| Message ID | 20240731201039.1011028-1-adityag@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | hw/ppc: Implement -dtb support for PowerNV | expand |
Hello Aditya, On 7/31/24 22:10, Aditya Gupta wrote: > Currently any device tree passed with -dtb option in QEMU, was ignored > by the PowerNV code. > > Read and pass the passed -dtb to the kernel, thus enabling easier > debugging with custom DTBs. > > The existing behaviour when -dtb is 'not' passed, is preserved as-is. > > But when a '-dtb' is passed, it completely overrides any dtb nodes or > changes QEMU might have done, such as '-append' arguments to the kernel > (which are mentioned in /chosen/bootargs in the dtb), hence add warning > when -dtb is being used > > Signed-off-by: Aditya Gupta <adityag@linux.ibm.com> > > --- > Changelog > =========== > v1: > + use 'g_file_get_contents' and add check for -append & -dtb as suggested by Daniel > --- > --- > hw/ppc/pnv.c | 25 ++++++++++++++++++++++--- > 1 file changed, 22 insertions(+), 3 deletions(-) > > diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c > index 3526852685b4..03600fa62cbd 100644 > --- a/hw/ppc/pnv.c > +++ b/hw/ppc/pnv.c > @@ -736,10 +736,21 @@ static void pnv_reset(MachineState *machine, ShutdownCause reason) > } > } > > - fdt = pnv_dt_create(machine); > + if (machine->dtb) { > + warn_report("with manually passed dtb, some options like '-append'" > + " will get ignored and the dtb passed will be used as-is"); This warning should come after all other checks. See below. > - /* Pack resulting tree */ > - _FDT((fdt_pack(fdt))); > + /* read the file 'machine->dtb', and load it into 'fdt' buffer */ > + if (!g_file_get_contents(machine->dtb, (gchar **)&fdt, NULL, NULL)) { > + error_report("Could not load dtb '%s'", machine->dtb); > + exit(1); > + } We should try to report such errors earlier than in reset. Can you please introduce a PnvMachineState::dtb attribute and initialize it in pnv_init() after ->initrd_filename. Thanks, C. > + } else { > + fdt = pnv_dt_create(machine); > + > + /* Pack resulting tree */ > + _FDT((fdt_pack(fdt))); > + } > > qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt)); > cpu_physical_memory_write(PNV_FDT_ADDR, fdt, fdt_totalsize(fdt)); > @@ -952,6 +963,14 @@ static void pnv_init(MachineState *machine) > g_free(sz); > exit(EXIT_FAILURE); > } > + > + /* checks for invalid option combinations */ > + if (machine->dtb && (strlen(machine->kernel_cmdline) != 0)) { > + error_report("-append and -dtb cannot be used together, as passed" > + " command line is ignored in case of custom dtb"); > + exit(EXIT_FAILURE); > + } > + > memory_region_add_subregion(get_system_memory(), 0, machine->ram); > > /*
On 8/1/24 09:44, Cédric Le Goater wrote: > >> - /* Pack resulting tree */ >> - _FDT((fdt_pack(fdt))); >> + /* read the file 'machine->dtb', and load it into 'fdt' buffer */ >> + if (!g_file_get_contents(machine->dtb, (gchar **)&fdt, NULL, NULL)) { >> + error_report("Could not load dtb '%s'", machine->dtb); >> + exit(1); >> + } > > We should try to report such errors earlier than in reset. > > Can you please introduce a PnvMachineState::dtb attribute and initialize it > in pnv_init() after ->initrd_filename. PnvMachineState::fdt might be a more appropriate name. Thanks, C.
