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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 C97D6C43382 for ; Tue, 25 Sep 2018 11:12:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B8A120843 for ; Tue, 25 Sep 2018 11:12:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7B8A120843 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728929AbeIYRTm (ORCPT ); Tue, 25 Sep 2018 13:19:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39816 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727570AbeIYRTm (ORCPT ); Tue, 25 Sep 2018 13:19:42 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D474462EAB; Tue, 25 Sep 2018 11:12:39 +0000 (UTC) Received: from kasong-desktop-nay-redhat-com.nay.redhat.com (unknown [10.66.128.41]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2E2811081316; Tue, 25 Sep 2018 11:12:33 +0000 (UTC) From: Kairui Song To: linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, thomas.lendacky@amd.com, brijesh.singh@amd.com, bp@suse.de, kasong@redhat.com, kexec@lists.infradead.org, dyoung@redhat.com Subject: [PATCH] x86/boot: Fix kexec booting failure after SEV early boot support Date: Tue, 25 Sep 2018 19:10:20 +0800 Message-Id: <20180925111020.23834-1-kasong@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 25 Sep 2018 11:12:40 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 1958b5fc4010 ("x86/boot: Add early boot support when running with SEV active") is causing kexec becomes sometimes unstable, kexec reboot won't start a second kernel bypassing BIOS boot process, instead, the system got reset. That's because, in get_sev_encryption_bit function, we are using 32-bit RIP-relative addressing to read the value of enc_bit, but kexec may alloc the early boot up code to a higher location, which is beyond 32-bit addressing limit. Some garbage will be read and get_sev_encryption_bit will return the wrong value, which lead to wrong memory page flag. This patch adds a get_sev_encryption_bit_64 function to avoid this problem. 64-bit early boot code will use this function instead, it uses native RIP addressing to read the enc_bit which have no problem with any location. Fixes: 1958b5fc4010 ("x86/boot: Add early boot support when running with SEV active") Signed-off-by: Kairui Song --- arch/x86/boot/compressed/mem_encrypt.S | 64 ++++++++++++++++++-------- 1 file changed, 45 insertions(+), 19 deletions(-) diff --git a/arch/x86/boot/compressed/mem_encrypt.S b/arch/x86/boot/compressed/mem_encrypt.S index eaa843a52907..41933550449a 100644 --- a/arch/x86/boot/compressed/mem_encrypt.S +++ b/arch/x86/boot/compressed/mem_encrypt.S @@ -18,27 +18,13 @@ .text .code32 -ENTRY(get_sev_encryption_bit) +do_get_sev_encryption_bit: xor %eax, %eax #ifdef CONFIG_AMD_MEM_ENCRYPT push %ebx push %ecx push %edx - push %edi - - /* - * RIP-relative addressing is needed to access the encryption bit - * variable. Since we are running in 32-bit mode we need this call/pop - * sequence to get the proper relative addressing. - */ - call 1f -1: popl %edi - subl $1b, %edi - - movl enc_bit(%edi), %eax - cmpl $0, %eax - jge .Lsev_exit /* Check if running under a hypervisor */ movl $1, %eax @@ -69,25 +55,65 @@ ENTRY(get_sev_encryption_bit) movl %ebx, %eax andl $0x3f, %eax /* Return the encryption bit location */ - movl %eax, enc_bit(%edi) jmp .Lsev_exit .Lno_sev: xor %eax, %eax - movl %eax, enc_bit(%edi) .Lsev_exit: - pop %edi pop %edx pop %ecx pop %ebx +#endif /* CONFIG_AMD_MEM_ENCRYPT */ + + ret + +ENTRY(get_sev_encryption_bit) + xor %eax, %eax + +#ifdef CONFIG_AMD_MEM_ENCRYPT + push %edi + + /* + * RIP-relative addressing is needed to access the encryption bit + * variable. Since we are running in 32-bit mode we need this call/pop + * sequence to get the proper relative addressing. + */ + call 1f +1: popl %edi + subl $1b, %edi + + movl enc_bit(%edi), %eax + cmpl $0, %eax + jge 2f + + call do_get_sev_encryption_bit + movl %eax, enc_bit(%edi) +2: + pop %edi #endif /* CONFIG_AMD_MEM_ENCRYPT */ ret ENDPROC(get_sev_encryption_bit) .code64 +ENTRY(get_sev_encryption_bit_64) + xor %rax, %rax + +#ifdef CONFIG_AMD_MEM_ENCRYPT + movl enc_bit(%rip), %eax + cmpl $0, %eax + jge 1f + + call do_get_sev_encryption_bit + movl %eax, enc_bit(%rip) +1: +#endif /* CONFIG_AMD_MEM_ENCRYPT */ + + ret +ENDPROC(get_sev_encryption_bit_64) + ENTRY(set_sev_encryption_mask) #ifdef CONFIG_AMD_MEM_ENCRYPT push %rbp @@ -95,7 +121,7 @@ ENTRY(set_sev_encryption_mask) movq %rsp, %rbp /* Save current stack pointer */ - call get_sev_encryption_bit /* Get the encryption bit position */ + call get_sev_encryption_bit_64 /* Get the encryption bit position */ testl %eax, %eax jz .Lno_sev_mask -- 2.17.1