On 2/17/25 12:49, Aditya Gupta wrote:
Linux expect a "ibm,opal/dump" node to know whether MPIPL (aka fadump)
is supported on the hardware.
Export the "ibm,opal/dump" node in QEMU's device tree for Linux to know
that PowerNV supports MPIPL.
With the commit, kernel boots thinking fadump is supported, and reserves
memory regions for fadump if "fadump=on" is passed in kernel cmdline:
Linux/PowerPC load: init=/bin/sh debug fadump=on
Finalizing device tree... flat tree at 0x20ebaca0
[ 1.005765851,5] DUMP: Payload sent metadata tag : 0x800002a8
[ 1.005980914,5] DUMP: Boot mem size : 0x40000000
[ 0.000000] opal fadump: Kernel metadata addr: 800002a8
[ 0.000000] fadump: Reserved 1024MB of memory at 0x00000040000000
(System RAM: 20480MB)
[ 0.000000] fadump: Initialized 0x40000000 bytes cma area at 1024MB
from 0x400102a8 bytes of memory reserved for firmware-assisted dump
Also, OPAL and Linux expect the "mpipl-boot" device tree node on a MPIPL
boot. Hence add "mpipl-boot" property in device tree on an MPIPL boot.
Hence after crash, Linux knows when it's a MPIPL/fadump boot:
[ 0.000000] opal fadump: Firmware-assisted dump is active.
[ 0.000000] fadump: Firmware-assisted dump is active.
[ 0.000000] fadump: Reserving 23552MB of memory at 0x00000040000000 for
preserving crash data
Do note that fadump boot in PowerNV seems to require more memory,
trying with 1GB causes this error by kernel:
[ 0.000000] fadump: Failed to find memory chunk for reservation!
And even with anything from 2GB - 19GB, the kernel fails to boot due to
some memory issues.
Trying with >20GB memory is recommended for now
Signed-off-by: Aditya Gupta <adit...@linux.ibm.com>
---
hw/ppc/pnv.c | 49 ++++++++++++++++++++++++++++++++++++++++
hw/ppc/pnv_sbe.c | 18 +++++++++++----
include/hw/ppc/pnv_sbe.h | 4 ++++
3 files changed, 67 insertions(+), 4 deletions(-)
diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
index 11fd477b71be..39ed3f873e9a 100644
--- a/hw/ppc/pnv.c
+++ b/hw/ppc/pnv.c
@@ -51,6 +51,7 @@
#include "hw/ppc/pnv_chip.h"
#include "hw/ppc/pnv_xscom.h"
#include "hw/ppc/pnv_pnor.h"
+#include "hw/ppc/pnv_sbe.h"
#include "hw/isa/isa.h"
#include "hw/char/serial-isa.h"
@@ -697,6 +698,26 @@ static void *pnv_dt_create(MachineState *machine)
pmc->dt_power_mgt(pnv, fdt);
}
+ /* Add "dump" node so kernel knows MPIPL (aka fadump) is supported */
+ off = fdt_add_subnode(fdt, 0, "ibm,opal");
+ if (off == -FDT_ERR_EXISTS) {
+ off = fdt_path_offset(fdt, "/ibm,opal");
+ }
+
+ _FDT(off);
+ off = fdt_add_subnode(fdt, off, "dump");
+ _FDT(off);
+ _FDT((fdt_setprop_string(fdt, off, "compatible", "ibm,opal-dump")));
+
+ /* Add kernel and initrd as fw-load-area */
+ uint64_t fw_load_area[4] = {
+ cpu_to_be64(KERNEL_LOAD_ADDR), cpu_to_be64(KERNEL_MAX_SIZE),
+ cpu_to_be64(INITRD_LOAD_ADDR), cpu_to_be64(INITRD_MAX_SIZE)
+ };
+
+ _FDT((fdt_setprop(fdt, off, "fw-load-area",
+ fw_load_area, sizeof(fw_load_area))));
+
Above could be wrapped in pnv_dt_mpipl(fdt) and called here?
