From patchwork Thu Sep 8 08:34:09 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Maxime Coquelin X-Patchwork-Id: 667535 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 3sVK3K1mcnz9s2G for ; Thu, 8 Sep 2016 22:12:45 +1000 (AEST) Received: from localhost ([::1]:47544 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bhyC9-0005P8-VA for incoming@patchwork.ozlabs.org; Thu, 08 Sep 2016 08:12:42 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37558) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bhums-0001pf-Gj for qemu-devel@nongnu.org; Thu, 08 Sep 2016 04:34:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bhump-0005TR-I9 for qemu-devel@nongnu.org; Thu, 08 Sep 2016 04:34:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35248) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bhump-0005T4-At for qemu-devel@nongnu.org; Thu, 08 Sep 2016 04:34:19 -0400 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E9CCFB6F28; Thu, 8 Sep 2016 08:34:18 +0000 (UTC) Received: from max-t460s.redhat.com (vpn1-4-117.ams2.redhat.com [10.36.4.117]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u888YCc3013403; Thu, 8 Sep 2016 04:34:16 -0400 From: Maxime Coquelin To: mst@redhat.com, qemu-devel@nongnu.org Date: Thu, 8 Sep 2016 10:34:09 +0200 Message-Id: <1473323650-13298-2-git-send-email-maxime.coquelin@redhat.com> In-Reply-To: <1473323650-13298-1-git-send-email-maxime.coquelin@redhat.com> References: <1473323650-13298-1-git-send-email-maxime.coquelin@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Thu, 08 Sep 2016 08:34:18 +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] Revert "Revert "vhost-user: Attempt to fix a race with set_mem_table."" X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: peter.maydell@linaro.org, marcandre.lureau@redhat.com, Maxime Coquelin , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , prerna.saxena@nutanix.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" This reverts commit 94c9cb31c04737f86be29afefbff401cd23bc24d. Analysis of the race shows that it would happen only when QEMU relies on TCG. Since commit cdafe929 ("vhost-user-test: Use libqos instead of pxe-virtio.rom"), vhost-user-test don't use TCG, so the race no more appear. Cc: Michael S. Tsirkin Cc: Marc-André Lureau Cc: Prerna Saxena Cc: Peter Maydell Signed-off-by: Maxime Coquelin --- hw/virtio/vhost-user.c | 127 ++++++++++++++++++++++++++----------------------- 1 file changed, 67 insertions(+), 60 deletions(-) diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index b57454a..1a7d53c 100644 --- a/hw/virtio/vhost-user.c +++ b/hw/virtio/vhost-user.c @@ -263,66 +263,6 @@ static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base, return 0; } -static int vhost_user_set_mem_table(struct vhost_dev *dev, - struct vhost_memory *mem) -{ - int fds[VHOST_MEMORY_MAX_NREGIONS]; - int i, fd; - size_t fd_num = 0; - bool reply_supported = virtio_has_feature(dev->protocol_features, - VHOST_USER_PROTOCOL_F_REPLY_ACK); - - VhostUserMsg msg = { - .request = VHOST_USER_SET_MEM_TABLE, - .flags = VHOST_USER_VERSION, - }; - - if (reply_supported) { - msg.flags |= VHOST_USER_NEED_REPLY_MASK; - } - - for (i = 0; i < dev->mem->nregions; ++i) { - struct vhost_memory_region *reg = dev->mem->regions + i; - ram_addr_t offset; - MemoryRegion *mr; - - assert((uintptr_t)reg->userspace_addr == reg->userspace_addr); - mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr, - &offset); - fd = memory_region_get_fd(mr); - if (fd > 0) { - msg.payload.memory.regions[fd_num].userspace_addr = reg->userspace_addr; - msg.payload.memory.regions[fd_num].memory_size = reg->memory_size; - msg.payload.memory.regions[fd_num].guest_phys_addr = reg->guest_phys_addr; - msg.payload.memory.regions[fd_num].mmap_offset = offset; - assert(fd_num < VHOST_MEMORY_MAX_NREGIONS); - fds[fd_num++] = fd; - } - } - - msg.payload.memory.nregions = fd_num; - - if (!fd_num) { - error_report("Failed initializing vhost-user memory map, " - "consider using -object memory-backend-file share=on"); - return -1; - } - - msg.size = sizeof(msg.payload.memory.nregions); - msg.size += sizeof(msg.payload.memory.padding); - msg.size += fd_num * sizeof(VhostUserMemoryRegion); - - if (vhost_user_write(dev, &msg, fds, fd_num) < 0) { - return -1; - } - - if (reply_supported) { - return process_message_reply(dev, msg.request); - } - - return 0; -} - static int vhost_user_set_vring_addr(struct vhost_dev *dev, struct vhost_vring_addr *addr) { @@ -537,6 +477,73 @@ static int vhost_user_get_features(struct vhost_dev *dev, uint64_t *features) return vhost_user_get_u64(dev, VHOST_USER_GET_FEATURES, features); } +static int vhost_user_set_mem_table(struct vhost_dev *dev, + struct vhost_memory *mem) +{ + int fds[VHOST_MEMORY_MAX_NREGIONS]; + int i, fd; + size_t fd_num = 0; + uint64_t features; + bool reply_supported = virtio_has_feature(dev->protocol_features, + VHOST_USER_PROTOCOL_F_REPLY_ACK); + + VhostUserMsg msg = { + .request = VHOST_USER_SET_MEM_TABLE, + .flags = VHOST_USER_VERSION, + }; + + if (reply_supported) { + msg.flags |= VHOST_USER_NEED_REPLY_MASK; + } + + for (i = 0; i < dev->mem->nregions; ++i) { + struct vhost_memory_region *reg = dev->mem->regions + i; + ram_addr_t offset; + MemoryRegion *mr; + + assert((uintptr_t)reg->userspace_addr == reg->userspace_addr); + mr = memory_region_from_host((void *)(uintptr_t)reg->userspace_addr, + &offset); + fd = memory_region_get_fd(mr); + if (fd > 0) { + msg.payload.memory.regions[fd_num].userspace_addr + = reg->userspace_addr; + msg.payload.memory.regions[fd_num].memory_size = reg->memory_size; + msg.payload.memory.regions[fd_num].guest_phys_addr + = reg->guest_phys_addr; + msg.payload.memory.regions[fd_num].mmap_offset = offset; + assert(fd_num < VHOST_MEMORY_MAX_NREGIONS); + fds[fd_num++] = fd; + } + } + + msg.payload.memory.nregions = fd_num; + + if (!fd_num) { + error_report("Failed initializing vhost-user memory map, " + "consider using -object memory-backend-file share=on"); + return -1; + } + + msg.size = sizeof(msg.payload.memory.nregions); + msg.size += sizeof(msg.payload.memory.padding); + msg.size += fd_num * sizeof(VhostUserMemoryRegion); + + vhost_user_write(dev, &msg, fds, fd_num); + + if (reply_supported) { + return process_message_reply(dev, msg.request); + } else { + /* Note: It is (yet) unknown when the client application has finished + * remapping the GPA. + * Attempt to prevent a race by sending a command that requires a reply. + */ + vhost_user_get_features(dev, &features); + } + + return 0; +} + static int vhost_user_set_owner(struct vhost_dev *dev) { VhostUserMsg msg = {