[PULL 25/32] hw/ppc: Implement fadump register command

[Harsh Prateek Bora <harshpb@linux.ibm.com>]

From: Aditya Gupta <adityag@linux.ibm.com>

Add skeleton to handle "ibm,configure-kernel-dump" rtas call in QEMU,
including register, unregister and invalidate commands.

The register just verifies the structure of the fadump memory structure
passed by kernel, and set fadump_registered in spapr state to true.

Verify basic details mandated by the PAPR, such as number of
inputs/output, and add handling for the three fadump commands:
regiser/unregister/invalidate.

The checks are based on the table in following requirement in PAPR v2.13:
    "R1–7.3.30–1. For the Configure Platform Assisted Kernel Dump option ..."

Relevant section for the register command in PAPR is:
    Section 7.3.30: "ibm,configure-kernel-dump RTAS call" (PAPR v2.13)

Note: Any modifications made by the kernel to the fadump memory
structure after the 'ibm,configure-kernel-dump' RTAS call returns will
not be reflected in QEMU, as QEMU retains the fadump memory structure
that was provided during fadump registration.

The kernel must unregister and re-register fadump to apply any changes
to the fadump memory structure.

Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Tested-by: Shivang Upadhyay <shivangu@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20251021134823.1861675-2-adityag@linux.ibm.com
Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
---
 include/hw/ppc/spapr.h        |  11 ++-
 include/hw/ppc/spapr_fadump.h |  69 +++++++++++++++++++
 hw/ppc/spapr_fadump.c         | 123 ++++++++++++++++++++++++++++++++++
 hw/ppc/spapr_rtas.c           |  71 ++++++++++++++++++++
 hw/ppc/meson.build            |   1 +
 5 files changed, 274 insertions(+), 1 deletion(-)
 create mode 100644 include/hw/ppc/spapr_fadump.h
 create mode 100644 hw/ppc/spapr_fadump.c

diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index b9d884745f..28cf2723d8 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -13,6 +13,7 @@
 #include "hw/ppc/xics.h"        /* For ICSState */
 #include "hw/ppc/spapr_tpm_proxy.h"
 #include "hw/ppc/spapr_nested.h" /* For SpaprMachineStateNested */
+#include "hw/ppc/spapr_fadump.h" /* For FadumpMemStruct */
 
 struct SpaprVioBus;
 struct SpaprPhbState;
@@ -267,6 +268,11 @@ struct SpaprMachineState {
     Error *fwnmi_migration_blocker;
 
     SpaprWatchdog wds[WDT_MAX_WATCHDOGS];
+
+    /* Fadump State */
+    bool fadump_registered;
+    bool fadump_dump_active;
+    FadumpMemStruct registered_fdm;
 };
 
 #define H_SUCCESS         0
@@ -692,6 +698,8 @@ void push_sregs_to_kvm_pr(SpaprMachineState *spapr);
 #define RTAS_OUT_PARAM_ERROR                    -3
 #define RTAS_OUT_NOT_SUPPORTED                  -3
 #define RTAS_OUT_NO_SUCH_INDICATOR              -3
+#define RTAS_OUT_DUMP_ALREADY_REGISTERED        -9
+#define RTAS_OUT_DUMP_ACTIVE                    -10
 #define RTAS_OUT_NOT_AUTHORIZED                 -9002
 #define RTAS_OUT_SYSPARM_PARAM_ERROR            -9999
 
@@ -754,8 +762,9 @@ void push_sregs_to_kvm_pr(SpaprMachineState *spapr);
 #define RTAS_IBM_SUSPEND_ME                     (RTAS_TOKEN_BASE + 0x2A)
 #define RTAS_IBM_NMI_REGISTER                   (RTAS_TOKEN_BASE + 0x2B)
 #define RTAS_IBM_NMI_INTERLOCK                  (RTAS_TOKEN_BASE + 0x2C)
+#define RTAS_CONFIGURE_KERNEL_DUMP              (RTAS_TOKEN_BASE + 0x2D)
 