return fdt;
}
@@ -714,6 +735,7 @@ static void pnv_reset(MachineState *machine, ResetType type)
PnvMachineState *pnv = PNV_MACHINE(machine);
IPMIBmc *bmc;
void *fdt;
+ int node_offset;
qemu_devices_reset(type);
@@ -744,6 +766,33 @@ static void pnv_reset(MachineState *machine, ResetType type)
_FDT((fdt_pack(fdt)));
}
+ /*
+ * If it's a MPIPL boot, add the "mpipl-boot" property, and reset the
+ * boolean for MPIPL boot for next boot
+ */
+ if (pnv_sbe_is_mpipl_boot()) {
+ void *fdt_copy = g_malloc0(FDT_MAX_SIZE);
Where is this getting free'ed ?
+
+ /* Create a writable copy of the fdt */
+ _FDT((fdt_open_into(fdt, fdt_copy, FDT_MAX_SIZE)));
+
+ node_offset = fdt_path_offset(fdt_copy, "/ibm,opal/dump");
+ _FDT((fdt_appendprop_u64(fdt_copy, node_offset, "mpipl-boot", 1)));
+
+ /* Update the fdt, and free the original fdt */
+ if (fdt != machine->fdt) {
+ /*
+ * Only free the fdt if it's not machine->fdt, to prevent
+ * double free, since we already free machine->fdt later
+ */
+ g_free(fdt);
+ }
+ fdt = fdt_copy;
+
+ /* This boot is an MPIPL, reset the boolean for next boot */
+ pnv_sbe_reset_is_next_boot_mpipl();
+ }
+
Could above be wrapped in pnv_reset_mpipl(fdt) and called if
pnv_sbe_is_mpipl_boot is true?
qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt));
cpu_physical_memory_write(PNV_FDT_ADDR, fdt, fdt_totalsize(fdt));
diff --git a/hw/ppc/pnv_sbe.c b/hw/ppc/pnv_sbe.c
index 3b50667226b5..671dc81c9501 100644
--- a/hw/ppc/pnv_sbe.c
+++ b/hw/ppc/pnv_sbe.c
@@ -216,6 +216,18 @@ struct proc_dump_area {
__be32 act_size; /* Actual data size */
} __packed;
+static bool is_next_boot_mpipl;
+
+bool pnv_sbe_is_mpipl_boot(void)
+{
+ return is_next_boot_mpipl;
+}
+
+void pnv_sbe_reset_is_next_boot_mpipl(void)
+{
+ is_next_boot_mpipl = false;
+}
+
static void pnv_sbe_set_host_doorbell(PnvSBE *sbe, uint64_t val)
{
val &= SBE_HOST_RESPONSE_MASK; /* Is this right? What does HW do? */
@@ -334,10 +346,8 @@ static void pnv_sbe_power9_xscom_ctrl_write(void *opaque,
hwaddr addr,
/* Save processor state */
pnv_mpipl_save_proc_regs();
- /*
- * TODO: Pass `mpipl` node in device tree to signify next
- * boot is an MPIPL boot
- */
+ /* Mark next boot as Memory-preserving boot */
+ is_next_boot_mpipl = true;
/* Then do a guest reset */
/*
diff --git a/include/hw/ppc/pnv_sbe.h b/include/hw/ppc/pnv_sbe.h
index f6cbcf990ed9..94bbdc7b6414 100644
--- a/include/hw/ppc/pnv_sbe.h
+++ b/include/hw/ppc/pnv_sbe.h
@@ -56,4 +56,8 @@ struct PnvSBEClass {
/* Helper to access stashed SKIBOOT_BASE */
bool pnv_sbe_mpipl_skiboot_base(void);
+/* Helpers to know if next boot is MPIPL boot */
+bool pnv_sbe_is_mpipl_boot(void);
+void pnv_sbe_reset_is_next_boot_mpipl(void);
Usually we have a set along with reset and helpers for modifying struct
members. Above helpers for a gloabl var seems a bit un-necessary. I
guess we want to keep such global vars inside relevant struct.
Thanks
Harsh
+
#endif /* PPC_PNV_SBE_H */
