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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 A8560C4332D for ; Thu, 19 Mar 2020 09:19:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 88C8A2077D for ; Thu, 19 Mar 2020 09:19:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727547AbgCSJTv (ORCPT ); Thu, 19 Mar 2020 05:19:51 -0400 Received: from 8bytes.org ([81.169.241.247]:52110 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727236AbgCSJO2 (ORCPT ); Thu, 19 Mar 2020 05:14:28 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 8CEAB2DF; Thu, 19 Mar 2020 10:14:18 +0100 (CET) From: Joerg Roedel To: x86@kernel.org Cc: hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Thomas Hellstrom , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , Kees Cook , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, Joerg Roedel , Joerg Roedel Subject: [PATCH 14/70] x86/boot/compressed/64: Add page-fault handler Date: Thu, 19 Mar 2020 10:13:11 +0100 Message-Id: <20200319091407.1481-15-joro@8bytes.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200319091407.1481-1-joro@8bytes.org> References: <20200319091407.1481-1-joro@8bytes.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joerg Roedel Install a page-fault handler to add an identity mapping to addresses not yet mapped. Also do some checking whether the error code is sane. This makes non SEV-ES machines use the exception handling infrastructure in the pre-decompressions boot code too, making it less likely to break in the future. Signed-off-by: Joerg Roedel --- arch/x86/boot/compressed/ident_map_64.c | 38 ++++++++++++++++++++++ arch/x86/boot/compressed/idt_64.c | 2 ++ arch/x86/boot/compressed/idt_handlers_64.S | 2 ++ arch/x86/boot/compressed/misc.h | 6 ++++ 4 files changed, 48 insertions(+) diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c index 3a2115582920..0865d181b85d 100644 --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -19,11 +19,13 @@ /* No PAGE_TABLE_ISOLATION support needed either: */ #undef CONFIG_PAGE_TABLE_ISOLATION +#include "error.h" #include "misc.h" /* These actually do the work of building the kernel identity maps. */ #include #include +#include /* Use the static base for this part of the boot process */ #undef __PAGE_OFFSET #define __PAGE_OFFSET __PAGE_OFFSET_BASE @@ -163,3 +165,39 @@ void finalize_identity_maps(void) { write_cr3(top_level_pgt); } + +static void pf_error(unsigned long error_code, unsigned long address, + struct pt_regs *regs) +{ + error_putstr("Unexpected page-fault:"); + error_putstr("\nError Code: "); + error_puthex(error_code); + error_putstr("\nCR2: 0x"); + error_puthex(address); + error_putstr("\nRIP relative to _head: 0x"); + error_puthex(regs->ip - (unsigned long)_head); + error_putstr("\n"); + + error("Stopping.\n"); +} + +void do_boot_page_fault(struct pt_regs *regs) +{ + unsigned long address = native_read_cr2(); + unsigned long error_code = regs->orig_ax; + + /* + * 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)) + pf_error(error_code, address, regs); + + /* + * Error code is sane - now identity map the 2M region around + * the faulting address. + */ + add_identity_map(address & PMD_MASK, PMD_SIZE); +} diff --git a/arch/x86/boot/compressed/idt_64.c b/arch/x86/boot/compressed/idt_64.c index 46ecea671b90..84ba57d9d436 100644 --- a/arch/x86/boot/compressed/idt_64.c +++ b/arch/x86/boot/compressed/idt_64.c @@ -39,5 +39,7 @@ void load_stage2_idt(void) { boot_idt_desc.address = (unsigned long)boot_idt; + set_idt_entry(X86_TRAP_PF, boot_pf_handler); + load_boot_idt(&boot_idt_desc); } diff --git a/arch/x86/boot/compressed/idt_handlers_64.S b/arch/x86/boot/compressed/idt_handlers_64.S index 3d86ab35ef52..bfb3fc5aa144 100644 --- a/arch/x86/boot/compressed/idt_handlers_64.S +++ b/arch/x86/boot/compressed/idt_handlers_64.S @@ -73,3 +73,5 @@ SYM_FUNC_END(\name) .text .code64 + +EXCEPTION_HANDLER boot_pf_handler do_boot_page_fault error_code=1 diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 3a030a878d53..eff4ed0b1cea 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -37,6 +37,9 @@ #define memptr unsigned #endif +/* boot/compressed/vmlinux start and end markers */ +extern char _head[], _end[]; + /* misc.c */ extern memptr free_mem_ptr; extern memptr free_mem_end_ptr; @@ -146,4 +149,7 @@ extern pteval_t __default_kernel_pte_mask; extern gate_desc boot_idt[BOOT_IDT_ENTRIES]; extern struct desc_ptr boot_idt_desc; +/* IDT Entry Points */ +void boot_pf_handler(void); + #endif /* BOOT_COMPRESSED_MISC_H */ -- 2.17.