From nobody Mon Feb 9 23:39:57 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1563978710; cv=none; d=zoho.com; s=zohoarc; b=oEWgSMx41AkJBO8C7olRswk8ISk19epmCX3gYi7rdbJgMeQQEEQqofJQdusj4kIctq71jr6ig3AONeuQCYDjm6BafxI+A3fSrI/CHCyJ+w8Z7NVqbaY+9qXfNBfmdEfCfxazQwOUhXs2kSAf2TTp6iEY4CPriHDdin326hK6ECY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1563978710; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=EeGz1LTu7VM46WJhK+qja7OPHyHv5EJdvvn2WwKvCZI=; b=Nuqs521mG8XjhbkJQHj2+CC7iwyQSuTiar/B2MsUgTwplOrRsHpQwptHnYlBoPTnRkyaZcuxFOKzbbcTanHgAQnjKvyJdkaHzqzTSC56cygDbhEyNV56w7TaGLBGaO+s8px6d3nGRjgzkqZFEH/rRVM0omPrDWoujofkNiSlcY0= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1563978710856120.85953498536571; Wed, 24 Jul 2019 07:31:50 -0700 (PDT) Received: from localhost ([::1]:52154 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqIIy-0003VF-BV for importer@patchew.org; Wed, 24 Jul 2019 10:31:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58760) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqIIc-0002Sd-Fk for qemu-devel@nongnu.org; Wed, 24 Jul 2019 10:31:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqIIb-000570-5z for qemu-devel@nongnu.org; Wed, 24 Jul 2019 10:31:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63211) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqIIa-00056J-UG for qemu-devel@nongnu.org; Wed, 24 Jul 2019 10:31:21 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 31D1B307CDFC; Wed, 24 Jul 2019 14:31:20 +0000 (UTC) Received: from steredhat.redhat.com (ovpn-117-46.ams2.redhat.com [10.36.117.46]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7B94260BEC; Wed, 24 Jul 2019 14:31:17 +0000 (UTC) From: Stefano Garzarella To: qemu-devel@nongnu.org Date: Wed, 24 Jul 2019 16:31:04 +0200 Message-Id: <20190724143105.307042-3-sgarzare@redhat.com> In-Reply-To: <20190724143105.307042-1-sgarzare@redhat.com> References: <20190724143105.307042-1-sgarzare@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.49]); Wed, 24 Jul 2019 14:31:20 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v4 2/3] elf-ops.h: Map into memory the ELF to load X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Eduardo Habkost , Sergio Lopez , "Michael S. Tsirkin" , Julio Montes , "Dr . David Alan Gilbert" , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" In order to reduce the memory footprint we map into memory the ELF to load using g_mapped_file_new_from_fd() instead of reading each sections. In this way we can share the ELF pages between multiple instances of QEMU. Suggested-by: Dr. David Alan Gilbert Suggested-by: Paolo Bonzini Signed-off-by: Stefano Garzarella --- v4: - fix the missing of g_mapped_file_unref() in the success case [Paolo] - fix the rom_add_elf_program() comment [Paolo] v3: - renamed 'GMappedFile *gmf' in 'GMappedFile *mapped_filed' for readabili= ty. - passed the GMappedFile* to rom_add_elf_program() to correctly handle the reference count. [Paolo] - set 'data' pointer only if 'file_size > 0' as the original behaviour [check-qtest-ppc64 fails without it] v2: - used g_mapped_file_new_from_fd() with 'writeble' set to 'true', since we can modify the mapped buffer. [Paolo, Peter] --- include/hw/elf_ops.h | 71 ++++++++++++++++++++++++++------------------ 1 file changed, 42 insertions(+), 29 deletions(-) diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h index fede37ee9c..1496d7e753 100644 --- a/include/hw/elf_ops.h +++ b/include/hw/elf_ops.h @@ -323,8 +323,9 @@ static int glue(load_elf, SZ)(const char *name, int fd, struct elfhdr ehdr; struct elf_phdr *phdr =3D NULL, *ph; int size, i, total_size; - elf_word