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=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 DC0ACC48BDF for ; Tue, 15 Jun 2021 10:52:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC4C461455 for ; Tue, 15 Jun 2021 10:52:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231805AbhFOKyY (ORCPT ); Tue, 15 Jun 2021 06:54:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45200 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231696AbhFOKyG (ORCPT ); Tue, 15 Jun 2021 06:54:06 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BDF5AC06175F; Tue, 15 Jun 2021 03:52:01 -0700 (PDT) Date: Tue, 15 Jun 2021 10:51:56 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1623754317; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ehTyxZ1zPqyQv+vzIOiUtO11ULsVjYxCXCKYkwBgtKU=; b=cT4LsHqWZbBg7Ua6+vJgu5CKP0vmP5UzNerY6aYXQMAO/eBtfPQe5TFdcn2Pm5UHg0/jPk h0NrsrxEnyPgLFQovWzxckq/rozyFF1pLZG69uFBE8qlhqlgAPCrmYgNK+qlLh20U6fzsE Zy+0PeBonys9r0oHNT328P+i55pQB+ckAVAwQfJEBurL9k6oypjlswVZo5bflNVw+eK6u9 o+r/kCJDj/cL0XmTI1qJw+44rt3U84CKIHU7Kjm14M5tahVr6j4ZEeG6OyIh+YrBkrzIzU w0u+woBP7x7aH5FoWAMIRwX7Af+I6Vv1C1hOEgRoAW2Sv8w5L2LcyQfNfXZJ4w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1623754317; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ehTyxZ1zPqyQv+vzIOiUtO11ULsVjYxCXCKYkwBgtKU=; b=hHxozy12bn9NkdueCvtnD2wQ2+09AhxE/WP7ohVPmOzVLdDV0JX/Yrhe8kmuD8bdNcVhsR t+O5vRQRDNfqNjAg== From: "tip-bot2 for Joerg Roedel" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/sev] x86/insn: Extend error reporting from insn_fetch_from_user[_inatomic]() Cc: Joerg Roedel , Borislav Petkov , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210614135327.9921-6-joro@8bytes.org> References: <20210614135327.9921-6-joro@8bytes.org> MIME-Version: 1.0 Message-ID: <162375431666.19906.425378072212766758.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/sev branch of tip: Commit-ID: 4aaa7eacd7cc7c10f269c7f2a01d044b375bed8e Gitweb: https://git.kernel.org/tip/4aaa7eacd7cc7c10f269c7f2a01d044b375bed8e Author: Joerg Roedel AuthorDate: Mon, 14 Jun 2021 15:53:26 +02:00 Committer: Borislav Petkov CommitterDate: Tue, 15 Jun 2021 11:39:30 +02:00 x86/insn: Extend error reporting from insn_fetch_from_user[_inatomic]() The error reporting from the insn_fetch_from_user*() functions is not very verbose. Extend it to include information on whether the linear RIP could not be calculated or whether the memory access faulted. This will be used in the SEV-ES code to propagate the correct exception depending on what went wrong during instruction fetch. [ bp: Massage comments. ] Signed-off-by: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210614135327.9921-6-joro@8bytes.org --- arch/x86/kernel/sev.c | 8 ++++---- arch/x86/kernel/umip.c | 10 ++++------ arch/x86/lib/insn-eval.c | 16 ++++++++-------- 3 files changed, 16 insertions(+), 18 deletions(-) diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 4fd997b..a1eeaa7 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -258,17 +258,17 @@ static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt, static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt) { char buffer[MAX_INSN_SIZE]; - int res; + int insn_bytes; - res = insn_fetch_from_user_inatomic(ctxt->regs, buffer); - if (!res) { + insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer); + if (insn_bytes <= 0) { ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; ctxt->fi.cr2 = ctxt->regs->ip; return ES_EXCEPTION; } - if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, res)) + if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes)) return ES_DECODE_FAILED; if (ctxt->insn.immediate.got) diff --git a/arch/x86/kernel/umip.c b/arch/x86/kernel/umip.c index 8daa70b..576b47e 100644 --- a/arch/x86/kernel/umip.c +++ b/arch/x86/kernel/umip.c @@ -346,14 +346,12 @@ bool fixup_umip_exception(struct pt_regs *regs) if (!regs) return false; - nr_copied = insn_fetch_from_user(regs, buf); - /* - * The insn_fetch_from_user above could have failed if user code - * is protected by a memory protection key. Give up on emulation - * in such a case. Should we issue a page fault? + * Give up on emulation if fetching the instruction failed. Should a + * page fault or a #GP be issued? */ - if (!nr_copied) + nr_copied = insn_fetch_from_user(regs, buf); + if (nr_copied <= 0) return false; if (!insn_decode_from_regs(&insn, regs, buf, nr_copied)) diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index 4eecb9c..a1d24fd 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -1448,9 +1448,9 @@ static int insn_get_effective_ip(struct pt_regs *regs, unsigned long *ip) * * Returns: * - * Number of instruction bytes copied. - * - * 0 if nothing was copied. + * - number of instruction bytes copied. + * - 0 if nothing was copied. + * - -EINVAL if the linear address of the instruction could not be calculated */ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) { @@ -1458,7 +1458,7 @@ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) int not_copied; if (insn_get_effective_ip(regs, &ip)) - return 0; + return -EINVAL; not_copied = copy_from_user(buf, (void __user *)ip, MAX_INSN_SIZE); @@ -1476,9 +1476,9 @@ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) * * Returns: * - * Number of instruction bytes copied. - * - * 0 if nothing was copied. + * - number of instruction bytes copied. + * - 0 if nothing was copied. + * - -EINVAL if the linear address of the instruction could not be calculated. */ int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) { @@ -1486,7 +1486,7 @@ int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_IN int not_copied; if (insn_get_effective_ip(regs, &ip)) - return 0; + return -EINVAL; not_copied = __copy_from_user_inatomic(buf, (void __user *)ip, MAX_INSN_SIZE);