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Tsirkin" , Stefan Hajnoczi , German Maglione , =?utf-8?q?Eugenio_P=C3=A9rez?= , Anton Kuchin Subject: [PATCH v5 7/7] vhost-user-fs: Implement internal migration Date: Mon, 16 Oct 2023 15:42:43 +0200 Message-ID: <20231016134243.68248-8-hreitz@redhat.com> In-Reply-To: <20231016134243.68248-1-hreitz@redhat.com> References: <20231016134243.68248-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 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 A virtio-fs device's VM state consists of: - the virtio device (vring) state (VMSTATE_VIRTIO_DEVICE) - the back-end's (virtiofsd's) internal state We get/set the latter via the new vhost operations to transfer migratory state. It is its own dedicated subsection, so that for external migration, it can be disabled. Reviewed-by: Stefan Hajnoczi Signed-off-by: Hanna Czenczek --- hw/virtio/vhost-user-fs.c | 101 +++++++++++++++++++++++++++++++++++++- 1 file changed, 100 insertions(+), 1 deletion(-) diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c index 49d699ffc2..eb91723855 100644 --- a/hw/virtio/vhost-user-fs.c +++ b/hw/virtio/vhost-user-fs.c @@ -298,9 +298,108 @@ static struct vhost_dev *vuf_get_vhost(VirtIODevice *vdev) return &fs->vhost_dev; } +/** + * Fetch the internal state from virtiofsd and save it to `f`. + */ +static int vuf_save_state(QEMUFile *f, void *pv, size_t size, + const VMStateField *field, JSONWriter *vmdesc) +{ + VirtIODevice *vdev = pv; + VHostUserFS *fs = VHOST_USER_FS(vdev); + Error *local_error = NULL; + int ret; + + ret = vhost_save_backend_state(&fs->vhost_dev, f, &local_error); + if (ret < 0) { + error_reportf_err(local_error, + "Error saving back-end state of %s device %s " + "(tag: \"%s\"): ", + vdev->name, vdev->parent_obj.canonical_path, + fs->conf.tag ?: ""); + return ret; + } + + return 0; +} + +/** + * Load virtiofsd's internal state from `f` and send it over to virtiofsd. + */ +static int vuf_load_state(QEMUFile *f, void *pv, size_t size, + const VMStateField *field) +{ + VirtIODevice *vdev = pv; + VHostUserFS *fs = VHOST_USER_FS(vdev); + Error *local_error = NULL; + int ret; + + ret = vhost_load_backend_state(&fs->vhost_dev, f, &local_error); + if (ret < 0) { + error_reportf_err(local_error, + "Error loading back-end state of %s device %s " + "(tag: \"%s\"): ", + vdev->name, vdev->parent_obj.canonical_path, + fs->conf.tag ?: ""); + return ret; + } + + return 0; +} + +static bool vuf_is_internal_migration(void *opaque) +{ + /* TODO: Return false when an external migration is requested */ + return true; +} + +static int vuf_check_migration_support(void *opaque) +{ + VirtIODevice *vdev = opaque; + VHostUserFS *fs = VHOST_USER_FS(vdev); + + if (!vhost_supports_device_state(&fs->vhost_dev)) { + error_report("Back-end of %s device %s (tag: \"%s\") does not support " + "migration through qemu", + vdev->name, vdev->parent_obj.canonical_path, + fs->conf.tag ?: ""); + return -ENOTSUP; + } + + return 0; +} + +static const VMStateDescription vuf_backend_vmstate; + static const VMStateDescription vuf_vmstate = { .name = "vhost-user-fs", - .unmigratable = 1, + .version_id = 0, + .fields = (VMStateField[]) { + VMSTATE_VIRTIO_DEVICE, + VMSTATE_END_OF_LIST() + }, + .subsections = (const VMStateDescription * []) { + &vuf_backend_vmstate, + NULL, + } +}; + +static const VMStateDescription vuf_backend_vmstate = { + .name = "vhost-user-fs-backend", + .version_id = 0, + .needed = vuf_is_internal_migration, + .pre_load = vuf_check_migration_support, + .pre_save = vuf_check_migration_support, + .fields = (VMStateField[]) { + { + .name = "back-end", + .info = &(const VMStateInfo) { + .name = "virtio-fs back-end state", + .get = vuf_load_state, + .put = vuf_save_state, + }, + }, + VMSTATE_END_OF_LIST() + }, }; static Property vuf_properties[] = {