From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DA789606A31C for ; Wed, 21 Oct 2026 08:20:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=xenproject.org header.i=@xenproject.org header.a=rsa-sha256 header.s=20200302mail header.b=Kf1FNC0l Received: from list by lists.xenproject.org with outflank-mailman.1456793.1669899 (Exim 4.92) (envelope-from ) id 1xJRY9-0000Pc-DU; Wed, 21 Oct 2026 08:19:53 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 1456793.1669899; Wed, 21 Oct 2026 08:19:53 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1xJRY9-0000PV-Av; Wed, 21 Oct 2026 08:19:53 +0000 Received: by outflank-mailman (input) for mailman id 1456793; Wed, 21 Oct 2026 08:19:51 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1xJRY7-0000PP-Qv for xen-devel@lists.xenproject.org; Wed, 21 Oct 2026 08:19:51 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.98.2) (envelope-from ) id 1xJRY7-00000005UT5-2UP2; Wed, 21 Oct 2026 08:19:51 +0000 Received: from 224.pool85-54-217.dynamic.orange.es ([85.54.217.224] helo=localhost) by xenbits.xenproject.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1xJRY7-0000000Bl8s-0zfO; Wed, 21 Oct 2026 08:19:51 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Post: List-Help: List-Subscribe: , Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xenproject.org; s=20200302mail; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=zih/YHTh2oXn5bNkn1DI2OrBDiu3Ur9QKpyCozdCFJY=; b=Kf1FNC0lTXhRYvnlX1yJbHCAIh FLBwR0DL0JIZnV3kq2jmVWvuccWzI7JaLrehx83w5psx3BlYPW29gD0duCvdS1WXurlV1C9PURKE+ YuQ5QYknErivNgYQupAavoMokhkkka5hxvHcPSS2FRfEW+aRl2YURKuyzawEsJSZCXYg=; Date: Wed, 21 Oct 2026 10:19:45 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Stefano Stabellini Cc: xen-devel@lists.xenproject.org, jbeulich@suse.com, andrew.cooper3@citrix.com, jason.andryuk@amd.com, teddy.astie@vates.tech Subject: Re: [PATCH] xen/x86/hvm: Propagate emulated CR2 writes to the VMCB Message-ID: References: <20261020213315.3641133-1-stefano.stabellini@amd.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20261020213315.3641133-1-stefano.stabellini@amd.com> X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Oct 20, 2026 at 02:33:15PM -0700, Stefano Stabellini wrote: > hvmemul_write_cr() updates guest_cr[2] but, unlike every other writer of > it, doesn't call hvm_update_guest_cr(). On SVM, CR2 is loaded from > the VMCB, so the emulated write never reaches the guest, and the next > VMExit overwrites guest_cr[2] with the stale VMCB value. > > Signed-off-by: Stefano Stabellini Acked-by: Roger Pau Monné I wonder whether there's more missing here, see below. > --- > xen/arch/x86/hvm/emulate.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c > index c09ea002ec..cd2831d34b 100644 > --- a/xen/arch/x86/hvm/emulate.c > +++ b/xen/arch/x86/hvm/emulate.c > @@ -2350,6 +2350,7 @@ static int cf_check hvmemul_write_cr( > > case 2: > curr->arch.hvm.guest_cr[2] = val; > + hvm_update_guest_cr(curr, 2); Looking at hvm_update_cr(), is this possibly also missing a call to nestedhvm_set_cr()? Thanks, Roger.