From: Eric Auger <eric.auger@redhat.com>

If there is a mismatch between the cpreg indexes found on both ends,
check whether a tolerance was registered for the given kvmidx. If any,
silence warning/errors.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20260420140552.104369-3-eric.auger@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/arm/machine.c    | 21 +++++++++++++++------
 target/arm/trace-events |  2 ++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/target/arm/machine.c b/target/arm/machine.c
index 50d80ffb68..b2bf129334 100644
--- a/target/arm/machine.c
+++ b/target/arm/machine.c
@@ -1063,25 +1063,34 @@ static void handle_cpreg_missing_in_incoming_stream(ARMCPU *cpu, uint64_t kvmidx
 {
     g_autofree gchar *name = print_register_name(kvmidx);
 
+    if (arm_cpu_match_cpreg_mig_tolerance(cpu, kvmidx,
+                                          0, 0, ToleranceNotOnBothEnds)) {
+        trace_tolerate_cpreg_missing_in_incoming_stream(name);
+        return;
+    }
     warn_report("%s: %s "
                 "expected by the destination but not in the incoming stream: "
                  "skip it", __func__, name);
 }
 
 /*
- * Handle the situation where @kvmidx is in the incoming stream
- * but not on destination. This currently fails the migration but
- * we plan to accomodate some exceptions, hence the boolean returned value.
+ * Handle the situation where @kvmidx is in the incoming
+ * stream but not on destination. This fails the migration if
+ * no cpreg mig tolerance is matched for this @kvmidx
+ * Return true if the migration should eventually fail
  */
 static bool handle_cpreg_only_in_incoming_stream(ARMCPU *cpu, uint64_t kvmidx)
 {
     g_autofree gchar *name = print_register_name(kvmidx);
-    bool fail = true;
 
+    if (arm_cpu_match_cpreg_mig_tolerance(cpu, kvmidx,
+                                          0, 0, ToleranceNotOnBothEnds)) {
+        trace_tolerate_cpreg_only_in_incoming_stream(name);
+        return false;
+    }
     error_report("%s: %s in the incoming stream but unknown on the "
                  "destination: fail migration", __func__, name);
-
-    return fail;
+    return true;
 }
 
 static int cpu_post_load(void *opaque, int version_id)
diff --git a/target/arm/trace-events b/target/arm/trace-events
index 2de0406f78..8502fb3265 100644
--- a/target/arm/trace-events
+++ b/target/arm/trace-events
@@ -29,3 +29,5 @@ arm_psci_call(uint64_t x0, uint64_t x1, uint64_t x2, uint64_t x3, uint32_t cpuid
 
 # machine.c
 cpu_post_load(uint32_t cpreg_vmstate_array_len, uint32_t cpreg_array_len) "cpreg_vmstate_array_len=%d cpreg_array_len=%d"
+tolerate_cpreg_missing_in_incoming_stream(char *name) "%s is missing in incoming stream but this is explicitly tolerated"
+tolerate_cpreg_only_in_incoming_stream(char *name) "%s is in incoming stream but not on destination but this is explicitly tolerated"
-- 
2.43.0