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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 AF3B0C433E6 for ; Wed, 17 Feb 2021 12:02:19 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 15C2E64E5B for ; Wed, 17 Feb 2021 12:02:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 15C2E64E5B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=8bytes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id C4C4F87223; Wed, 17 Feb 2021 12:02:18 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id YM77ShXS92VX; Wed, 17 Feb 2021 12:02:18 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 398AC87243; Wed, 17 Feb 2021 12:02:18 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2146BC013A; Wed, 17 Feb 2021 12:02:18 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id B2E48C08A1 for ; Wed, 17 Feb 2021 12:02:15 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 9EEA16F5DB for ; Wed, 17 Feb 2021 12:02:15 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 4R-Ygm0r8IL4 for ; Wed, 17 Feb 2021 12:02:14 +0000 (UTC) Received: by smtp3.osuosl.org (Postfix, from userid 1001) id DF93D6F59D; Wed, 17 Feb 2021 12:02:14 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from theia.8bytes.org (8bytes.org [81.169.241.247]) by smtp3.osuosl.org (Postfix) with ESMTPS id 1A6566F55A for ; Wed, 17 Feb 2021 12:02:12 +0000 (UTC) Received: from cap.home.8bytes.org (p549adcf6.dip0.t-ipconnect.de [84.154.220.246]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by theia.8bytes.org (Postfix) with ESMTPSA id 36CF337C; Wed, 17 Feb 2021 13:02:09 +0100 (CET) From: Joerg Roedel To: x86@kernel.org Subject: [PATCH 2/3] x86/sev-es: Check if regs->sp is trusted before adjusting #VC IST stack Date: Wed, 17 Feb 2021 13:01:42 +0100 Message-Id: <20210217120143.6106-3-joro@8bytes.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210217120143.6106-1-joro@8bytes.org> References: <20210217120143.6106-1-joro@8bytes.org> MIME-Version: 1.0 Cc: kvm@vger.kernel.org, Peter Zijlstra , Dave Hansen , virtualization@lists.linux-foundation.org, Arvind Sankar , hpa@zytor.com, Jiri Slaby , Joerg Roedel , David Rientjes , Martin Radev , Tom Lendacky , Joerg Roedel , Kees Cook , Cfir Cohen , Andy Lutomirski , Dan Williams , Juergen Gross , Mike Stunes , Sean Christopherson , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Masami Hiramatsu , Erdem Aktas X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" From: Joerg Roedel The code in the NMI handler to adjust the #VC handler IST stack is needed in case an NMI hits when the #VC handler is still using its IST stack. But the check for this condition also needs to look if the regs->sp value is trusted, meaning it was not set by user-space. Extend the check to not use regs->sp when the NMI interrupted user-space code or the SYSCALL gap. Reported-by: Andy Lutomirski Fixes: 315562c9af3d5 ("x86/sev-es: Adjust #VC IST Stack on entering NMI handler") Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Joerg Roedel --- arch/x86/kernel/sev-es.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 84c1821819af..0df38b185d53 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -144,7 +144,9 @@ void noinstr __sev_es_ist_enter(struct pt_regs *regs) old_ist = __this_cpu_read(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC]); /* Make room on the IST stack */ - if (on_vc_stack(regs->sp)) + if (on_vc_stack(regs->sp) && + !user_mode(regs) && + !from_syscall_gap(regs)) new_ist = ALIGN_DOWN(regs->sp, 8) - sizeof(old_ist); else new_ist = old_ist - sizeof(old_ist); -- 2.30.0 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization