linux-kernel - RE: [PATCH v5 05/16] x86/cpu: Defer CR pinning setup until after EFI initialization

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <SJ1PR11MB6083BB83EE16AEAD6D3F7C1BFC4B2@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date: Tue, 29 Oct 2024 23:18:29 +0000
From: "Luck, Tony" <tony.luck@...el.com>
To: "H. Peter Anvin" <hpa@...or.com>, "Hansen, Dave" <dave.hansen@...el.com>,
	"Mehta, Sohil" <sohil.mehta@...el.com>, Alexander Shishkin
	<alexander.shishkin@...ux.intel.com>, Andy Lutomirski <luto@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
	"x86@...nel.org" <x86@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Ard
 Biesheuvel <ardb@...nel.org>, "Paul E. McKenney" <paulmck@...nel.org>, Josh
 Poimboeuf <jpoimboe@...nel.org>, Xiongwei Song <xiongwei.song@...driver.com>,
	"Li, Xin3" <xin3.li@...el.com>, "Mike Rapoport (IBM)" <rppt@...nel.org>,
	Brijesh Singh <brijesh.singh@....com>, Michael Roth <michael.roth@....com>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>, Alexey Kardashevskiy
	<aik@....com>
CC: Jonathan Corbet <corbet@....net>, Ingo Molnar <mingo@...nel.org>, "Pawan
 Gupta" <pawan.kumar.gupta@...ux.intel.com>, Daniel Sneddon
	<daniel.sneddon@...ux.intel.com>, "Huang, Kai" <kai.huang@...el.com>,
	Sandipan Das <sandipan.das@....com>, Breno Leitao <leitao@...ian.org>,
	"Edgecombe, Rick P" <rick.p.edgecombe@...el.com>, Alexei Starovoitov
	<ast@...nel.org>, Hou Tao <houtao1@...wei.com>, Juergen Gross
	<jgross@...e.com>, Vegard Nossum <vegard.nossum@...cle.com>, Kees Cook
	<kees@...nel.org>, Eric Biggers <ebiggers@...gle.com>, Jason Gunthorpe
	<jgg@...pe.ca>, "Masami Hiramatsu (Google)" <mhiramat@...nel.org>, "Andrew
 Morton" <akpm@...ux-foundation.org>, Luis Chamberlain <mcgrof@...nel.org>,
	Yuntao Wang <ytcoode@...il.com>, Rasmus Villemoes <linux@...musvillemoes.dk>,
	Christophe Leroy <christophe.leroy@...roup.eu>, Tejun Heo <tj@...nel.org>,
	Changbin Du <changbin.du@...wei.com>, Huang Shijie
	<shijie@...amperecomputing.com>, Geert Uytterhoeven
	<geert+renesas@...der.be>, Namhyung Kim <namhyung@...nel.org>, "Arnaldo
 Carvalho de Melo" <acme@...hat.com>, "linux-doc@...r.kernel.org"
	<linux-doc@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-efi@...r.kernel.org"
	<linux-efi@...r.kernel.org>
Subject: RE: [PATCH v5 05/16] x86/cpu: Defer CR pinning setup until after EFI
 initialization

>> Yeah, I was talking about 64-bit only.  On 32-bit PAE a PGD maps 1/4 of
>> the address space which is totally unworkable for stealing.
>
> But it is also not necessary.

So maybe we could make the 64-bit version of use_temporary_mm()
use some reserved address mapping to a reserved PGD in the upper
half of address space, and the 32-bit version continue to use "user"
addresses. It's unclear to me whether adding complexity here would be
worth it to remove the 64-bit STAC/CLAC text patching issues.

-Tony