Re: [Qemu-devel] [RFC PATCH v2 20/35] multi-process: Add QMP & extend HMP commands to list remote info

[Stefan Hajnoczi]

On Mon, Jun 17, 2019 at 7:28 PM <address@hidden> wrote:
>
> From: Jagannathan Raman <address@hidden>
>
> Add query-remote QMP command and extend "info" HMP command, to list
> the remote objects used by QEMU.
>
> Signed-off-by: Jagannathan Raman <address@hidden>
> Signed-off-by: John G Johnson <address@hidden>
> Signed-off-by: Elena Ufimtseva <address@hidden>
> ---
>  hmp-commands-info.hx          | 16 +++++++
>  hmp.h                         |  1 +
>  hw/proxy/Makefile.objs        |  1 +
>  hw/proxy/monitor.c            | 88 +++++++++++++++++++++++++++++++++++
>  include/hw/proxy/qemu-proxy.h |  1 +
>  qapi/block-core.json          | 29 ++++++++++++
>  6 files changed, 136 insertions(+)
>  create mode 100644 hw/proxy/monitor.c
>
> diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
> index c59444c461..b145e755eb 100644
> --- a/hmp-commands-info.hx
> +++ b/hmp-commands-info.hx
> @@ -932,6 +932,22 @@ STEXI
>  Show SEV information.
>  ETEXI
>
> +#if defined(CONFIG_MPQEMU)
> +    {
> +        .name       = "remote",
> +        .args_type  = "",
> +        .params     = "",
> +        .help       = "list remote objects",
> +        .cmd        = hmp_info_remote,
> +    },
> +
> +STEXI
> +@item remote
> +@findex remote
> +list remote objects.
> +ETEXI
> +#endif
> +
>  STEXI
>  @end table
>  ETEXI
> diff --git a/hmp.h b/hmp.h
> index 43617f2646..6919f99218 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -150,5 +150,6 @@ void hmp_hotpluggable_cpus(Monitor *mon, const QDict 
> *qdict);
>  void hmp_info_vm_generation_id(Monitor *mon, const QDict *qdict);
>  void hmp_info_memory_size_summary(Monitor *mon, const QDict *qdict);
>  void hmp_info_sev(Monitor *mon, const QDict *qdict);
> +void hmp_info_remote(Monitor *mon, const QDict *qdict);
>
>  #endif
> diff --git a/hw/proxy/Makefile.objs b/hw/proxy/Makefile.objs
> index f562f5a0e9..e6420602b8 100644
> --- a/hw/proxy/Makefile.objs
> +++ b/hw/proxy/Makefile.objs
> @@ -1,2 +1,3 @@
>  common-obj-$(CONFIG_MPQEMU) += qemu-proxy.o
>  common-obj-$(CONFIG_MPQEMU) += proxy-lsi53c895a.o
> +common-obj-$(CONFIG_MPQEMU) += monitor.o
> diff --git a/hw/proxy/monitor.c b/hw/proxy/monitor.c
> new file mode 100644
> index 0000000000..694f34a446
> --- /dev/null
> +++ b/hw/proxy/monitor.c
> @@ -0,0 +1,88 @@
> +/*
> + * QEMU monitor command handler for multi-process QEMU
> + *
> + * Copyright 2019, Oracle and/or its affiliates.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a 
> copy
> + * of this software and associated documentation files (the "Software"), to 
> deal
> + * in the Software without restriction, including without limitation the 
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include <sys/types.h>
> +
> +#include "qemu/osdep.h"
> +#include "qapi/qapi-types-block-core.h"
> +#include "qapi/qapi-commands-block-core.h"
> +#include "monitor/monitor.h"
> +#include "qemu/option.h"
> +#include "hmp.h"
> +#include "hw/boards.h"
> +#include "hw/proxy/qemu-proxy.h"
> +
> +/*
> + * TODO: Is there a callback where the allocated memory for QMP could be 
> free'd

QAPI objects are freed by the monitor.  The QAPI code generator
produces a function for freeing each QAPI object and the monitor will
call it after sending the response to the monitor client.

> + */
> +RemoteProcList *qmp_query_remote(Error **errp)
> +{
> +    MachineState *ms = MACHINE(current_machine);
> +    RemoteProcList *proclist, *proc;
> +    GHashTableIter itr;
> +    PCIProxyDev *pdev;
> +    PCIProxyDevClass *k;

This shouldn't be limited to PCI.  From what I can tell this is an
implementation detail, so it's fine for now.  Just make sure not to
put PCI-specific things in the QMP interface so that we can use this
for other devices in the future (USB, etc).