From patchwork Tue Jul 23 14:04:44 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefano Garzarella X-Patchwork-Id: 11054571 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 016FC912 for ; Tue, 23 Jul 2019 14:05:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E5A7C286C0 for ; Tue, 23 Jul 2019 14:05:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D9F39286B8; Tue, 23 Jul 2019 14:05:21 +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 5D7EC286AD for ; Tue, 23 Jul 2019 14:05:21 +0000 (UTC) Received: from localhost ([::1]:42774 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpvPs-00085P-De for patchwork-qemu-devel@patchwork.kernel.org; Tue, 23 Jul 2019 10:05:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43396) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpvPc-0006zI-C8 for qemu-devel@nongnu.org; Tue, 23 Jul 2019 10:05:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hpvPa-0005ai-TQ for qemu-devel@nongnu.org; Tue, 23 Jul 2019 10:05:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52844) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hpvPa-0005Zv-M8 for qemu-devel@nongnu.org; Tue, 23 Jul 2019 10:05:02 -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 DA7B72CD7EB; Tue, 23 Jul 2019 14:05:01 +0000 (UTC) Received: from steredhat.redhat.com (ovpn-116-45.ams2.redhat.com [10.36.116.45]) by smtp.corp.redhat.com (Postfix) with ESMTP id 55A1C17B80; Tue, 23 Jul 2019 14:04:57 +0000 (UTC) From: Stefano Garzarella To: qemu-devel@nongnu.org Date: Tue, 23 Jul 2019 16:04:44 +0200 Message-Id: <20190723140445.12748-2-sgarzare@redhat.com> In-Reply-To: <20190723140445.12748-1-sgarzare@redhat.com> References: <20190723140445.12748-1-sgarzare@redhat.com> MIME-Version: 1.0 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 [10.5.110.29]); Tue, 23 Jul 2019 14:05:01 +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 v2 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: Peter Maydell , Eduardo Habkost , Sergio Lopez , "Michael S. Tsirkin" , Julio Montes , "Dr . David Alan Gilbert" , 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 --- 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 | 64 ++++++++++++++++++++++++-------------------- 1 file changed, 35 insertions(+), 29 deletions(-) diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h index 690f9238c8..d80e7ad20c 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 +410,31 @@ static int glue(load_elf, SZ)(const char *name, int fd, } } + /* + * 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. + */ + gmf = g_mapped_file_new_from_fd(fd, true, 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 +523,16 @@ 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 +540,6 @@ 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 +555,15 @@ 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 +577,6 @@ 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 +588,7 @@ 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; }