-#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2D)
+#define RTAS_TOKEN_MAX                          (RTAS_TOKEN_BASE + 0x2E)
 
 /* RTAS ibm,get-system-parameter token values */
 #define RTAS_SYSPARM_SPLPAR_CHARACTERISTICS      20
diff --git a/include/hw/ppc/spapr_fadump.h b/include/hw/ppc/spapr_fadump.h
new file mode 100644
index 0000000000..f64f339204
--- /dev/null
+++ b/include/hw/ppc/spapr_fadump.h
@@ -0,0 +1,69 @@
+/*
+ * Firmware Assisted Dump in PSeries
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef PPC_SPAPR_FADUMP_H
+#define PPC_SPAPR_FADUMP_H
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+
+/* Fadump commands */
+#define FADUMP_CMD_REGISTER            1
+#define FADUMP_CMD_UNREGISTER          2
+#define FADUMP_CMD_INVALIDATE          3
+
+#define FADUMP_VERSION                 1
+
+/*
+ * The Firmware Assisted Dump Memory structure supports a maximum of 10 sections
+ * in the dump memory structure. Presently, three sections are used for
+ * CPU state data, HPTE & Parameters area, while the remaining seven sections
+ * can be used for boot memory regions.
+ */
+#define FADUMP_MAX_SECTIONS            10
+
+typedef struct FadumpSection FadumpSection;
+typedef struct FadumpSectionHeader FadumpSectionHeader;
+typedef struct FadumpMemStruct FadumpMemStruct;
+
+struct SpaprMachineState;
+
+/* Kernel Dump section info */
+/* All fields are in big-endian */
+struct FadumpSection {
+    uint32_t    request_flag;
+    uint16_t    source_data_type;
+    uint16_t    error_flags;
+    uint64_t    source_address;
+    uint64_t    source_len;
+    uint64_t    bytes_dumped;
+    uint64_t    destination_address;
+};
+
+/* ibm,configure-kernel-dump header. */
+struct FadumpSectionHeader {
+    uint32_t    dump_format_version;
+    uint16_t    dump_num_sections;
+    uint16_t    dump_status_flag;
+    uint32_t    offset_first_dump_section;
+
+    /* Fields for disk dump option. */
+    uint32_t    dd_block_size;
+    uint64_t    dd_block_offset;
+    uint64_t    dd_num_blocks;
+    uint32_t    dd_offset_disk_path;
+
+    /* Maximum time allowed to prevent an automatic dump-reboot. */
+    uint32_t    max_time_auto;
+};
+
+/* Note: All the data in these structures is in big-endian */
+struct FadumpMemStruct {
+    FadumpSectionHeader header;
+    FadumpSection       rgn[FADUMP_MAX_SECTIONS];
+};
+
+uint32_t do_fadump_register(struct SpaprMachineState *, target_ulong);
+#endif /* PPC_SPAPR_FADUMP_H */
diff --git a/hw/ppc/spapr_fadump.c b/hw/ppc/spapr_fadump.c
new file mode 100644
index 0000000000..2c9f024c2d
--- /dev/null
+++ b/hw/ppc/spapr_fadump.c
@@ -0,0 +1,123 @@
+/*
+ * Firmware Assisted Dump in PSeries
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "hw/ppc/spapr.h"
+
+/*
+ * Handle the "FADUMP_CMD_REGISTER" command in 'ibm,configure-kernel-dump'
+ *
+ * Note: Any changes made by the kernel to the fadump memory struct won't
+ * reflect in QEMU after the 'ibm,configure-kernel-dump' RTAS call has returned,
+ * as we store the passed fadump memory structure passed during fadump
+ * registration.
+ * Kernel has to invalidate & re-register fadump, if it intends to make any
+ * changes to the fadump memory structure
+ *
+ * Returns:
+ *  * RTAS_OUT_SUCCESS: On successful registration
+ *  * RTAS_OUT_PARAM_ERROR: If parameters are not correct, eg. too many
+ *                          sections, invalid memory addresses that we are
+ *                          unable to read, etc
+ *  * RTAS_OUT_DUMP_ALREADY_REGISTERED: Dump already registered
