From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f200.google.com (mail-wr0-f200.google.com [209.85.128.200]) by kanga.kvack.org (Postfix) with ESMTP id 7220B6B0294 for ; Tue, 16 Jan 2018 14:55:45 -0500 (EST) Received: by mail-wr0-f200.google.com with SMTP id h1so11417754wre.20 for ; Tue, 16 Jan 2018 11:55:45 -0800 (PST) Received: from theia.8bytes.org (8bytes.org. [2a01:238:4383:600:38bc:a715:4b6d:a889]) by mx.google.com with ESMTPS id h2si2689332edf.540.2018.01.16.11.55.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Jan 2018 11:55:44 -0800 (PST) Date: Tue, 16 Jan 2018 20:55:43 +0100 From: Joerg Roedel Subject: Re: [RFC PATCH 00/16] PTI support for x86-32 Message-ID: <20180116195543.GG28161@8bytes.org> References: <1516120619-1159-1-git-send-email-joro@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds Cc: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , the arch/x86 maintainers , Linux Kernel Mailing List , linux-mm , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , Brian Gerst , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , "Liguori, Anthony" , Daniel Gruss , Hugh Dickins , Kees Cook , Andrea Arcangeli , Waiman Long , Joerg Roedel Hi Linus, On Tue, Jan 16, 2018 at 10:59:01AM -0800, Linus Torvalds wrote: > Yes, I'm very happy to see that this is actually not nearly as bad as > I feared it might be, Yeah, I was looking at the original PTI patches and my impression was that a lot of the complicated stuff (like setting up the cpu_entry_area) was already in there for 32 bit too. So it was mostly about the entry code and some changes to the 32bit page-table code. > Some of those #ifdef's in the PTI code you added might want more > commentary about what the exact differences are. And maybe they could > be done more cleanly with some abstraction. But nothing looked > _horrible_. I'll add more comments and better abstraction, Dave has already suggested some improvements here. Reading some of my comments again, they need a rework anyway. > .. and please run all the segment and syscall selfchecks that Andy has written. Didn't know about them yet, thanks. I will run them too in my testing > Xen PV and PTI don't work together even on x86-64 afaik, the Xen > people apparently felt it wasn't worth it. See the > > if (hypervisor_is_type(X86_HYPER_XEN_PV)) { > pti_print_if_insecure("disabled on XEN PV."); > return; > } > > in pti_check_boottime_disable(). But I might have broken something for them anyway, honestly I didn't pay much attention to the XEN_PV case as I was trying to get it running here. My hope is that someone who knows Xen better than I do will help out :) Regards, Joerg -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org