[PATCH v2 0/6] kconfig: express dependency of individual boards on libfdt

[PATCH v2 0/6] kconfig: express dependency of individual boards on libfdt

[Paolo Bonzini]

This is a follow up to the "default y" patch series at
https://lore.kernel.org/qemu-devel/20240423131612.28362-1-pbonzini@redhat.com/
and shows an example of what that series enables.

With this change, individual boards will be enabled/disabled depending
on whether libfdt is present or not.  In particular, x86 will simply
disable microvm and build the "traditional" chipsets if libfdt is not
found.

All boards or targets that need libfdt now have an explicit "depends on
FDT" (sometimes the boards delegate that to the target).  TARGET_NEED_FDT
is only used for targets that absolutely cannot build without libfdt,
or for which all boards require it.

For simplicity, patch 1 simplifies the libfdt handling in meson.build,
removing the ability to force use of the subproject.  There is no
use case that I can imagine, if you want to use the subproject just
delete libfdt from your OS installation.

Paolo

v1->v2:
- use libfdt CPPFLAGS when building target-specific files
- limited scope of libfdt detection changes: keep it enabled when building
  --without-default-features (see commit message for 0577e84d374,
  "configure: Disable capstone and slirp in the --without-default-features
  mode", 2022-02-21)
- patch 6 does not 
- split patch 3 in two parts
- fix compilation errors due to missing qmp_dumpdtb/hmp_dumpdtb
- make MIPS_BOSTON depend on FDT

Paolo Bonzini (6):
  meson: pick libfdt from common_ss when building target-specific files
  meson: move libfdt together with other dependencies
  kconfig: allow compiling out QEMU device tree code per target
  kconfig: express dependency of individual boards on libfdt
  hw/xtensa: require libfdt
  configs: disable emulators that require it if libfdt is not found

 configs/targets/aarch64-softmmu.mak      |   1 +
 configs/targets/arm-softmmu.mak          |   1 +
 configs/targets/i386-softmmu.mak         |   1 -
 configs/targets/loongarch64-softmmu.mak  |   1 +
 configs/targets/microblaze-softmmu.mak   |   1 +
 configs/targets/microblazeel-softmmu.mak |   1 +
 configs/targets/mips64el-softmmu.mak     |   1 -
 configs/targets/or1k-softmmu.mak         |   1 +
 configs/targets/ppc-softmmu.mak          |   1 -
 configs/targets/ppc64-softmmu.mak        |   1 +
 configs/targets/riscv32-softmmu.mak      |   1 +
 configs/targets/riscv64-softmmu.mak      |   1 +
 configs/targets/rx-softmmu.mak           |   1 +
 configs/targets/x86_64-softmmu.mak       |   1 -
 meson.build                              | 100 +++++++++++++----------
 include/monitor/hmp.h                    |   1 +
 include/sysemu/device_tree.h             |   1 -
 hw/xtensa/xtfpga.c                       |   9 --
 monitor/hmp-cmds.c                       |  17 ++++
 system/device_tree-stub.c                |  10 +++
 system/device_tree.c                     |  14 ----
 .gitlab-ci.d/buildtest.yml               |   8 +-
 Kconfig.host                             |   3 +
 hw/arm/Kconfig                           |   5 ++
 hw/arm/meson.build                       |   2 +-
 hw/core/Kconfig                          |   9 +-
 hw/core/meson.build                      |   2 +-
 hw/i386/Kconfig                          |   3 +-
 hw/loongarch/Kconfig                     |   3 +-
 hw/loongarch/meson.build                 |   2 +-
 hw/mips/Kconfig                          |   3 +-
 hw/mips/meson.build                      |   2 +-
 hw/openrisc/Kconfig                      |   2 +
 hw/openrisc/meson.build                  |   4 +-
 hw/ppc/Kconfig                           |  15 ++--
 hw/ppc/meson.build                       |   4 +-
 hw/riscv/Kconfig                         |   4 +
 hw/riscv/meson.build                     |   2 +-
 hw/rx/Kconfig                            |   3 +-
 hw/xtensa/Kconfig                        |   3 +-
 system/meson.build                       |   4 +-
 target/arm/Kconfig                       |   2 +
 target/microblaze/Kconfig                |   1 +
 target/openrisc/Kconfig                  |   1 +
 target/riscv/Kconfig                     |   2 +
 45 files changed, 154 insertions(+), 101 deletions(-)
 create mode 100644 system/device_tree-stub.c

-- 
2.45.0

[PATCH 1/6] meson: pick libfdt from common_ss when building target-specific files

[Paolo Bonzini]

Avoid having to list dependencies such as libfdt twice, both on common_ss
and specific_ss.  Instead, just take all the dependencies in common_ss
and allow the target-specific libqemu-*.fa library to use them.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 meson.build              | 14 +++++++++++---
 hw/arm/meson.build       |  2 +-
 hw/loongarch/meson.build |  2 +-
 hw/mips/meson.build      |  2 +-
 hw/openrisc/meson.build  |  4 ++--
 hw/ppc/meson.build       |  4 +---
 hw/riscv/meson.build     |  2 +-
 7 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/meson.build b/meson.build
index 43da4923721..7ca0ba4987f 100644
--- a/meson.build
+++ b/meson.build
@@ -3868,15 +3868,23 @@ foreach target : target_dirs
 
   target_common = common_ss.apply(config_target, strict: false)
   objects = common_all.extract_objects(target_common.sources())
-  deps = target_common.dependencies()
+  arch_deps += target_common.dependencies()
 
   target_specific = specific_ss.apply(config_target, strict: false)
   arch_srcs += target_specific.sources()
   arch_deps += target_specific.dependencies()
 
