From patchwork Tue Oct 6 13:33:23 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Fedin X-Patchwork-Id: 526767 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org 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 62E33140082 for ; Wed, 7 Oct 2015 00:34:34 +1100 (AEDT) Received: from localhost ([::1]:51698 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZjSO0-0005Aq-7q for incoming@patchwork.ozlabs.org; Tue, 06 Oct 2015 09:34:32 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49824) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZjSN6-0003rq-A6 for qemu-devel@nongnu.org; Tue, 06 Oct 2015 09:33:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZjSN2-0004IJ-Rw for qemu-devel@nongnu.org; Tue, 06 Oct 2015 09:33:36 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:21801) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZjSN2-0004Hs-Jy for qemu-devel@nongnu.org; Tue, 06 Oct 2015 09:33:32 -0400 Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout1.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NVS00JCHWBTK0C0@mailout1.w1.samsung.com> for qemu-devel@nongnu.org; Tue, 06 Oct 2015 14:33:29 +0100 (BST) X-AuditID: cbfec7f5-f794b6d000001495-c8-5613cda9ba1e Received: from eusync3.samsung.com ( [203.254.199.213]) by eucpsbgm2.samsung.com (EUCPMTA) with SMTP id 8D.25.05269.9ADC3165; Tue, 6 Oct 2015 14:33:29 +0100 (BST) Received: from fedinw7x64 ([106.109.131.169]) by eusync3.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTPA id <0NVS0088PWBQRE70@eusync3.samsung.com>; Tue, 06 Oct 2015 14:33:29 +0100 (BST) From: Pavel Fedin To: qemu-devel@nongnu.org Date: Tue, 06 Oct 2015 16:33:23 +0300 Message-id: <017e01d1003b$959bc820$c0d35860$@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit X-Mailer: Microsoft Outlook 14.0 Thread-index: AdEAOw/3HurzjuUUQyqifHTXjiv5DQ== Content-language: ru X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrALMWRmVeSWpSXmKPExsVy+t/xq7orzwqHGcxfrW7x5N93RovjvTtY HJg8nlzbzOQxYepSlgCmKC6blNSczLLUIn27BK6MzRu3MRd8MqxoeXefrYHxtlIXIyeHhICJ xPTXl1ghbDGJC/fWs4HYQgJLGSX6D8V3MXIB2d8ZJdY9nsIIkmATUJc4/fUDC4gtIiAp8bvr NDOIzSygJrFt4VywuLCAtcSlGZvAhrIIqEps2vkPzOYVsJRY0PORBcIWlPgx+R4LRK+WxPqd x5kgbHmJzWveMkMcpCCx4+xrRohdehKT/81lhKgRkZj27x7zBEaBWUhGzUIyahaSUbOQtCxg ZFnFKJpamlxQnJSea6RXnJhbXJqXrpecn7uJERKuX3cwLj1mdYhRgINRiYdX4qZQmBBrYllx Ze4hRgkOZiURXoUjwmFCvCmJlVWpRfnxRaU5qcWHGKU5WJTEeWfueh8iJJCeWJKanZpakFoE k2Xi4JRqYJR8vsuxxItJd2Uqx62v8vwVgj3np3zMvD5lWsqypXbsl/cfiu4Xedydvf3sgytL d2e8OWek+3z2qwUrt6ZbiSj/FpsSb/5ei+W2uU7Y46/PVn91mnclp/hV4KEeje7i1zMmuT+q ueZy2m3q0VM/op3al0xYNIHR/lHvtjvWAu8cHxyKbX/bX9mpxFKckWioxVxUnAgAdulh1VMC AAA= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 210.118.77.11 Cc: 'Michael Tokarev' Subject: [Qemu-devel] [PATCH v4] ivshmem: allow the sharing of hugepages X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org This patch permits to share memory areas that do not specifically belong to /dev/shm. In such case, the file must be already present when launching qemu. A new parameter 'file' has been added to specify the file to use. A use case for this patch is sharing huge pages available through a hugetlbfs mountpoint. Signed-off-by: Damien Millescamps Signed-off-by: Pavel Fedin --- 2 years passed since the last review of this, and the original author never came back. So i decided to pick up this work because my project is interested in this feature. I am keeping patch version numbering, but the original changelog was lost. Relevant thread here: https://lists.gnu.org/archive/html/qemu-trivial/2013-09/msg00148.html v3 => v4: - Fixed documentation and wordings according to the last review - Report also actual error messages - Added missing exit() - Fixed up code style according to latest checkpatch rules --- docs/specs/ivshmem_device_spec.txt | 7 ++-- hw/misc/ivshmem.c | 67 +++++++++++++++++++++++++------------- 2 files changed, 50 insertions(+), 24 deletions(-) diff --git a/docs/specs/ivshmem_device_spec.txt b/docs/specs/ivshmem_device_spec.txt