From patchwork Mon Jan 7 14:13:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Durrant X-Patchwork-Id: 10750645 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CD94113BF for ; Mon, 7 Jan 2019 14:30:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B98CF28A80 for ; Mon, 7 Jan 2019 14:30:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id ACA2D28A82; Mon, 7 Jan 2019 14:30:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A495B28A80 for ; Mon, 7 Jan 2019 14:30:17 +0000 (UTC) Received: from localhost ([127.0.0.1]:37768 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ggVuy-0005wk-Uh for patchwork-qemu-devel@patchwork.kernel.org; Mon, 07 Jan 2019 09:30:17 -0500 Received: from eggs.gnu.org ([209.51.188.92]:60301) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ggVtZ-0004XA-Aj for qemu-devel@nongnu.org; Mon, 07 Jan 2019 09:28:51 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ggVtU-0002rf-0j for qemu-devel@nongnu.org; Mon, 07 Jan 2019 09:28:49 -0500 Received: from smtp03.citrix.com ([162.221.156.55]:23081) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ggVtT-0002pY-DL; Mon, 07 Jan 2019 09:28:43 -0500 X-IronPort-AV: E=Sophos;i="5.56,451,1539648000"; d="scan'208";a="74966322" From: Paul Durrant To: , , Date: Mon, 7 Jan 2019 14:13:06 +0000 Message-ID: <20190107141309.15774-16-paul.durrant@citrix.com> X-Mailer: git-send-email 2.20.1.2.gb21ebb6 In-Reply-To: <20190107141309.15774-1-paul.durrant@citrix.com> References: <20190107141309.15774-1-paul.durrant@citrix.com> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 162.221.156.55 Subject: [Qemu-devel] [PATCH v8 15/18] xen: add a mechanism to automatically create XenDevice-s... 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: Anthony Perard , Paul Durrant , Stefano Stabellini Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP ...that maintains compatibility with existing Xen toolstacks. Xen toolstacks instantiate PV backends by simply writing information into xenstore and expecting a backend implementation to be watching for this. This patch adds a new 'xen-backend' module to allow individual XenDevice implementations to register create and destroy functions. The creator will be called when a tool-stack instantiates a new backend in this way, and the destructor will then be called after the resulting XenDevice object is unrealized. To support this it is also necessary to add new watchers into the XenBus implementation to handle enumeration of new backends and also destruction of XenDevice-s when the toolstack sets the backend 'online' key to 0. NOTE: This patch only adds the framework. A subsequent patch will add a creator function for xen-block devices. Signed-off-by: Paul Durrant Reviewed-by: Anthony Perard --- Cc: Stefano Stabellini v5: - Added destructor function, therefore Anthony's R-b is not carried from v4 v3: - Use a xenstore transaction in enumeration code to ensure consistent parameters - Not adding Anthony's R-b because of change v2: - Sort out error paths and error reporting --- hw/xen/Makefile.objs | 2 +- hw/xen/trace-events | 3 + hw/xen/xen-backend.c | 165 +++++++++++++++++++++++++++++++++++ hw/xen/xen-bus.c | 164 +++++++++++++++++++++++++++++++++- include/hw/xen/xen-backend.h | 39 +++++++++ include/hw/xen/xen-bus.h | 1 + include/qemu/module.h | 3 + 7 files changed, 375 insertions(+), 2 deletions(-) create mode 100644 hw/xen/xen-backend.c create mode 100644 include/hw/xen/xen-backend.h diff --git a/hw/xen/Makefile.objs b/hw/xen/Makefile.objs index 77c0868190..84df60a928 100644 --- a/hw/xen/Makefile.objs +++ b/hw/xen/Makefile.objs @@ -1,5 +1,5 @@ # xen backend driver support -common-obj-$(CONFIG_XEN) += xen-legacy-backend.o xen_devconfig.o xen_pvdev.o xen-common.o xen-bus.o xen-bus-helper.o +common-obj-$(CONFIG_XEN) += xen-legacy-backend.o xen_devconfig.o xen_pvdev.o xen-common.o xen-bus.o xen-bus-helper.o xen-backend.o obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen-host-pci-device.o obj-$(CONFIG_XEN_PCI_PASSTHROUGH) += xen_pt.o xen_pt_config_init.o xen_pt_graphics.o xen_pt_msi.o diff --git a/hw/xen/trace-events b/hw/xen/trace-events index d4651bdb30..f6944624b2 100644 --- a/hw/xen/trace-events +++ b/hw/xen/trace-events @@ -16,6 +16,9 @@ xen_domid_restrict(int err) "err: %u" # include/hw/xen/xen-bus.c xen_bus_realize(void) "" xen_bus_unrealize(void) "" +xen_bus_enumerate(void) "" +xen_bus_type_enumerate(const char *type) "type: %s" +xen_bus_backend_create(const char *type, const char *path) "type: %s path: %s" xen_bus_add_watch(const char *node, const char *key, char *token) "node: %s key: %s token: %s" xen_bus_remove_watch(const char *node, const char *key, char *token) "node: %s key: %s token: %s" xen_bus_watch(const char *token) "token: %s" diff --git a/hw/xen/xen-backend.c b/hw/xen/xen-backend.c new file mode 100644 index 0000000000..da065f81b7 --- /dev/null +++ b/hw/xen/xen-backend.c @@ -0,0 +1,165 @@ +/* + * Copyright (c) 2018 Citrix Systems Inc. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "qemu/error-report.h" +#include "qapi/error.h" +#include "hw/xen/xen-backend.h" +#include "hw/xen/xen-bus.h" + +typedef struct XenBackendImpl { + const char *type; + XenBackendDeviceCreate create; + XenBackendDeviceDestroy destroy; +} XenBackendImpl; + +struct XenBackendInstance { + QLIST_ENTRY(XenBackendInstance) entry; + const XenBackendImpl *impl; + XenBus *xenbus; + char *name; + XenDevice *xendev; +}; + +static GHashTable *xen_backend_table_get(void) +{ + static GHashTable *table; + + if (table == NULL) { + table = g_hash_table_new(g_str_hash, g_str_equal); + } + + return table; +} + +static void xen_backend_table_add(XenBackendImpl *impl) +{ + g_hash_table_insert(xen_backend_table_get(), (void *)impl->type, impl); +} + +static const XenBackendImpl *xen_backend_table_lookup(const char *type) +{ + return g_hash_table_lookup(xen_backend_table_get(), type); +} + +void xen_backend_register(const XenBackendInfo *info) +{ + XenBackendImpl *impl = g_new0(XenBackendImpl, 1); + + g_assert(info->type); + + if (xen_backend_table_lookup(info->type)) { + error_report("attempt to register duplicate Xen backend type '%s'", + info->type); + abort(); + } + + if (!info->create) { + error_report("backend type '%s' has no creator", info->type); + abort(); + } + + impl->type = info->type; + impl->create = info->create; + impl->destroy = info->destroy; + + xen_backend_table_add(impl); +} + +static QLIST_HEAD(, XenBackendInstance) backend_list; + +static void xen_backend_list_add(XenBackendInstance *backend) +{ + QLIST_INSERT_HEAD(&backend_list, backend, entry); +} + +static XenBackendInstance *xen_backend_list_find(XenDevice *xendev) +{ + XenBackendInstance *backend; + + QLIST_FOREACH(backend, &backend_list, entry) { + if (backend->xendev == xendev) { + return backend; + } + } + + return NULL; +} + +static void xen_backend_list_remove(XenBackendInstance *backend) +{ + QLIST_REMOVE(backend, entry); +} + +void xen_backend_device_create(XenBus *xenbus, const char *type, + const char *name, QDict *opts, Error **errp) +{ + const XenBackendImpl *impl = xen_backend_table_lookup(type); + XenBackendInstance *backend; + Error *local_error = NULL; + + if (!impl) { + return; + } + + backend = g_new0(XenBackendInstance, 1); + backend->xenbus = xenbus; + backend->name = g_strdup(name); + + impl->create(backend, opts, &local_error); + if (local_error) { + error_propagate(errp, local_error); + g_free(backend->name); + g_free(backend); + return; + } + + backend->impl = impl; + xen_backend_list_add(backend); +} + +XenBus *xen_backend_get_bus(XenBackendInstance *backend) +{ + return backend->xenbus; +} + +const char *xen_backend_get_name(XenBackendInstance *backend) +{ + return backend->name; +} + +void xen_backend_set_device(XenBackendInstance *backend, + XenDevice *xendev) +{ + g_assert(!backend->xendev); + backend->xendev = xendev; +} + +XenDevice *xen_backend_get_device(XenBackendInstance *backend) +{ + return backend->xendev; +} + + +bool xen_backend_try_device_destroy(XenDevice *xendev, Error **errp) +{ + XenBackendInstance *backend = xen_backend_list_find(xendev); + const XenBackendImpl *impl; + + if (!backend) { + return false; + } + + impl = backend->impl; + impl->destroy(backend, errp); + + xen_backend_list_remove(backend); + g_free(backend->name); + g_free(backend); + + return true; +} diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index a22aa49921..f90bcf2342 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -11,10 +11,12 @@ #include "hw/hw.h" #include "hw/sysbus.h" #include "hw/xen/xen.h" +#include "hw/xen/xen-backend.h" #include "hw/xen/xen-bus.h" #include "hw/xen/xen-bus-helper.h" #include "monitor/monitor.h" #include "qapi/error.h" +#include "qapi/qmp/qdict.h" #include "sysemu/sysemu.h" #include "trace.h" @@ -190,12 +192,151 @@ static void xen_bus_remove_watch(XenBus *xenbus, XenWatch *watch, free_watch(watch); } +static void xen_bus_backend_create(XenBus *xenbus, const char *type, + const char *name, char *path, + Error **errp) +{ + xs_transaction_t tid; + char **key; + QDict *opts; + unsigned int i, n; + Error *local_err = NULL; + + trace_xen_bus_backend_create(type, path); + +again: + tid = xs_transaction_start(xenbus->xsh); + if (tid == XBT_NULL) { + error_setg(errp, "failed xs_transaction_start"); + return; + } + + key = xs_directory(xenbus->xsh, tid, path, &n); + if (!key) { + if (!xs_transaction_end(xenbus->xsh, tid, true)) { + error_setg_errno(errp, errno, "failed xs_transaction_end"); + } + return; + } + + opts = qdict_new(); + for (i = 0; i < n; i++) { + char *val; + + /* + * Assume anything found in the xenstore backend area, other than + * the keys created for a generic XenDevice, are parameters + * to be used to configure the backend. + */ + if (!strcmp(key[i], "state") || + !strcmp(key[i], "online") || + !strcmp(key[i], "frontend") || + !strcmp(key[i], "frontend-id") || + !strcmp(key[i], "hotplug-status")) + continue; + + if (xs_node_scanf(xenbus->xsh, tid, path, key[i], NULL, "%ms", + &val) == 1) { + qdict_put_str(opts, key[i], val); + free(val); + } + } + + free(key); + + if (!xs_transaction_end(xenbus->xsh, tid, false)) { + qobject_unref(opts); + + if (errno == EAGAIN) { + goto again; + } + + error_setg_errno(errp, errno, "failed xs_transaction_end"); + return; + } + + xen_backend_device_create(xenbus, type, name, opts, &local_err); + qobject_unref(opts); + + if (local_err) { + error_propagate_prepend(errp, local_err, + "failed to create '%s' device '%s': ", + type, name); + } +} + +static void xen_bus_type_enumerate(XenBus *xenbus, const char *type) +{ + char *domain_path = g_strdup_printf("backend/%s/%u", type, xen_domid); + char **backend; + unsigned int i, n; + + trace_xen_bus_type_enumerate(type); + + backend = xs_directory(xenbus->xsh, XBT_NULL, domain_path, &n); + if (!backend) { + goto out; + } + + for (i = 0; i < n; i++) { + char *backend_path = g_strdup_printf("%s/%s", domain_path, + backend[i]); + enum xenbus_state backend_state; + + if (xs_node_scanf(xenbus->xsh, XBT_NULL, backend_path, "state", + NULL, "%u", &backend_state) != 1) + backend_state = XenbusStateUnknown; + + if (backend_state == XenbusStateInitialising) { + Error *local_err = NULL; + + xen_bus_backend_create(xenbus, type, backend[i], backend_path, + &local_err); + if (local_err) { + error_report_err(local_err); + } + } + + g_free(backend_path); + } + + free(backend); + +out: + g_free(domain_path); +} + +static void xen_bus_enumerate(void *opaque) +{ + XenBus *xenbus = opaque; + char **type; + unsigned int i, n; + + trace_xen_bus_enumerate(); + + type = xs_directory(xenbus->xsh, XBT_NULL, "backend", &n); + if (!type) { + return; + } + + for (i = 0; i < n; i++) { + xen_bus_type_enumerate(xenbus, type[i]); + } + + free(type); +} + static