+  # allow using headers from the dependencies but do not include the sources,
+  # because this emulator only needs those in "objects".  For external
+  # dependencies, the full dependency is included below in the executable.
+  lib_deps = []
+  foreach dep : arch_deps
+    lib_deps += dep.partial_dependency(compile_args: true, includes: true)
+  endforeach
+
   lib = static_library('qemu-' + target,
                  sources: arch_srcs + genh,
-                 dependencies: arch_deps,
+                 dependencies: lib_deps,
                  objects: objects,
                  include_directories: target_inc,
                  c_args: c_args,
@@ -3924,7 +3932,7 @@ foreach target : target_dirs
     emulator = executable(exe_name, exe['sources'],
                install: true,
                c_args: c_args,
-               dependencies: arch_deps + deps + exe['dependencies'],
+               dependencies: arch_deps + exe['dependencies'],
                objects: lib.extract_all_objects(recursive: true),
                link_depends: [block_syms, qemu_syms],
                link_args: link_args,
diff --git a/hw/arm/meson.build b/hw/arm/meson.build
index 6808135c1f7..aefde0c69a3 100644
--- a/hw/arm/meson.build
+++ b/hw/arm/meson.build
@@ -1,5 +1,5 @@
 arm_ss = ss.source_set()
-arm_ss.add(files('boot.c'), fdt)
+arm_ss.add(files('boot.c'))
 arm_ss.add(when: 'CONFIG_ARM_VIRT', if_true: files('virt.c'))
 arm_ss.add(when: 'CONFIG_ACPI', if_true: files('virt-acpi-build.c'))
 arm_ss.add(when: 'CONFIG_DIGIC', if_true: files('digic_boards.c'))
diff --git a/hw/loongarch/meson.build b/hw/loongarch/meson.build
index d306d82c2ee..bce7ebac97e 100644
--- a/hw/loongarch/meson.build
+++ b/hw/loongarch/meson.build
@@ -3,7 +3,7 @@ loongarch_ss.add(files(
     'fw_cfg.c',
     'boot.c',
 ))
-loongarch_ss.add(when: 'CONFIG_LOONGARCH_VIRT', if_true: [files('virt.c'), fdt])
+loongarch_ss.add(when: 'CONFIG_LOONGARCH_VIRT', if_true: files('virt.c'))
 loongarch_ss.add(when: 'CONFIG_ACPI', if_true: files('acpi-build.c'))
 
 hw_arch += {'loongarch': loongarch_ss}
diff --git a/hw/mips/meson.build b/hw/mips/meson.build
index f06d88f3430..ca37c42d900 100644
--- a/hw/mips/meson.build
+++ b/hw/mips/meson.build
@@ -9,7 +9,7 @@ if 'CONFIG_TCG' in config_all_accel
 mips_ss.add(when: 'CONFIG_JAZZ', if_true: files('jazz.c'))
 mips_ss.add(when: 'CONFIG_MIPSSIM', if_true: files('mipssim.c'))
 mips_ss.add(when: 'CONFIG_FULOONG', if_true: files('fuloong2e.c'))
-mips_ss.add(when: 'CONFIG_MIPS_BOSTON', if_true: [files('boston.c'), fdt])
+mips_ss.add(when: 'CONFIG_MIPS_BOSTON', if_true: files('boston.c'))
 endif
 
 hw_arch += {'mips': mips_ss}
diff --git a/hw/openrisc/meson.build b/hw/openrisc/meson.build
index 2dbc6365bb7..82f1f0ef1cc 100644
--- a/hw/openrisc/meson.build
+++ b/hw/openrisc/meson.build
@@ -1,7 +1,7 @@
 openrisc_ss = ss.source_set()
 openrisc_ss.add(files('cputimer.c'))
 openrisc_ss.add(files('boot.c'))
-openrisc_ss.add(when: 'CONFIG_OR1K_SIM', if_true: [files('openrisc_sim.c'), fdt])
-openrisc_ss.add(when: 'CONFIG_OR1K_VIRT', if_true: [files('virt.c'), fdt])
+openrisc_ss.add(when: 'CONFIG_OR1K_SIM', if_true: files('openrisc_sim.c'))
+openrisc_ss.add(when: 'CONFIG_OR1K_VIRT', if_true: files('virt.c'))
 
 hw_arch += {'openrisc': openrisc_ss}
diff --git a/hw/ppc/meson.build b/hw/ppc/meson.build
index d096636ee7f..3ebbf329bcc 100644
--- a/hw/ppc/meson.build
+++ b/hw/ppc/meson.build
@@ -3,9 +3,7 @@ ppc_ss.add(files(
   'ppc.c',
   'ppc_booke.c',
 ))
-ppc_ss.add(when: 'CONFIG_FDT_PPC', if_true: [files(
-  'fdt.c',
-), fdt])
+ppc_ss.add(when: 'CONFIG_FDT_PPC', if_true: files('fdt.c'))
 ppc_ss.add(when: 'CONFIG_FW_CFG_PPC', if_true: files('fw_cfg.c'))
 
 # IBM pSeries (sPAPR)
diff --git a/hw/riscv/meson.build b/hw/riscv/meson.build
index 2f7ee81be3c..f872674093a 100644
--- a/hw/riscv/meson.build
+++ b/hw/riscv/meson.build
@@ -1,5 +1,5 @@
 riscv_ss = ss.source_set()
-riscv_ss.add(files('boot.c'), fdt)
+riscv_ss.add(files('boot.c'))
 riscv_ss.add(when: 'CONFIG_RISCV_NUMA', if_true: files('numa.c'))
 riscv_ss.add(files('riscv_hart.c'))
 riscv_ss.add(when: 'CONFIG_OPENTITAN', if_true: files('opentitan.c'))
-- 
2.45.0

[PATCH 2/6] meson: move libfdt together with other dependencies

[Paolo Bonzini]

Move the libfdt detection code together with other dependencies instead
of keeping it with subprojects.  This has the disadvantage of performing
the detection even if no target requires libfdt; but it has the advantage
that Kconfig will be able to observe the availability of the library.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 meson.build | 79 ++++++++++++++++++++++++++---------------------------
 1 file changed, 38 insertions(+), 41 deletions(-)

diff --git a/meson.build b/meson.build
index 7ca0ba4987f..2e7e2b15406 100644
--- a/meson.build
+++ b/meson.build
@@ -1858,6 +1858,34 @@ if numa.found() and not cc.links('''
   endif
 endif
 
+fdt = not_found
+fdt_opt = get_option('fdt')
+if fdt_opt == 'enabled' and get_option('wrap_mode') == 'nodownload'
+  fdt_opt = 'system'
+endif
+if fdt_opt in ['enabled', 'system'] or (fdt_opt == 'auto' and have_system)
+  fdt = cc.find_library('fdt', required: fdt_opt == 'system')
+  if fdt.found() and cc.links('''
+     #include <libfdt.h>
+     #include <libfdt_env.h>
+     int main(void) { fdt_find_max_phandle(NULL, NULL); return 0; }''',
+       dependencies: fdt)
+    fdt_opt = 'system'
+  elif fdt_opt != 'system'
+    fdt_opt = get_option('wrap_mode') == 'nodownload' ? 'disabled' : 'internal'
+    fdt = not_found
+  else
+    error('system libfdt is too old (1.5.1 or newer required)')
+  endif
+endif
+if fdt_opt == 'internal'
+  assert(not fdt.found())
+  libfdt_proj = subproject('dtc', required: true,
+                           default_options: ['tools=false',  'yaml=disabled',
+                                             'python=disabled', 'default_library=static'])
+  fdt = libfdt_proj.get_variable('libfdt_dep')
+endif
+
 rdma = not_found
 if not get_option('rdma').auto() or have_system
   libumad = cc.find_library('ibumad', required: get_option('rdma'))
@@ -2199,6 +2227,7 @@ config_host_data.set('CONFIG_BSD', host_os in bsd_oses)
 config_host_data.set('CONFIG_CAPSTONE', capstone.found())
 config_host_data.set('CONFIG_COCOA', cocoa.found())
 config_host_data.set('CONFIG_DARWIN', host_os == 'darwin')
+config_host_data.set('CONFIG_FDT', fdt.found())
 config_host_data.set('CONFIG_FUZZ', get_option('fuzzing'))
 config_host_data.set('CONFIG_GCOV', get_option('b_coverage'))
 config_host_data.set('CONFIG_LIBUDEV', libudev.found())
@@ -3025,14 +3054,16 @@ foreach target : target_dirs
     error('No accelerator available for target @0@'.format(target))
   endif
 
