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
| ||
|
Date: Wed, 1 Nov 2017 13:31:34 -0700 From: Andy Lutomirski <luto@...nel.org> To: Dave Hansen <dave.hansen@...ux.intel.com> Cc: Andy Lutomirski <luto@...nel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linux-mm@...ck.org" <linux-mm@...ck.org>, moritz.lipp@...k.tugraz.at, Daniel Gruss <daniel.gruss@...k.tugraz.at>, michael.schwarz@...k.tugraz.at, Linus Torvalds <torvalds@...ux-foundation.org>, Kees Cook <keescook@...gle.com>, Hugh Dickins <hughd@...gle.com>, X86 ML <x86@...nel.org> Subject: Re: [PATCH 21/23] x86, pcid, kaiser: allow flushing for future ASID switches On Wed, Nov 1, 2017 at 7:17 AM, Dave Hansen <dave.hansen@...ux.intel.com> wrote: > On 11/01/2017 01:03 AM, Andy Lutomirski wrote: >>> This ensures that any futuee context switches will do a full flush >>> of the TLB so they pick up the changes. >> I'm convuced. What was wrong with the old code? I guess I just don't >> see what the problem is that is solved by this patch. > > Instead of flushing *now* with INVPCID, this lets us flush *later* with > CR3. It just hijacks the code that you already have that flushes CR3 > when loading a new ASID by making all ASIDs look new in the future. > > We have to load CR3 anyway, so we might as well just do this flush then. Would it make more sense to put it in flush_tlb_func_common() instead? Also, I don't understand what clear_non_loaded_ctxs() is trying to do. It looks like it's invalidating all the other logical address spaces. And I don't see why you want a all_other_ctxs_invalid variable. Isn't the goal to mark a single ASID as needing a *user* flush the next time we switch to user mode using that ASID? Your code seems like it's going to flush a lot of *kernel* PCIDs. Can you explain the overall logic?
Powered by blists - more mailing lists