From: Michael Kropaczek <michael.kropac...@solidigm.com> Description:
Currently namespaces could be configured as follows: 1. Legacy Namespace - just one namespace within Nvme controller's where the back-end was specified for nvme device by -drive parameter pointing directly to the image file. 2. Additional Namespaces - specified by nvme-ns devices each having its own back-end. To have multiple namespaces each needed to be specified at Qemu's command line being associated with the most recently defined nvme-bus from nvme device. If a such additional namespace should be attached and/or detached by the guest OS, nvme controller has to be linked with another device nvme-subsys. All that have a static nature, all need to be specified at the Qemu's command line, all specified virtual nvme entities will be processed during Qemu's start-up then created and provided to the guest OS. To have a support for nvme create-ns and delete-ns commands with specified parameters a different approach is needed. Virtual devices representing namespaces need to be created and/or deleted during Qemu's running session, at anytime. The back-end image sizes for a namespace must accommodate the payload size and size of metadata resulted from specified parameters. The total capacity of the nvme controller altogether with un-allocated capacity needs to be taken into account and updated according to nvme create-ns and delete-ns commands respectively. Here is the approach: The nvme device will get new parameter: - auto-ns-path, which specifies the path to the storage area where back-end image and necessary config files located stored. The virtual devices representing namespaces will be created dynamically during the Qemu running session following issuance of nvme create-ns and delete-ns commands from the guest OS. QOM classes and instances will be created utilizing existing configuration scheme used during Qemu's start-up. Back-end image files will be neither created nor deleted during Qemu's startup or running session. Instead a set of back-end image files and relevant config will be created by qemu-img tool with createns sub-command prior to Qemu's session. Required parameters are: -S serial number which must match serial parameter of qemu-system-xx -device nvme command line specification, -C total capacity, and optional -N that will set a maximal limit on number of allowed namespaces (default 256) which will be followed by path name pointing to storage location corresponding to auto-ns-path of qemu-system-xx -device nvme parameter. Those created back-end image files will be pre-loaded during Qemu's start-up and then during running Qemu's session will be associated or disassociated with QOM namespaces virtual instances, as a result of issuing nvme create-ns or delete-ns commands. The associated back-end image file for relevant namespace will be re-sized as follows: delete-ns command will truncate image file to the size of 0, whereas create-ns command will re-size the image file to the size provided by nvme create-ns command parameters. Truncating/re-sizing is a result of blk_truncate() API which utilizes co-routines and should not block Qemu main thread while scheduling AIO operations. It is assured that all settings will retain over Qemu's start-ups and shutdowns. The implementation makes it possible to combine the existing "Additional Namespace" implementation with the new "Managed Namespaces". Those will coexist with obvious restrictions, like both will share the same NsIds space, "static" namespaces cannot be deleted or if its NsId specified at Qemu's command line will conflicts with previously created one by nvme create-ns (and retained), this will lead to an abort of Qemu at its start up. Michael Kropaczek (2): hw/nvme: Support for Namespaces Management from guest OS - create-ns hw/nvme: Support for Namespaces Management from guest OS - delete-ns docs/system/devices/nvme.rst | 56 ++++++- hw/nvme/cfg_key_checker.c | 51 ++++++ hw/nvme/ctrl-cfg.c | 181 ++++++++++++++++++++ hw/nvme/ctrl.c | 282 +++++++++++++++++++++++++++++++- hw/nvme/meson.build | 2 +- hw/nvme/ns-backend.c | 239 +++++++++++++++++++++++++++ hw/nvme/ns.c | 308 +++++++++++++++++++++++++++++++---- hw/nvme/nvme.h | 33 +++- hw/nvme/trace-events | 3 + include/block/nvme.h | 31 ++++ include/hw/nvme/ctrl-cfg.h | 24 +++ include/hw/nvme/ns-cfg.h | 28 ++++ include/hw/nvme/nvme-cfg.h | 201 +++++++++++++++++++++++ qemu-img-cmds.hx | 6 + qemu-img.c | 134 +++++++++++++++ 15 files changed, 1542 insertions(+), 37 deletions(-) create mode 100644 hw/nvme/cfg_key_checker.c create mode 100644 hw/nvme/ctrl-cfg.c create mode 100644 hw/nvme/ns-backend.c create mode 100644 include/hw/nvme/ctrl-cfg.h create mode 100644 include/hw/nvme/ns-cfg.h create mode 100644 include/hw/nvme/nvme-cfg.h -- 2.37.3
