On 06/12/25 11:26 am, Aditya Gupta wrote:
Implement copying of memory region, as mentioned by MDST and MDDT
tables.
Copy the memory regions from source to destination in chunks of 32MB
Note, qemu can fail preserving a particular entry due to any reason,
such as:
* region length mis-matching in MDST & MDDT
* failed copy due to access/decode/etc memory issues
HDAT doesn't specify any field in MDRT to notify host about such errors.
Though HDAT section "15.3.1.3 Memory Dump Results Table (MDRT)" says:
The Memory Dump Results Table is a list of the memory ranges that
have been included in the dump
Based on above statement, it looks like MDRT should include only those
regions which are successfully captured in the dump, hence, regions
which qemu fails to dump, just get skipped, and will not have a
corresponding entry in MDRT
Yeah. No error status is looked for by kernel. It tries to export
/proc/vmcore with how much ever firmware succeeds in preserving..
Signed-off-by: Aditya Gupta <[email protected]>
---
hw/ppc/pnv_mpipl.c | 157 +++++++++++++++++++++++++++++++++++++
include/hw/ppc/pnv_mpipl.h | 83 ++++++++++++++++++++
2 files changed, 240 insertions(+)
diff --git a/hw/ppc/pnv_mpipl.c b/hw/ppc/pnv_mpipl.c
index d8c9b7a428b7..a4f7113a44fd 100644
--- a/hw/ppc/pnv_mpipl.c
+++ b/hw/ppc/pnv_mpipl.c
@@ -5,12 +5,169 @@
*/
#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/units.h"
+#include "system/address-spaces.h"
#include "system/runstate.h"
#include "hw/ppc/pnv.h"
#include "hw/ppc/pnv_mpipl.h"
+#include <math.h>
+
+#define MDST_TABLE_RELOCATED \
+ (pnv->mpipl_state.skiboot_base + MDST_TABLE_OFF)
+#define MDDT_TABLE_RELOCATED \
+ (pnv->mpipl_state.skiboot_base + MDDT_TABLE_OFF)
+
+/*
+ * Preserve the memory regions as pointed by MDST table
+ *
+ * During this, the memory region pointed by entries in MDST, are 'copied'
+ * as it is to the memory region pointed by corresponding entry in MDDT
+ *
+ * Notes: All reads should consider data coming from skiboot as bigendian,
+ * and data written should also be in big-endian
+ */
+static bool pnv_mpipl_preserve_mem(PnvMachineState *pnv)
+{
+ g_autofree MdstTableEntry *mdst = g_malloc(MDST_TABLE_SIZE);
+ g_autofree MddtTableEntry *mddt = g_malloc(MDDT_TABLE_SIZE);
+ g_autofree MdrtTableEntry *mdrt = g_malloc0(MDRT_TABLE_SIZE);
+ AddressSpace *default_as = &address_space_memory;
+ MemTxResult io_result;
+ MemTxAttrs attrs;
+ uint64_t src_addr, dest_addr;
+ uint32_t src_len;
+ uint64_t num_chunks;
+ int mdrt_idx = 0;
+
+ /* Mark the memory transactions as privileged memory access */
+ attrs.user = 0;
+ attrs.memory = 1;
+
+ if (pnv->mpipl_state.mdrt_table) {
+ /*
+ * MDRT table allocated from some past crash, free the memory to
+ * prevent memory leak
+ */
+ g_free(pnv->mpipl_state.mdrt_table);
+ pnv->mpipl_state.num_mdrt_entries = 0;
+ }
+
+ io_result = address_space_read(default_as, MDST_TABLE_RELOCATED, attrs,
+ mdst, MDST_TABLE_SIZE);
+ if (io_result != MEMTX_OK) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "MPIPL: Failed to read MDST table at: 0x%lx\n",
+ MDST_TABLE_RELOCATED);
+
+ return false;
+ }
+
+ io_result = address_space_read(default_as, MDDT_TABLE_RELOCATED, attrs,
+ mddt, MDDT_TABLE_SIZE);
+ if (io_result != MEMTX_OK) {
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "MPIPL: Failed to read MDDT table at: 0x%lx\n",
+ MDDT_TABLE_RELOCATED);
+
+ return false;
+ }
+
+ /* Try to read all entries */
+ for (int i = 0; i < MDST_MAX_ENTRIES; ++i) {
+ g_autofree uint8_t *copy_buffer = NULL;
+ bool is_copy_failed = false;
+
+ /* Considering entry with address and size as 0, as end of table */
+ if ((mdst[i].addr == 0) && (mdst[i].size == 0)) {
+ break;
+ }
+
+ if (mdst[i].size != mddt[i].size) {
+ qemu_log_mask(LOG_TRACE,
+ "Warning: Invalid entry, size mismatch in MDST & MDDT\n");
+ continue;
+ }
+
+ if (mdst[i].data_region != mddt[i].data_region) {
+ qemu_log_mask(LOG_TRACE,
+ "Warning: Invalid entry, region mismatch in MDST &
MDDT\n");
+ continue;
+ }
+
+ src_addr = be64_to_cpu(mdst[i].addr) & ~HRMOR_BIT;
+ dest_addr = be64_to_cpu(mddt[i].addr) & ~HRMOR_BIT;
+ src_len = be32_to_cpu(mddt[i].size);
data_len sounds more appropriate instead of src_len here, especially
as we are using mddt length..
- Hari
