| Message ID | 1455643738-6068-1-git-send-email-peter.maydell@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 02/16/16 18:28, Peter Maydell wrote: > The current documentation of chardev mux=on is rather brief and opaque; > expand it to hopefully be a bit more helpful. > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > There was some discussion on #qemu yesterday evening about multiplexing, > and "make the docs a bit less confusing" was one suggestion... > > v1->v2 changes: > * include examples of the multiplexer use > * mention that some other command options implicitly create a mux > * link to the documentation of the mux's escape keys > * fix up the documentation of mux escape keys so it can actually > be linked to > * drop the not-implemented "Ctrl-a ?" from the docs > * improve the documentation of the mux keys a bit (in particular > mentioning -echr, and being more generic than just "console/monitor") > > Our doc structure overall is pretty busted (why is all the documentation > of generic stuff like -chardev lurking in "PC system emulation", for > instance), so this is about as far as I want to go in cleaning up > for now... > > qemu-doc.texi | 30 ++++++++++++++++++++---------- > qemu-options.hx | 45 +++++++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 63 insertions(+), 12 deletions(-) > > diff --git a/qemu-doc.texi b/qemu-doc.texi > index c324da8..bc9dd13 100644 > --- a/qemu-doc.texi > +++ b/qemu-doc.texi > @@ -158,7 +158,8 @@ TODO (no longer available) > * pcsys_introduction:: Introduction > * pcsys_quickstart:: Quick Start > * sec_invocation:: Invocation > -* pcsys_keys:: Keys > +* pcsys_keys:: Keys in the graphical frontends > +* mux_keys:: Keys in the character backend multiplexer > * pcsys_monitor:: QEMU Monitor > * disk_images:: Disk Images > * pcsys_network:: Network emulation > @@ -272,7 +273,7 @@ targets do not need a disk image. > @c man end > > @node pcsys_keys > -@section Keys > +@section Keys in the graphical frontends > > @c man begin OPTIONS > > @@ -322,15 +323,23 @@ Toggle mouse and keyboard grab. > In the virtual consoles, you can use @key{Ctrl-Up}, @key{Ctrl-Down}, > @key{Ctrl-PageUp} and @key{Ctrl-PageDown} to move in the back log. > > -@kindex Ctrl-a h > -During emulation, if you are using the @option{-nographic} option, use > -@key{Ctrl-a h} to get terminal commands: > +@c man end > + > +@node mux_keys > +@section Keys in the character backend multiplexer > + > +@c man begin OPTIONS > + > +During emulation, if you are using a character backend multiplexer > +(which is the default if you are using @option{-nographic}) then > +several commands are available via an escape sequence. These > +key sequences all start with an escape character, which is @key{Ctrl-a} > +by default, but can be changed with @option{-echr}. The list below assumes > +you're using the default. > > @table @key > @item Ctrl-a h > @kindex Ctrl-a h > -@item Ctrl-a ? > -@kindex Ctrl-a ? > Print this help > @item Ctrl-a x > @kindex Ctrl-a x > @@ -346,10 +355,11 @@ Toggle console timestamps > Send break (magic sysrq in Linux) > @item Ctrl-a c > @kindex Ctrl-a c > -Switch between console and monitor > +Rotate between the frontends connected to the multiplexer (usually > +this switches between the monitor and the console) > @item Ctrl-a Ctrl-a > -@kindex Ctrl-a a > -Send Ctrl-a > +@kindex Ctrl-a Ctrl-a > +Send the escape character to the frontend > @end table > @c man end > > diff --git a/qemu-options.hx b/qemu-options.hx > index 2f0465e..7e6762e 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -2162,8 +2162,49 @@ All devices must have an id, which can be any string up to 127 characters long. > It is used to uniquely identify this device in other command line directives. > > A character device may be used in multiplexing mode by multiple front-ends. > -The key sequence of @key{Control-a} and @key{c} will rotate the input focus > -between attached front-ends. Specify @option{mux=on} to enable this mode. > +Specify @option{mux=on} to enable this mode. > +A multiplexer is a "1:N" device, and here the "1" end is your specified chardev > +backend, and the "N" end is the various parts of QEMU that can talk to a chardev. > +If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will > +create a multiplexer with your specified ID, and you can then configure multiple > +front ends to use that chardev ID for their input/output. Up to four different > +front ends can be connected to a single multiplexed chardev. (Without > +multiplexing enabled, a chardev can only be used by a single front end.) > +For instance you could use this to allow a single stdio chardev to be used by > +two serial ports and the QEMU monitor: > + > +@example > +-chardev stdio,mux=on,id=char0 \ > +-mon chardev=char0,mode=readline,default \ > +-serial chardev:char0 \ > +-serial chardev:char0 > +@end example > + > +You can have more than one