From patchwork Mon Oct 16 12:39:29 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 13423173 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7AF99CDB474 for ; Mon, 16 Oct 2023 12:39:48 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.617510.960135 (Exim 4.92) (envelope-from ) id 1qsMsm-0001wL-4b; Mon, 16 Oct 2023 12:39:40 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 617510.960135; Mon, 16 Oct 2023 12:39:40 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qsMsm-0001wE-1y; Mon, 16 Oct 2023 12:39:40 +0000 Received: by outflank-mailman (input) for mailman id 617510; Mon, 16 Oct 2023 12:39:39 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qsMsl-0001w4-6z for xen-devel@lists.xenproject.org; Mon, 16 Oct 2023 12:39:39 +0000 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id 1108a001-6c21-11ee-9b0e-b553b5be7939; Mon, 16 Oct 2023 14:39:37 +0200 (CEST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 9FCDA1F37F; Mon, 16 Oct 2023 12:39:35 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 27145133B7; Mon, 16 Oct 2023 12:39:35 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 8jQZCAcvLWX4IgAAMHmgww (envelope-from ); Mon, 16 Oct 2023 12:39:35 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 1108a001-6c21-11ee-9b0e-b553b5be7939 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1697459975; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=TrHQ0ELhL7iWzaPXNchammsXfJ1VpjNzr9oy6lA6Krc=; b=YzXXQasXeVaCM4rll76gJ/cRr0gpD70UiJXXyCcxaVKzwc9L4AXNbvBrVwebwOapoEgD/V kOvKYPLYE1drK+oaVua+5/yuA0E3o3tYXm/4BGroCwxVwrDXMIXbHrdl6BnhOJf4Kxonoe BdcUCorSEAPEtsoXqKVKuI5f9GWDvX4= From: Juergen Gross To: linux-kernel@vger.kernel.org, x86@kernel.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org Cc: Juergen Gross , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Ajay Kaher , Alexey Makhalov , VMware PV-Drivers Reviewers , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Boris Ostrovsky , xen-devel@lists.xenproject.org Subject: [PATCH v2 0/4] x86/paravirt: Get rid of paravirt patching Date: Mon, 16 Oct 2023 14:39:29 +0200 Message-Id: <20231016123933.17284-1-jgross@suse.com> X-Mailer: git-send-email 2.35.3 MIME-Version: 1.0 Authentication-Results: smtp-out2.suse.de; none X-Spamd-Result: default: False [4.05 / 50.00]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; R_MISSING_CHARSET(2.50)[]; MIME_GOOD(-0.10)[text/plain]; BROKEN_CONTENT_TYPE(1.50)[]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; NEURAL_HAM_SHORT(-0.85)[-0.851]; NEURAL_SPAM_LONG(3.00)[1.000]; RCPT_COUNT_TWELVE(0.00)[18]; MID_CONTAINS_FROM(1.00)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-3.00)[100.00%] This is a small series getting rid of paravirt patching by switching completely to alternative patching for the same functionality. The basic idea is to add the capability to switch from indirect to direct calls via a special alternative patching option. This removes _some_ of the paravirt macro maze, but most of it needs to stay due to the need of hiding the call instructions from the compiler in order to avoid needless register save/restore. What is going away is the nasty stacking of alternative and paravirt patching and (of course) the special .parainstructions linker section. I have tested the series on bare metal and as Xen PV domain to still work. Note that objtool might need some changes to cope with the new indirect call patching mechanism. Additionally some paravirt handling can probably be removed from it. Changes in V2: - split last patch into 2 - rebase of patch 2 as suggested by Peter - addressed Peter's comments for patch 3 Juergen Gross (4): x86/paravirt: move some functions and defines to alternative x86/alternative: add indirect call patching x86/paravirt: switch mixed paravirt/alternative calls to alternative_2 x86/paravirt: remove no longer needed paravirt patching code arch/x86/include/asm/alternative.h | 26 ++++- arch/x86/include/asm/paravirt.h | 79 +++++---------- arch/x86/include/asm/paravirt_types.h | 73 +++----------- arch/x86/include/asm/qspinlock_paravirt.h | 4 +- arch/x86/include/asm/text-patching.h | 12 --- arch/x86/kernel/alternative.c | 116 ++++++++++------------ arch/x86/kernel/callthunks.c | 17 ++-- arch/x86/kernel/kvm.c | 4 +- arch/x86/kernel/module.c | 20 +--- arch/x86/kernel/paravirt.c | 54 ++-------- arch/x86/kernel/vmlinux.lds.S | 13 --- arch/x86/tools/relocs.c | 2 +- arch/x86/xen/irq.c | 2 +- 13 files changed, 137 insertions(+), 285 deletions(-)