-  actual_target_dirs += target
   config_target += keyval.load('configs/targets' / target + '.mak')
   config_target += { 'TARGET_' + config_target['TARGET_ARCH'].to_upper(): 'y' }
 
-  if 'TARGET_NEED_FDT' in config_target
+  if 'TARGET_NEED_FDT' in config_target and not fdt.found()
     fdt_required += target
+    continue
   endif
 
+  actual_target_dirs += target
+
   # Add default keys
   if 'TARGET_BASE_ARCH' not in config_target
     config_target += {'TARGET_BASE_ARCH': config_target['TARGET_ARCH']}
@@ -3120,6 +3151,10 @@ genh += custom_target('config-poison.h',
                       command: [find_program('scripts/make-config-poison.sh'),
                                 target_configs_h])
 
+if fdt_required.length() > 0
+  error('fdt disabled but required by targets ' + ', '.join(fdt_required))
+endif
+
 ###############
 # Subprojects #
 ###############
@@ -3130,44 +3165,6 @@ if have_system and vfio_user_server_allowed
   libvfio_user_dep = libvfio_user_proj.get_variable('libvfio_user_dep')
 endif
 
-fdt = not_found
-fdt_opt = get_option('fdt')
-if fdt_required.length() > 0 or fdt_opt == 'enabled'
-  if fdt_opt == 'disabled'
-    error('fdt disabled but required by targets ' + ', '.join(fdt_required))
-  endif
-
-  if fdt_opt in ['enabled', 'auto', 'system']
-    if get_option('wrap_mode') == 'nodownload'
-      fdt_opt = 'system'
-    endif
-    fdt = cc.find_library('fdt', required: fdt_opt == 'system')
-    if fdt.found() and cc.links('''
-       #include <libfdt.h>
-       #include <libfdt_env.h>
-       int main(void) { fdt_find_max_phandle(NULL, NULL); return 0; }''',
-         dependencies: fdt)
-      fdt_opt = 'system'
-    elif fdt_opt == 'system'
-       error('system libfdt requested, but it is too old (1.5.1 or newer required)')
-    else
-      fdt_opt = 'internal'
-      fdt = not_found
-    endif
-  endif
-  if not fdt.found()
-    assert(fdt_opt == 'internal')
-    libfdt_proj = subproject('dtc', required: true,
-                             default_options: ['tools=false',  'yaml=disabled',
-                                               'python=disabled', 'default_library=static'])
-    fdt = libfdt_proj.get_variable('libfdt_dep')
-  endif
-else
-  fdt_opt = 'disabled'
-endif
-
-config_host_data.set('CONFIG_FDT', fdt.found())
-
 vhost_user = not_found
 if host_os == 'linux' and have_vhost_user
   libvhost_user = subproject('libvhost-user')
@@ -4419,7 +4416,7 @@ summary_info += {'Linux AIO support': libaio}
 summary_info += {'Linux io_uring support': linux_io_uring}
 summary_info += {'ATTR/XATTR support': libattr}
 summary_info += {'RDMA support':      rdma}
-summary_info += {'fdt support':       fdt_opt == 'disabled' ? false : fdt_opt}
+summary_info += {'fdt support':       fdt_opt == 'internal' ? 'internal' : fdt}
 summary_info += {'libcap-ng support': libcap_ng}
 summary_info += {'bpf support':       libbpf}
 summary_info += {'rbd support':       rbd}
-- 
2.45.0

[PATCH 3/6] kconfig: allow compiling out QEMU device tree code per target

[Paolo Bonzini]

Introduce a new Kconfig symbol, CONFIG_DEVICE_TREE, that specifies whether
to include the common device tree code in system/device_tree.c and to
link to libfdt.  For now, include it unconditionally if libfdt is
available.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 meson.build                  |  1 +
 include/monitor/hmp.h        |  1 +
 include/sysemu/device_tree.h |  1 -
 monitor/hmp-cmds.c           | 17 +++++++++++++++++
 system/device_tree-stub.c    | 10 ++++++++++
 system/device_tree.c         | 14 --------------
 Kconfig.host                 |  4 ++++
 hw/core/Kconfig              |  9 ++++++++-
 hw/core/meson.build          |  2 +-
 system/meson.build           |  4 +++-
 10 files changed, 45 insertions(+), 18 deletions(-)
 create mode 100644 system/device_tree-stub.c

diff --git a/meson.build b/meson.build
index 2e7e2b15406..d8f259d2610 100644
--- a/meson.build
+++ b/meson.build
@@ -2990,6 +2990,7 @@ host_kconfig = \
   (have_ivshmem ? ['CONFIG_IVSHMEM=y'] : []) + \
   (opengl.found() ? ['CONFIG_OPENGL=y'] : []) + \
   (x11.found() ? ['CONFIG_X11=y'] : []) + \
+  (fdt.found() ? ['CONFIG_FDT=y'] : []) + \
   (have_vhost_user ? ['CONFIG_VHOST_USER=y'] : []) + \
   (have_vhost_vdpa ? ['CONFIG_VHOST_VDPA=y'] : []) + \
   (have_vhost_kernel ? ['CONFIG_VHOST_KERNEL=y'] : []) + \
diff --git a/include/monitor/hmp.h b/include/monitor/hmp.h
index f4cf8f6717d..954f3c83ad9 100644
--- a/include/monitor/hmp.h
+++ b/include/monitor/hmp.h
@@ -180,5 +180,6 @@ void hmp_ioport_write(Monitor *mon, const QDict *qdict);
 void hmp_boot_set(Monitor *mon, const QDict *qdict);
 void hmp_info_mtree(Monitor *mon, const QDict *qdict);
 void hmp_info_cryptodev(Monitor *mon, const QDict *qdict);
+void hmp_dumpdtb(Monitor *mon, const QDict *qdict);
 
