[Qemu-devel] [PATCH qom-cpu v4 13/18] memory_mapping: Cleanup qemu_get_guest_memory_mapping()

["Andreas Färber" <afaerber@suse.de>]

We relied on the CPUClass::get_memory_mapping() implementation being a
no-op when paging is disabled for that CPU. Therefore we can just as well
iterate over all CPUs to retrieve mappings.

This allows to use qemu_for_each_cpu() instead of open-coding CPU loops.

Pass any Error out into dump_init() and have it actually stop on errors.
Whether it is unsupported on a certain CPU can be checked by looking for
a NULL CPUClass::get_memory_mapping field.

Signed-off-by: Andreas Färber <afaerber@suse.de>
---
 dump.c                          |  7 +++++-
 include/sysemu/memory_mapping.h |  8 +------
 memory_mapping.c                | 52 ++++++++++++++++++++++++-----------------
 3 files changed, 38 insertions(+), 29 deletions(-)

diff --git a/dump.c b/dump.c
index c0d3da5..b44dafc 100644
--- a/dump.c
+++ b/dump.c
@@ -706,6 +706,7 @@ static int dump_init(DumpState *s, int fd, bool paging, bool has_filter,
 {
     CPUArchState *env;
     int nr_cpus;
+    Error *err = NULL;
     int ret;
 
     if (runstate_is_running()) {
@@ -756,7 +757,11 @@ static int dump_init(DumpState *s, int fd, bool paging, bool has_filter,
     /* get memory mapping */
     memory_mapping_list_init(&s->list);
     if (paging) {
-        qemu_get_guest_memory_mapping(&s->list);
+        qemu_get_guest_memory_mapping(&s->list, &err);
+        if (err != NULL) {
+            error_propagate(errp, err);
+            goto cleanup;
+        }
     } else {
         qemu_get_guest_simple_memory_mapping(&s->list);
     }
diff --git a/include/sysemu/memory_mapping.h b/include/sysemu/memory_mapping.h
index c47e6ee..6dfb68d 100644
--- a/include/sysemu/memory_mapping.h
+++ b/include/sysemu/memory_mapping.h
@@ -45,13 +45,7 @@ void memory_mapping_list_free(MemoryMappingList *list);
 
 void memory_mapping_list_init(MemoryMappingList *list);
 
-/*
- * Return value:
- *    0: success
- *   -1: failed
- *   -2: unsupported
- */
-int qemu_get_guest_memory_mapping(MemoryMappingList *list);
+void qemu_get_guest_memory_mapping(MemoryMappingList *list, Error **errp);
 
 /* get guest's memory mapping without do paging(virtual address is 0). */
 void qemu_get_guest_simple_memory_mapping(MemoryMappingList *list);
diff --git a/memory_mapping.c b/memory_mapping.c
index 9bd24ce..a19be54 100644
--- a/memory_mapping.c
+++ b/memory_mapping.c
@@ -165,36 +165,48 @@ void memory_mapping_list_init(MemoryMappingList *list)
     QTAILQ_INIT(&list->head);
 }
 
-static CPUArchState *find_paging_enabled_cpu(CPUArchState *start_cpu)
+static void find_paging_enabled_cpu(CPUState *cpu, void *data)
 {
-    CPUArchState *env;
+    bool *ret = data;
 
-    for (env = start_cpu; env != NULL; env = env->next_cpu) {
-        if (cpu_paging_enabled(ENV_GET_CPU(env))) {
-            return env;
-        }
+    if (*ret) {
+        return;
     }
+    *ret = cpu_paging_enabled(cpu);
+}
+
+typedef struct GetGuestMemoryMappingData {
+    MemoryMappingList *list;
+    Error *err;
+} GetGuestMemoryMappingData;
+
+static void qemu_get_one_guest_memory_mapping(CPUState *cpu, void *data)
+{
+    GetGuestMemoryMappingData *s = data;
 
-    return NULL;
+    if (s->err != NULL || !cpu_paging_enabled(cpu)) {
+        return;
+    }
+    cpu_get_memory_mapping(cpu, s->list, &s->err);
 }
 
-int qemu_get_guest_memory_mapping(MemoryMappingList *list)
+void qemu_get_guest_memory_mapping(MemoryMappingList *list, Error **errp)
 {
-    CPUArchState *env, *first_paging_enabled_cpu;
+    GetGuestMemoryMappingData s = {
+        .list = list,
+        .err = NULL,
+    };
+    bool paging_enabled = false;
     RAMBlock *block;
     ram_addr_t offset, length;
 
-    first_paging_enabled_cpu = find_paging_enabled_cpu(first_cpu);
-    if (first_paging_enabled_cpu) {
-        for (env = first_paging_enabled_cpu; env != NULL; env = env->next_cpu) {
-            Error *err = NULL;
-            cpu_get_memory_mapping(ENV_GET_CPU(env), list, &err);
-            if (err) {
-                error_free(err);
-                return -1;
-            }
+    qemu_for_each_cpu(find_paging_enabled_cpu, &paging_enabled);
+    if (paging_enabled) {
+        qemu_for_each_cpu(qemu_get_one_guest_memory_mapping, &s);
+        if (s.err != NULL) {
+            error_propagate(errp, s.err);
         }
-        return 0;
+        return;
     }
 
     /*
@@ -206,8 +218,6 @@ int qemu_get_guest_memory_mapping(MemoryMappingList *list)
         length = block->length;
         create_new_memory_mapping(list, offset, offset, length);
     }
-
-    return 0;
 }
 
 void qemu_get_guest_simple_memory_mapping(MemoryMappingList *list)
-- 
1.8.1.4