@@ -459,6 +459,8 @@ static int __init rtas_fadump_process(struct fw_dump *fadump_conf)
/* Check if the dump data is valid. */
for (int i = 0; i < be16_to_cpu(fdm_active->header.dump_num_sections); i++) {
int type = be16_to_cpu(fdm_active->rgn[i].source_data_type);
+ uint64_t bytes_dumped = be64_to_cpu(fdm_active->rgn[i].bytes_dumped);
+ uint64_t source_len = be64_to_cpu(fdm_active->rgn[i].source_len);
int rc = 0;
switch (type) {
@@ -469,10 +471,20 @@ static int __init rtas_fadump_process(struct fw_dump *fadump_conf)
pr_err("Dump taken by platform is not valid (%d)\n", i);
rc = -EINVAL;
}
- if (fdm_active->rgn[i].bytes_dumped != fdm_active->rgn[i].source_len) {
+
+ /*
+ * Make sure that dump is collected for entire region.
+ * CPU_STATE_DATA region is allowed to dump less than allocated space.
+ */
+ if (!(bytes_dumped == source_len ||
+ (type == RTAS_FADUMP_CPU_STATE_DATA && bytes_dumped <= source_len))) {
+
pr_err("Dump taken by platform is incomplete (%d)\n", i);
+ pr_debug("type -> %d, bytes_dumped -> %llx, source_len -> %llx\n",
+ type, bytes_dumped, source_len);
rc = -EINVAL;
}
+
if (rc) {
pr_warn("Region type: %u src addr: 0x%llx dest addr: 0x%llx\n",
be16_to_cpu(fdm_active->rgn[i].source_data_type),
@@ -482,7 +494,7 @@ static int __init rtas_fadump_process(struct fw_dump *fadump_conf)
}
break;
case RTAS_FADUMP_PARAM_AREA:
- if (fdm_active->rgn[i].bytes_dumped != fdm_active->rgn[i].source_len ||
+ if (bytes_dumped != source_len ||
fdm_active->rgn[i].error_flags != 0) {
pr_warn("Failed to process additional parameters! Proceeding anyway..\n");
fadump_conf->param_area = 0;
During Fadump in Qemu VM, when maxcpus value is set to more than current cpus, following failure is observed. [ 0.045806] [ T1] rtas fadump: Dump taken by platform is incomplete (0) This is because the CPU_STATE_DATA is allocated for maxcpus, while the data is only filled for current cpus. As per current implementation of Fadump, dumped_bytes and source_len for a region have to match, Which is failing for qemu's case, Even tough the dumped bytes are reported correctly for only the current cpus. After this /proc/vmcore generatition also fails. Allowing dumped_bytes to be lesser than or equal to allocated length, for CPU_STATE_DATA Fadump region. Reported-by: Anushree Mathur <anushree.mathur@linux.vnet.ibm.com> Closes: https://lore.kernel.org/all/5e66daf4-3f55-4044-94a5-4f50bb040849@linux.ibm.com/T/#u Signed-off-by: Shivang Upadhyay <shivangu@linux.ibm.com> --- Changelog: v4: removed extra blank line. v3: https://lore.kernel.org/all/20260827075803.2240934-1-shivangu@linux.ibm.com/ removed extra variable. v2: https://lore.kernel.org/all/20260826125626.2108771-1-shivangu@linux.ibm.com/ Only allowing lesser size for CPU_STATE_DATE Fadump region. v1: https://lore.kernel.org/qemu-devel/20260429065127.366813-1-shivangu@linux.ibm.com/ --- arch/powerpc/platforms/pseries/rtas-fadump.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)