 #endif
diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h
index 8eab3959341..eb601522f88 100644
--- a/include/sysemu/device_tree.h
+++ b/include/sysemu/device_tree.h
@@ -134,7 +134,6 @@ 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/hmp-cmds.c b/monitor/hmp-cmds.c
index 871898ac46b..ea79148ee85 100644
--- a/monitor/hmp-cmds.c
+++ b/monitor/hmp-cmds.c
@@ -22,6 +22,7 @@
 #include "monitor/monitor-internal.h"
 #include "qapi/error.h"
 #include "qapi/qapi-commands-control.h"
+#include "qapi/qapi-commands-machine.h"
 #include "qapi/qapi-commands-misc.h"
 #include "qapi/qmp/qdict.h"
 #include "qemu/cutils.h"
@@ -443,3 +444,19 @@ void hmp_info_mtree(Monitor *mon, const QDict *qdict)
 
     mtree_info(flatview, dispatch_tree, owner, disabled);
 }
+
+#if defined(CONFIG_FDT)
+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);
+
+    if (hmp_handle_error(mon, local_err)) {
+        return;
+    }
+
+    monitor_printf(mon, "dtb dumped to %s", filename);
+}
+#endif
diff --git a/system/device_tree-stub.c b/system/device_tree-stub.c
new file mode 100644
index 00000000000..bddda6fa37a
--- /dev/null
+++ b/system/device_tree-stub.c
@@ -0,0 +1,10 @@
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qapi/qapi-commands-machine.h"
+
+#ifdef CONFIG_FDT
+void qmp_dumpdtb(const char *filename, Error **errp)
+{
+    error_setg(errp, "This machine doesn't have a FDT");
+}
+#endif
diff --git a/system/device_tree.c b/system/device_tree.c
index eb5166ca360..2e38259d34f 100644
--- a/system/device_tree.c
+++ b/system/device_tree.c
@@ -668,20 +668,6 @@ void qmp_dumpdtb(const char *filename, Error **errp)
     }
 }
 
-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);
-
-    if (hmp_handle_error(mon, local_err)) {
-        return;
-    }
-
-    info_report("dtb dumped to %s", filename);
-}
-
 void qemu_fdt_randomize_seeds(void *fdt)
 {
     int noffset, poffset, len;
diff --git a/Kconfig.host b/Kconfig.host
index f6a2a131e6c..a0d4a52131e 100644
--- a/Kconfig.host
+++ b/Kconfig.host
@@ -23,6 +23,10 @@ config IVSHMEM
 config TPM
     bool
 
+config FDT
+    bool
+    select DEVICE_TREE
+
 config VHOST_USER
     bool
 
diff --git a/hw/core/Kconfig b/hw/core/Kconfig
index 9397503656d..24411f59306 100644
--- a/hw/core/Kconfig
+++ b/hw/core/Kconfig
@@ -4,8 +4,14 @@ config EMPTY_SLOT
 config PTIMER
     bool
 
+config DEVICE_TREE
+    bool
+    # fail the build if libfdt not found
+    depends on FDT
+
 config FITLOADER
     bool
+    depends on DEVICE_TREE
 
 config GENERIC_LOADER
     bool
@@ -14,13 +20,14 @@ config GENERIC_LOADER
 config GUEST_LOADER
     bool
     default y
-    depends on TCG
+    depends on TCG && DEVICE_TREE
 
 config OR_IRQ
     bool
 
 config PLATFORM_BUS
     bool
+    depends on DEVICE_TREE
 
 config REGISTER
     bool
diff --git a/hw/core/meson.build b/hw/core/meson.build
index f20d4143f7a..a3d9bab9f42 100644
--- a/hw/core/meson.build
+++ b/hw/core/meson.build
@@ -16,7 +16,7 @@ common_ss.add(files('cpu-common.c'))
 common_ss.add(files('machine-smp.c'))
 system_ss.add(when: 'CONFIG_FITLOADER', if_true: files('loader-fit.c'))
 system_ss.add(when: 'CONFIG_GENERIC_LOADER', if_true: files('generic-loader.c'))
-system_ss.add(when: ['CONFIG_GUEST_LOADER', fdt], if_true: files('guest-loader.c'))
+system_ss.add(when: 'CONFIG_GUEST_LOADER', if_true: files('guest-loader.c'))
 system_ss.add(when: 'CONFIG_OR_IRQ', if_true: files('or-irq.c'))
 system_ss.add(when: 'CONFIG_PLATFORM_BUS', if_true: files('platform-bus.c'))
 system_ss.add(when: 'CONFIG_PTIMER', if_true: files('ptimer.c'))
diff --git a/system/meson.build b/system/meson.build
index 25e21172505..a296270cb00 100644
--- a/system/meson.build
+++ b/system/meson.build
@@ -32,7 +32,9 @@ if have_tpm
 endif
 
 system_ss.add(when: seccomp, if_true: files('qemu-seccomp.c'))
-system_ss.add(when: fdt, if_true: files('device_tree.c'))
+system_ss.add(when: 'CONFIG_DEVICE_TREE',
+              if_true: [fdt, files('device_tree.c')],
+              if_false: files('device_tree-stub.c'))
 if host_os == 'linux'
   system_ss.add(files('async-teardown.c'))
 endif
-- 
2.45.0

[PATCH 4/6] kconfig: express dependency of individual boards on libfdt

[Paolo Bonzini]

Now that boards are enabled by default and the "CONFIG_FOO=y"
entries are gone from configs/devices/, there cannot be any more
a conflicts between the default contents of configs/devices/
and a failed "depends on" clause.

With this change, each individual board or target can express
whether it needs FDT.  It can then include the common code in the
build via "select DEVICE_TREE", which will also as tell meson to link
with libfdt.

This allows building non-microvm x86 emulators without having
libfdt available.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 Kconfig.host              |  1 -
 hw/arm/Kconfig            |  5 +++++
 hw/i386/Kconfig           |  3 ++-
 hw/loongarch/Kconfig      |  3 ++-
 hw/mips/Kconfig           |  3 ++-
 hw/openrisc/Kconfig       |  2 ++
 hw/ppc/Kconfig            | 15 ++++++++-------
 hw/riscv/Kconfig          |  4 ++++
 hw/rx/Kconfig             |  3 ++-
 hw/xtensa/Kconfig         |  1 +
 target/arm/Kconfig        |  2 ++
 target/microblaze/Kconfig |  1 +
 target/openrisc/Kconfig   |  1 +
 target/riscv/Kconfig      |  2 ++
 14 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/Kconfig.host b/Kconfig.host
index a0d4a52131e..17f405004b3 100644
--- a/Kconfig.host
+++ b/Kconfig.host
@@ -25,7 +25,6 @@ config TPM
 
