Daniel Henrique Barboza <danielhb...@gmail.com> writes: > To save the FDT blob we have the '-machine dumpdtb=<file>' property. > With this property set, the machine saves the FDT in <file> and exit. > The created file can then be converted to plain text dts format using > 'dtc'. > > There's nothing particularly sophisticated into saving the FDT that > can't be done with the machine at any state, as long as the machine has > a valid FDT to be saved. > > The 'dumpdtb' command receives a 'filename' paramenter and, if a valid > FDT is available, it'll save it in a file 'filename'. In short, this is > a '-machine dumpdtb' that can be fired on demand via QMP/HMP. > > A valid FDT consists of a FDT that was created using libfdt being > retrieved via 'current_machine->fdt' in device_tree.c. This condition is > met by most FDT users in QEMU. > > This command will always be executed in-band (i.e. holding BQL), > avoiding potential race conditions with machines that might change the > FDT during runtime (e.g. PowerPC 'pseries' machine). > > Cc: Dr. David Alan Gilbert <dgilb...@redhat.com> > Cc: Markus Armbruster <arm...@redhat.com> > Cc: Alistair Francis <alistair.fran...@wdc.com> > Cc: David Gibson <da...@gibson.dropbear.id.au> > Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com> > --- > hmp-commands.hx | 15 +++++++++++++++ > include/sysemu/device_tree.h | 1 + > monitor/misc.c | 1 + > qapi/machine.json | 18 ++++++++++++++++++ > softmmu/device_tree.c | 31 +++++++++++++++++++++++++++++++ > 5 files changed, 66 insertions(+) > > diff --git a/hmp-commands.hx b/hmp-commands.hx > index 182e639d14..9a3e57504f 100644 > --- a/hmp-commands.hx > +++ b/hmp-commands.hx > @@ -1800,3 +1800,18 @@ ERST > "\n\t\t\t\t\t limit on a specified virtual cpu", > .cmd = hmp_cancel_vcpu_dirty_limit, > }, > + > +#if defined(CONFIG_FDT) > +SRST > +``dumpdtb`` *filename* > + Save the FDT in the 'filename' file to be decoded using dtc. > + Requires 'libfdt' support.
Does the #if suppress the documentation snippet when !defined(CONFIG_FDT)? If yes, the "Requires" line is redundant. Other conditional commands don't have such lines. > +ERST > + { > + .name = "dumpdtb", > + .args_type = "filename:F", > + .params = "filename", > + .help = "save the FDT in the 'filename' file to be decoded > using dtc", > + .cmd = hmp_dumpdtb, > + }, > +#endif > diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h > index ef060a9759..e7c5441f56 100644 > --- a/include/sysemu/device_tree.h > +++ b/include/sysemu/device_tree.h > @@ -136,6 +136,7 @@ int qemu_fdt_add_path(void *fdt, const char *path); > } while (0) > > void qemu_fdt_dumpdtb(void *fdt, int size); > +void hmp_dumpdtb(Monitor *mon, const QDict *qdict); > > /** > * qemu_fdt_setprop_sized_cells_from_array: > diff --git a/monitor/misc.c b/monitor/misc.c > index 3d2312ba8d..e7dd63030b 100644 > --- a/monitor/misc.c > +++ b/monitor/misc.c > @@ -49,6 +49,7 @@ > #include "sysemu/blockdev.h" > #include "sysemu/sysemu.h" > #include "sysemu/tpm.h" > +#include "sysemu/device_tree.h" > #include "qapi/qmp/qdict.h" > #include "qapi/qmp/qerror.h" > #include "qapi/qmp/qstring.h" > diff --git a/qapi/machine.json b/qapi/machine.json > index 6afd1936b0..f968a5d343 100644 > --- a/qapi/machine.json > +++ b/qapi/machine.json > @@ -1664,3 +1664,21 @@ > '*size': 'size', > '*max-size': 'size', > '*slots': 'uint64' } } > + > +## > +# @dumpdtb: > +# > +# Save the FDT in dtb format. Requires 'libfdt' support. We rarely document conditionals like this. It's kind of redundant with the If CONFIG_FDT part in the generated documentation. Aside: this "If" part could certainly be improved. > +# > +# @filename: name of the FDT file to be created > +# > +# Since: 7.2 > +# > +# Example: > +# {"execute": "dumpdtb"} > +# "arguments": { "filename": "/tmp/fdt.dtb" } } Excuse my nitpicking... Creating files with a fixed filename in /tmp is a bad habit, and this example promotes it. We have similar examples elsewhere. Still, I'd prefer not to add more. > +# > +## > +{ 'command': 'dumpdtb', > + 'data': { 'filename': 'str' }, > + 'if': 'CONFIG_FDT' } > diff --git a/softmmu/device_tree.c b/softmmu/device_tree.c > index 6ca3fad285..cdd41b6de6 100644 > --- a/softmmu/device_tree.c > +++ b/softmmu/device_tree.c > @@ -26,6 +26,9 @@ > #include "hw/loader.h" > #include "hw/boards.h" > #include "qemu/config-file.h" > +#include "qapi/qapi-commands-machine.h" > +#include "qapi/qmp/qdict.h" > +#include "monitor/hmp.h" > > #include <libfdt.h> > > @@ -643,3 +646,31 @@ out: > g_free(propcells); > return ret; > } > + > +void qmp_dumpdtb(const char *filename, Error **errp) > +{ > + g_autoptr(GError) err = NULL; > + int size; > + > + if (!current_machine->fdt) { > + error_setg(errp, "Unable to find the machine FDT"); Perhaps: "this machine doesn't have an FDT". > + return; > + } > + > + size = fdt_totalsize(current_machine->fdt); > + > + if (!g_file_set_contents(filename, current_machine->fdt, size, &err)) { > + error_setg(errp, "Error saving FDT to file %s: %s", > + filename, err->message); > + } > +} > + > +void hmp_dumpdtb(Monitor *mon, const QDict *qdict) > +{ > + const char *filename = qdict_get_str(qdict, "filename"); > + Error *local_err = NULL; > + > + qmp_dumpdtb(filename, &local_err); > + > + hmp_handle_error(mon, local_err); > +}