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: [PATCH 14/70] x86/boot/compressed/64: Add page-fault handler Date: Thu, 19 Mar 2020 10:13:11 +0100 Message-ID: <20200319091407.1481-15-joro@8bytes.org> References: <20200319091407.1481-1-joro@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200319091407.1481-1-joro@8bytes.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" To: x86@kernel.org Cc: Juergen Gross , Tom Lendacky , Thomas Hellstrom , Joerg Roedel , Kees Cook , kvm@vger.kernel.org, Peter Zijlstra , Joerg Roedel , Dave Hansen , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Andy Lutomirski , hpa@zytor.com, Dan Williams , Jiri Slaby List-Id: virtualization@lists.linuxfoundation.org From: Joerg Roedel Install a page-fault handler to add an identity mapping to addresses not yet mapped. Also do some checking whether the error code is sane. This makes non SEV-ES machines use the exception handling infrastructure in the pre-decompressions boot code too, making it less likely to break in the future. Signed-off-by: Joerg Roedel --- arch/x86/boot/compressed/ident_map_64.c | 38 ++++++++++++++++++++++ arch/x86/boot/compressed/idt_64.c | 2 ++ arch/x86/boot/compressed/idt_handlers_64.S | 2 ++ arch/x86/boot/compressed/misc.h | 6 ++++ 4 files changed, 48 insertions(+) diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c index 3a2115582920..0865d181b85d 100644 --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -19,11 +19,13 @@ /* No PAGE_TABLE_ISOLATION support needed either: */ #undef CONFIG_PAGE_TABLE_ISOLATION +#include "error.h" #include "misc.h" /* These actually do the work of building the kernel identity maps. */ #include #include +#include /* Use the static base for this part of the boot process */ #undef __PAGE_OFFSET #define __PAGE_OFFSET __PAGE_OFFSET_BASE @@ -163,3 +165,39 @@ void finalize_identity_maps(void) { write_cr3(top_level_pgt); } + +static void pf_error(unsigned long error_code, unsigned long address, + struct pt_regs *regs) +{ + error_putstr("Unexpected page-fault:"); + error_putstr("\nError Code: "); + error_puthex(error_code); + error_putstr("\nCR2: 0x"); + error_puthex(address); + error_putstr("\nRIP relative to _head: 0x"); + error_puthex(regs->ip - (unsigned long)_head); + error_putstr("\n"); + + error("Stopping.\n"); +} + +void do_boot_page_fault(struct pt_regs *regs) +{ + unsigned long address = native_read_cr2(); + unsigned long error_code = regs->orig_ax; + + /* + * 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)) + pf_error(error_code, address, regs); + + /* + * Error code is sane - now identity map the 2M region around + * the faulting address. + */ + add_identity_map(address & PMD_MASK, PMD_SIZE); +} diff --git a/arch/x86/boot/compressed/idt_64.c b/arch/x86/boot/compressed/idt_64.c index 46ecea671b90..84ba57d9d436 100644 --- a/arch/x86/boot/compressed/idt_64.c +++ b/arch/x86/boot/compressed/idt_64.c @@ -39,5 +39,7 @@ void load_stage2_idt(void) { boot_idt_desc.address = (unsigned long)boot_idt; + set_idt_entry(X86_TRAP_PF, boot_pf_handler); + load_boot_idt(&boot_idt_desc); } diff --git a/arch/x86/boot/compressed/idt_handlers_64.S b/arch/x86/boot/compressed/idt_handlers_64.S index 3d86ab35ef52..bfb3fc5aa144 100644 --- a/arch/x86/boot/compressed/idt_handlers_64.S +++ b/arch/x86/boot/compressed/idt_handlers_64.S @@ -73,3 +73,5 @@ SYM_FUNC_END(\name) .text .code64 + +EXCEPTION_HANDLER boot_pf_handler do_boot_page_fault error_code=1 diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 3a030a878d53..eff4ed0b1cea 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -37,6 +37,9 @@ #define memptr unsigned #endif +/* boot/compressed/vmlinux start and end markers */ +extern char _head[], _end[]; + /* misc.c */ extern memptr free_mem_ptr; extern memptr free_mem_end_ptr; @@ -146,4 +149,7 @@ extern pteval_t __default_kernel_pte_mask; extern gate_desc boot_idt[BOOT_IDT_ENTRIES]; extern struct desc_ptr boot_idt_desc; +/* IDT Entry Points */ +void boot_pf_handler(void); + #endif /* BOOT_COMPRESSED_MISC_H */ -- 2.17.1