[Qemu-devel] [PATCH qemu v3 0/2] memory/hmp: Print owners/parents in "info mtree"

[Qemu-devel] [PATCH qemu v3 0/2] memory/hmp: Print owners/parents in "info mtree"

[Alexey Kardashevskiy]

This is a debug extension to "into mtree" to print a memory region owner/parent.

This is based on sha1
e609fa7 Peter Maydell "Merge remote-tracking branch 'remotes/edgar/tags/edgar/xilinx-next-2018-05-29-v1.for-upstream' into staging".

Please comment. Thanks.



Alexey Kardashevskiy (2):
  object: Handle objects with no parents
  memory/hmp: Print owners/parents in "info mtree"

 include/exec/memory.h |  2 +-
 memory.c              | 68 +++++++++++++++++++++++++++++++++++++++++++--------
 monitor.c             |  4 ++-
 qom/object.c          | 10 ++++++--
 hmp-commands-info.hx  |  7 +++---
 5 files changed, 74 insertions(+), 17 deletions(-)

-- 
2.11.0

[Qemu-devel] [PATCH qemu v3 1/2] object: Handle objects with no parents

[Alexey Kardashevskiy]

At the moment object_get_canonical_path() crashes if the object or one
of its parents does not have a parent, for example, a KVM accelerator
object.

This adds a check for obj!=NULL in a loop to prevent the crash.
In order not to return a wrong path, this checks for currently resolved
partial path and does not add a leading slash to tell the reader that
the path is partial as the owner object is detached.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---

I have not tested the case with obj==NULL and path!=NULL as this is
for objects which have parents which are not attached to the root
and we do not have such objects in current QEMU afaict but I kept it
just in case.

---
Changes:
v3:
* do not check for obj->parent
* return NULL or incomplete path depending on the situation
---
 qom/object.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/qom/object.c b/qom/object.c
index 0fc9720..05138ba 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1669,7 +1669,7 @@ gchar *object_get_canonical_path(Object *obj)
     Object *root = object_get_root();
     char *newpath, *path = NULL;
 
-    while (obj != root) {
+    while (obj && obj != root) {
         char *component = object_get_canonical_path_component(obj);
 
         if (path) {
@@ -1684,7 +1684,13 @@ gchar *object_get_canonical_path(Object *obj)
         obj = obj->parent;
     }
 
-    newpath = g_strdup_printf("/%s", path ? path : "");
+    if (obj && path) {
+        newpath = g_strdup_printf("/%s", path);
+    } else if (path) {
+        newpath = g_strdup(path);
+    } else {
+        newpath = NULL;
+    }
     g_free(path);
 
     return newpath;
-- 
2.11.0

[Qemu-devel] [PATCH qemu v3 2/2] memory/hmp: Print owners/parents in "info mtree"

[Alexey Kardashevskiy]

This adds owners/parents (which are the same, just occasionally
owner==NULL) printing for memory regions; a new '-o' flag
enabled new output.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v3:
* removed QOM's "id" property as there are no objects left which would
have this property and own an MR

v2:
* cleanups
---
 include/exec/memory.h |  2 +-
 memory.c              | 68 +++++++++++++++++++++++++++++++++++++++++++--------
 monitor.c             |  4 ++-
 hmp-commands-info.hx  |  7 +++---
 4 files changed, 66 insertions(+), 15 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 525619a..b98e918 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -1541,7 +1541,7 @@ void memory_global_dirty_log_start(void);
 void memory_global_dirty_log_stop(void);
 
 void mtree_info(fprintf_function mon_printf, void *f, bool flatview,
-                bool dispatch_tree);
+                bool dispatch_tree, bool owner);
 
 /**
  * memory_region_request_mmio_ptr: request a pointer to an mmio
diff --git a/memory.c b/memory.c
index fc7f9b7..d742bb2 100644
--- a/memory.c
+++ b/memory.c
@@ -2830,10 +2830,45 @@ typedef QTAILQ_HEAD(mrqueue, MemoryRegionList) MemoryRegionListHead;
                            int128_sub((size), int128_one())) : 0)
 #define MTREE_INDENT "  "
 
