From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.4 required=3.0 tests=BUG6152_INVALID_DATE_TZ_ABSURD,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INVALID_DATE_TZ_ABSURD,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F83EC47E49 for ; Mon, 4 Nov 2019 11:04:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7644C21D81 for ; Mon, 4 Nov 2019 11:04:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1572865457; bh=A7rFAwGDcqnX0eiWPTh+R5Gh0TAKD8nijZSUmk51Cmg=; h=To:Subject:Date:From:Cc:In-Reply-To:References:List-ID:From; b=t/2ZLRZsREE3h/xcBv3WuavpSxTFGA2lNVmGytx9CS0r7MlPva9YgiCKSALcIRbAi 6txMWWx278BjM/bB/ffXZ3mRzCYGEJjiBYRo8B9CZl2p9DZ0c72LzixoWAxqldvrGY DGdcvDTNMazxMzEB54esmx353bgFl4QnXr1atIDo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728877AbfKDLEQ (ORCPT ); Mon, 4 Nov 2019 06:04:16 -0500 Received: from inca-roads.misterjones.org ([213.251.177.50]:54707 "EHLO inca-roads.misterjones.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728522AbfKDLEP (ORCPT ); Mon, 4 Nov 2019 06:04:15 -0500 Received: from www-data by cheepnis.misterjones.org with local (Exim 4.80) (envelope-from ) id 1iRa95-0003Mx-DL; Mon, 04 Nov 2019 12:03:39 +0100 To: Sami Tolvanen Subject: Re: [PATCH v4 03/17] arm64: kvm: stop treating register x18 as caller save X-PHP-Originating-Script: 0:main.inc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 04 Nov 2019 12:13:00 +0109 From: Marc Zyngier Cc: Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , Nick Desaulniers , Jann Horn , Miguel Ojeda , Masahiro Yamada , , , , In-Reply-To: <20191101221150.116536-4-samitolvanen@google.com> References: <20191018161033.261971-1-samitolvanen@google.com> <20191101221150.116536-1-samitolvanen@google.com> <20191101221150.116536-4-samitolvanen@google.com> Message-ID: <79e8f958cbde52a3d90aec24dd4638d9@www.loen.fr> X-Sender: maz@kernel.org User-Agent: Roundcube Webmail/0.7.2 X-SA-Exim-Connect-IP: X-SA-Exim-Rcpt-To: samitolvanen@google.com, will@kernel.org, catalin.marinas@arm.com, rostedt@goodmis.org, mhiramat@kernel.org, ard.biesheuvel@linaro.org, dave.martin@arm.com, keescook@chromium.org, labbott@redhat.com, mark.rutland@arm.com, ndesaulniers@google.com, jannh@google.com, miguel.ojeda.sandonis@gmail.com, yamada.masahiro@socionext.com, clang-built-linux@googlegroups.com, kernel-hardening@lists.openwall.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on cheepnis.misterjones.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sami, On 2019-11-01 23:20, Sami Tolvanen wrote: > From: Ard Biesheuvel > > In preparation of reserving x18, stop treating it as caller save in > the KVM guest entry/exit code. Currently, the code assumes there is > no need to preserve it for the host, given that it would have been > assumed clobbered anyway by the function call to __guest_enter(). > Instead, preserve its value and restore it upon return. > > Link: https://patchwork.kernel.org/patch/9836891/ > Signed-off-by: Ard Biesheuvel > [Sami: updated commit message, switched from x18 to x29 for the guest > context] > Signed-off-by: Sami Tolvanen > Reviewed-by: Kees Cook If you intend for this to be merged via the arm64 tree, please add my Reviewed-by: Marc Zyngier Thanks, M. -- Jazz is not dead. It just smells funny...