hw/ppc/pnv.c | 10 ++++++++-- tests/functional/ppc64/test_powernv.py | 19 +++++++++++++++++++ 2 files changed, 27 insertions(+), 2 deletions(-)
Currently powerpc pnv machines doesnt respect `-dtb` argument passed from outside. During cpu start content of machine->fdt is overwritten by `pnv_dt_create`. This was previously found and fixed, during the discussion for dumpdtb issue [1]. But reintroduced in MPIPL support [2]. Saddly it skipped in the review phase [3]. Adding a functional test for checking the external dtb case in powernv11. [1] https://lore.kernel.org/all/20260323231612.GA2637687@ax162/ [2] https://lore.kernel.org/qemu-devel/20260310124619.3909045-8-adityag@linux.ibm.com/ [3] https://lore.kernel.org/qemu-devel/abAmBV7g_bGNw0Ax@shivang.upadyay/ Shivang Upadhyay (2): ppc/pnv: avoid regenerating DTB if external DTB is present ppc/pnv: add test to verify external DTB is honored hw/ppc/pnv.c | 10 ++++++++-- tests/functional/ppc64/test_powernv.py | 19 +++++++++++++++++++ 2 files changed, 27 insertions(+), 2 deletions(-) -- 2.54.0
Currently powerpc pnv machines doesnt respect `-dtb` argument passed from outside. During cpu start content of machine->fdt is overwritten by `pnv_dt_create`. This was previously found and fixed, during the discussion for dumpdtb issue [1]. But reintroduced in MPIPL support [2]. Saddly it skipped in the review phase [3]. Adding a functional test for checking the external dtb case in powernv11. [1] https://lore.kernel.org/all/20260323231612.GA2637687@ax162/ [2] https://lore.kernel.org/qemu-devel/20260310124619.3909045-8-adityag@linux.ibm.com/ [3] https://lore.kernel.org/qemu-devel/abAmBV7g_bGNw0Ax@shivang.upadyay/ Changelog * V1: https://lore.kernel.org/all/20260623063156.1110370-1-shivangu@linux.ibm.com/ - change dtb from power10 to power11 - refactored pnv_reset code to not `load_device_tree` on each iteration. - added commit message body. Shivang Upadhyay (2): ppc/pnv: avoid regenerating DTB if external DTB is present ppc/pnv: add test to verify external DTB is honored hw/ppc/pnv.c | 10 +++++++--- tests/functional/ppc64/test_powernv.py | 19 +++++++++++++++++++ 2 files changed, 26 insertions(+), 3 deletions(-) -- 2.54.0
Currently externally provided dtb is overwritten in `pnv_reset`.
Fix this by only creating dtb if not provided from `-dtb`.
Signed-off-by: Shivang Upadhyay <shivangu@linux.ibm.com>
---
hw/ppc/pnv.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 62812f22f8..e44fb7e2dc 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -803,9 +803,13 @@ static void pnv_reset(MachineState *machine, ResetType type)
mpipl_write_succeeded = do_mpipl_write(pnv);
}
- /* Regenerate device tree */
- fdt = pnv_dt_create(machine);
- _FDT((fdt_pack(fdt)));
+ /* Only create new dt if not provided in -dtb */
+ if (!machine->dtb) {
+ fdt = pnv_dt_create(machine);
+ _FDT((fdt_pack(fdt)));
+ } else {
+ fdt = machine->fdt;
+ }
/*
* If it's a MPIPL boot, add the "mpipl-boot" property, and reset the
--
2.54.0On 26/06/26 04:52PM, Shivang Upadhyay wrote:
> Currently externally provided dtb is overwritten in `pnv_reset`.
> Fix this by only creating dtb if not provided from `-dtb`.
>
> Signed-off-by: Shivang Upadhyay <shivangu@linux.ibm.com>
> ---
> hw/ppc/pnv.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> index 62812f22f8..e44fb7e2dc 100644
> --- a/hw/ppc/pnv.c
> +++ b/hw/ppc/pnv.c
> @@ -803,9 +803,13 @@ static void pnv_reset(MachineState *machine, ResetType type)
> mpipl_write_succeeded = do_mpipl_write(pnv);
> }
>
> - /* Regenerate device tree */
> - fdt = pnv_dt_create(machine);
> - _FDT((fdt_pack(fdt)));
> + /* Only create new dt if not provided in -dtb */
> + if (!machine->dtb) {
> + fdt = pnv_dt_create(machine);
> + _FDT((fdt_pack(fdt)));
> + } else {
> + fdt = machine->fdt;
> + }
nit: indent is wrong
with indentation fixed, feel free to add:
Reviewed-by: Aditya Gupta <adityag@linux.ibm.com>
- Aditya G
Test boots a powernv11 machine, using a custom dtb.
Custom dtb has the following bootargs.
chosen {
bootargs = "hello world";
};
Test Checks wheather above bootargs make it to kernel's command line.