+static void mtree_expand_owner(fprintf_function mon_printf, void *f,
+                               const char *label, Object *obj)
+{
+    DeviceState *dev = (DeviceState *) object_dynamic_cast(obj, TYPE_DEVICE);
+
+    mon_printf(f, " %s:{%s", label, dev ? "dev" : "obj");
+    if (dev && dev->id) {
+        mon_printf(f, " id=%s", dev->id);
+    } else {
+        gchar *canonical_path = object_get_canonical_path(obj);
+        mon_printf(f, " path=%s", canonical_path);
+        g_free(canonical_path);
+    }
+    mon_printf(f, "}");
+}
+
+static void mtree_print_mr_owner(fprintf_function mon_printf, void *f,
+                                 const MemoryRegion *mr)
+{
+    Object *owner = mr->owner;
+    Object *parent = memory_region_owner((MemoryRegion *)mr);
+
+    if (!owner && !parent) {
+        mon_printf(f, " orphan");
+        return;
+    }
+    if (owner) {
+        mtree_expand_owner(mon_printf, f, "owner", owner);
+    }
+    if (parent && parent != owner) {
+        mtree_expand_owner(mon_printf, f, "parent", parent);
+    }
+}
+
 static void mtree_print_mr(fprintf_function mon_printf, void *f,
                            const MemoryRegion *mr, unsigned int level,
                            hwaddr base,
-                           MemoryRegionListHead *alias_print_queue)
+                           MemoryRegionListHead *alias_print_queue,
+                           bool owner)
 {
     MemoryRegionList *new_ml, *ml, *next_ml;
     MemoryRegionListHead submr_print_queue;
@@ -2879,7 +2914,7 @@ static void mtree_print_mr(fprintf_function mon_printf, void *f,
         }
         mon_printf(f, TARGET_FMT_plx "-" TARGET_FMT_plx
                    " (prio %d, %s): alias %s @%s " TARGET_FMT_plx
-                   "-" TARGET_FMT_plx "%s\n",
+                   "-" TARGET_FMT_plx "%s",
                    cur_start, cur_end,
                    mr->priority,
                    memory_region_type((MemoryRegion *)mr),
@@ -2888,15 +2923,22 @@ static void mtree_print_mr(fprintf_function mon_printf, void *f,
                    mr->alias_offset,
                    mr->alias_offset + MR_SIZE(mr->size),
                    mr->enabled ? "" : " [disabled]");
+        if (owner) {
+            mtree_print_mr_owner(mon_printf, f, mr);
+        }
     } else {
         mon_printf(f,
-                   TARGET_FMT_plx "-" TARGET_FMT_plx " (prio %d, %s): %s%s\n",
+                   TARGET_FMT_plx "-" TARGET_FMT_plx " (prio %d, %s): %s%s",
                    cur_start, cur_end,
                    mr->priority,
                    memory_region_type((MemoryRegion *)mr),
                    memory_region_name(mr),
                    mr->enabled ? "" : " [disabled]");
+        if (owner) {
+            mtree_print_mr_owner(mon_printf, f, mr);
+        }
     }
+    mon_printf(f, "\n");
 
     QTAILQ_INIT(&submr_print_queue);
 
@@ -2919,7 +2961,7 @@ static void mtree_print_mr(fprintf_function mon_printf, void *f,
 
     QTAILQ_FOREACH(ml, &submr_print_queue, mrqueue) {
         mtree_print_mr(mon_printf, f, ml->mr, level + 1, cur_start,
-                       alias_print_queue);
+                       alias_print_queue, owner);
     }
 
