On 2/17/25 12:47, Aditya Gupta wrote:
While the first kernel boots, it registers memory regions for fadump
such as:
* CPU state data (has to be populated by the platform)
* HPTE state data (has to be populated by the platform)
* Real Mode Regions (platform should copy it to requested
destination addresses)
* OS defined regions (such as parameter save area)
Platform is also expected to modify the 'bytes_dumped' to the length of
data preserved/copied by platform (ideally same as the source length
passed by kernel).
The kernel passes source address and length for the memory regions, and
a destination address to where the memory is to be copied.
Implement the preserving/copying of the Real Mode Regions and the
Parameter Save Area in QEMU Pseries
Signed-off-by: Aditya Gupta <adit...@linux.ibm.com>
---
hw/ppc/spapr_rtas.c | 117 ++++++++++++++++++++++++++++++++++++++++-
include/hw/ppc/spapr.h | 27 +++++++++-
2 files changed, 142 insertions(+), 2 deletions(-)
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 01c82375f03d..9b29cadab2c9 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -344,6 +344,120 @@ static void rtas_ibm_set_system_parameter(PowerPCCPU *cpu,
struct fadump_metadata fadump_metadata;
bool is_next_boot_fadump;
+/* Preserve the memory locations registered for fadump */
+static bool fadump_preserve_mem(void)
+{
+ struct rtas_fadump_mem_struct *fdm = &fadump_metadata.registered_fdm;
+ uint64_t next_section_addr;
+ int dump_num_sections, data_type;
+ uint64_t src_addr, src_len, dest_addr;
+ void *copy_buffer;
+
+ assert(fadump_metadata.fadump_registered);
+ assert(fadump_metadata.fdm_addr != -1);
+
+ /* Read the fadump header passed during fadump registration */
+ cpu_physical_memory_read(fadump_metadata.fdm_addr,
+ &fdm->header, sizeof(fdm->header));
+
+ /* Verify that we understand the fadump header version */
+ if (fdm->header.dump_format_version != cpu_to_be32(FADUMP_VERSION)) {
+ /*
+ * Dump format version is unknown and likely changed from the time
+ * of fadump registration. Back out now.
+ */
+ return false;
+ }
+
+ dump_num_sections = be16_to_cpu(fdm->header.dump_num_sections);
+
+ if (dump_num_sections > FADUMP_MAX_SECTIONS) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "FADUMP: Too many sections: %d\n", fdm->header.dump_num_sections);
+ return false;
+ }
+
+ next_section_addr =
+ fadump_metadata.fdm_addr +
+ be32_to_cpu(fdm->header.offset_first_dump_section);
+
+ /*
+ * Handle all sections
+ *
+ * CPU State Data and HPTE regions are handled in their own cases
+ *
+ * RMR regions and any custom OS reserved regions such as parameter
+ * save area, are handled by simply copying the source region to
+ * destination address
+ */
+ for (int i = 0; i < dump_num_sections; ++i) {
+ /* Read the fadump section from memory */
+ cpu_physical_memory_read(next_section_addr,
+ &fdm->rgn[i], sizeof(fdm->rgn[i]));
+
+ next_section_addr += sizeof(fdm->rgn[i]);
+
+ data_type = be16_to_cpu(fdm->rgn[i].source_data_type);
+ src_addr = be64_to_cpu(fdm->rgn[i].source_address);
+ src_len = be64_to_cpu(fdm->rgn[i].source_len);
+ dest_addr = be64_to_cpu(fdm->rgn[i].destination_address);
+
+ /* Reset error_flags & bytes_dumped for now */
+ fdm->rgn[i].error_flags = 0;
+ fdm->rgn[i].bytes_dumped = 0;
+
+ if (be32_to_cpu(fdm->rgn[i].request_flag) != FADUMP_REQUEST_FLAG) {
+ qemu_log_mask(LOG_UNIMP,
+ "FADUMP: Skipping copying region as not requested\n");
+ continue;
+ }
+
+ switch (data_type) {
+ case FADUMP_CPU_STATE_DATA:
+ /* TODO: Add CPU state data */
+ break;
+ case FADUMP_HPTE_REGION:
+ /* TODO: Add hpte state data */
+ break;
+ case FADUMP_REAL_MODE_REGION:
+ case FADUMP_PARAM_AREA:
+ /* Skip copy if source and destination are same (eg. param area) */
+ if (src_addr != dest_addr) {
+ copy_buffer = g_malloc(src_len + 1);
+ if (copy_buffer == NULL) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "FADUMP: Failed allocating memory for copying reserved
memory regions\n");
+ fdm->rgn[i].error_flags =
+ cpu_to_be16(FADUMP_ERROR_LENGTH_EXCEEDS_SOURCE);
+
+ continue;
+ }
+
+ /* Copy the source region to destination */
+ cpu_physical_memory_read(src_addr, copy_buffer, src_len);
+ cpu_physical_memory_write(dest_addr, copy_buffer, src_len);
+ g_free(copy_buffer);
+ }
+
+ /*
+ * Considering cpu_physical_memory_write would have copied the
+ * complete region
+ */
+ fdm->rgn[i].bytes_dumped = cpu_to_be64(src_len);
Is this really valid for FADUMP_PARAM_AREA where we intend to skip copy?
+
+ break;
+ default:
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "FADUMP: Skipping unknown source data type: %d\n", data_type);
+
+ fdm->rgn[i].error_flags =
+ cpu_to_be16(FADUMP_ERROR_INVALID_DATA_TYPE);
+ }
+ }
+
+ return true;
+}
+
static void trigger_fadump_boot(target_ulong spapr_retcode)
{
/*
@@ -353,7 +467,8 @@ static void trigger_fadump_boot(target_ulong spapr_retcode)
*/
pause_all_vcpus();
- if (true /* TODO: Preserve memory registered for fadump */) {
+ /* Preserve the memory locations registered for fadump */
+ if (!fadump_preserve_mem()) {
This change can be avoided as suggested in previous patch.
/* Failed to preserve the registered memory regions */
rtas_st(spapr_retcode, 0, RTAS_OUT_HW_ERROR);
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index efa2f891a8a7..a80704187583 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -776,7 +776,32 @@ void push_sregs_to_kvm_pr(SpaprMachineState *spapr);
#define FADUMP_CMD_UNREGISTER 2
#define FADUMP_CMD_INVALIDATE 3
-#define FADUMP_VERSION 1
+#define FADUMP_VERSION 1
This change can be avoided if taken care initially.
Thanks
Harsh
+
+/*
+ * 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
+#define RTAS_FADUMP_MAX_BOOT_MEM_REGS 7
+
+/* Firmware provided dump sections */
+#define FADUMP_CPU_STATE_DATA 0x0001
+#define FADUMP_HPTE_REGION 0x0002
+#define FADUMP_REAL_MODE_REGION 0x0011
+
+/* OS defined sections */
+#define FADUMP_PARAM_AREA 0x0100
+
+/* Dump request flag */
+#define FADUMP_REQUEST_FLAG 0x00000001
+
+/* Dump status flag */
+#define FADUMP_ERROR_INVALID_DATA_TYPE 0x8000
+#define FADUMP_ERROR_INVALID_SOURCE_ADDR 0x4000
+#define FADUMP_ERROR_LENGTH_EXCEEDS_SOURCE 0x2000
/*
* The Firmware Assisted Dump Memory structure supports a maximum of 10
sections
