{"id":2221319,"url":"http://patchwork.ozlabs.org/api/1.0/patches/2221319/?format=json","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.0/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260409070114.11313-2-matthieu@min.io>","date":"2026-04-09T07:01:10","name":"[1/2] hw/nvme: add namespace hotplug support","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"089a6e1b9f1796a90356ea16f66613834e6a7dec","submitter":{"id":93098,"url":"http://patchwork.ozlabs.org/api/1.0/people/93098/?format=json","name":"mr-083","email":"matthieu@minio.io"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260409070114.11313-2-matthieu@min.io/mbox/","series":[{"id":499254,"url":"http://patchwork.ozlabs.org/api/1.0/series/499254/?format=json","date":"2026-04-09T07:01:10","name":"NVMe namespace hotplug and drive reconnection support","version":1,"mbox":"http://patchwork.ozlabs.org/series/499254/mbox/"}],"check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2221319/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n secure) header.d=minio.io header.i=@minio.io header.a=rsa-sha256\n header.s=minio header.b=POVnGdR5;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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charset=UTF-8","Content-Transfer-Encoding":"8bit","Received-SPF":"pass client-ip=2a00:1450:4864:20::330;\n envelope-from=matthieu@minio.io; helo=mail-wm1-x330.google.com","X-Spam_score_int":"-10","X-Spam_score":"-1.1","X-Spam_bar":"-","X-Spam_report":"(-1.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n HK_NAME_MR_MRS=0.998,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=no autolearn_force=no","X-Spam_action":"no action","X-Mailman-Approved-At":"Thu, 09 Apr 2026 04:19:22 -0400","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"Add hotplug support for nvme-ns devices on the NvmeBus. This enables\nnamespace-level hot-swap without removing the NVMe controller, which\nis how physical NVMe drives behave when hot-swapped in the same PCIe\nslot.\n\nMark nvme-ns devices as hotpluggable and register the NvmeBus as a\nhotplug handler with proper plug and unplug callbacks:\n\n- plug: attach namespace to all started controllers and send an\n Asynchronous Event Notification (AEN) with NS_ATTR_CHANGED so\n the guest kernel rescans namespaces\n- unplug: detach from all controllers, send AEN, remove from\n subsystem, then unrealize the device\n\nThe plug handler skips controllers that haven't started yet\n(qs_created == false) to avoid interfering with boot-time namespace\nattachment in nvme_start_ctrl().\n\nBoth the controller bus and subsystem bus are configured as hotplug\nhandlers via qbus_set_bus_hotplug_handler() since nvme-ns devices\nmay reparent to the subsystem bus during realize.\n\nSigned-off-by: Matthieu Receveur \n---\n hw/nvme/ctrl.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++\n hw/nvme/ns.c | 1 +\n hw/nvme/subsys.c | 2 ++\n 3 files changed, 88 insertions(+)","diff":"diff --git a/hw/nvme/ctrl.c b/hw/nvme/ctrl.c\nindex be6c7028cb..5502e4ea2b 100644\n--- a/hw/nvme/ctrl.c\n+++ b/hw/nvme/ctrl.c\n@@ -206,6 +206,7 @@\n #include \"system/hostmem.h\"\n #include \"hw/pci/msix.h\"\n #include \"hw/pci/pcie_sriov.h\"\n+#include \"hw/core/qdev.h\"\n #include \"system/spdm-socket.h\"\n #include \"migration/vmstate.h\"\n \n@@ -9293,6 +9294,7 @@ static void nvme_realize(PCIDevice *pci_dev, Error **errp)\n }\n \n qbus_init(&n->bus, sizeof(NvmeBus), TYPE_NVME_BUS, dev, dev->id);\n+ qbus_set_bus_hotplug_handler(BUS(&n->bus));\n \n if (nvme_init_subsys(n, errp)) {\n return;\n@@ -9553,10 +9555,93 @@ static const TypeInfo nvme_info = {\n },\n };\n \n+static void nvme_ns_hot_plug(HotplugHandler *hotplug_dev, DeviceState *dev,\n+ Error **errp)\n+{\n+ NvmeNamespace *ns = NVME_NS(dev);\n+ NvmeSubsystem *subsys = ns->subsys;\n+ uint32_t nsid = ns->params.nsid;\n+ int i;\n+\n+ /*\n+ * Attach to all started controllers and notify via AEN.