From nobody Wed Sep 17 22:22:06 2025 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 B3DECC4167B for ; Thu, 15 Dec 2022 12:42:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230030AbiLOMlr (ORCPT ); Thu, 15 Dec 2022 07:41:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229905AbiLOMlY (ORCPT ); Thu, 15 Dec 2022 07:41:24 -0500 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAD0D27916; Thu, 15 Dec 2022 04:40:24 -0800 (PST) Received: from localhost.localdomain (unknown [83.149.199.65]) by mail.ispras.ru (Postfix) with ESMTPSA id 3C6D740737AF; Thu, 15 Dec 2022 12:40:23 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru 3C6D740737AF DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1671108023; bh=KkRKm6qcAmh0kiXQ21qOF8qFcABzU2w96OZgSYkHTXk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=obfol3CWp8LzXplKHkyHUZG/d7EfhBPFxgNTXiq/+9N8zDYn8ZUrazpcQ4bVXwJ2r K84oqYuP8j8keBSAxnJ3M0/tyucNLJbN6LEyFF9wedck8+HdFNuJb30hP0EVXy+rmU Mj7tXclEFv5gACAMJ1Rgv50xHd23feclvEs1SYc0= 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 , "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 v4 09/26] x86/boot: Remove mapping from page fault handler Date: Thu, 15 Dec 2022 15:38:00 +0300 Message-Id: X-Mailer: git-send-email 2.37.4 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. Tested-by: Mario Limonciello Tested-by: Peter Jones Signed-off-by: Evgeniy Baskov Reviewed-by: Ard Biesheuvel --- 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/compre= ssed/ident_map_64.c index fec795a4ce23..ba5108c58a4e 100644 --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -386,27 +386,21 @@ 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 2.37.4