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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0D59C433EF for ; Thu, 4 Nov 2021 17:01:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97EB261247 for ; Thu, 4 Nov 2021 17:01:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232241AbhKDREQ (ORCPT ); Thu, 4 Nov 2021 13:04:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231956AbhKDRDq (ORCPT ); Thu, 4 Nov 2021 13:03:46 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D814BC061210 for ; Thu, 4 Nov 2021 10:01:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=wdCGYsbyem/WgX1a1Isn0JFwEGFMgSk5yqoSwmFEJgY=; b=RXZZDnCtLuRRklyrYIVRKTAJa5 Jd18EFhOUVZbh5rkei201lBpmlJ7i/GDSPq88lvuJ6YCTRHM140f9i4rZUnqffD8sgis8K09u1lt+ +lCWETZOV1W4qg8ZLLx2RCkVLFsRe+m1FuKWDamXMfdS+QkSuTvkf2arGQaNdbx+Jp38Q+/2J8icD c2RqpjJY6NsRG9dG1QLohIHxp5w2f/XmMd92RXZJfwy9+TLBleOeVO3eAa0k6VmRh5+G7/YPJ3JrN DYaxpp+9/UljOBpZ0LXSdLRfRIzoDpiQIlOBCMCi7oqhvJbw4bem7r5rXQbyyOMN/WQjWQ/utwFCR IEZXZTxw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1mig2Y-0060Ft-1A; Thu, 04 Nov 2021 16:57:11 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 60BDF302148; Thu, 4 Nov 2021 17:56:35 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 4B3892DD49FB5; Thu, 4 Nov 2021 17:56:35 +0100 (CET) Message-ID: <20211104165525.408049586@infradead.org> User-Agent: quilt/0.66 Date: Thu, 04 Nov 2021 17:47:44 +0100 From: Peter Zijlstra To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, jpoimboe@redhat.com, mark.rutland@arm.com, dvyukov@google.com, seanjc@google.com, pbonzini@redhat.com, mbenes@suse.cz Subject: [RFC][PATCH 15/22] x86,vmx: Remove .fixup usage References: <20211104164729.226550532@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the vmread exceptin path, use the, thus far, unused output register to push the @fault argument onto the stack. This, in turn, enables the exception handler to not do pushes and only modify that register when an exception does occur. Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/kvm/vmx/vmx_ops.h | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) --- a/arch/x86/kvm/vmx/vmx_ops.h +++ b/arch/x86/kvm/vmx/vmx_ops.h @@ -80,9 +80,11 @@ static __always_inline unsigned long __v * @field, and bounce through the trampoline to preserve * volatile registers. */ - "push $0\n\t" + "xorl %k1, %k1\n\t" + "2:\n\t" + "push %1\n\t" "push %2\n\t" - "2:call vmread_error_trampoline\n\t" + "call vmread_error_trampoline\n\t" /* * Unwind the stack. Note, the trampoline zeros out the @@ -93,12 +95,8 @@ static __always_inline unsigned long __v "3:\n\t" /* VMREAD faulted. As above, except push '1' for @fault. */ - ".pushsection .fixup, \"ax\"\n\t" - "4: push $1\n\t" - "push %2\n\t" - "jmp 2b\n\t" - ".popsection\n\t" - _ASM_EXTABLE(1b, 4b) + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_ONE_REG, %1) + : ASM_CALL_CONSTRAINT, "=r"(value) : "r"(field) : "cc"); return value; }