From patchwork Tue Jul 23 09:07:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Garzarella X-Patchwork-Id: 11054143 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 13C82912 for ; Tue, 23 Jul 2019 09:08:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 02BA2284AF for ; Tue, 23 Jul 2019 09:08:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id EAF1528592; Tue, 23 Jul 2019 09:08:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 77D60284AF for ; Tue, 23 Jul 2019 09:08:02 +0000 (UTC) Received: from localhost ([::1]:40452 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpqm9-00053v-9x for patchwork-qemu-devel@patchwork.kernel.org; Tue, 23 Jul 2019 05:08:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:41545) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpqll-0003Su-3M for qemu-devel@nongnu.org; Tue, 23 Jul 2019 05:07:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hpqlj-00024X-2s for qemu-devel@nongnu.org; Tue, 23 Jul 2019 05:07:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:28182) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hpqlh-00021g-2C for qemu-devel@nongnu.org; Tue, 23 Jul 2019 05:07:34 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 918D23084242; Tue, 23 Jul 2019 09:07:30 +0000 (UTC) Received: from steredhat.redhat.com (unknown [10.36.118.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id D0F2B5D9C5; Tue, 23 Jul 2019 09:07:26 +0000 (UTC) From: Stefano Garzarella To: qemu-devel@nongnu.org Date: Tue, 23 Jul 2019 11:07:17 +0200 Message-Id: <20190723090718.14590-2-sgarzare@redhat.com> In-Reply-To: <20190723090718.14590-1-sgarzare@redhat.com> References: <20190723090718.14590-1-sgarzare@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Tue, 23 Jul 2019 09:07:30 +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] [PATCH 1/2] 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: Eduardo Habkost , Sergio Lopez , "Michael S. Tsirkin" , Julio Montes , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP 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 --- include/hw/elf_ops.h | 59 ++++++++++++++++++++++---------------------- 1 file changed, 30 insertions(+), 29 deletions(-) diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h index 690f9238c8..69ce8dea74 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 = 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 = (uint64_t)-1, high = 0; + GMappedFile *gmf = NULL; uint8_t *data = NULL; char label[128]; int ret = ELF_LOAD_FAILED; @@ -409,22 +410,26 @@ static int glue(load_elf, SZ)(const char *name, int fd, } } + gmf = g_mapped_file_new_from_fd(fd, false, NULL); + if (!gmf) { + goto fail; + } + total_size = 0; for(i = 0; i < ehdr.e_phnum; i++) { ph = &phdr[i]; if (ph->p_type == PT_LOAD) { mem_size = ph->p_memsz; /* Size of the ROM */ file_size = ph->p_filesz; /* Size of the allocated data */ - data = 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) != file_size) { - goto fail; - } + data_offset = ph->p_offset; /* Offset where the data is located */ + + if (g_mapped_file_get_length(gmf) < file_size + data_offset) { + goto fail; } + data = (uint8_t *)g_mapped_file_get_contents(gmf); + data += data_offset; + /* The ELF spec is somewhat vague about the purpose of the * physical address field. One common use in the embedded world * is that physical address field specifies the load address @@ -513,17 +518,16 @@ static int glue(load_elf, SZ)(const char *name, int fd, *pentry = ehdr.e_entry - ph->p_vaddr + ph->p_paddr; } - if (mem_size == 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 != 0) { if (load_rom) { snprintf(label, sizeof(label), "phdr #%d: %s", i, name); - + /* Increments the reference count to avoid the unmap */ + g_mapped_file_ref(gmf); /* rom_add_elf_program() seize the ownership of 'data' */ rom_add_elf_program(label, data, file_size, mem_size, addr, as); @@ -531,7 +535,6 @@ static int glue(load_elf, SZ)(const char *name, int fd, address_space_write(as ? as : &address_space_memory, addr, MEMTXATTRS_UNSPECIFIED, data, file_size); - g_free(data); } } @@ -547,16 +550,15 @@ static int glue(load_elf, SZ)(const char *name, int fd, struct elf_note *nhdr = NULL; file_size = ph->p_filesz; /* Size of the range of ELF notes */ - data = 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) != file_size) { - goto fail; - } + data_offset = ph->p_offset; /* Offset where the notes are located */ + + if (g_mapped_file_get_length(gmf) < file_size + data_offset) { + goto fail; } + data = (uint8_t *)g_mapped_file_get_contents(gmf); + data += data_offset; + /* * Search the ELF notes to find one with a type matching the * value passed in via 'translate_opaque' @@ -570,7 +572,6 @@ static int glue(load_elf, SZ)(const char *name, int fd, sizeof(struct elf_note) == sizeof(struct elf64_note); elf_note_fn((void *)nhdr, (void *)&ph->p_align, is64); } - g_free(data); data = NULL; } } @@ -582,7 +583,7 @@ static int glue(load_elf, SZ)(const char *name, int fd, *highaddr = (uint64_t)(elf_sword)high; return total_size; fail: - g_free(data); + g_mapped_file_unref(gmf); g_free(phdr); return ret; }