From patchwork Tue Mar 14 10:13:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evgeniy Baskov X-Patchwork-Id: 663806 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 9C8B0C74A44 for ; Tue, 14 Mar 2023 10:16:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230516AbjCNKQ6 (ORCPT ); Tue, 14 Mar 2023 06:16:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230445AbjCNKQe (ORCPT ); Tue, 14 Mar 2023 06:16:34 -0400 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3AED392F0C; Tue, 14 Mar 2023 03:16:04 -0700 (PDT) Received: from localhost.localdomain (unknown [83.149.199.65]) by mail.ispras.ru (Postfix) with ESMTPSA id 759B94076B51; Tue, 14 Mar 2023 10:16:02 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru 759B94076B51 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1678788962; bh=KQX50IDaA6jZ2kthtK8SXDuugyihF8jwWgQGjoDSXQ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KjQYisjfZxZMV6h4m+SHY/QIVeA5iWeLKlreyZ85e4KK9cIyEmIPmZQyE654zZ1CU m61kYU1rLJ4noPb5EZpmpeIFyD6fr/Q0K/v9kn1xDsZsxdwDVjBj+DQAIzYG/Y7hhe wSsXQ2o3Afrd6yrxTnu+4zpucAJtk+9SLq9+olis= From: Evgeniy Baskov To: Ard Biesheuvel Cc: Evgeniy Baskov , Borislav Petkov , Andy Lutomirski , Dave Hansen , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexey Khoroshilov , Peter Jones , Gerd Hoffmann , "Limonciello, Mario" , joeyli , lvc-project@linuxtesting.org, x86@kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH v5 09/27] x86/boot: Remove mapping from page fault handler Date: Tue, 14 Mar 2023 13:13:36 +0300 Message-Id: X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org After every implicit mapping is removed, this code is no longer needed. Remove memory mapping from page fault handler to ensure that there are no hidden invalid memory accesses. Tested-by: Mario Limonciello Signed-off-by: Evgeniy Baskov --- arch/x86/boot/compressed/ident_map_64.c | 26 ++++++++++--------------- 1 file changed, 10 insertions(+), 16 deletions(-) diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c index eb28ce9812c5..378f99b1d7e8 100644 --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -393,27 +393,21 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code) { unsigned long address = native_read_cr2(); unsigned long end; - bool ghcb_fault; + char *msg; - ghcb_fault = sev_es_check_ghcb_fault(address); + if (sev_es_check_ghcb_fault(address)) + msg = "Page-fault on GHCB page:"; + else + msg = "Unexpected page-fault:"; address &= PMD_MASK; end = address + PMD_SIZE; /* - * Check for unexpected error codes. Unexpected are: - * - Faults on present pages - * - User faults - * - Reserved bits set - */ - if (error_code & (X86_PF_PROT | X86_PF_USER | X86_PF_RSVD)) - do_pf_error("Unexpected page-fault:", error_code, address, regs->ip); - else if (ghcb_fault) - do_pf_error("Page-fault on GHCB page:", error_code, address, regs->ip); - - /* - * Error code is sane - now identity map the 2M region around - * the faulting address. + * Since all memory allocations are made explicit + * now, every page fault at this stage is an + * error and the error handler is there only + * for debug purposes. */ - kernel_add_identity_map(address, end, MAP_WRITE); + do_pf_error(msg, error_code, address, regs->ip); }