From: Aditya Gupta <[email protected]>
According to PAPR:
R1–7.3.30–3. When the platform receives an ibm,os-term RTAS call, or
on a system reset without an ibm,nmi-interlock RTAS call, if the
platform has a dump structure registered through the
ibm,configure-kernel-dump call, the platform must process each
registered kernel dump section as required and, when available,
present the dump structure information to the operating system
through the “ibm,kernel-dump” property, updated with status for each
dump section, until the dump has been invalidated through the
ibm,configure-kernel-dump RTAS call.
If Fadump has been registered, trigger an Fadump boot (memory preserving
boot), if QEMU recieves a 'ibm,os-term' rtas call.
Implementing the fadump boot as:
* pause all vcpus (will need to save registers later)
* preserve memory regions specified by fadump (will be implemented
in future)
* do a memory preserving reboot (GUEST_RESET in QEMU doesn't clear
the memory)
Memory regions registered by fadump will be handled in a later patch.
Note: Preserving memory regions is not implemented yet so on an
"ibm,os-term" call will just trigger a reboot in QEMU if fadump is
registered, and the second kernel will boot as a normal boot (not
fadump boot)
Signed-off-by: Aditya Gupta <[email protected]>
Reviewed-by: Sourabh Jain <[email protected]>
Tested-by: Shivang Upadhyay <[email protected]>
Link:
https://lore.kernel.org/qemu-devel/[email protected]
Signed-off-by: Harsh Prateek Bora <[email protected]>
---
include/hw/ppc/spapr_fadump.h | 6 +++
hw/ppc/spapr_fadump.c | 77 +++++++++++++++++++++++++++++++++++
hw/ppc/spapr_rtas.c | 5 +++
3 files changed, 88 insertions(+)
diff --git a/include/hw/ppc/spapr_fadump.h b/include/hw/ppc/spapr_fadump.h
index f64f339204..1cb90c9d63 100644
--- a/include/hw/ppc/spapr_fadump.h
+++ b/include/hw/ppc/spapr_fadump.h
@@ -16,6 +16,11 @@
#define FADUMP_VERSION 1
+/* Dump status flags */
+#define FADUMP_STATUS_DUMP_PERFORMED 0x8000
+#define FADUMP_STATUS_DUMP_TRIGGERED 0x4000
+#define FADUMP_STATUS_DUMP_ERROR 0x2000
+
/*
* The Firmware Assisted Dump Memory structure supports a maximum of 10
sections
* in the dump memory structure. Presently, three sections are used for
@@ -66,4 +71,5 @@ struct FadumpMemStruct {
};
uint32_t do_fadump_register(struct SpaprMachineState *, target_ulong);
+void trigger_fadump_boot(struct SpaprMachineState *, target_ulong);
#endif /* PPC_SPAPR_FADUMP_H */
diff --git a/hw/ppc/spapr_fadump.c b/hw/ppc/spapr_fadump.c
index 2c9f024c2d..53e5c12c76 100644
--- a/hw/ppc/spapr_fadump.c
+++ b/hw/ppc/spapr_fadump.c
@@ -7,6 +7,7 @@
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "hw/ppc/spapr.h"
+#include "system/cpus.h"
/*
* Handle the "FADUMP_CMD_REGISTER" command in 'ibm,configure-kernel-dump'
@@ -121,3 +122,79 @@ uint32_t do_fadump_register(SpaprMachineState *spapr,
target_ulong args)
return RTAS_OUT_SUCCESS;
}
+
+/* Preserve the memory locations registered for fadump */
+static bool fadump_preserve_mem(void)
+{
+ /*
+ * TODO: Implement preserving memory regions requested during fadump
+ * registration
+ */
+ return false;
+}
+
+/*
+ * Trigger a fadump boot, ie. next boot will be a crashkernel/fadump boot
+ * with fadump dump active.
+ *
+ * This is triggered by ibm,os-term RTAS call, if fadump was registered.
+ *
+ * It preserves the memory and sets 'FADUMP_STATUS_DUMP_TRIGGERED' as
+ * fadump status, which can be used later to add the "ibm,kernel-dump"
+ * device tree node as presence of 'FADUMP_STATUS_DUMP_TRIGGERED' signifies
+ * next boot as fadump boot in our case
+ */
+void trigger_fadump_boot(SpaprMachineState *spapr, target_ulong spapr_retcode)
+{
+ FadumpSectionHeader *header = &spapr->registered_fdm.header;
+
+ pause_all_vcpus();
+
+ /* Preserve the memory locations registered for fadump */
+ if (!fadump_preserve_mem()) {
+ /* Failed to preserve the registered memory regions */
+ rtas_st(spapr_retcode, 0, RTAS_OUT_HW_ERROR);
+
+ /* Cause a reboot */
+ qemu_system_guest_panicked(NULL);
+ return;
+ }
+
+ /*
+ * Mark next boot as fadump boot
+ *
+ * Note: These is some bit of assumption involved here, as PAPR doesn't
+ * specify any use of the dump status flags, nor does the kernel use it
+ *
+ * But from description in Table 136 in PAPR v2.13, it looks like:
+ * FADUMP_STATUS_DUMP_TRIGGERED
+ * = Dump was triggered by the previous system boot (PAPR says)
+ * = Next boot will be a fadump boot (Assumed)
+ *
+ * FADUMP_STATUS_DUMP_PERFORMED
+ * = Dump performed (Set to 0 by caller of the
+ * ibm,configure-kernel-dump call) (PAPR says)
+ * = Firmware has performed the copying/dump of requested regions
+ * (Assumed)
+ * = Dump is active for the next boot (Assumed)
+ */
+ header->dump_status_flag = cpu_to_be16(
+ FADUMP_STATUS_DUMP_TRIGGERED | /* Next boot will be fadump boot */
+ FADUMP_STATUS_DUMP_PERFORMED /* Dump is active */
+ );
+
+ /* Reset fadump_registered for next boot */
+ spapr->fadump_registered = false;
+ spapr->fadump_dump_active = true;
+
+ /*
+ * Then do a guest reset
+ *
+ * Requirement:
+ * GUEST_RESET is expected to NOT clear the memory, as is the case when
+ * this is merged
+ */
+ qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
+
+ rtas_st(spapr_retcode, 0, RTAS_OUT_SUCCESS);
+}
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 6042fc72e5..1f78fe406e 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -420,6 +420,11 @@ static void rtas_ibm_os_term(PowerPCCPU *cpu,
target_ulong msgaddr = rtas_ld(args, 0);
char msg[512];
+ if (spapr->fadump_registered) {
+ /* If fadump boot works, control won't come back here */
+ return trigger_fadump_boot(spapr, rets);
+ }
+
cpu_physical_memory_read(msgaddr, msg, sizeof(msg) - 1);
msg[sizeof(msg) - 1] = 0;
--
2.43.5