multiplexer in a system configuration; for instance > +you could have a TCP port multiplexed between UART 0 and UART 1, and stdio > +multiplexed between the QEMU monitor and a parallel port: > + > +@example > +-chardev stdio,mux=on,id=char0 \ > +-mon chardev=char0,mode=readline,default \ > +-parallel chardev:char0 \ > +-chardev tcp,...,mux=on,id=char1 \ > +-serial chardev:char1 \ > +-serial chardev:char1 > +@end example > + > +When you're using a multiplexed character device, some escape sequences are > +interpreted in the input. @xref{mux_keys, Keys in the character backend > +multiplexer}. > + > +Note that some other command line options may implicitly create multiplexed > +character backends; for instance @option{-serial mon:stdio} creates a > +multiplexed stdio backend connected to the serial port and the QEMU monitor, > +and @option{-nographic} also multiplexes the console and the monitor to > +stdio. > + > +There is currently no support for multiplexing in the other direction > +(where a single QEMU front end takes input and output from multiple chardevs). > > Every backend supports the @option{logfile} option, which supplies the path > to a file to record all data transmitted via the backend. The @option{logappend} > not claiming to be an expert on this, but still: Reviewed-by: Laszlo Ersek <lersek@redhat.com>
On Tue, Feb 16, 2016 at 05:28:58PM +0000, Peter Maydell wrote: > The current documentation of chardev mux=on is rather brief and opaque; > expand it to hopefully be a bit more helpful. > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > There was some discussion on #qemu yesterday evening about multiplexing, > and "make the docs a bit less confusing" was one suggestion... > > v1->v2 changes: > * include examples of the multiplexer use > * mention that some other command options implicitly create a mux > * link to the documentation of the mux's escape keys > * fix up the documentation of mux escape keys so it can actually > be linked to > * drop the not-implemented "Ctrl-a ?" from the docs > * improve the documentation of the mux keys a bit (in particular > mentioning -echr, and being more generic than just "console/monitor") > > Our doc structure overall is pretty busted (why is all the documentation > of generic stuff like -chardev lurking in "PC system emulation", for > instance), so this is about as far as I want to go in cleaning up > for now... > > qemu-doc.texi | 30 ++++++++++++++++++++---------- > qemu-options.hx | 45 +++++++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 63 insertions(+), 12 deletions(-) > > diff --git a/qemu-doc.texi b/qemu-doc.texi > index c324da8..bc9dd13 100644 > --- a/qemu-doc.texi > +++ b/qemu-doc.texi > @@ -158,7 +158,8 @@ TODO (no longer available) > * pcsys_introduction:: Introduction > * pcsys_quickstart:: Quick Start > * sec_invocation:: Invocation > -* pcsys_keys:: Keys > +* pcsys_keys:: Keys in the graphical frontends > +* mux_keys:: Keys in the character backend multiplexer > * pcsys_monitor:: QEMU Monitor > * disk_images:: Disk Images > * pcsys_network:: Network emulation > @@ -272,7 +273,7 @@ targets do not need a disk image. > @c man end > > @node pcsys_keys > -@section Keys > +@section Keys in the graphical frontends > > @c man begin OPTIONS > > @@ -322,15 +323,23 @@ Toggle mouse and keyboard grab. > In the virtual consoles, you can use @key{Ctrl-Up}, @key{Ctrl-Down}, > @key{Ctrl-PageUp} and @key{Ctrl-PageDown} to move in the back log. > > -@kindex Ctrl-a h > -During emulation, if you are using the @option{-nographic} option, use > -@key{Ctrl-a h} to get terminal commands: > +@c man end > + > +@node mux_keys > +@section Keys in the character backend multiplexer > + > +@c man begin OPTIONS > + > +During emulation, if you are using a character backend multiplexer > +(which is the default if you are using @option{-nographic}) then > +several commands are available via an escape sequence. These > +key sequences all start with an escape character, which is @key{Ctrl-a} > +by default, but can be changed with @option{-echr}. The list below assumes > +you're using the default. > > @table @key > @item Ctrl-a h > @kindex Ctrl-a h > -@item Ctrl-a ? > -@kindex Ctrl-a ? > Print this help > @item Ctrl-a x > @kindex Ctrl-a x > @@ -346,10 +355,11 @@ Toggle console timestamps > Send break (magic sysrq in Linux) > @item Ctrl-a c > @kindex Ctrl-a c > -Switch between console and monitor > +Rotate between the frontends connected to the multiplexer (usually > +this switches between the monitor and the console) > @item Ctrl-a Ctrl-a > -@kindex Ctrl-a a > -Send Ctrl-a > +@kindex Ctrl-a Ctrl-a > +Send the escape character to the frontend > @end table > @c man end > > diff --git a/qemu-options.hx b/qemu-options.hx > index 2f0465e..7e6762e 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -2162,8 +2162,49 @@ All devices must have an id, which can be any string up to 