From patchwork Fri Mar 18 17:01:18 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Markus Armbruster X-Patchwork-Id: 8622541 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 4A8E79F44D for ; Fri, 18 Mar 2016 17:18:57 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 876A12026F for ; Fri, 18 Mar 2016 17:18:56 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 94DD42022A for ; Fri, 18 Mar 2016 17:18:55 +0000 (UTC) Received: from localhost ([::1]:45189 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1agy34-0007GW-PY for patchwork-qemu-devel@patchwork.kernel.org; Fri, 18 Mar 2016 13:18:54 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41994) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1agxmR-0006mi-Gx for qemu-devel@nongnu.org; Fri, 18 Mar 2016 13:01:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1agxmL-00089c-UU for qemu-devel@nongnu.org; Fri, 18 Mar 2016 13:01:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55301) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1agxmL-00089B-Md for qemu-devel@nongnu.org; Fri, 18 Mar 2016 13:01:37 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (Postfix) with ESMTPS id 4BC00C0A1985 for ; Fri, 18 Mar 2016 17:01:37 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-34.ams2.redhat.com [10.36.116.34]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u2IH1Xl7009481 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Fri, 18 Mar 2016 13:01:36 -0400 Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id EF13A3006AF7; Fri, 18 Mar 2016 18:01:28 +0100 (CET) From: Markus Armbruster To: qemu-devel@nongnu.org Date: Fri, 18 Mar 2016 18:01:18 +0100 Message-Id: <1458320487-19603-32-git-send-email-armbru@redhat.com> In-Reply-To: <1458320487-19603-1-git-send-email-armbru@redhat.com> References: <1458320487-19603-1-git-send-email-armbru@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 31/40] ivshmem: Implement shm=... with a memory backend 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP ivshmem has its very own code to create and map shared memory. Replace that with an implicitly created memory backend. Reduces the number of ways we create BAR 2 from three to two. The memory-backend-file is currently available only with CONFIG_LINUX, so this adds a second Linuxism to ivshmem (the other one is eventfd). Should we ever need to make it portable to systems where memory-backend-file can't be made to serve, we could create a memory-backend-shmem that allocates memory with shm_open(). Bonus fix: shared memory files are now created with permissions 0655 instead of 0777. Signed-off-by: Markus Armbruster Reviewed-by: Paolo Bonzini Message-Id: <1458066895-20632-32-git-send-email-armbru@redhat.com> --- hw/misc/ivshmem.c | 79 ++++++++++++++++--------------------------------------- 1 file changed, 23 insertions(+), 56 deletions(-) diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c index 66c713e..138ae9d 100644 --- a/hw/misc/ivshmem.c +++ b/hw/misc/ivshmem.c @@ -26,6 +26,7 @@ #include "migration/migration.h" #include "qemu/error-report.h" #include "qemu/event_notifier.h" +#include "qom/object_interfaces.h" #include "sysemu/char.h" #include "sysemu/hostmem.h" #include "qapi/visitor.h" @@ -369,31 +370,6 @@ static int check_shm_size(IVShmemState *s, int fd, Error **errp) } } -/* create the shared memory BAR when we are not using the server, so we can - * create the BAR and map the memory immediately */ -static int create_shared_memory_BAR(IVShmemState *s, int fd, uint8_t attr, - Error **errp) -{ - void * ptr; - - ptr = mmap(0, s->ivshmem_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); - if (ptr == MAP_FAILED) { - error_setg_errno(errp, errno, "Failed to mmap shared memory"); - return -1; - } - - memory_region_init_ram_ptr(&s->ivshmem, OBJECT(s), "ivshmem.bar2", - s->ivshmem_size, ptr); - qemu_set_ram_fd(memory_region_get_ram_addr(&s->ivshmem), fd); - vmstate_register_ram(&s->ivshmem, DEVICE(s)); - memory_region_add_subregion(&s->bar, 0, &s->ivshmem); - - /* region for shared memory */ - pci_register_bar(PCI_DEVICE(s), 2, attr, &s->bar); - - return 0; -} - static void ivshmem_add_eventfd(IVShmemState *s, int posn, int i) { memory_region_add_eventfd(&s->ivshmem_mmio, @@ -837,6 +813,23 @@ static void ivshmem_write_config(PCIDevice *pdev, uint32_t address, } } +static void desugar_shm(IVShmemState *s) +{ + Object *obj; + char *path; + + obj = object_new("memory-backend-file"); + path = g_strdup_printf("/dev/shm/%s", s->shmobj); + object_property_set_str(obj, path, "mem-path", &error_abort); + g_free(path); + object_property_set_int(obj, s->ivshmem_size, "size", &error_abort); + object_property_set_bool(obj, true, "share", &error_abort); + object_property_add_child(OBJECT(s), "internal-shm-backend", obj, + &error_abort); + user_creatable_complete(obj, &error_abort); + s->hostmem = MEMORY_BACKEND(obj); +} + static void pci_ivshmem_realize(PCIDevice *dev, Error **errp) { IVShmemState *s = IVSHMEM(dev); @@ -915,6 +908,10 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error **errp) attr |= PCI_BASE_ADDRESS_MEM_TYPE_64; } + if (s->shmobj) { + desugar_shm(s); + } + if (s->hostmem != NULL) { MemoryRegion *mr; @@ -925,7 +922,7 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error **errp) vmstate_register_ram(mr, DEVICE(s)); memory_region_add_subregion(&s->bar, 0, mr); pci_register_bar(PCI_DEVICE(s), 2, attr, &s->bar); - } else if (s->server_chr != NULL) { + } else { IVSHMEM_DPRINTF("using shared memory server (socket = %s)\n", s->server_chr->filename); @@ -952,36 +949,6 @@ static void pci_ivshmem_realize(PCIDevice *dev, Error **errp) error_setg(errp, "failed to initialize interrupts"); return; } - } else { - /* just map the file immediately, we're not using a server */ - int fd; - - 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"); - } - - } else if ((fd = shm_open(s->shmobj, O_CREAT|O_RDWR, - S_IRWXU|S_IRWXG|S_IRWXO)) < 0) { - error_setg(errp, "could not open shared file"); - return; - } - - if (check_shm_size(s, fd, errp) == -1) { - return; - } - - create_shared_memory_BAR(s, fd, attr, &err); - if (err) { - error_propagate(errp, err); - return; - } } if (s->role_val == IVSHMEM_PEER) {