mem_size, file_size; + elf_word mem_size, file_size, data_offset; uint64_t addr, low =3D (uint64_t)-1, high =3D 0; + GMappedFile *mapped_file =3D NULL; uint8_t *data =3D NULL; char label[128]; int ret =3D ELF_LOAD_FAILED; @@ -409,20 +410,32 @@ static int glue(load_elf, SZ)(const char *name, int f= d, } } =20 + /* + * Since we want to be able to modify the mapped buffer, we set the + * 'writeble' parameter to 'true'. Modifications to the buffer are not + * written back to the file. + */ + mapped_file =3D g_mapped_file_new_from_fd(fd, true, NULL); + if (!mapped_file) { + goto fail; + } + total_size =3D 0; for(i =3D 0; i < ehdr.e_phnum; i++) { ph =3D &phdr[i]; if (ph->p_type =3D=3D PT_LOAD) { mem_size =3D ph->p_memsz; /* Size of the ROM */ file_size =3D ph->p_filesz; /* Size of the allocated data */ - data =3D g_malloc0(file_size); - if (ph->p_filesz > 0) { - if (lseek(fd, ph->p_offset, SEEK_SET) < 0) { - goto fail; - } - if (read(fd, data, file_size) !=3D file_size) { + data_offset =3D ph->p_offset; /* Offset where the data is loca= ted */ + + if (file_size > 0) { + if (g_mapped_file_get_length(mapped_file) < + file_size + data_offset) { goto fail; } + + data =3D (uint8_t *)g_mapped_file_get_contents(mapped_file= ); + data +=3D data_offset; } =20 /* The ELF spec is somewhat vague about the purpose of the @@ -513,25 +526,25 @@ static int glue(load_elf, SZ)(const char *name, int f= d, *pentry =3D ehdr.e_entry - ph->p_vaddr + ph->p_paddr; } =20 - if (mem_size =3D=3D 0) { - /* Some ELF files really do have segments of zero size; - * just ignore them rather than trying to create empty - * ROM blobs, because the zero-length blob can falsely - * trigger the overlapping-ROM-blobs check. - */ - g_free(data); - } else { + /* Some ELF files really do have segments of zero size; + * just ignore them rather than trying to create empty + * ROM blobs, because the zero-length blob can falsely + * trigger the overlapping-ROM-blobs check. + */ + if (mem_size !=3D 0) { if (load_rom) { snprintf(label, sizeof(label), "phdr #%d: %s", i, name= ); =20 - /* rom_add_elf_program() seize the ownership of 'data'= */ - rom_add_elf_program(label, NULL, data, file_size, mem_= size, - addr, as); + /* + * rom_add_elf_program() takes its own reference to + * 'mapped_file'. + */ + rom_add_elf_program(label, mapped_file, data, file_siz= e, + mem_size, addr, as); } else { address_space_write(as ? as : &address_space_memory, addr, MEMTXATTRS_UNSPECIFIED, data, file_size); - g_free(data); } } =20 @@ -547,14 +560,16 @@ static int glue(load_elf, SZ)(const char *name, int f= d, struct elf_note *nhdr =3D NULL; =20 file_size =3D ph->p_filesz; /* Size of the range of ELF notes = */ - data =3D g_malloc0(file_size); - if (ph->p_filesz > 0) { - if (lseek(fd, ph->p_offset, SEEK_SET) < 0) { - goto fail; - } - if (read(fd, data, file_size) !=3D file_size) { + data_offset =3D ph->p_offset; /* Offset where the notes are lo= cated */ + + if (file_size > 0) { + if (g_mapped_file_get_length(mapped_file) < + file_size + data_offset) { goto fail; } + + data =3D (uint8_t *)g_mapped_file_get_contents(mapped_file= ); + data +=3D data_offset; } =20 /* @@ -570,19 +585,17 @@ static int glue(load_elf, SZ)(const char *name, int f= d, sizeof(struct elf_note) =3D=3D sizeof(struct elf64_not= e); elf_note_fn((void *)nhdr, (void *)&ph->p_align, is64); } - g_free(data); data =3D NULL; } } =20 - g_free(phdr); if (lowaddr) *lowaddr =3D (uint64_t)(elf_sword)low; if (highaddr) *highaddr =3D (uint64_t)(elf_sword)high; - return total_size; + ret =3D total_size; fail: - g_free(data); + g_mapped_file_unref(mapped_file); g_free(phdr); return ret; } --=20 2.20.1