt@linux.vnet.ibm.com, kuzuno@gmail.com, mgross@linux.intel.com In-Reply-To: To: Dave Hansen X-Mailer: iPhone Mail (17E262) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On May 12, 2020, at 10:45 AM, Dave Hansen wrote: >=20 > =EF=BB=BFOn 5/4/20 7:49 AM, Alexandre Chartre wrote: >> This version 4 of the kernel Address Space Isolation (ASI) RFC. I have >> broken it down into three distinct parts: >>=20 >> - Part I: ASI Infrastructure and PTI (this part) >> - Part II: Decorated Page-Table >> - Part III: ASI Test Driver and CLI >>=20 >> Part I is similar to RFCv3 [3] with some small bug fixes. Parts II and II= I >> extend the initial patchset: part II introduces decorated page-table in >> order to provide convenient page-table management functions, and part III= >> provides a driver and CLI for testing ASI (using parts I and II). >=20 > These look interesting. I haven't found any holes in your methods, > although the interrupt depth tracking worries me a bit. I tried and > failed to do a similar thing with PTI in the NMI path, but you might > have just bested me there. :) >=20 > It's very interesting that you've been able to implement PTI underneath > all of this, and the "test driver" is really entertaining! >=20 > That said, this is working in some of the nastiest corners of the x86 > code and this is going to take quite an investment to get reviewed. I'm > not *quite* sure it's all worth it. >=20 > So, this isn't being ignored, I'm just not quite sure what to do with > it, yet. I=E2=80=99m going to wait until the dust settles on tglx=E2=80=99s big entry= rework before I look at this.=