index 667a862..8b108e7 100644 --- a/docs/specs/ivshmem_device_spec.txt +++ b/docs/specs/ivshmem_device_spec.txt @@ -4,8 +4,11 @@ Device Specification for Inter-VM shared memory device The Inter-VM shared memory device is designed to share a region of memory to userspace in multiple virtual guests. The memory region does not belong to any -guest, but is a POSIX memory object on the host. Optionally, the device may -support sending interrupts to other guests sharing the same memory region. +guest, but is a either a POSIX memory object or a mmap'd file (for instance, +hugepage-backed file) on the host. + +Optionally, the device may support sending interrupts to other guests sharing +the same memory region. The Inter-VM PCI device diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c index cc76989..999ed7d 100644 --- a/hw/misc/ivshmem.c +++ b/hw/misc/ivshmem.c @@ -100,9 +100,10 @@ typedef struct IVShmemState { Error *migration_blocker; - char * shmobj; - char * sizearg; - char * role; + char *shmobj; + char *fileobj; + char *sizearg; + char *role; int role_val; /* scalar to avoid multiple string comparisons */ } IVShmemState; @@ -769,9 +770,9 @@ static int pci_ivshmem_init(PCIDevice *dev) /* if we get a UNIX socket as the parameter we will talk * to the ivshmem server to receive the memory region */ - if (s->shmobj != NULL) { + if (s->shmobj != NULL || s->fileobj != NULL) { error_report("WARNING: do not specify both 'chardev' " - "and 'shm' with ivshmem"); + "and 'shm' or 'file' with ivshmem"); } IVSHMEM_DPRINTF("using shared memory server (socket = %s)\n", @@ -797,28 +798,49 @@ static int pci_ivshmem_init(PCIDevice *dev) } else { /* just map the file immediately, we're not using a server */ int fd; + int is_shm = !!(s->shmobj != NULL); + int is_file = !!(s->fileobj != NULL); - if (s->shmobj == NULL) { - error_report("Must specify 'chardev' or 'shm' to ivshmem"); + if (!(is_shm ^ is_file)) { + error_report("Must specify one of 'chardev', 'shm' or 'file' " + "to ivshmem"); exit(1); } - IVSHMEM_DPRINTF("using shm_open (shm object = %s)\n", s->shmobj); - - /* try opening with O_EXCL and if it succeeds zero the memory - * by truncating to 0 */ - if ((fd = shm_open(s->shmobj, O_CREAT|O_RDWR|O_EXCL, - S_IRWXU|S_IRWXG|S_IRWXO)) > 0) { - /* truncate file to length PCI device's memory */ - if (ftruncate(fd, s->ivshmem_size) != 0) { - error_report("could not truncate shared file"); + if (is_shm) { + IVSHMEM_DPRINTF("using shm_open (shm object = %s)\n", s->shmobj); + + /* try opening with O_EXCL and if it succeeds zero the memory + * by truncating to 0 */ + fd = shm_open(s->shmobj, O_CREAT|O_RDWR|O_EXCL, + S_IRWXU|S_IRWXG|S_IRWXO); + if (fd > 0) { + /* truncate file to length PCI device's memory */ + if (ftruncate(fd, s->ivshmem_size) != 0) { + error_report("could not truncate shared file: %s", + strerror(errno)); + exit(1); + } + } else { + fd = shm_open(s->shmobj, O_CREAT|O_RDWR, + S_IRWXU|S_IRWXG|S_IRWXO); + if (fd < 0) { + error_report("could not open shared file: %s", + strerror(errno)); + exit(1); + } + } + } else { + IVSHMEM_DPRINTF("using open (file object = %s)\n", s->fileobj); + + /* try opening a mmap's file. This file must have been previously + * created on the host */ + fd = open(s->fileobj, O_RDWR); + if (fd < 0) { + error_report("ivshmem: could not open file: %s\n", + strerror(errno)); + exit(-1); } - - } else if ((fd = shm_open(s->shmobj, O_CREAT|O_RDWR, - S_IRWXU|S_IRWXG|S_IRWXO)) < 0) { - error_report("could not open shared file"); - exit(1); - } if (check_shm_size(s, fd) == -1) { @@ -856,6 +878,7 @@ static Property ivshmem_properties[] = { DEFINE_PROP_BIT("ioeventfd", IVShmemState, features, IVSHMEM_IOEVENTFD, false), DEFINE_PROP_BIT("msi", IVShmemState, features, IVSHMEM_MSI, true), DEFINE_PROP_STRING("shm", IVShmemState, shmobj), + DEFINE_PROP_STRING("file", IVShmemState, fileobj), DEFINE_PROP_STRING("role", IVShmemState, role), DEFINE_PROP_UINT32("use64", IVShmemState, ivshmem_64bit, 1), DEFINE_PROP_END_OF_LIST(),