From nobody Sun Apr 12 04:22:12 2026 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 D669DC00144 for ; Mon, 1 Aug 2022 16:39:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233904AbiHAQjb (ORCPT ); Mon, 1 Aug 2022 12:39:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233274AbiHAQjN (ORCPT ); Mon, 1 Aug 2022 12:39:13 -0400 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A35FEC0C for ; Mon, 1 Aug 2022 09:39:12 -0700 (PDT) Received: from localhost.localdomain (unknown [92.49.173.143]) by mail.ispras.ru (Postfix) with ESMTPSA id D9A09407626A; Mon, 1 Aug 2022 16:39:10 +0000 (UTC) From: Evgeniy Baskov To: Borislav Petkov Cc: Evgeniy Baskov , Dave Hansen , Ingo Molnar , Thomas Gleixner , Andy Lutomirski , Peter Zijlstra , x86@kernel.org, linux-kernel@vger.kernel.org, Alexey Khoroshilov Subject: [PATCH 8/8] x86/boot: Remove mapping from page fault handler Date: Mon, 1 Aug 2022 19:39:05 +0300 Message-Id: <25ecf8d7109600757b69ea167cc964419878ec21.1659369873.git.baskov@ispras.ru> X-Mailer: git-send-email 2.35.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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. Signed-off-by: Evgeniy Baskov diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compre= ssed/ident_map_64.c index 04022c080114..ad24289cc224 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, unsigne= d long error_code) { unsigned long address =3D native_read_cr2(); unsigned long end; - bool ghcb_fault; + char *msg; =20 - ghcb_fault =3D sev_es_check_ghcb_fault(address); + if (sev_es_check_ghcb_fault(address)) + msg =3D "Page-fault on GHCB page:"; + else + msg =3D "Unexpected page-fault:"; =20 address &=3D PMD_MASK; end =3D address + PMD_SIZE; =20 /* - * 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); } --=20 2.35.1