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Re: [Qemu-devel] [PATCH 2/4] QAPI: Introduce memchar-write QMP command
From: |
Luiz Capitulino |
Subject: |
Re: [Qemu-devel] [PATCH 2/4] QAPI: Introduce memchar-write QMP command |
Date: |
Mon, 29 Oct 2012 11:23:02 -0200 |
On Mon, 29 Oct 2012 12:10:24 +0800
Lei Li <address@hidden> wrote:
> On 10/27/2012 01:17 AM, Luiz Capitulino wrote:
> > On Fri, 26 Oct 2012 19:21:50 +0800
> > Lei Li <address@hidden> wrote:
> >
> >> Signed-off-by: Lei Li <address@hidden>
> >> ---
> >> hmp-commands.hx | 17 +++++++++++++++++
> >> hmp.c | 15 +++++++++++++++
> >> hmp.h | 1 +
> >> qapi-schema.json | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> >> qemu-char.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
> >> qmp-commands.hx | 34 ++++++++++++++++++++++++++++++++++
> >> 6 files changed, 158 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/hmp-commands.hx b/hmp-commands.hx
> >> index e0b537d..a37b8e9 100644
> >> --- a/hmp-commands.hx
> >> +++ b/hmp-commands.hx
> >> @@ -825,6 +825,23 @@ Inject an NMI on the given CPU (x86 only).
> >> ETEXI
> >>
> >> {
> >> + .name = "memchar_write",
> >> + .args_type = "chardev:s,data:s",
> >> + .params = "chardev data",
> >> + .mhandler.cmd = hmp_memchar_write,
> >> + },
> >> +
> >> +STEXI
> >> address@hidden memchar_write @var{chardev} @var{data}
> >> address@hidden memchar_write
> >> +Provide writing interface for CirMemCharDriver. Write @var{data}
> >> +to cirmemchr char device. Note that we will add 'control' options
> >> +for read and write command that specifies behavior when the queue
> >> +is full/empty, for now just assume a drop behaver in these two commands.
> > You can drop everything after "Note".
> >
> ok
>
> >> +
> >> +ETEXI
> >> +
> >> + {
> >> .name = "migrate",
> >> .args_type = "detach:-d,blk:-b,inc:-i,uri:s",
> >> .params = "[-d] [-b] [-i] uri",
> >> diff --git a/hmp.c b/hmp.c
> >> index 2b97982..082985b 100644
> >> --- a/hmp.c
> >> +++ b/hmp.c
> >> @@ -683,6 +683,21 @@ void hmp_pmemsave(Monitor *mon, const QDict *qdict)
> >> hmp_handle_error(mon, &errp);
> >> }
> >>
> >> +void hmp_memchar_write(Monitor *mon, const QDict *qdict)
> >> +{
> >> + uint32_t size;
> >> + const char *chardev = qdict_get_str(qdict, "chardev");
> >> + const char *data = qdict_get_str(qdict, "data");
> >> + enum DataFormat format;
> > Why do you need this variable?
>
> Sure, I will drop this.
>
> >> + Error *errp = NULL;
> >> +
> >> + size = strlen(data);
> >> + format = DATA_FORMAT_UTF8;
> >> + qmp_memchar_write(chardev, size, data, true, format, &errp);
> >> +
> >> + hmp_handle_error(mon, &errp);
> >> +}
> >> +
> >> static void hmp_cont_cb(void *opaque, int err)
> >> {
> >> if (!err) {
> >> diff --git a/hmp.h b/hmp.h
> >> index 71ea384..406ebb1 100644
> >> --- a/hmp.h
> >> +++ b/hmp.h
> >> @@ -43,6 +43,7 @@ void hmp_system_powerdown(Monitor *mon, const QDict
> >> *qdict);
> >> void hmp_cpu(Monitor *mon, const QDict *qdict);
> >> void hmp_memsave(Monitor *mon, const QDict *qdict);
> >> void hmp_pmemsave(Monitor *mon, const QDict *qdict);
> >> +void hmp_memchar_write(Monitor *mon, const QDict *qdict);
> >> void hmp_cont(Monitor *mon, const QDict *qdict);
> >> void hmp_system_wakeup(Monitor *mon, const QDict *qdict);
> >> void hmp_inject_nmi(Monitor *mon, const QDict *qdict);
> >> diff --git a/qapi-schema.json b/qapi-schema.json
> >> index c615ee2..43ef6bc 100644
> >> --- a/qapi-schema.json
> >> +++ b/qapi-schema.json
> >> @@ -325,6 +325,53 @@
> >> { 'command': 'query-chardev', 'returns': ['ChardevInfo'] }
> >>
> >> ##
> >> +# @DataFormat:
> >> +#
> >> +# An enumeration of data format. The default value would
> >> +# be utf8.
> > Please, remove the "default value" part. This is decided by the command
> > using this type.
>
> Now the option format is optional, if it's not set then default by 'utf8'.
> I think it's a reasonable behaver. :)
What I meant is that the right place to say what the value is is in
the command documentation, not in @DataFormat doc. Here, only having
"An enumeration of data encodings" is fine.
> >> +#
> >> +# @utf8: The data format is 'utf8'.
> >> +#
> >> +# @base64: The data format is 'base64'.
> >> +#
> >> +# Note: The data format start with 'utf8' and 'base64',
> >> +# will support other data format as well.
> > Please, drop this note. It's not needed.
> >
> ok
>
> >> +#
> >> +# Since: 1.3
> >> +##
> >> +{ 'enum': 'DataFormat'
> >> + 'data': [ 'utf8', 'base64' ] }
> >> +
> >> +##
> >> +# @memchar-write:
> >> +#
> >> +# 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. Should be power of 2.
