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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 D065EC433DB for ; Sat, 6 Feb 2021 05:00:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9334864F91 for ; Sat, 6 Feb 2021 05:00:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230423AbhBFE7r (ORCPT ); Fri, 5 Feb 2021 23:59:47 -0500 Received: from mga09.intel.com ([134.134.136.24]:63380 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231695AbhBFDgT (ORCPT ); Fri, 5 Feb 2021 22:36:19 -0500 IronPort-SDR: CiktdtmvipERApxn/couDuAkmeDNcvCJDnR0Kz+QH4HzK45XwO1iQwJrohCaBJ+gHsdg5sh/Sm 1m4Sxs7cbXuQ== X-IronPort-AV: E=McAfee;i="6000,8403,9886"; a="181650740" X-IronPort-AV: E=Sophos;i="5.81,156,1610438400"; d="scan'208";a="181650740" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Feb 2021 15:39:12 -0800 IronPort-SDR: R4J1MgSFA/P7FuNA/CBJOA8oGULjjKuwMEtZ+eTRWwEfGQSD/i4Z2NESl3/hARURjr7lJpE8QR odobaPOD8Z9g== X-IronPort-AV: E=Sophos;i="5.81,156,1610438400"; d="scan'208";a="416183933" Received: from mdhake-mobl.amr.corp.intel.com (HELO skuppusw-mobl5.amr.corp.intel.com) ([10.209.53.25]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Feb 2021 15:39:12 -0800 From: Kuppuswamy Sathyanarayanan To: Peter Zijlstra , Andy Lutomirski , Dave Hansen Cc: Andi Kleen , Kirill Shutemov , Kuppuswamy Sathyanarayanan , Dan Williams , Raj Ashok , Sean Christopherson , linux-kernel@vger.kernel.org, Sean Christopherson , Kai Huang , Kuppuswamy Sathyanarayanan Subject: [RFC v1 15/26] x86/boot: Add a trampoline for APs booting in 64-bit mode Date: Fri, 5 Feb 2021 15:38:32 -0800 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sean Christopherson Add a trampoline for booting APs in 64-bit mode via a software handoff with BIOS, and use the new trampoline for the ACPI MP wake protocol used by TDX. Extend the real mode IDT pointer by four bytes to support LIDT in 64-bit mode. For the GDT pointer, create a new entry as the existing storage for the pointer occupies the zero entry in the GDT itself. Reported-by: Kai Huang Signed-off-by: Sean Christopherson Reviewed-by: Andi Kleen Signed-off-by: Kuppuswamy Sathyanarayanan --- arch/x86/include/asm/realmode.h | 1 + arch/x86/kernel/smpboot.c | 5 +++ arch/x86/realmode/rm/header.S | 1 + arch/x86/realmode/rm/trampoline_64.S | 49 +++++++++++++++++++++++- arch/x86/realmode/rm/trampoline_common.S | 5 ++- 5 files changed, 58 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/realmode.h b/arch/x86/include/asm/realmode.h index 5db5d083c873..5066c8b35e7c 100644 --- a/arch/x86/include/asm/realmode.h +++ b/arch/x86/include/asm/realmode.h @@ -25,6 +25,7 @@ struct real_mode_header { u32 sev_es_trampoline_start; #endif #ifdef CONFIG_X86_64 + u32 trampoline_start64; u32 trampoline_pgd; #endif /* ACPI S3 wakeup */ diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 8ca66af96a54..11dd0deb4810 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1035,6 +1035,11 @@ static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle, unsigned long boot_error = 0; unsigned long timeout; +#ifdef CONFIG_X86_64 + if (is_tdx_guest()) + start_ip = real_mode_header->trampoline_start64; +#endif + idle->thread.sp = (unsigned long)task_pt_regs(idle); early_gdt_descr.address = (unsigned long)get_cpu_gdt_rw(cpu); initial_code = (unsigned long)start_secondary; diff --git a/arch/x86/realmode/rm/header.S b/arch/x86/realmode/rm/header.S index 8c1db5bf5d78..2eb62be6d256 100644 --- a/arch/x86/realmode/rm/header.S +++ b/arch/x86/realmode/rm/header.S @@ -24,6 +24,7 @@ SYM_DATA_START(real_mode_header) .long pa_sev_es_trampoline_start #endif #ifdef CONFIG_X86_64 + .long pa_trampoline_start64 .long pa_trampoline_pgd; #endif /* ACPI S3 wakeup */ diff --git a/arch/x86/realmode/rm/trampoline_64.S b/arch/x86/realmode/rm/trampoline_64.S index 84c5d1b33d10..12b734b1da8b 100644 --- a/arch/x86/realmode/rm/trampoline_64.S +++ b/arch/x86/realmode/rm/trampoline_64.S @@ -143,13 +143,20 @@ SYM_CODE_START(startup_32) movl %eax, %cr3 # Set up EFER + movl $MSR_EFER, %ecx + rdmsr + cmp pa_tr_efer, %eax + jne .Lwrite_efer + cmp pa_tr_efer + 4, %edx + je .Ldone_efer +.Lwrite_efer: movl pa_tr_efer, %eax movl pa_tr_efer + 4, %edx - movl $MSR_EFER, %ecx wrmsr +.Ldone_efer: # Enable paging and in turn activate Long Mode - movl $(X86_CR0_PG | X86_CR0_WP | X86_CR0_PE), %eax + movl $(X86_CR0_PG | X86_CR0_WP | X86_CR0_NE | X86_CR0_PE), %eax movl %eax, %cr0 /* @@ -161,6 +168,19 @@ SYM_CODE_START(startup_32) ljmpl $__KERNEL_CS, $pa_startup_64 SYM_CODE_END(startup_32) +SYM_CODE_START(pa_trampoline_compat) + /* + * In compatibility mode. Prep ESP and DX for startup_32, then disable + * paging and complete the switch to legacy 32-bit mode. + */ + movl $rm_stack_end, %esp + movw $__KERNEL_DS, %dx + + movl $(X86_CR0_NE | X86_CR0_PE), %eax + movl %eax, %cr0 + ljmpl $__KERNEL32_CS, $pa_startup_32 +SYM_CODE_END(pa_trampoline_compat) + .section ".text64","ax" .code64 .balign 4 @@ -169,6 +189,20 @@ SYM_CODE_START(startup_64) jmpq *tr_start(%rip) SYM_CODE_END(startup_64) +SYM_CODE_START(trampoline_start64) + /* + * APs start here on a direct transfer from 64-bit BIOS with identity + * mapped page tables. Load the kernel's GDT in order to gear down to + * 32-bit mode (to handle 4-level vs. 5-level paging), and to (re)load + * segment registers. Load the zero IDT so any fault triggers a + * shutdown instead of jumping back into BIOS. + */ + lidt tr_idt(%rip) + lgdt tr_gdt64(%rip) + + ljmpl *tr_compat(%rip) +SYM_CODE_END(trampoline_start64) + .section ".rodata","a" # Duplicate the global descriptor table # so the kernel can live anywhere @@ -182,6 +216,17 @@ SYM_DATA_START(tr_gdt) .quad 0x00cf93000000ffff # __KERNEL_DS SYM_DATA_END_LABEL(tr_gdt, SYM_L_LOCAL, tr_gdt_end) +SYM_DATA_START(tr_gdt64) + .short tr_gdt_end - tr_gdt - 1 # gdt limit + .long pa_tr_gdt + .long 0 +SYM_DATA_END(tr_gdt64) + +SYM_DATA_START(tr_compat) + .long pa_trampoline_compat + .short __KERNEL32_CS +SYM_DATA_END(tr_compat) + .bss .balign PAGE_SIZE SYM_DATA(trampoline_pgd, .space PAGE_SIZE) diff --git a/arch/x86/realmode/rm/trampoline_common.S b/arch/x86/realmode/rm/trampoline_common.S index 5033e640f957..506d5897112a 100644 --- a/arch/x86/realmode/rm/trampoline_common.S +++ b/arch/x86/realmode/rm/trampoline_common.S @@ -1,4 +1,7 @@ /* SPDX-License-Identifier: GPL-2.0 */ .section ".rodata","a" .balign 16 -SYM_DATA_LOCAL(tr_idt, .fill 1, 6, 0) +SYM_DATA_START_LOCAL(tr_idt) + .short 0 + .quad 0 +SYM_DATA_END(tr_idt) -- 2.25.1