 config FDT
     bool
-    select DEVICE_TREE
 
 config VHOST_USER
     bool
diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
index 98c264ed219..8b97683a45e 100644
--- a/hw/arm/Kconfig
+++ b/hw/arm/Kconfig
@@ -15,6 +15,7 @@ config ARM_VIRT
     select ACPI
     select ARM_SMMUV3
     select GPIO_KEY
+    select DEVICE_TREE
     select FW_CFG_DMA
     select PCI_EXPRESS
     select PCI_EXPRESS_GENERIC_BRIDGE
@@ -265,6 +266,7 @@ config SBSA_REF
     default y
     depends on TCG && AARCH64
     imply PCI_DEVICES
+    select DEVICE_TREE
     select AHCI
     select ARM_SMMUV3
     select GPIO_KEY
@@ -347,6 +349,7 @@ config VEXPRESS
     bool
     default y
     depends on TCG && ARM
+    select DEVICE_TREE
     select A9MPCORE
     select A15MPCORE
     select ARM_MPTIMER
@@ -492,6 +495,7 @@ config XLNX_ZYNQMP_ARM
     select CPU_CLUSTER
     select DDC
     select DPCD
+    select DEVICE_TREE
     select SDHCI
     select SSI
     select SSI_M25P80
@@ -509,6 +513,7 @@ config XLNX_VERSAL
     depends on TCG && AARCH64
     select ARM_GIC
     select CPU_CLUSTER
+    select DEVICE_TREE
     select PL011
     select CADENCE
     select VIRTIO_MMIO
diff --git a/hw/i386/Kconfig b/hw/i386/Kconfig
index 4362164962c..5af47f4bf2f 100644
--- a/hw/i386/Kconfig
+++ b/hw/i386/Kconfig
@@ -115,7 +115,8 @@ config Q35
 config MICROVM
     bool
     default y
-    depends on I386
+    depends on I386 && FDT
+    select DEVICE_TREE
     select SERIAL_ISA # for serial_hds_isa_init()
     select ISA_BUS
     select APIC
diff --git a/hw/loongarch/Kconfig b/hw/loongarch/Kconfig
index 78640505630..830cfef72db 100644
--- a/hw/loongarch/Kconfig
+++ b/hw/loongarch/Kconfig
@@ -1,7 +1,8 @@
 config LOONGARCH_VIRT
     bool
     default y
-    depends on LOONGARCH64
+    depends on LOONGARCH64 && FDT
+    select DEVICE_TREE
     select PCI
     select PCI_EXPRESS_GENERIC_BRIDGE
     imply VIRTIO_VGA
diff --git a/hw/mips/Kconfig b/hw/mips/Kconfig
index 9bccb363eb9..a7f26edebe8 100644
--- a/hw/mips/Kconfig
+++ b/hw/mips/Kconfig
@@ -80,9 +80,10 @@ config MIPS_CPS
 config MIPS_BOSTON
     bool
     default y
-    depends on MIPS64 && !TARGET_BIG_ENDIAN
+    depends on MIPS64 && !TARGET_BIG_ENDIAN && FDT
     imply PCI_DEVICES
     imply TEST_DEVICES
+    select DEVICE_TREE
     select FITLOADER
     select MIPS_CPS
     select PCI_EXPRESS_XILINX
diff --git a/hw/openrisc/Kconfig b/hw/openrisc/Kconfig
index 9c9015e0a5d..76b953c62c2 100644
--- a/hw/openrisc/Kconfig
+++ b/hw/openrisc/Kconfig
@@ -2,6 +2,7 @@ config OR1K_SIM
     bool
     default y
     depends on OPENRISC
+    select DEVICE_TREE
     select SERIAL
     select OPENCORES_ETH
     select OMPIC
@@ -14,6 +15,7 @@ config OR1K_VIRT
     imply PCI_DEVICES
     imply VIRTIO_VGA
     imply TEST_DEVICES
+    select DEVICE_TREE
     select PCI
     select PCI_EXPRESS_GENERIC_BRIDGE
     select GOLDFISH_RTC
diff --git a/hw/ppc/Kconfig b/hw/ppc/Kconfig
index 78f83e78ce5..347212f4dba 100644
--- a/hw/ppc/Kconfig
+++ b/hw/ppc/Kconfig
@@ -1,7 +1,7 @@
 config PSERIES
     bool
     default y
-    depends on PPC64
+    depends on PPC64 && FDT
     imply USB_OHCI_PCI
     imply PCI_DEVICES
     imply TEST_DEVICES
@@ -26,7 +26,7 @@ config SPAPR_RNG
 config POWERNV
     bool
     default y
-    depends on PPC64
+    depends on PPC64 && FDT
     imply PCI_DEVICES
     imply TEST_DEVICES
     select ISA_IPMI_BT
@@ -52,7 +52,7 @@ config PPC405
 config PPC440
     bool
     default y
-    depends on PPC
+    depends on PPC && FDT
     imply PCI_DEVICES
     imply TEST_DEVICES
     imply E1000_PCI
@@ -71,7 +71,7 @@ config PPC4XX
 config SAM460EX
     bool
     default y
-    depends on PPC
+    depends on PPC && FDT
     select PFLASH_CFI01
     select IDE_SII3112
     select M41T80
@@ -168,19 +168,19 @@ config E500
 config E500PLAT
     bool
     default y
-    depends on PPC
+    depends on PPC && FDT
     select E500
 
 config MPC8544DS
     bool
     default y
-    depends on PPC
+    depends on PPC && FDT
     select E500
 
 config VIRTEX
     bool
     default y
-    depends on PPC
+    depends on PPC && FDT
     select PPC4XX
     select PFLASH_CFI01
     select SERIAL
@@ -193,6 +193,7 @@ config FW_CFG_PPC
     bool
 
 config FDT_PPC
+    select DEVICE_TREE
     bool
 
 config VOF
diff --git a/hw/riscv/Kconfig b/hw/riscv/Kconfig
index 5f5f9e31bb0..a2030e3a6ff 100644
--- a/hw/riscv/Kconfig
+++ b/hw/riscv/Kconfig
@@ -12,6 +12,7 @@ config MICROCHIP_PFSOC
     depends on RISCV64
     select CADENCE_SDHCI
     select CPU_CLUSTER
+    select DEVICE_TREE
     select MCHP_PFSOC_DMC
     select MCHP_PFSOC_IOSCB
     select MCHP_PFSOC_MMUART
@@ -37,6 +38,7 @@ config RISCV_VIRT
     imply VIRTIO_VGA
     imply TEST_DEVICES
     imply TPM_TIS_SYSBUS
+    select DEVICE_TREE
     select RISCV_NUMA
     select GOLDFISH_RTC
     select PCI
@@ -82,6 +84,7 @@ config SIFIVE_U
     depends on RISCV32 || RISCV64
     select CADENCE
     select CPU_CLUSTER
+    select DEVICE_TREE
     select RISCV_ACLINT
     select SIFIVE_GPIO
     select SIFIVE_PDMA
@@ -99,6 +102,7 @@ config SPIKE
     bool
     default y
     depends on RISCV32 || RISCV64
+    select DEVICE_TREE
     select RISCV_NUMA
     select HTIF
     select RISCV_ACLINT
diff --git a/hw/rx/Kconfig b/hw/rx/Kconfig
index b2fa2b7eec3..aa9242d1ef6 100644
--- a/hw/rx/Kconfig
+++ b/hw/rx/Kconfig
@@ -8,5 +8,6 @@ config RX62N_MCU
 config RX_GDBSIM
     bool
     default y
-    depends on RX
+    depends on RX && FDT
+    select DEVICE_TREE
     select RX62N_MCU
diff --git a/hw/xtensa/Kconfig b/hw/xtensa/Kconfig
index 443b415c2ba..8ea283a7a3b 100644
--- a/hw/xtensa/Kconfig
+++ b/hw/xtensa/Kconfig
@@ -15,6 +15,7 @@ config XTENSA_XTFPGA
     bool
     default y
     depends on XTENSA
+    imply DEVICE_TREE
     select OPENCORES_ETH
     select PFLASH_CFI01
     select SERIAL
diff --git a/target/arm/Kconfig b/target/arm/Kconfig
index 5847c5a74a7..7f8a2217ae1 100644
--- a/target/arm/Kconfig
+++ b/target/arm/Kconfig
@@ -6,6 +6,8 @@ config ARM
     # translate.c v7m helpers under ARM_V7M.
     select ARM_V7M if TCG
 
