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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 19864C48BE5 for ; Thu, 17 Jun 2021 15:02:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F186F613AA for ; Thu, 17 Jun 2021 15:02:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233095AbhFQPEk (ORCPT ); Thu, 17 Jun 2021 11:04:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232267AbhFQPEi (ORCPT ); Thu, 17 Jun 2021 11:04:38 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8AB8CC061574; Thu, 17 Jun 2021 08:02:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=V9go7Y/UucnNrXIa1S8r+WI1e5UGRrj5UmJdJeNO/dA=; b=DH3TBb6PTIQLbsLVSV75pzrQdw YOvlaQGhwgDxkO+n6YHcCAQcekOch3TTkgmTSQyJSG+PTfbr9rhv8w+vKtjZcSboPUa0yed3OM6Xv O2jUrIlTuYUi1y9vgYNACiS7Lc+7ouOb55q+Nq6PJsitEvRbdvdo2XiQhbmMvNFacge2ptH3eu7lm kSPZJfLJpFpr7d6jZ/bbyyUf75MzrK66LY/+Mz9z5jfs6Fexynhfz7Qqc0uisvf4WVdV/gybL68W9 5mQy5IpZrCBaK6A9Zus6JuMao0B8Fy0DFPW3ThfNH2q2ELD5/gn0XQHA7VNHkqqrlpUPYOsjOVAqp ixUOZqwg==; 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 1lttVj-009Fr5-UE; Thu, 17 Jun 2021 15:00:57 +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) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 48ADC300252; Thu, 17 Jun 2021 17:00:48 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 31A2A2BD52F2F; Thu, 17 Jun 2021 17:00:48 +0200 (CEST) Date: Thu, 17 Jun 2021 17:00:48 +0200 From: Peter Zijlstra To: Joerg Roedel Cc: x86@kernel.org, Joerg Roedel , hpa@zytor.com, Andy Lutomirski , Dave Hansen , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , Martin Radev , Arvind Sankar , linux-coco@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v6 1/2] x86/sev: Make sure IRQs are disabled while GHCB is active Message-ID: References: <20210616184913.13064-1-joro@8bytes.org> <20210616184913.13064-2-joro@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210616184913.13064-2-joro@8bytes.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 16, 2021 at 08:49:12PM +0200, Joerg Roedel wrote: > static void sev_es_ap_hlt_loop(void) > { > struct ghcb_state state; > + unsigned long flags; > struct ghcb *ghcb; > > - ghcb = sev_es_get_ghcb(&state); > + local_irq_save(flags); > + > + ghcb = __sev_get_ghcb(&state); > > while (true) { > vc_ghcb_invalidate(ghcb); > @@ -692,7 +704,9 @@ static void sev_es_ap_hlt_loop(void) > break; > } > > - sev_es_put_ghcb(&state); > + __sev_put_ghcb(&state); > + > + local_irq_restore(flags); > } I think this is broken, at this point RCU is quite dead on this CPU and local_irq_save/restore include tracing and all sorts. Also, shouldn't IRQs already be disabled by the time we get here?