void xen_bus_unrealize(BusState *bus, Error **errp) { XenBus *xenbus = XEN_BUS(bus); trace_xen_bus_unrealize(); + if (xenbus->backend_watch) { + xen_bus_remove_watch(xenbus, xenbus->backend_watch, NULL); + xenbus->backend_watch = NULL; + } + if (!xenbus->xsh) { return; } @@ -231,6 +372,7 @@ static void xen_bus_realize(BusState *bus, Error **errp) { XenBus *xenbus = XEN_BUS(bus); unsigned int domid; + Error *local_err = NULL; trace_xen_bus_realize(); @@ -250,6 +392,18 @@ static void xen_bus_realize(BusState *bus, Error **errp) notifier_list_init(&xenbus->watch_notifiers); qemu_set_fd_handler(xs_fileno(xenbus->xsh), xen_bus_watch, NULL, xenbus); + + module_call_init(MODULE_INIT_XEN_BACKEND); + + xenbus->backend_watch = + xen_bus_add_watch(xenbus, "", /* domain root node */ + "backend", xen_bus_enumerate, xenbus, &local_err); + if (local_err) { + /* This need not be treated as a hard error so don't propagate */ + error_reportf_err(local_err, + "failed to set up enumeration watch: "); + } + return; fail: @@ -407,7 +561,15 @@ static void xen_device_backend_changed(void *opaque) xendev->backend_state == XenbusStateInitialising || xendev->backend_state == XenbusStateInitWait || xendev->backend_state == XenbusStateUnknown)) { - object_unparent(OBJECT(xendev)); + Error *local_err = NULL; + + if (!xen_backend_try_device_destroy(xendev, &local_err)) { + object_unparent(OBJECT(xendev)); + } + + if (local_err) { + error_report_err(local_err); + } } } diff --git a/include/hw/xen/xen-backend.h b/include/hw/xen/xen-backend.h new file mode 100644 index 0000000000..010d712638 --- /dev/null +++ b/include/hw/xen/xen-backend.h @@ -0,0 +1,39 @@ +/* + * Copyright (c) 2018 Citrix Systems Inc. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#ifndef HW_XEN_BACKEND_H +#define HW_XEN_BACKEND_H + +#include "hw/xen/xen-bus.h" + +typedef struct XenBackendInstance XenBackendInstance; + +typedef void (*XenBackendDeviceCreate)(XenBackendInstance *backend, + QDict *opts, Error **errp); +typedef void (*XenBackendDeviceDestroy)(XenBackendInstance *backend, + Error **errp); + +typedef struct XenBackendInfo { + const char *type; + XenBackendDeviceCreate create; + XenBackendDeviceDestroy destroy; +} XenBackendInfo; + +XenBus *xen_backend_get_bus(XenBackendInstance *backend); +const char *xen_backend_get_name(XenBackendInstance *backend); + +void xen_backend_set_device(XenBackendInstance *backend, + XenDevice *xendevice); +XenDevice *xen_backend_get_device(XenBackendInstance *backend); + +void xen_backend_register(const XenBackendInfo *info); + +void xen_backend_device_create(XenBus *xenbus, const char *type, + const char *name, QDict *opts, Error **errp); +bool xen_backend_try_device_destroy(XenDevice *xendev, Error **errp); + +#endif /* HW_XEN_BACKEND_H */ diff --git a/include/hw/xen/xen-bus.h b/include/hw/xen/xen-bus.h index 0834cb3a7e..e55a5de5f1 100644 --- a/include/hw/xen/xen-bus.h +++ b/include/hw/xen/xen-bus.h @@ -65,6 +65,7 @@ typedef struct XenBus { domid_t backend_id; struct xs_handle *xsh; NotifierList watch_notifiers; + XenWatch *backend_watch; } XenBus; typedef struct XenBusClass { diff --git a/include/qemu/module.h b/include/qemu/module.h index 54300ab6e5..55dd2beea8 100644 --- a/include/qemu/module.h +++ b/include/qemu/module.h @@ -44,6 +44,7 @@ typedef enum { MODULE_INIT_OPTS, MODULE_INIT_QOM, MODULE_INIT_TRACE, + MODULE_INIT_XEN_BACKEND, MODULE_INIT_MAX } module_init_type; @@ -51,6 +52,8 @@ typedef enum { #define opts_init(function) module_init(function, MODULE_INIT_OPTS) #define type_init(function) module_init(function, MODULE_INIT_QOM) #define trace_init(function) module_init(function, MODULE_INIT_TRACE) +#define xen_backend_init(function) module_init(function, \ + MODULE_INIT_XEN_BACKEND) #define block_module_load_one(lib) module_load_one("block-", lib) #define ui_module_load_one(lib) module_load_one("ui-", lib)