+    select DEVICE_TREE # needed by boot.c
+
 config AARCH64
     bool
     select ARM
diff --git a/target/microblaze/Kconfig b/target/microblaze/Kconfig
index a5410d9218d..e91d58d88f2 100644
--- a/target/microblaze/Kconfig
+++ b/target/microblaze/Kconfig
@@ -1,2 +1,3 @@
 config MICROBLAZE
     bool
+    select DEVICE_TREE # needed by boot.c
diff --git a/target/openrisc/Kconfig b/target/openrisc/Kconfig
index e0da4ac1dfc..cd66c2e3b6c 100644
--- a/target/openrisc/Kconfig
+++ b/target/openrisc/Kconfig
@@ -1,2 +1,3 @@
 config OPENRISC
     bool
+    select DEVICE_TREE # needed by boot.c
diff --git a/target/riscv/Kconfig b/target/riscv/Kconfig
index adb7de3f37d..5f30df22f2f 100644
--- a/target/riscv/Kconfig
+++ b/target/riscv/Kconfig
@@ -1,7 +1,9 @@
 config RISCV32
     bool
     select ARM_COMPATIBLE_SEMIHOSTING # for do_common_semihosting()
+    select DEVICE_TREE # needed by boot.c
 
 config RISCV64
     bool
     select ARM_COMPATIBLE_SEMIHOSTING # for do_common_semihosting()
+    select DEVICE_TREE # needed by boot.c
-- 
2.45.0

[PATCH 5/6] hw/xtensa: require libfdt

[Paolo Bonzini]

All other boards require libfdt if it can be used (including for example
i386/x86_64), so change the "imply" to "select" and always allow -dtb
in qemu-system-xtensa.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 hw/xtensa/xtfpga.c | 9 ---------
 hw/xtensa/Kconfig  | 4 ++--
 2 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index f49e6591dc2..955e8867a36 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -356,7 +356,6 @@ static void xtfpga_init(const XtfpgaBoardDesc *board, MachineState *machine)
             cur_tagptr = put_tag(cur_tagptr, BP_TAG_COMMAND_LINE,
                                  strlen(kernel_cmdline) + 1, kernel_cmdline);
         }
-#ifdef CONFIG_FDT
         if (dtb_filename) {
             int fdt_size;
             void *fdt = load_device_tree(dtb_filename, &fdt_size);
@@ -373,14 +372,6 @@ static void xtfpga_init(const XtfpgaBoardDesc *board, MachineState *machine)
             cur_lowmem = QEMU_ALIGN_UP(cur_lowmem + fdt_size, 4 * KiB);
             g_free(fdt);
         }
-#else
-        if (dtb_filename) {
-            error_report("could not load DTB '%s': "
-                         "FDT support is not configured in QEMU",
-                         dtb_filename);
-            exit(EXIT_FAILURE);
-        }
-#endif
         if (initrd_filename) {
             BpMemInfo initrd_location = { 0 };
             int initrd_size = load_ramdisk(initrd_filename, cur_lowmem,
diff --git a/hw/xtensa/Kconfig b/hw/xtensa/Kconfig
index 8ea283a7a3b..fc5c785cfac 100644
--- a/hw/xtensa/Kconfig
+++ b/hw/xtensa/Kconfig
@@ -14,8 +14,8 @@ config XTENSA_VIRT
 config XTENSA_XTFPGA
     bool
     default y
-    depends on XTENSA
-    imply DEVICE_TREE
+    depends on XTENSA && FDT
+    select DEVICE_TREE
     select OPENCORES_ETH
     select PFLASH_CFI01
     select SERIAL
-- 
2.45.0

[PATCH 6/6] configs: disable emulators that require it if libfdt is not found

[Paolo Bonzini]

Since boards can express their dependency on libfdt and
system/device_tree.c, only leave TARGET_NEED_FDT if the target has a
hard dependency.