127 characters long. > It is used to uniquely identify this device in other command line directives. > > A character device may be used in multiplexing mode by multiple front-ends. > -The key sequence of @key{Control-a} and @key{c} will rotate the input focus > -between attached front-ends. Specify @option{mux=on} to enable this mode. > +Specify @option{mux=on} to enable this mode. > +A multiplexer is a "1:N" device, and here the "1" end is your specified chardev > +backend, and the "N" end is the various parts of QEMU that can talk to a chardev. > +If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will > +create a multiplexer with your specified ID, and you can then configure multiple > +front ends to use that chardev ID for their input/output. Up to four different > +front ends can be connected to a single multiplexed chardev. (Without > +multiplexing enabled, a chardev can only be used by a single front end.) > +For instance you could use this to allow a single stdio chardev to be used by > +two serial ports and the QEMU monitor: > + > +@example > +-chardev stdio,mux=on,id=char0 \ > +-mon chardev=char0,mode=readline,default \ > +-serial chardev:char0 \ > +-serial chardev:char0 > +@end example > + > +You can have more than one multiplexer in a system configuration; for instance > +you could have a TCP port multiplexed between UART 0 and UART 1, and stdio > +multiplexed between the QEMU monitor and a parallel port: > + > +@example > +-chardev stdio,mux=on,id=char0 \ > +-mon chardev=char0,mode=readline,default \ > +-parallel chardev:char0 \ > +-chardev tcp,...,mux=on,id=char1 \ > +-serial chardev:char1 \ > +-serial chardev:char1 > +@end example > + > +When you're using a multiplexed character device, some escape sequences are > +interpreted in the input. @xref{mux_keys, Keys in the character backend > +multiplexer}. > + > +Note that some other command line options may implicitly create multiplexed > +character backends; for instance @option{-serial mon:stdio} creates a > +multiplexed stdio backend connected to the serial port and the QEMU monitor, > +and @option{-nographic} also multiplexes the console and the monitor to > +stdio. > + > +There is currently no support for multiplexing in the other direction > +(where a single QEMU front end takes input and output from multiple chardevs). > > Every backend supports the @option{logfile} option, which supplies the path > to a file to record all data transmitted via the backend. The @option{logappend} Nice. Reads a whole lot clearer (contextual description, followed by a practical example and related additional information) than before. And as a user of QEMU, I could follow if I pay attention carefully. :-) Thanks! FWIW: Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com>
On Tue, Feb 16, 2016 at 05:28:58PM +0000, Peter Maydell wrote: > The current documentation of chardev mux=on is rather brief and opaque; > expand it to hopefully be a bit more helpful. > > Signed-off-by: Peter Maydell <peter.maydell@linaro.org> > --- > There was some discussion on #qemu yesterday evening about multiplexing, > and "make the docs a bit less confusing" was one suggestion... > > v1->v2 changes: > * include examples of the multiplexer use > * mention that some other command options implicitly create a mux > * link to the documentation of the mux's escape keys > * fix up the documentation of mux escape keys so it can actually > be linked to > * drop the not-implemented "Ctrl-a ?" from the docs > * improve the documentation of the mux keys a bit (in particular > mentioning -echr, and being more generic than just "console/monitor") > > Our doc structure overall is pretty busted (why is all the documentation > of generic stuff like -chardev lurking in "PC system emulation", for > instance), so this is about as far as I want to go in cleaning up > for now... > > qemu-doc.texi | 30 ++++++++++++++++++++---------- > qemu-options.hx | 45 +++++++++++++++++++++++++++++++++++++++++++-- > 2 files changed, 63 insertions(+), 12 deletions(-) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/qemu-doc.texi b/qemu-doc.texi index c324da8..bc9dd13 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -158,7 +158,8 @@ TODO (no longer available) * pcsys_introduction:: Introduction * pcsys_quickstart:: Quick Start * sec_invocation:: Invocation -* pcsys_keys:: Keys +* pcsys_keys:: Keys in the graphical frontends +* mux_keys:: Keys in the character backend multiplexer * pcsys_monitor:: QEMU Monitor * disk_images:: Disk Images * pcsys_network:: Network emulation @@ -272,7 +273,7 @@ targets do not need a disk image. @c man end @node pcsys_keys -@section Keys +@section Keys in the graphical frontends @c man begin OPTIONS @@ -322,15 +323,23 @@ Toggle mouse and keyboard grab. In the virtual consoles, you can use @key{Ctrl-Up}, @key{Ctrl-Down}, @key{Ctrl-PageUp} and @key{Ctrl-PageDown} to move in the back