+ *  * RTAS_OUT_HW_ERROR: Misc issue such as memory access failures
+ */
+uint32_t do_fadump_register(SpaprMachineState *spapr, target_ulong args)
+{
+    FadumpSectionHeader header;
+    FadumpSection regions[FADUMP_MAX_SECTIONS] = {0};
+    target_ulong fdm_addr = rtas_ld(args, 1);
+    target_ulong fdm_size = rtas_ld(args, 2);
+    AddressSpace *default_as = &address_space_memory;
+    MemTxResult io_result;
+    MemTxAttrs attrs;
+    uint64_t next_section_addr;
+    uint16_t dump_num_sections;
+
+    /* Mark the memory transaction as privileged memory access */
+    attrs.user = 0;
+    attrs.memory = 1;
+
+    if (spapr->fadump_registered) {
+        /* FADump already registered */
+        return RTAS_OUT_DUMP_ALREADY_REGISTERED;
+    }
+
+    if (spapr->fadump_dump_active) {
+        return RTAS_OUT_DUMP_ACTIVE;
+    }
+
+    if (fdm_size < sizeof(FadumpSectionHeader)) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "FADump: Header size is invalid: " TARGET_FMT_lu "\n", fdm_size);
+        return RTAS_OUT_PARAM_ERROR;
+    }
+
+    /* Ensure fdm_addr points to a valid RMR-memory/RMA-memory buffer */
+    if ((fdm_addr <= 0) || ((fdm_addr + fdm_size) > spapr->rma_size)) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "FADump: Invalid fdm address: " TARGET_FMT_lu "\n", fdm_addr);
+        return RTAS_OUT_PARAM_ERROR;
+    }
+
+    /* Try to read the passed fadump header */
+    io_result = address_space_read(default_as, fdm_addr, attrs,
+            &header, sizeof(header));
+    if (io_result != MEMTX_OK) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "FADump: Unable to read fdm: " TARGET_FMT_lu "\n", fdm_addr);
+
+        return RTAS_OUT_HW_ERROR;
+    }
+
+    /* Verify that we understand the fadump header version */
+    if (header.dump_format_version != cpu_to_be32(FADUMP_VERSION)) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "FADump: Unknown fadump header version: 0x%x\n",
+            header.dump_format_version);
+        return RTAS_OUT_PARAM_ERROR;
+    }
+
+    /* Reset dump status flags */
+    header.dump_status_flag = 0;
+
+    dump_num_sections = be16_to_cpu(header.dump_num_sections);
+
+    if (dump_num_sections > FADUMP_MAX_SECTIONS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "FADump: Too many sections: %d sections\n", dump_num_sections);
+        return RTAS_OUT_PARAM_ERROR;
+    }
+
+    next_section_addr =
+        fdm_addr +
+        be32_to_cpu(header.offset_first_dump_section);
+
+    for (int i = 0; i < dump_num_sections; ++i) {
+        /* Read the fadump section from memory */
+        io_result = address_space_read(default_as, next_section_addr, attrs,
+                &regions[i], sizeof(regions[i]));
+        if (io_result != MEMTX_OK) {
+            qemu_log_mask(LOG_UNIMP,
+                "FADump: Unable to read fadump %dth section\n", i);
+            return RTAS_OUT_PARAM_ERROR;
+        }
+
+        next_section_addr += sizeof(regions[i]);
+    }
+
+    spapr->fadump_registered = true;
+    spapr->fadump_dump_active = false;
+
+    /* Store the registered fadump memory struct */
+    spapr->registered_fdm.header = header;
+    for (int i = 0; i < dump_num_sections; ++i) {
+        spapr->registered_fdm.rgn[i] = regions[i];
+    }
+
+    return RTAS_OUT_SUCCESS;
+}
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 143bc8c379..6042fc72e5 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -344,6 +344,73 @@ static void rtas_ibm_set_system_parameter(PowerPCCPU *cpu,
     rtas_st(rets, 0, ret);
 }
 