Those emulators will be skipped if libfdt is disabled, or if it
is "auto" and not found and --disable-download is passed; unless
the target is mentioned explicitly in --target-list, in which case
the build will fail.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 configs/targets/aarch64-softmmu.mak      | 1 +
 configs/targets/arm-softmmu.mak          | 1 +
 configs/targets/i386-softmmu.mak         | 1 -
 configs/targets/loongarch64-softmmu.mak  | 1 +
 configs/targets/microblaze-softmmu.mak   | 1 +
 configs/targets/microblazeel-softmmu.mak | 1 +
 configs/targets/mips64el-softmmu.mak     | 1 -
 configs/targets/or1k-softmmu.mak         | 1 +
 configs/targets/ppc-softmmu.mak          | 1 -
 configs/targets/ppc64-softmmu.mak        | 1 +
 configs/targets/riscv32-softmmu.mak      | 1 +
 configs/targets/riscv64-softmmu.mak      | 1 +
 configs/targets/rx-softmmu.mak           | 1 +
 configs/targets/x86_64-softmmu.mak       | 1 -
 meson.build                              | 6 +++++-
 .gitlab-ci.d/buildtest.yml               | 8 ++++----
 16 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/configs/targets/aarch64-softmmu.mak b/configs/targets/aarch64-softmmu.mak
index 83c22391a69..84cb32dc2f4 100644
--- a/configs/targets/aarch64-softmmu.mak
+++ b/configs/targets/aarch64-softmmu.mak
@@ -3,4 +3,5 @@ TARGET_BASE_ARCH=arm
 TARGET_SUPPORTS_MTTCG=y
 TARGET_KVM_HAVE_GUEST_DEBUG=y
 TARGET_XML_FILES= gdb-xml/aarch64-core.xml gdb-xml/aarch64-fpu.xml gdb-xml/arm-core.xml gdb-xml/arm-vfp.xml gdb-xml/arm-vfp3.xml gdb-xml/arm-vfp-sysregs.xml gdb-xml/arm-neon.xml gdb-xml/arm-m-profile.xml gdb-xml/arm-m-profile-mve.xml gdb-xml/aarch64-pauth.xml
+# needed by boot.c
 TARGET_NEED_FDT=y
diff --git a/configs/targets/arm-softmmu.mak b/configs/targets/arm-softmmu.mak
index 92c8349b964..bf390b7a8de 100644
--- a/configs/targets/arm-softmmu.mak
+++ b/configs/targets/arm-softmmu.mak
@@ -1,4 +1,5 @@
 TARGET_ARCH=arm
 TARGET_SUPPORTS_MTTCG=y
 TARGET_XML_FILES= gdb-xml/arm-core.xml gdb-xml/arm-vfp.xml gdb-xml/arm-vfp3.xml gdb-xml/arm-vfp-sysregs.xml gdb-xml/arm-neon.xml gdb-xml/arm-m-profile.xml gdb-xml/arm-m-profile-mve.xml
+# needed by boot.c
 TARGET_NEED_FDT=y
diff --git a/configs/targets/i386-softmmu.mak b/configs/targets/i386-softmmu.mak
index d61b5076134..2ac69d5ba37 100644
--- a/configs/targets/i386-softmmu.mak
+++ b/configs/targets/i386-softmmu.mak
@@ -1,5 +1,4 @@
 TARGET_ARCH=i386
 TARGET_SUPPORTS_MTTCG=y
-TARGET_NEED_FDT=y
 TARGET_KVM_HAVE_GUEST_DEBUG=y
 TARGET_XML_FILES= gdb-xml/i386-32bit.xml
diff --git a/configs/targets/loongarch64-softmmu.mak b/configs/targets/loongarch64-softmmu.mak
index f23780fdd89..84beb19b90a 100644
--- a/configs/targets/loongarch64-softmmu.mak
+++ b/configs/targets/loongarch64-softmmu.mak
@@ -2,4 +2,5 @@ TARGET_ARCH=loongarch64
 TARGET_BASE_ARCH=loongarch
 TARGET_SUPPORTS_MTTCG=y
 TARGET_XML_FILES= gdb-xml/loongarch-base32.xml gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu.xml
+# all boards require libfdt
 TARGET_NEED_FDT=y
diff --git a/configs/targets/microblaze-softmmu.mak b/configs/targets/microblaze-softmmu.mak
index e84c0cc7283..eea266d4f3d 100644
--- a/configs/targets/microblaze-softmmu.mak
+++ b/configs/targets/microblaze-softmmu.mak
@@ -1,5 +1,6 @@
 TARGET_ARCH=microblaze
 TARGET_BIG_ENDIAN=y
 TARGET_SUPPORTS_MTTCG=y
+# needed by boot.c
 TARGET_NEED_FDT=y
 TARGET_XML_FILES=gdb-xml/microblaze-core.xml gdb-xml/microblaze-stack-protect.xml
diff --git a/configs/targets/microblazeel-softmmu.mak b/configs/targets/microblazeel-softmmu.mak
index 9b688036bd3..77b968acad3 100644
--- a/configs/targets/microblazeel-softmmu.mak
+++ b/configs/targets/microblazeel-softmmu.mak
@@ -1,4 +1,5 @@
 TARGET_ARCH=microblaze
 TARGET_SUPPORTS_MTTCG=y
+# needed by boot.c
 TARGET_NEED_FDT=y
 TARGET_XML_FILES=gdb-xml/microblaze-core.xml gdb-xml/microblaze-stack-protect.xml
diff --git a/configs/targets/mips64el-softmmu.mak b/configs/targets/mips64el-softmmu.mak
index 8d9ab3ddc4b..3864daa7364 100644
--- a/configs/targets/mips64el-softmmu.mak
+++ b/configs/targets/mips64el-softmmu.mak
@@ -1,3 +1,2 @@
 TARGET_ARCH=mips64
 TARGET_BASE_ARCH=mips
-TARGET_NEED_FDT=y
diff --git a/configs/targets/or1k-softmmu.mak b/configs/targets/or1k-softmmu.mak
index 432f855a30a..0341cb2a6b3 100644
--- a/configs/targets/or1k-softmmu.mak
+++ b/configs/targets/or1k-softmmu.mak
@@ -1,4 +1,5 @@
 TARGET_ARCH=openrisc
 TARGET_SUPPORTS_MTTCG=y
 TARGET_BIG_ENDIAN=y
+# needed by boot.c and all boards
 TARGET_NEED_FDT=y
diff --git a/configs/targets/ppc-softmmu.mak b/configs/targets/ppc-softmmu.mak
index f3ea9c98f75..53120dab41d 100644
--- a/configs/targets/ppc-softmmu.mak
+++ b/configs/targets/ppc-softmmu.mak
@@ -2,4 +2,3 @@ TARGET_ARCH=ppc
 TARGET_BIG_ENDIAN=y
 TARGET_KVM_HAVE_GUEST_DEBUG=y
 TARGET_XML_FILES= gdb-xml/power-core.xml gdb-xml/power-fpu.xml gdb-xml/power-altivec.xml gdb-xml/power-spe.xml
-TARGET_NEED_FDT=y
diff --git a/configs/targets/ppc64-softmmu.mak b/configs/targets/ppc64-softmmu.mak
index 1db8d8381d0..40881d93968 100644
--- a/configs/targets/ppc64-softmmu.mak
+++ b/configs/targets/ppc64-softmmu.mak
@@ -4,4 +4,5 @@ TARGET_BIG_ENDIAN=y
 TARGET_SUPPORTS_MTTCG=y
 TARGET_KVM_HAVE_GUEST_DEBUG=y
 TARGET_XML_FILES= gdb-xml/power64-core.xml gdb-xml/power-fpu.xml gdb-xml/power-altivec.xml gdb-xml/power-spe.xml gdb-xml/power-vsx.xml
+# all boards require libfdt
 TARGET_NEED_FDT=y
diff --git a/configs/targets/riscv32-softmmu.mak b/configs/targets/riscv32-softmmu.mak
index d8b71cddcd4..338182d5b89 100644
--- a/configs/targets/riscv32-softmmu.mak
+++ b/configs/targets/riscv32-softmmu.mak
@@ -2,4 +2,5 @@ TARGET_ARCH=riscv32
 TARGET_BASE_ARCH=riscv
 TARGET_SUPPORTS_MTTCG=y
 TARGET_XML_FILES= gdb-xml/riscv-32bit-cpu.xml gdb-xml/riscv-32bit-fpu.xml gdb-xml/riscv-64bit-fpu.xml gdb-xml/riscv-32bit-virtual.xml
+# needed by boot.c
 TARGET_NEED_FDT=y
diff --git a/configs/targets/riscv64-softmmu.mak b/configs/targets/riscv64-softmmu.mak
index 7c0e7eeb429..f688ffa7bce 100644
--- a/configs/targets/riscv64-softmmu.mak
+++ b/configs/targets/riscv64-softmmu.mak
@@ -2,4 +2,5 @@ TARGET_ARCH=riscv64
 TARGET_BASE_ARCH=riscv
 TARGET_SUPPORTS_MTTCG=y
 TARGET_XML_FILES= gdb-xml/riscv-64bit-cpu.xml gdb-xml/riscv-32bit-fpu.xml gdb-xml/riscv-64bit-fpu.xml gdb-xml/riscv-64bit-virtual.xml
+# needed by boot.c
 TARGET_NEED_FDT=y
diff --git a/configs/targets/rx-softmmu.mak b/configs/targets/rx-softmmu.mak
index 0c458b2d07c..706bbe6062c 100644
--- a/configs/targets/rx-softmmu.mak
+++ b/configs/targets/rx-softmmu.mak
@@ -1,3 +1,4 @@
 TARGET_ARCH=rx
 TARGET_XML_FILES= gdb-xml/rx-core.xml
+# all boards require libfdt
 TARGET_NEED_FDT=y
diff --git a/configs/targets/x86_64-softmmu.mak b/configs/targets/x86_64-softmmu.mak
index c5f882e5ba1..e12ac3dc59b 100644
--- a/configs/targets/x86_64-softmmu.mak
+++ b/configs/targets/x86_64-softmmu.mak
@@ -1,6 +1,5 @@
 TARGET_ARCH=x86_64
 TARGET_BASE_ARCH=i386
 TARGET_SUPPORTS_MTTCG=y
-TARGET_NEED_FDT=y
 TARGET_KVM_HAVE_GUEST_DEBUG=y
 TARGET_XML_FILES= gdb-xml/i386-64bit.xml
diff --git a/meson.build b/meson.build
index d8f259d2610..b8b3e7d73f5 100644
--- a/meson.build
+++ b/meson.build
@@ -3059,7 +3059,11 @@ foreach target : target_dirs
   config_target += { 'TARGET_' + config_target['TARGET_ARCH'].to_upper(): 'y' }
 