log. -@kindex Ctrl-a h -During emulation, if you are using the @option{-nographic} option, use -@key{Ctrl-a h} to get terminal commands: +@c man end + +@node mux_keys +@section Keys in the character backend multiplexer + +@c man begin OPTIONS + +During emulation, if you are using a character backend multiplexer +(which is the default if you are using @option{-nographic}) then +several commands are available via an escape sequence. These +key sequences all start with an escape character, which is @key{Ctrl-a} +by default, but can be changed with @option{-echr}. The list below assumes +you're using the default. @table @key @item Ctrl-a h @kindex Ctrl-a h -@item Ctrl-a ? -@kindex Ctrl-a ? Print this help @item Ctrl-a x @kindex Ctrl-a x @@ -346,10 +355,11 @@ Toggle console timestamps Send break (magic sysrq in Linux) @item Ctrl-a c @kindex Ctrl-a c -Switch between console and monitor +Rotate between the frontends connected to the multiplexer (usually +this switches between the monitor and the console) @item Ctrl-a Ctrl-a -@kindex Ctrl-a a -Send Ctrl-a +@kindex Ctrl-a Ctrl-a +Send the escape character to the frontend @end table @c man end diff --git a/qemu-options.hx b/qemu-options.hx index 2f0465e..7e6762e 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -2162,8 +2162,49 @@ All devices must have an id, which can be any string up to 127 characters long. It is used to uniquely identify this device in other command line directives. A character device may be used in multiplexing mode by multiple front-ends. -The key sequence of @key{Control-a} and @key{c} will rotate the input focus -between attached front-ends. Specify @option{mux=on} to enable this mode. +Specify @option{mux=on} to enable this mode. +A multiplexer is a "1:N" device, and here the "1" end is your specified chardev +backend, and the "N" end is the various parts of QEMU that can talk to a chardev. +If you create a chardev with @option{id=myid} and @option{mux=on}, QEMU will +create a multiplexer with your specified ID, and you can then configure multiple +front ends to use that chardev ID for their input/output. Up to four different +front ends can be connected to a single multiplexed chardev. (Without +multiplexing enabled, a chardev can only be used by a single front end.) +For instance you could use this to allow a single stdio chardev to be used by +two serial ports and the QEMU monitor: + +@example +-chardev stdio,mux=on,id=char0 \ +-mon chardev=char0,mode=readline,default \ +-serial chardev:char0 \ +-serial chardev:char0 +@end example + +You can have more than one multiplexer in a system configuration; for instance +you could have a TCP port multiplexed between UART 0 and UART 1, and stdio +multiplexed between the QEMU monitor and a parallel port: + +@example +-chardev stdio,mux=on,id=char0 \ +-mon chardev=char0,mode=readline,default \ +-parallel chardev:char0 \ +-chardev tcp,...,mux=on,id=char1 \ +-serial chardev:char1 \ +-serial chardev:char1 +@end example + +When you're using a multiplexed character device, some escape sequences are +interpreted in the input. @xref{mux_keys, Keys in the character backend +multiplexer}. + +Note that some other command line options may implicitly create multiplexed +character backends; for instance @option{-serial mon:stdio} creates a +multiplexed stdio backend connected to the serial port and the QEMU monitor, +and @option{-nographic} also multiplexes the console and the monitor to +stdio. + +There is currently no support for multiplexing in the other direction +(where a single QEMU front end takes input and output from multiple chardevs). Every backend supports the @option{logfile} option, which supplies the path to a file to record all data transmitted via the backend. The @option{logappend}
The current documentation of chardev mux=on is rather brief and opaque; expand it to hopefully be a bit more helpful. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> --- There was some discussion on #qemu yesterday evening about multiplexing, and "make the docs a bit less confusing" was one suggestion... v1->v2 changes: * include examples of the multiplexer use * mention that some other command options implicitly create a mux * link to the documentation of the mux's escape keys * fix up the documentation of mux escape keys so it can actually be linked to * drop the not-implemented "Ctrl-a ?" from the docs * improve the documentation of the mux keys a bit (in particular mentioning -echr, and being more generic than just "console/monitor") Our doc structure overall is pretty busted (why is all the documentation of generic stuff like -chardev lurking in "PC system emulation", for instance), so this is about as far as I want to go in cleaning up for now... qemu-doc.texi | 30 ++++++++++++++++++++---------- qemu-options.hx | 45 +++++++++++++++++++++++++++++++++++++++++++-- 2 files changed, 63 insertions(+), 12 deletions(-)