> >> +#
> >> +# @data: the source data write to memchar.
> >> +#
> >> +# @format: #optional the format of the data write to memchardev, by
> >> +# default is 'utf8'.
> >> +#
> >> +# Returns: Nothing on success
> >> +# If @chardev is not a valid memchr device, DeviceNotFound
> >> +#
> >> +# Notes: The option 'block' is not supported now due to the miss
> >> +# feature in qmp. Will add it later when we gain the necessary
> >> +# infrastructure enhancement. For now just assume 'drop' behaver
> >> +# for this command.
> > Please, replace this note with an explanation of the current behavior. No
> > need to talk about the future.
>
> Sure.
>
> >> +#
> >> +# Since: 1.3
> >> +##
> >> +{ 'command': 'memchar-write',
> >> + 'data': {'chardev': 'str', 'size': 'int', 'data': 'str',
> >> + '*format': 'DataFormat'} }
> >> +
> >> +##
> >> # @CommandInfo:
> >> #
> >> # Information about a QMP command
> >> diff --git a/qemu-char.c b/qemu-char.c
> >> index c3ec43d..6114e29 100644
> >> --- a/qemu-char.c
> >> +++ b/qemu-char.c
> >> @@ -2717,6 +2717,50 @@ fail:
> >> return NULL;
> >> }
> >>
> >> +void qmp_memchar_write(const char *chardev, int64_t size,
> >> + const char *data, bool has_format,
> >> + enum DataFormat format,
> >> + Error **errp)
> >> +{
> >> + CharDriverState *chr;
> >> + guchar *write_data;
> >> + int ret;
> >> + gsize write_count;
> >> +
> >> + chr = qemu_chr_find(chardev);
> >> + if (!chr) {
> >> + error_set(errp, QERR_DEVICE_NOT_FOUND, chardev);
> >> + return;
> >> + }
> >> +
> >> + if (strcmp(chr->filename, "memchr") != 0) {
> >> + error_setg(errp,"%s is not memory char device\n", chardev);
> >> + return;
> >> + }
> > This is wrong, as it's unreliable. A hackish (but hopefully correct) way
> > of doing this would be to check chr->init against the circmem init function.
> > But please, put this behind a function because it's ugly.
>
> Hmm, I guess it's because the chr->filename could be NULL. but we can still
> get it since CharDriverState keeps the inited type of backend. I am not sure
> that check chr->init against the cirmem init funciton could work, I'll have
> a try.
>
> >
> >> +
> >> + /* XXX: For the sync command as 'block', waiting for the qmp
> >> + * to support necessary feature. Now just act as 'drop' */
> > Please, replace this note with an explanation of the current behavior.
>
> ok.
>
> >> + if (cirmem_chr_is_full(chr)) {
> >> + error_setg(errp, "Failed to write to memchr %s", chardev);
> >> + return;
> >> + }
> >> +
> >> + write_count = (gsize)size;
> >> +
> >> + if (has_format && (format == DATA_FORMAT_BASE64)) {
> >> + write_data = g_base64_decode(data, &write_count);
> >> + } else {
> >> + write_data = (uint8_t *)data;
> >> + }
> >> +
> >> + ret = cirmem_chr_write(chr, write_data, write_count);
> > IIRC circmem_chr_write() doesn't check if write_count if a power of two,
> > what happens if it isn't?
>
> I have considered your suggestion on this in v4. The reason why I did not
> add the assert is that I think we have already check with this when cirmem
> init, so there is no need to check it again. Correct me if I am wrong. :)
I was actually asking an honest question: does cirmem_chr_write() assume
that len is a power of two? If yes, what if the user doesn't pass a
power of two value to qmp_memchar_write()?
>
> >> +
> >> + if (ret < 0) {
> >> + error_setg(errp, "Failed to write to memchr %s", chardev);
> >> + 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 5ba8c48..7548b9b 100644
> >> --- a/qmp-commands.hx
> >> +++ b/qmp-commands.hx
> >> @@ -466,6 +466,40 @@ Note: inject-nmi fails when the guest doesn't support
> >> injecting.
> >> EQMP
> >>
> >> {
> >> + .name = "memchar-write",
> >> + .args_type = "chardev:s,size:i,data:s,format:s?,control:s?",
> > You've dropped 'control', haven't you?
>
> Yes, sorry I forgot to drop here.. :(
>
> >
> >> + .help = "write size of data to memchar chardev",
> >> + .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, should be power of 2 (json-int)
> >> +- "data": the source data writed to memchar (json-string)
> >> +- "format": the data format write to memchardev, default is
> >> + utf8. (json-string, optional)
> >> + - Possible values: "utf8", "base64"
> >> +
> >> +Example:
> >> +
> >> +-> { "execute": "memchar-write",
> >> + "arguments": { "chardev": foo,
> >> + "size": 8,
> >> + "data": "abcdefgh",
> >> + "format": "utf8" } }
> >> +<- { "return": {} }
> >> +
> >> +EQMP
> >> +
> >> + {
> >> .name = "xen-save-devices-state",
> >> .args_type = "filename:F",
> >> .mhandler.cmd_new = qmp_marshal_input_xen_save_devices_state,
> >
>
>
[Qemu-devel] [PATCH 4/4] HMP: Introduce console command, Lei Li, 2012/10/26
[Qemu-devel] [PATCH 3/4] QAPI: Introduce memchar-read QMP command, Lei Li, 2012/10/26