Hello Cedric, >> <...snip...> >> >> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c >> index 3526852685b4..03600fa62cbd 100644 >> --- a/hw/ppc/pnv.c >> +++ b/hw/ppc/pnv.c >> @@ -736,10 +736,21 @@ static void pnv_reset(MachineState *machine, >> ShutdownCause reason) >> } >> } >> - fdt = pnv_dt_create(machine); >> + if (machine->dtb) { >> + warn_report("with manually passed dtb, some options like >> '-append'" >> + " will get ignored and the dtb passed will be used >> as-is"); > > This warning should come after all other checks. See below. > > >> - /* Pack resulting tree */ >> - _FDT((fdt_pack(fdt))); >> + /* read the file 'machine->dtb', and load it into 'fdt' >> buffer */ >> + if (!g_file_get_contents(machine->dtb, (gchar **)&fdt, NULL, >> NULL)) { >> + error_report("Could not load dtb '%s'", machine->dtb); >> + exit(1); >> + } > > We should try to report such errors earlier than in reset. > Thanks, I will remember this from next time. > Can you please introduce a PnvMachineState::dtb attribute and > initialize it > in pnv_init() after ->initrd_filename. > Sure, I will move it to pnv_init. Thanks, Aditya Gupta > > > Thanks, > > C. > > > >> + } else { >> + fdt = pnv_dt_create(machine); >> + >> + /* Pack resulting tree */ >> + _FDT((fdt_pack(fdt))); >> + } >> qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt)); >> cpu_physical_memory_write(PNV_FDT_ADDR, fdt, fdt_totalsize(fdt)); >> @@ -952,6 +963,14 @@ static void pnv_init(MachineState *machine) >> g_free(sz); >> exit(EXIT_FAILURE); >> } >> + >> + /* checks for invalid option combinations */ >> + if (machine->dtb && (strlen(machine->kernel_cmdline) != 0)) { >> + error_report("-append and -dtb cannot be used together, as >> passed" >> + " command line is ignored in case of custom dtb"); >> + exit(EXIT_FAILURE); >> + } >> + >> memory_region_add_subregion(get_system_memory(), 0, machine->ram); >> /* >
diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c index 3526852685b4..03600fa62cbd 100644 --- a/hw/ppc/pnv.c +++ b/hw/ppc/pnv.c @@ -736,10 +736,21 @@ static void pnv_reset(MachineState *machine, ShutdownCause reason) } } - fdt = pnv_dt_create(machine); + if (machine->dtb) { + warn_report("with manually passed dtb, some options like '-append'" + " will get ignored and the dtb passed will be used as-is"); - /* Pack resulting tree */ - _FDT((fdt_pack(fdt))); + /* read the file 'machine->dtb', and load it into 'fdt' buffer */ + if (!g_file_get_contents(machine->dtb, (gchar **)&fdt, NULL, NULL)) { + error_report("Could not load dtb '%s'", machine->dtb); + exit(1); + } + } else { + fdt = pnv_dt_create(machine); + + /* Pack resulting tree */ + _FDT((fdt_pack(fdt))); + } qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt)); cpu_physical_memory_write(PNV_FDT_ADDR, fdt, fdt_totalsize(fdt)); @@ -952,6 +963,14 @@ static void pnv_init(MachineState *machine) g_free(sz); exit(EXIT_FAILURE); } + + /* checks for invalid option combinations */ + if (machine->dtb && (strlen(machine->kernel_cmdline) != 0)) { + error_report("-append and -dtb cannot be used together, as passed" + " command line is ignored in case of custom dtb"); + exit(EXIT_FAILURE); + } + memory_region_add_subregion(get_system_memory(), 0, machine->ram); /*
Currently any device tree passed with -dtb option in QEMU, was ignored by the PowerNV code. Read and pass the passed -dtb to the kernel, thus enabling easier debugging with custom DTBs. The existing behaviour when -dtb is 'not' passed, is preserved as-is. But when a '-dtb' is passed, it completely overrides any dtb nodes or changes QEMU might have done, such as '-append' arguments to the kernel (which are mentioned in /chosen/bootargs in the dtb), hence add warning when -dtb is being used Signed-off-by: Aditya Gupta <adityag@linux.ibm.com> --- Changelog =========== v1: + use 'g_file_get_contents' and add check for -append & -dtb as suggested by Daniel --- --- hw/ppc/pnv.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-)