From patchwork Tue Oct 25 12:47:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 619077 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2AB9C38A2D for ; Tue, 25 Oct 2022 12:51:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232495AbiJYMvg (ORCPT ); Tue, 25 Oct 2022 08:51:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232498AbiJYMu7 (ORCPT ); Tue, 25 Oct 2022 08:50:59 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E377E196B6B for ; Tue, 25 Oct 2022 05:48:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666702110; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Hjv4lWsvg+hFAXBQVxvDxYwhYVqBj8cP/nEGapoZ4V4=; b=g094t0nAFqLXiaCzw7pwdycUijCbd+irF5QDLXGjJrhPXge22483iria6pVXRBSR+IRpWQ 5pdt+EmwEnMSZRp3v6GhHSzkME93dG7WKJYIeu43g4NowKH82X4BuJOPnFvIPS2+avDCWm URkYTfIwJtrm1LEZhxcsmmzZo0qFWig= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-324-aTUiDCU9MBmHNJh1D0eb3A-1; Tue, 25 Oct 2022 08:48:29 -0400 X-MC-Unique: aTUiDCU9MBmHNJh1D0eb3A-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 51CDE101246E; Tue, 25 Oct 2022 12:48:28 +0000 (UTC) Received: from amdlaptop.tlv.redhat.com (dhcp-4-238.tlv.redhat.com [10.35.4.238]) by smtp.corp.redhat.com (Postfix) with ESMTP id F274F40C6E13; Tue, 25 Oct 2022 12:48:24 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: Thomas Gleixner , Yang Zhong , x86@kernel.org, Jim Mattson , Vitaly Kuznetsov , Paolo Bonzini , Sean Christopherson , Wanpeng Li , Shuah Khan , Guang Zeng , Joerg Roedel , Maxim Levitsky , linux-kernel@vger.kernel.org, Dave Hansen , Ingo Molnar , linux-kselftest@vger.kernel.org, Kees Cook , "H. Peter Anvin" , Wei Wang , Borislav Petkov Subject: [PATCH RESEND v4 10/23] KVM: x86: emulator: em_sysexit should update ctxt->mode Date: Tue, 25 Oct 2022 15:47:28 +0300 Message-Id: <20221025124741.228045-11-mlevitsk@redhat.com> In-Reply-To: <20221025124741.228045-1-mlevitsk@redhat.com> References: <20221025124741.228045-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org SYSEXIT is one of the instructions that can change the processor mode, thus ctxt->mode should be updated after it. Note that this is likely a benign bug, because the only problematic mode change is from 32 bit to 64 bit which can lead to truncation of RIP, and it is not possible to do with sysexit, since sysexit running in 32 bit mode will be limited to 32 bit version. Signed-off-by: Maxim Levitsky --- arch/x86/kvm/emulate.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 671f7e5871ff70..e23c984d6aae09 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2525,6 +2525,7 @@ static int em_sysexit(struct x86_emulate_ctxt *ctxt) ops->set_segment(ctxt, ss_sel, &ss, 0, VCPU_SREG_SS); ctxt->_eip = rdx; + ctxt->mode = usermode; *reg_write(ctxt, VCPU_REGS_RSP) = rcx; return X86EMUL_CONTINUE;