   if 'TARGET_NEED_FDT' in config_target and not fdt.found()
-    fdt_required += target
+    if default_targets
+      warning('Disabling ' + target + ' due to missing libfdt')
+    else
+      fdt_required += target
+    endif
     continue
   endif
 
diff --git a/.gitlab-ci.d/buildtest.yml b/.gitlab-ci.d/buildtest.yml
index e9402a68a79..92ca396c195 100644
--- a/.gitlab-ci.d/buildtest.yml
+++ b/.gitlab-ci.d/buildtest.yml
@@ -648,8 +648,8 @@ build-tci:
     - make check-tcg
 
 # Check our reduced build configurations
-# requires libfdt: aarch64, arm, i386, loongarch64, microblaze, microblazeel,
-#   mips64el, or1k, ppc, ppc64, riscv32, riscv64, rx, x86_64
+# requires libfdt: aarch64, arm, loongarch64, microblaze, microblazeel,
+#   or1k, ppc64, riscv32, riscv64, rx
 # does not build without boards: i386, loongarch64, s390x, sh4, sh4eb, x86_64
 build-without-defaults:
   extends: .native_build_job_template
@@ -665,7 +665,8 @@ build-without-defaults:
       --disable-qom-cast-debug
       --disable-strip
     TARGETS: alpha-softmmu avr-softmmu cris-softmmu hppa-softmmu m68k-softmmu
-      mips-softmmu mips64-softmmu mipsel-softmmu sparc-softmmu
+      mips-softmmu mips64-softmmu mipsel-softmmu mips64el-softmmu
+      ppc-softmmu sparc-softmmu
       sparc64-softmmu tricore-softmmu xtensa-softmmu xtensaeb-softmmu
       hexagon-linux-user i386-linux-user s390x-linux-user
     MAKE_CHECK_ARGS: check
-- 
2.45.0

Re: [PATCH 2/6] meson: move libfdt together with other dependencies

[Philippe Mathieu-Daudé]

On 8/5/24 09:51, Paolo Bonzini wrote:
> Move the libfdt detection code together with other dependencies instead
> of keeping it with subprojects.  This has the disadvantage of performing
> the detection even if no target requires libfdt; but it has the advantage
> that Kconfig will be able to observe the availability of the library.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   meson.build | 79 ++++++++++++++++++++++++++---------------------------
>   1 file changed, 38 insertions(+), 41 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Re: [PATCH 1/6] meson: pick libfdt from common_ss when building target-specific files

[Philippe Mathieu-Daudé]

On 8/5/24 09:51, Paolo Bonzini wrote:
> Avoid having to list dependencies such as libfdt twice, both on common_ss
> and specific_ss.  Instead, just take all the dependencies in common_ss
> and allow the target-specific libqemu-*.fa library to use them.
> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>   meson.build              | 14 +++++++++++---
>   hw/arm/meson.build       |  2 +-
>   hw/loongarch/meson.build |  2 +-
>   hw/mips/meson.build      |  2 +-
>   hw/openrisc/meson.build  |  4 ++--
>   hw/ppc/meson.build       |  4 +---
>   hw/riscv/meson.build     |  2 +-
>   7 files changed, 18 insertions(+), 12 deletions(-)


>     target_common = common_ss.apply(config_target, strict: false)
>     objects = common_all.extract_objects(target_common.sources())
> -  deps = target_common.dependencies()
> +  arch_deps += target_common.dependencies()
>   
>     target_specific = specific_ss.apply(config_target, strict: false)
>     arch_srcs += target_specific.sources()
>     arch_deps += target_specific.dependencies()
>   
> +  # allow using headers from the dependencies but do not include the sources,
> +  # because this emulator only needs those in "objects".  For external
> +  # dependencies, the full dependency is included below in the executable.
> +  lib_deps = []
> +  foreach dep : arch_deps
> +    lib_deps += dep.partial_dependency(compile_args: true, includes: true)

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> +  endforeach
> +
>     lib = static_library('qemu-' + target,
>                    sources: arch_srcs + genh,
> -                 dependencies: arch_deps,
> +                 dependencies: lib_deps,
>                    objects: objects,
>                    include_directories: target_inc,
>                    c_args: c_args,
> @@ -3924,7 +3932,7 @@ foreach target : target_dirs
>       emulator = executable(exe_name, exe['sources'],
>                  install: true,
>                  c_args: c_args,
> -               dependencies: arch_deps + deps + exe['dependencies'],
> +               dependencies: arch_deps + exe['dependencies'],