Re: [Qemu-devel] [RFC PATCH 3/4] qmp: Introduce memchar_write QMP command

[Anthony Liguori <aliguori@us.ibm.com>]

Lei Li <lilei@linux.vnet.ibm.com> writes:

> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
> ---
>  qapi-schema.json |   20 ++++++++++++++++++++
>  qemu-char.c      |   19 +++++++++++++++++++
>  qmp-commands.hx  |   29 +++++++++++++++++++++++++++++
>  3 files changed, 68 insertions(+), 0 deletions(-)
>
> diff --git a/qapi-schema.json b/qapi-schema.json
> index bc55ed2..3c8530f 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -206,6 +206,26 @@
>  { 'command': 'query-chardev', 'returns': ['ChardevInfo'] }
>  
>  ##
> +# @memchar_write:

memchar-write as Eric suggested.

> +#
> +# Provide writing interface for memchardev. Write data to memchar
> +# char device.
> +#
> +# @chardev: the name of the memchar char device.
> +#
> +# @size: the size to write in bytes.
> +#
> +# @data: the source data write to memchar.
> +#
> +# Returns: Nothing on success
> +#          If an I/O error occurs while writing, IOError
> +#
> +# Since: 1.2
> +##
> +{ 'command': 'memchar_write',
> +  'data': {'chardev': 'str', 'size': 'int', 'data': 'str'} }

You should add another option which is '*format': 'DataFormat'.

DataFormat would be an enum and would include: "utf8", "base64" to start
with.  The default value would be utf8.  You'll need to be careful to
scrub the output of memchar-read of any non-UTF8 character to make sure
what you are returning is UTF8 clean.

> +
> +##
>  # @CommandInfo:
>  #
>  # Information about a QMP command
> diff --git a/qemu-char.c b/qemu-char.c
> index 087c92d..1012e65 100644
> --- a/qemu-char.c
> +++ b/qemu-char.c
> @@ -2636,6 +2636,25 @@ size_t qemu_chr_mem_osize(const CharDriverState *chr)
>      return d->cbuf_count;
>  }
>  
> +void qmp_memchar_write(const char *chardev, int64_t size,
> +                       uint8_t *data, Error **errp)
> +{
> +    CharDriverState *chr;
> +    int ret;
> +
> +    chr = qemu_chr_find(chardev);
> +
> +    if(!chr) {
> +        qemu_chr_init_mem(chr, size);
> +    }

Indenting is off here (need a space after the if).  Plus chr is still
NULL after this returns.  I don't think you should do lazy init here.
If qemu_chr_find() returns NULL, you should throw an error.

Regards,

Anthony Liguori

> +
> +    ret = mem_chr_write(chr, data, size);
> +    if (ret <= 0) {
> +        error_set(errp, QERR_IO_ERROR);
> +        return;
> +    }
> +}
> +
>  QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename)
>  {
>      char host[65], port[33], width[8], height[8];
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index e3cf3c5..182f1e6 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -441,6 +441,35 @@ Note: inject-nmi is only supported for x86 guest currently, it will
>  EQMP
>  
>      {
> +        .name       = "memchar_write",
> +        .args_type  = "chardev:s,size:i,data:s",
> +        .mhandler.cmd_new = qmp_marshal_input_memchar_write,
> +    },
> +
> +SQMP
> +memchar_write
> +-------------
> +
> +Provide writing interface for memchardev. Write data to memchar
> +char device.
> +
> +Arguments:
> +
> +- "chardev": the name of the char device, must be unique (json-string)
> +- "size": the memory size, in bytes (json-int)
> +- "data": the source data writed to memchar (json-string)
> +
> +Example:
> +
> +-> { "execute": "memchar_write",
> +                "arguments": { "chardev": foo,
> +                               "size": 1000,
> +                               "data": "data string" } }
> +<- { "return": {} }
> +
> +EQMP
> +
> +    {
>          .name       = "xen-save-devices-state",
>          .args_type  = "filename:F",
>      .mhandler.cmd_new = qmp_marshal_input_xen_save_devices_state,
> -- 
> 1.7.7.6