\n+ * Skip controllers that haven't started yet (boot-time realize) —\n+ * nvme_start_ctrl() will attach namespaces during controller init.\n+ */\n+ for (i = 0; i < NVME_MAX_CONTROLLERS; i++) {\n+ NvmeCtrl *ctrl = nvme_subsys_ctrl(subsys, i);\n+ if (!ctrl || !ctrl->qs_created) {\n+ continue;\n+ }\n+\n+ if (nvme_csi_supported(ctrl, ns->csi) && !ns->params.detached) {\n+ nvme_attach_ns(ctrl, ns);\n+ nvme_update_dsm_limits(ctrl, ns);\n+\n+ if (!test_and_set_bit(nsid, ctrl->changed_nsids)) {\n+ nvme_enqueue_event(ctrl, NVME_AER_TYPE_NOTICE,\n+ NVME_AER_INFO_NOTICE_NS_ATTR_CHANGED,\n+ NVME_LOG_CHANGED_NSLIST);\n+ }\n+ }\n+ }\n+}\n+\n+static void nvme_ns_hot_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,\n+ Error **errp)\n+{\n+ NvmeNamespace *ns = NVME_NS(dev);\n+ NvmeSubsystem *subsys = ns->subsys;\n+ uint32_t nsid = ns->params.nsid;\n+ int i;\n+\n+ /*\n+ * Detach from all controllers and notify the guest via AEN.\n+ * Must happen before unrealize to avoid use-after-free when the\n+ * guest sends I/O to a freed namespace.\n+ */\n+ for (i = 0; i < NVME_MAX_CONTROLLERS; i++) {\n+ NvmeCtrl *ctrl = nvme_subsys_ctrl(subsys, i);\n+ if (!ctrl || !nvme_ns(ctrl, nsid)) {\n+ continue;\n+ }\n+\n+ nvme_detach_ns(ctrl, ns);\n+ nvme_update_dsm_limits(ctrl, NULL);\n+\n+ if (!test_and_set_bit(nsid, ctrl->changed_nsids)) {\n+ nvme_enqueue_event(ctrl, NVME_AER_TYPE_NOTICE,\n+ NVME_AER_INFO_NOTICE_NS_ATTR_CHANGED,\n+ NVME_LOG_CHANGED_NSLIST);\n+ }\n+ }\n+\n+ /* Remove from subsystem namespace list. */\n+ subsys->namespaces[nsid] = NULL;\n+\n+ /*\n+ * Unrealize: drain I/O, flush, cleanup structures, remove from QOM.\n+ * nvme_ns_unrealize() handles drain/shutdown/cleanup internally.\n+ */\n+ qdev_unrealize(dev);\n+}\n+\n+static void nvme_bus_class_init(ObjectClass *klass, const void *data)\n+{\n+ HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);\n+ hc->plug = nvme_ns_hot_plug;\n+ hc->unplug = nvme_ns_hot_unplug;\n+}\n+\n static const TypeInfo nvme_bus_info = {\n .name = TYPE_NVME_BUS,\n .parent = TYPE_BUS,\n .instance_size = sizeof(NvmeBus),\n+ .class_init = nvme_bus_class_init,\n+ .interfaces = (const InterfaceInfo[]) {\n+ { TYPE_HOTPLUG_HANDLER },\n+ { }\n+ },\n };\n \n static void nvme_register_types(void)\ndiff --git a/hw/nvme/ns.c b/hw/nvme/ns.c\nindex b0106eaa5c..eb628c0734 100644\n--- a/hw/nvme/ns.c\n+++ b/hw/nvme/ns.c\n@@ -937,6 +937,7 @@ static void nvme_ns_class_init(ObjectClass *oc, const void *data)\n dc->bus_type = TYPE_NVME_BUS;\n dc->realize = nvme_ns_realize;\n dc->unrealize = nvme_ns_unrealize;\n+ dc->hotpluggable = true;\n device_class_set_props(dc, nvme_ns_props);\n dc->desc = \"Virtual NVMe namespace\";\n }\ndiff --git a/hw/nvme/subsys.c b/hw/nvme/subsys.c\nindex 777e1c620f..fa35055d3c 100644\n--- a/hw/nvme/subsys.c\n+++ b/hw/nvme/subsys.c\n@@ -9,6 +9,7 @@\n #include \"qemu/osdep.h\"\n #include \"qemu/units.h\"\n #include \"qapi/error.h\"\n+#include \"hw/core/qdev.h\"\n \n #include \"nvme.h\"\n \n@@ -205,6 +206,7 @@ static void nvme_subsys_realize(DeviceState *dev, Error **errp)\n NvmeSubsystem *subsys = NVME_SUBSYS(dev);\n \n qbus_init(&subsys->bus, sizeof(NvmeBus), TYPE_NVME_BUS, dev, dev->id);\n+ qbus_set_bus_hotplug_handler(BUS(&subsys->bus));\n \n nvme_subsys_setup(subsys, errp);\n }\n","prefixes":["1/2"]}