From nobody Tue Feb 10 04:16:53 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=1566284955; cv=none; d=zoho.com; s=zohoarc; b=JCojjOIOXPp5MoK0/UuZuaUQhBVbOaOtMkElVRx2eKCDfUcWajRiefqneFaHw3aVS6eJ/scbU0EXCsGKNYx7yUy0G1pO2pScwMEnPRz0KzMzON0BAA4FWGkCfOCS9R3YcM03eg0lb4VFU1skCJeY0JfiVatNbd8cly57hB/4nOI= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1566284955; h=Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=uvI/6frxv2frc0flnfPqGe/VgPr01yA9dg/p0H73xkQ=; b=WmqYobG34mWL7a60f3mYt0Ry7iL0U83oPfRfbsREarWMJNseOic8JR5dNvxWTjfJShXI2CXeLRyF5sD4CmeMAY7vwdCmnQO313F8XC9NMHpcV+L5/Z/1aB2IpogR5d1jfxQQzjws+Nwb7B1Wgs1jmberVRzISQzp6P3eXPShXSk= 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 1566284955200356.1722050567096; Tue, 20 Aug 2019 00:09:15 -0700 (PDT) Received: from localhost ([::1]:33840 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hzyGX-00064h-DX for importer@patchew.org; Tue, 20 Aug 2019 03:09:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42430) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hzy7z-00053s-Cb for qemu-devel@nongnu.org; Tue, 20 Aug 2019 03:00:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hzy7t-0002lb-FG for qemu-devel@nongnu.org; Tue, 20 Aug 2019 03:00:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60218) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hzy7s-0002ij-QG for qemu-devel@nongnu.org; Tue, 20 Aug 2019 03:00:17 -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 E08D34628B for ; Tue, 20 Aug 2019 07:00:13 +0000 (UTC) Received: from 640k.localdomain.com (ovpn-112-20.ams2.redhat.com [10.36.112.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id ADF2A17BBB; Tue, 20 Aug 2019 07:00:11 +0000 (UTC) From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Tue, 20 Aug 2019 08:59:23 +0200 Message-Id: <1566284395-30287-5-git-send-email-pbonzini@redhat.com> In-Reply-To: <1566284395-30287-1-git-send-email-pbonzini@redhat.com> References: <1566284395-30287-1-git-send-email-pbonzini@redhat.com> 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 [10.5.110.29]); Tue, 20 Aug 2019 07:00:13 +0000 (UTC) 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] [PULL 04/36] 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: Stefano Garzarella Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Stefano Garzarella 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 Message-Id: <20190724143105.307042-3-sgarzare@redhat.com> Signed-off-by: Paolo Bonzini --- 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 fede37e..1496d7e 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 1.8.3.1