From patchwork Sun Oct 15 03:22:58 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 825907 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3yF6Lh2M91z9sNr for ; Sun, 15 Oct 2017 14:26:36 +1100 (AEDT) Received: from localhost ([::1]:55961 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e3ZZS-0004Ya-7H for incoming@patchwork.ozlabs.org; Sat, 14 Oct 2017 23:26:34 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48833) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e3ZW3-0002Cw-JI for qemu-devel@nongnu.org; Sat, 14 Oct 2017 23:23:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e3ZW2-0006Hm-I4 for qemu-devel@nongnu.org; Sat, 14 Oct 2017 23:23:03 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56856) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e3ZW2-0006GF-8y for qemu-devel@nongnu.org; Sat, 14 Oct 2017 23:23:02 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5D5EC80463; Sun, 15 Oct 2017 03:23:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 5D5EC80463 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=mst@redhat.com Received: from redhat.com (ovpn-120-178.rdu2.redhat.com [10.10.120.178]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7C6E761F3E; Sun, 15 Oct 2017 03:22:58 +0000 (UTC) Date: Sun, 15 Oct 2017 06:22:58 +0300 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <1508036858-13479-7-git-send-email-mst@redhat.com> References: <1508036858-13479-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1508036858-13479-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Sun, 15 Oct 2017 03:23:01 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 06/26] dump: update phys_base header field based on VMCOREINFO content X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , =?utf-8?q?Marc-Andr=C3=A9?= Lureau Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Marc-AndrĂ© Lureau If the guest note is VMCOREINFO, try to get phys_base from it. Signed-off-by: Marc-AndrĂ© Lureau Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- docs/specs/vmcoreinfo.txt | 8 +++++++ dump.c | 56 +++++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 62 insertions(+), 2 deletions(-) diff --git a/docs/specs/vmcoreinfo.txt b/docs/specs/vmcoreinfo.txt index 2868a77..8212610 100644 --- a/docs/specs/vmcoreinfo.txt +++ b/docs/specs/vmcoreinfo.txt @@ -39,3 +39,11 @@ qemu dumps. The note format/class must be of the target bitness and the size must be less than 1Mb. + +If the ELF note name is "VMCOREINFO", it is expected to be the Linux +vmcoreinfo note (see Documentation/ABI/testing/sysfs-kernel-vmcoreinfo +in Linux source). In this case, qemu dump code will read the content +as a key=value text file, looking for "NUMBER(phys_base)" key +value. The value is expected to be more accurate than architecture +guess of the value. This is useful for KASLR-enabled guest with +ancient tools not handling the VMCOREINFO note. diff --git a/dump.c b/dump.c index 1479f1f..5674512 100644 --- a/dump.c +++ b/dump.c @@ -779,6 +779,23 @@ static void get_note_sizes(DumpState *s, const void *note, } } +static bool note_name_equal(DumpState *s, + const uint8_t *note, const char *name) +{ + int len = strlen(name) + 1; + uint64_t head_size, name_size; + + get_note_sizes(s, note, &head_size, &name_size, NULL); + head_size = ROUND_UP(head_size, 4); + + if (name_size != len || + memcmp(note + head_size, "VMCOREINFO", len)) { + return false; + } + + return true; +} + /* write common header, sub header and elf note to vmcore */ static void create_header32(DumpState *s, Error **errp) { @@ -1553,6 +1570,39 @@ static int64_t dump_calculate_size(DumpState *s) return total; } +static void vmcoreinfo_update_phys_base(DumpState *s) +{ + uint64_t size, note_head_size, name_size, phys_base; + char **lines; + uint8_t *vmci; + size_t i; + + if (!note_name_equal(s, s->guest_note, "VMCOREINFO")) { + return; + } + + get_note_sizes(s, s->guest_note, ¬e_head_size, &name_size, &size); + note_head_size = ROUND_UP(note_head_size, 4); + + vmci = s->guest_note + note_head_size + ROUND_UP(name_size, 4); + *(vmci + size) = '\0'; + + lines = g_strsplit((char *)vmci, "\n", -1); + for (i = 0; lines[i]; i++) { + if (g_str_has_prefix(lines[i], "NUMBER(phys_base)=")) { + if (qemu_strtou64(lines[i] + 18, NULL, 16, + &phys_base) < 0) { + warn_report("Failed to read NUMBER(phys_base)="); + } else { + s->dump_info.phys_base = phys_base; + } + break; + } + } + + g_strfreev(lines); +} + static void dump_init(DumpState *s, int fd, bool has_format, DumpGuestMemoryFormat format, bool paging, bool has_filter, int64_t begin, int64_t length, Error **errp) @@ -1636,8 +1686,9 @@ static void dump_init(DumpState *s, int fd, bool has_format, } /* - * The goal of this block is to copy the guest note out of - * the guest. Failure to do so is not fatal for dumping. + * The goal of this block is to (a) update the previously guessed + * phys_base, (b) copy the guest note out of the guest. + * Failure to do so is not fatal for dumping. */ if (vmci) { uint64_t addr, note_head_size, name_size, desc_size; @@ -1670,6 +1721,7 @@ static void dump_init(DumpState *s, int fd, bool has_format, g_free(s->guest_note); s->guest_note = NULL; } else { + vmcoreinfo_update_phys_base(s); s->note_size += s->guest_note_size; } }