From nobody Mon Mar 23 21:25:01 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass(p=reject dis=none) header.from=citrix.com ARC-Seal: i=1; a=rsa-sha256; t=1773923191; cv=none; d=zohomail.com; s=zohoarc; b=JE+FeeFdEDuGqgxgVlFvpA9PISwVNQ3gPp8ZDCXIpE52z+EoRr0DBcvjtbUpUsP5Mr5Nn3InXlpTnszledEanJoEhz8Lf8P38rbzN60Ejd/G+ImbeZ2TuX18kDkt8oX+QsEpp9cXAXhdESlt98n/XJ2y9uY0ZWwKj6MTMhd5XEY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1773923191; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=sNvCSrOBffuTtzSMMrot8orJxzRk8BMjuPIbTAHvYz0=; b=ImNB1MxiCDUraE95dXPBIK/JEWNhGoDngL2EBG5l5+lSSXTFqYgDlVqmagQ08b+25oN8omk11fO+d7U7vub35F8LnMyj+g+yQy3r9OEp3G9CtKod7p2xEMzBvpkRqW/naIU/00pqzZuFkGQjBlEuUWpjeTL4Csu2iZxBO44RAmc= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass header.from= (p=reject dis=none) Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1773923191873204.50086251521168; Thu, 19 Mar 2026 05:26:31 -0700 (PDT) Received: from list by lists.xenproject.org with outflank-mailman.1257012.1551470 (Exim 4.92) (envelope-from ) id 1w3CRq-00084J-9T; Thu, 19 Mar 2026 12:25:58 +0000 Received: by outflank-mailman (output) from mailman id 1257012.1551470; Thu, 19 Mar 2026 12:25:58 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1w3CRq-00084B-4u; Thu, 19 Mar 2026 12:25:58 +0000 Received: by outflank-mailman (input) for mailman id 1257012; Thu, 19 Mar 2026 12:25:56 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1w3CRo-0007dl-I6 for xen-devel@lists.xenproject.org; Thu, 19 Mar 2026 12:25:56 +0000 Received: from mail-wm1-x330.google.com (mail-wm1-x330.google.com [2a00:1450:4864:20::330]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id c673dd97-238e-11f1-b164-2bf370ae4941; Thu, 19 Mar 2026 13:25:54 +0100 (CET) Received: by mail-wm1-x330.google.com with SMTP id 5b1f17b1804b1-4852afd42ceso6482595e9.2 for ; Thu, 19 Mar 2026 05:25:54 -0700 (PDT) Received: from localhost.localdomain (host-92-22-18-152.as13285.net. [92.22.18.152]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-486f8c350aesm60831395e9.4.2026.03.19.05.25.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Mar 2026 05:25:52 -0700 (PDT) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: c673dd97-238e-11f1-b164-2bf370ae4941 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1773923154; x=1774527954; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=sNvCSrOBffuTtzSMMrot8orJxzRk8BMjuPIbTAHvYz0=; b=RNlQOr+bemU/6niK4DzhTF2Od9gVL/MBhqUOzn9suiBZguQt2vtiVoFwiKR4/2xtbC A9VpZ4XFwBsgFWDM3VVCqztOJMs7T3LjMinREbNG8jCyanwu4sMEUa4/4kXa2BpTjIsM 73Zyb3VBSt+4q0DCyyReAo7IUDb6JS+rOnHfI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1773923154; x=1774527954; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=sNvCSrOBffuTtzSMMrot8orJxzRk8BMjuPIbTAHvYz0=; b=ZYcwk3kieH2lg2UFwiMEaZRVY30TO2m3TbPIgmW/jDik0g3PtyFaDC7sgVMbR59tI4 yK8bRCNYG678g2ieGeqy9Wk8ih9ClxpoyaJdwD60kTvWseaireafMaRg9vaoivXOtNox TbV/uEUF9YiOEkRqNv9iYjbQz+Jef/UT5+fN9nOdKjX7YY+ZYXk5Ko4hYZwOiVW9RirC vThzSGK1Gaxf+7HXFsVkc9pMI8+Z7ckOswtf6nIRklJeZH8l6zYfr4/+wq2fO9TpBJ42 dQDKr7D7zEHHKk/c3m6lv58QhXnM9fW9+CUwDLDRO8aQmC8RPUKY2E5vSg47AP7wbkL1 oX9w== X-Gm-Message-State: AOJu0YxNyqpbRK5ajzhPjDcBCqlEcoM1ff+muyFXL+i1sZ4qw8/bVd9g gs1jO5JT6jA262MKcwAEK25kzXJd4DpoAzDyuSsxDoMzjZswIDAYlPM7FQ52ZJdx06J2yrGCiaI 3Ey7u X-Gm-Gg: ATEYQzwGb2JlxZUqeKPYarVO3QR7lKAVuHFX+17f8Rc040d/gXrHR4sG9LCAJ629cI+ ht1VEL+XwSTSFmr4wOXUTTqAPIxzaJJChmemI4DP+IcqHeizxRYa24LPotjwn7ksD+4tilbPkKh AK2jnMJhQq7TTlP+nBTxNkTWRj0F0lTzEzPnnJtx5TLNA3Ewd7yLk2OY42YQBPXJzdZfZV0fDp5 GlsBCfJ2/tl3zUonNe0eC65wGwPmqYrCbIC0FBjFX0C3iEd0CvtfbQ9ZEaW1pz4OkgcJNF2f00y N/zeXvssYt517ZI2MFryK/Bd4fOJtTY4H/aAqBmSBmYo4Rh1qjaSvrm2vf+WzRmVPtjLlJQJD5y RsU+jW51SGAZ3FWZnQVswz4eJyRP8e5BZ0MQ3RdboFytXzH51LvcksPsTgh6EDb2UvaLAGKVMrx C7ujO41TgLHLAaEk74xg/X6IRnyf5/fB0atZ/tvsiX8fRqEzlJ/j3Tjdg8l+IoPbtOoIj019A= X-Received: by 2002:a05:600c:4ed4:b0:485:3c2d:d02b with SMTP id 5b1f17b1804b1-486f4444050mr121170235e9.22.1773923153070; Thu, 19 Mar 2026 05:25:53 -0700 (PDT) From: Andrew Cooper To: Xen-devel Cc: Andrew Cooper , Jan Beulich , =?UTF-8?q?Roger=20Pau=20Monn=C3=A9?= Subject: [PATCH 2/4] x86/kexec: Fix and expands comments for kexec_reloc() Date: Thu, 19 Mar 2026 12:25:47 +0000 Message-Id: <20260319122549.922724-3-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260319122549.922724-1-andrew.cooper3@citrix.com> References: <20260319122549.922724-1-andrew.cooper3@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @citrix.com) X-ZM-MESSAGEID: 1773923192496158500 The order of shutdown is delicate. Explain things a little better. Fix two comments about leaving Long Mode. Signed-off-by: Andrew Cooper --- CC: Jan Beulich CC: Roger Pau Monn=C3=A9 --- xen/arch/x86/x86_64/kexec_reloc.S | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/xen/arch/x86/x86_64/kexec_reloc.S b/xen/arch/x86/x86_64/kexec_= reloc.S index b52d31a654e0..d0951ea1e1c4 100644 --- a/xen/arch/x86/x86_64/kexec_reloc.S +++ b/xen/arch/x86/x86_64/kexec_reloc.S @@ -27,6 +27,14 @@ .section .text.kexec, "ax", @progbits .code64 =20 + /* + * kexec_reloc() is entered in it's natural position within Xen. + * + * A copy of .text.kexec is identity mapped at %rdi within the + * pagetables in %rsi. Xen's .text is mapped into %rsi at it's hi= gh + * alias allowing to pivot, but most other things including the st= acks + * are not mapped. + */ FUNC(kexec_reloc, PAGE_SIZE) /* %rdi - code page maddr */ /* %rsi - page table maddr */ @@ -36,10 +44,17 @@ FUNC(kexec_reloc, PAGE_SIZE) =20 movq %rcx, %rbp =20 - /* Setup stack. */ + /* + * Move to the identity mapped stack. + * + * Note this mapping doesn't exist until the pagetable switch. + */ leaq (.Lreloc_stack_base - kexec_reloc)(%rdi), %rsp =20 - /* Load reloc page table. */ + /* + * Move to the relocation pagetables. Xen's .text is mapped allow= ing + * the pivot, but very little else is. + */ movq %rsi, %cr3 =20 /* Jump to identity mapped code. */ @@ -153,12 +168,12 @@ FUNC_LOCAL(compatibility_mode) movl %eax, %gs movl %eax, %ss =20 - /* Disable paging and therefore leave 64 bit mode. */ + /* Disable paging and therefore leave long mode. */ movl %cr0, %eax andl $~X86_CR0_PG, %eax movl %eax, %cr0 =20 - /* Disable long mode */ + /* Clear EFER.LME */ movl $MSR_EFER, %ecx rdmsr andl $~EFER_LME, %eax --=20 2.39.5