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: 599598 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 3qRX5N3Gglz9s6n for ; Sat, 19 Mar 2016 04:19:20 +1100 (AEDT) Received: from localhost ([::1]:45196 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1agy3S-0000Fx-H5 for incoming@patchwork.ozlabs.org; Fri, 18 Mar 2016 13:19:18 -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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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) {