Signed-off-by: Shivang Upadhyay <shivangu@linux.ibm.com>
---
tests/functional/ppc64/test_powernv.py | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/tests/functional/ppc64/test_powernv.py b/tests/functional/ppc64/test_powernv.py
index 0ea6c93e42..cb8f6545a0 100755
--- a/tests/functional/ppc64/test_powernv.py
+++ b/tests/functional/ppc64/test_powernv.py
@@ -27,6 +27,11 @@ class PowernvMachine(LinuxKernelTest):
'buildroot/qemu_ppc64le_powernv8-2025.02/rootfs.ext2'),
'aee2192b692077c4bde31cb56ce474424b358f17cec323d5c94af3970c9aada2')
+ # testdtb for power11, which contains string "hello world" in command line
+ ASSET_SAMPLE_DTB = Asset(
+ ('https://github.com/roz3x/qemu/raw/refs/heads/sample-dtb/output.dtb'),
+ 'ea1271516264eea1eb58a067a99d0c2ca9528be8dc7d4e46bb2d5ae0d42fc568')
+
def do_test_linux_boot(self, command_line = KERNEL_COMMON_COMMAND_LINE):
self.require_accelerator("tcg")
kernel_path = self.ASSET_KERNEL.fetch()
@@ -104,6 +109,20 @@ def do_test_ppc64_powernv(self, proc):
# Device detection output driven by udev probing is sometimes cut off
# from console output, suspect S14silence-console init script.
+ def test_ppc64_powernv_external_dtb(self):
+ self.set_machine('powernv11')
+ self.require_accelerator("tcg")
+
+ kernel_path = self.ASSET_KERNEL.fetch()
+ sample_dtb_path = self.ASSET_SAMPLE_DTB.fetch()
+ self.vm.set_console()
+ self.vm.add_args('-kernel', kernel_path,
+ '-dtb', sample_dtb_path)
+ self.vm.launch()
+
+ # check if custom dtb is reflected or not
+ wait_for_console_pattern(self, "Kernel command line: hello world", self.panic_message)
+
def test_powernv8(self):
self.set_machine('powernv8')
self.do_test_ppc64_powernv('P8')
--
2.54.0On 26/06/26 04:52PM, Shivang Upadhyay wrote:
> Test boots a powernv11 machine, using a custom dtb.
> Custom dtb has the following bootargs.
>
> chosen {
> bootargs = "hello world";
> };
>
> Test Checks wheather above bootargs make it to kernel's command line.
nit: s/wheather/whether
> + # testdtb for power11, which contains string "hello world" in command line
> + ASSET_SAMPLE_DTB = Asset(
> + ('https://github.com/roz3x/qemu/raw/refs/heads/sample-dtb/output.dtb'),
> + 'ea1271516264eea1eb58a067a99d0c2ca9528be8dc7d4e46bb2d5ae0d42fc568')
nit: since you are anyways sending a v3, can you rename output.dtb to
something like qemu-powernv10.dtb, etc so in future you don't modify
this generic path unknowingly ?
> +
> def do_test_linux_boot(self, command_line = KERNEL_COMMON_COMMAND_LINE):
> self.require_accelerator("tcg")
> kernel_path = self.ASSET_KERNEL.fetch()
> @@ -104,6 +109,20 @@ def do_test_ppc64_powernv(self, proc):
> # Device detection output driven by udev probing is sometimes cut off
> # from console output, suspect S14silence-console init script.
>
> + def test_ppc64_powernv_external_dtb(self):
> + self.set_machine('powernv11')
> + self.require_accelerator("tcg")
> +
> + kernel_path = self.ASSET_KERNEL.fetch()
> + sample_dtb_path = self.ASSET_SAMPLE_DTB.fetch()
> + self.vm.set_console()
> + self.vm.add_args('-kernel', kernel_path,
> + '-dtb', sample_dtb_path)
> + self.vm.launch()
> +
> + # check if custom dtb is reflected or not
> + wait_for_console_pattern(self, "Kernel command line: hello world", self.panic_message)
> +
Reviewed-by: Aditya Gupta <adityag@linux.ibm.com>
Thanks,
- Aditya G
On Mon, 2026-06-29 at 17:23 +0530, Aditya Gupta wrote:
> > + # testdtb for power11, which contains string "hello world" in
> > command line
> > + ASSET_SAMPLE_DTB = Asset(
> > +
> > ('https://github.com/roz3x/qemu/raw/refs/heads/sample-dtb/output.dt
> > b'),
> > +
> > 'ea1271516264eea1eb58a067a99d0c2ca9528be8dc7d4e46bb2d5ae0d42fc568')
>
> nit: since you are anyways sending a v3, can you rename output.dtb to
> something like qemu-powernv10.dtb, etc so in future you don't modify
> this generic path unknowingly ?
Yeah, Sounds like a good idea.
Ill send the next revision.
~Shivang.
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