Daniel Henrique Barboza <danielhb...@gmail.com> writes: > Reading the FDT requires that the user saves the fdt_blob and then use > 'dtc' to read the contents. Saving the file and using 'dtc' is a strong > use case when we need to compare two FDTs, but it's a lot of steps if > you want to do quick check on a certain node or property. > > 'info fdt' retrieves FDT nodes (and properties, later on) and print it > to the user. This can be used to check the FDT on running machines > without having to save the blob and use 'dtc'. > > The implementation is based on the premise that the machine thas a FDT > created using libfdt and pointed by 'machine->fdt'. As long as this > pre-requisite is met the machine should be able to support it. > > For now we're going to add the required QMP/HMP boilerplate and the > capability of printing the name of the properties of a given node. Next > patches will extend 'info fdt' to be able to print nodes recursively, > and then individual properties. > > 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). > > 'info fdt' is not something that we expect to be used aside from debugging, > so we're implementing it in QMP as 'x-query-fdt'. > > This is an example of 'info fdt' fetching the '/chosen' node of the > pSeries machine: > > (qemu) info fdt /chosen > chosen { > ibm,architecture-vec-5; > rng-seed; > ibm,arch-vec-5-platform-support; > linux,pci-probe-only; > stdout-path; > linux,stdout-path; > qemu,graphic-depth; > qemu,graphic-height; > qemu,graphic-width; > }; > > And the same node for the aarch64 'virt' machine: > > (qemu) info fdt /chosen > chosen { > stdout-path; > rng-seed; > kaslr-seed; > }; > > Cc: Dr. David Alan Gilbert <dgilb...@redhat.com> > Acked-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > Signed-off-by: Daniel Henrique Barboza <danielhb...@gmail.com> > --- > hmp-commands-info.hx | 13 ++++++++++ > include/monitor/hmp.h | 1 + > include/sysemu/device_tree.h | 4 +++ > monitor/hmp-cmds.c | 13 ++++++++++ > monitor/qmp-cmds.c | 12 +++++++++ > qapi/machine.json | 19 +++++++++++++++ > softmmu/device_tree.c | 47 ++++++++++++++++++++++++++++++++++++ > 7 files changed, 109 insertions(+) > > diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx > index 188d9ece3b..743b48865d 100644 > --- a/hmp-commands-info.hx > +++ b/hmp-commands-info.hx > @@ -921,3 +921,16 @@ SRST > ``stats`` > Show runtime-collected statistics > ERST > + > + { > + .name = "fdt", > + .args_type = "nodepath:s", > + .params = "nodepath", > + .help = "show firmware device tree node given its path", > + .cmd = hmp_info_fdt, > + }, > + > +SRST > + ``info fdt`` > + Show a firmware device tree node given its path. Requires libfdt. > +ERST > diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h > index d7f324da59..c0883dd1e3 100644 > --- a/include/monitor/hmp.h > +++ b/include/monitor/hmp.h > @@ -135,6 +135,7 @@ void hmp_set_vcpu_dirty_limit(Monitor *mon, const QDict > *qdict); > void hmp_cancel_vcpu_dirty_limit(Monitor *mon, const QDict *qdict); > void hmp_info_vcpu_dirty_limit(Monitor *mon, const QDict *qdict); > void hmp_dumpdtb(Monitor *mon, const QDict *qdict); > +void hmp_info_fdt(Monitor *mon, const QDict *qdict); > void hmp_human_readable_text_helper(Monitor *mon, > HumanReadableText *(*qmp_handler)(Error > **)); > void hmp_info_stats(Monitor *mon, const QDict *qdict); > diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h > index bf7684e4ed..057d13e397 100644 > --- a/include/sysemu/device_tree.h > +++ b/include/sysemu/device_tree.h > @@ -14,6 +14,8 @@ > #ifndef DEVICE_TREE_H > #define DEVICE_TREE_H > > +#include "qapi/qapi-types-common.h" > + > void *create_device_tree(int *sizep); > void *load_device_tree(const char *filename_path, int *sizep); > #ifdef CONFIG_LINUX > @@ -137,6 +139,8 @@ int qemu_fdt_add_path(void *fdt, const char *path); > > void qemu_fdt_dumpdtb(void *fdt, int size); > void qemu_fdt_qmp_dumpdtb(const char *filename, Error **errp); > +HumanReadableText *qemu_fdt_qmp_query_fdt(const char *nodepath, > + Error **errp); > > /** > * qemu_fdt_setprop_sized_cells_from_array: > diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c > index 1c7bfd3b9d..93a4103afa 100644 > --- a/monitor/hmp-cmds.c > +++ b/monitor/hmp-cmds.c > @@ -2484,3 +2484,16 @@ void hmp_dumpdtb(Monitor *mon, const QDict *qdict) > hmp_handle_error(mon, local_err); > } > } > + > +void hmp_info_fdt(Monitor *mon, const QDict *qdict) > +{ > + const char *nodepath = qdict_get_str(qdict, "nodepath"); > + Error *err = NULL; > + g_autoptr(HumanReadableText) info = qmp_x_query_fdt(nodepath, &err); > + > + if (hmp_handle_error(mon, err)) { > + return; > + } > + > + monitor_printf(mon, "%s", info->human_readable_text); > +} > diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c > index 8415aca08c..db2c6aa7da 100644 > --- a/monitor/qmp-cmds.c > +++ b/monitor/qmp-cmds.c > @@ -603,9 +603,21 @@ void qmp_dumpdtb(const char *filename, Error **errp) > { > return qemu_fdt_qmp_dumpdtb(filename, errp); > } > + > +HumanReadableText *qmp_x_query_fdt(const char *nodepath, Error **errp) > +{ > + return qemu_fdt_qmp_query_fdt(nodepath, errp); > +} > #else > void qmp_dumpdtb(const char *filename, Error **errp) > { > error_setg(errp, "dumpdtb requires libfdt"); > } > + > +HumanReadableText *qmp_x_query_fdt(const char *nodepath, Error **errp) > +{ > + error_setg(errp, "this command requires libfdt"); > + > + return NULL; > +} > #endif > diff --git a/qapi/machine.json b/qapi/machine.json > index aeb013f3dd..96cff541ca 100644 > --- a/qapi/machine.json > +++ b/qapi/machine.json > @@ -1681,3 +1681,22 @@ > ## > { 'command': 'dumpdtb', > 'data': { 'filename': 'str' } } > + > +## > +# @x-query-fdt: > +# > +# Query for FDT element (node or property). Requires 'libfdt'. > +# > +# @nodepath: the path of the FDT node to be retrieved
In a QAPI schema, we separate words by dashes unless there's a compelling reason not to. Thus: @node-path. > +# > +# Features: > +# @unstable: This command is meant for debugging. > +# > +# Returns: FDT node > +# > +# Since: 7.2 > +## > +{ 'command': 'x-query-fdt', > + 'data': { 'nodepath': 'str' }, > + 'returns': 'HumanReadableText', > + 'features': [ 'unstable' ] } Same question as for the previous patch: why isn't this 'if': 'CONFIG_FDT'? [...]