+/* Papr Section 7.4.9 ibm,configure-kernel-dump RTAS call */
+static void rtas_configure_kernel_dump(PowerPCCPU *cpu,
+                                   SpaprMachineState *spapr,
+                                   uint32_t token, uint32_t nargs,
+                                   target_ulong args,
+                                   uint32_t nret, target_ulong rets)
+{
+    target_ulong cmd = rtas_ld(args, 0);
+    uint32_t ret_val;
+
+    /* Number of outputs has to be 1 */
+    if (nret != 1) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "FADump: ibm,configure-kernel-dump called with nret != 1.\n");
+        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+        return;
+    }
+
+    /* Number of inputs has to be 3 */
+    if (nargs != 3) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+            "FADump: ibm,configure-kernel-dump called with nargs != 3.\n");
+        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+        return;
+    }
+
+    switch (cmd) {
+    case FADUMP_CMD_REGISTER:
+        ret_val = do_fadump_register(spapr, args);
+        if (ret_val != RTAS_OUT_SUCCESS) {
+            rtas_st(rets, 0, ret_val);
+            return;
+        }
+        break;
+    case FADUMP_CMD_UNREGISTER:
+        if (spapr->fadump_dump_active) {
+            rtas_st(rets, 0, RTAS_OUT_DUMP_ACTIVE);
+            return;
+        }
+
+        spapr->fadump_registered = false;
+        spapr->fadump_dump_active = false;
+        memset(&spapr->registered_fdm, 0, sizeof(spapr->registered_fdm));
+        break;
+    case FADUMP_CMD_INVALIDATE:
+        if (!spapr->fadump_dump_active) {
+            qemu_log_mask(LOG_GUEST_ERROR,
+                "FADump: Nothing to invalidate, no dump active\n");
+
+            rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+        }
+
+        spapr->fadump_registered = false;
+        spapr->fadump_dump_active = false;
+        memset(&spapr->registered_fdm, 0, sizeof(spapr->registered_fdm));
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                "FADump: Unknown command: " TARGET_FMT_lu "\n", cmd);
+
+        rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
+        return;
+    }
+
+    rtas_st(rets, 0, RTAS_OUT_SUCCESS);
+}
+
 static void rtas_ibm_os_term(PowerPCCPU *cpu,
                             SpaprMachineState *spapr,
                             uint32_t token, uint32_t nargs,
@@ -659,6 +726,10 @@ static void core_rtas_register_types(void)
     spapr_rtas_register(RTAS_IBM_NMI_INTERLOCK, "ibm,nmi-interlock",
                         rtas_ibm_nmi_interlock);
 
+    /* Register fadump rtas call */
+    spapr_rtas_register(RTAS_CONFIGURE_KERNEL_DUMP, "ibm,configure-kernel-dump",
+                        rtas_configure_kernel_dump);
+
     qtest_set_command_cb(spapr_qtest_callback);
 }
 
diff --git a/hw/ppc/meson.build b/hw/ppc/meson.build
index 170b90ae7d..6b7c1f4f49 100644
--- a/hw/ppc/meson.build
+++ b/hw/ppc/meson.build
@@ -26,6 +26,7 @@ ppc_ss.add(when: 'CONFIG_PSERIES', if_true: files(
   'spapr_nvdimm.c',
   'spapr_rtas_ddw.c',
   'spapr_numa.c',
+  'spapr_fadump.c',
   'pef.c',
 ))
 ppc_ss.add(when: ['CONFIG_PSERIES', 'CONFIG_TCG'], if_true: files(
-- 
2.43.5