     QTAILQ_FOREACH_SAFE(ml, &submr_print_queue, mrqueue, next_ml) {
@@ -2932,6 +2974,7 @@ struct FlatViewInfo {
     void *f;
     int counter;
     bool dispatch_tree;
+    bool owner;
 };
 
 static void mtree_print_flatview(gpointer key, gpointer value,
@@ -2972,7 +3015,7 @@ static void mtree_print_flatview(gpointer key, gpointer value,
         mr = range->mr;
         if (range->offset_in_region) {
             p(f, MTREE_INDENT TARGET_FMT_plx "-"
-              TARGET_FMT_plx " (prio %d, %s): %s @" TARGET_FMT_plx "\n",
+              TARGET_FMT_plx " (prio %d, %s): %s @" TARGET_FMT_plx,
               int128_get64(range->addr.start),
               int128_get64(range->addr.start) + MR_SIZE(range->addr.size),
               mr->priority,
@@ -2981,13 +3024,17 @@ static void mtree_print_flatview(gpointer key, gpointer value,
               range->offset_in_region);
         } else {
             p(f, MTREE_INDENT TARGET_FMT_plx "-"
-              TARGET_FMT_plx " (prio %d, %s): %s\n",
+              TARGET_FMT_plx " (prio %d, %s): %s",
               int128_get64(range->addr.start),
               int128_get64(range->addr.start) + MR_SIZE(range->addr.size),
               mr->priority,
               range->readonly ? "rom" : memory_region_type(mr),
               memory_region_name(mr));
         }
+        if (fvi->owner) {
+            mtree_print_mr_owner(p, f, mr);
+        }
+        p(f, "\n");
         range++;
     }
 
@@ -3013,7 +3060,7 @@ static gboolean mtree_info_flatview_free(gpointer key, gpointer value,
 }
 
 void mtree_info(fprintf_function mon_printf, void *f, bool flatview,
-                bool dispatch_tree)
+                bool dispatch_tree, bool owner)
 {
     MemoryRegionListHead ml_head;
     MemoryRegionList *ml, *ml2;
@@ -3025,7 +3072,8 @@ void mtree_info(fprintf_function mon_printf, void *f, bool flatview,
             .mon_printf = mon_printf,
             .f = f,
             .counter = 0,
-            .dispatch_tree = dispatch_tree
+            .dispatch_tree = dispatch_tree,
+            .owner = owner,
         };
         GArray *fv_address_spaces;
         GHashTable *views = g_hash_table_new(g_direct_hash, g_direct_equal);
@@ -3057,14 +3105,14 @@ void mtree_info(fprintf_function mon_printf, void *f, bool flatview,
 
     QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
         mon_printf(f, "address-space: %s\n", as->name);
-        mtree_print_mr(mon_printf, f, as->root, 1, 0, &ml_head);
+        mtree_print_mr(mon_printf, f, as->root, 1, 0, &ml_head, owner);
         mon_printf(f, "\n");
     }
 
     /* print aliased regions */
     QTAILQ_FOREACH(ml, &ml_head, mrqueue) {
         mon_printf(f, "memory-region: %s\n", memory_region_name(ml->mr));
-        mtree_print_mr(mon_printf, f, ml->mr, 1, 0, &ml_head);
+        mtree_print_mr(mon_printf, f, ml->mr, 1, 0, &ml_head, owner);
         mon_printf(f, "\n");
     }
 
diff --git a/monitor.c b/monitor.c
index 46814af..443460e 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1966,8 +1966,10 @@ static void hmp_info_mtree(Monitor *mon, const QDict *qdict)
 {
     bool flatview = qdict_get_try_bool(qdict, "flatview", false);
     bool dispatch_tree = qdict_get_try_bool(qdict, "dispatch_tree", false);
+    bool owner = qdict_get_try_bool(qdict, "owner", false);
 
-    mtree_info((fprintf_function)monitor_printf, mon, flatview, dispatch_tree);
+    mtree_info((fprintf_function)monitor_printf, mon, flatview, dispatch_tree,
+               owner);
 }
 
 static void hmp_info_numa(Monitor *mon, const QDict *qdict)
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index ddfcd5a..5956495 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -250,10 +250,11 @@ ETEXI
 
     {
         .name       = "mtree",
-        .args_type  = "flatview:-f,dispatch_tree:-d",
-        .params     = "[-f][-d]",
+        .args_type  = "flatview:-f,dispatch_tree:-d,owner:-o",
+        .params     = "[-f][-d][-o]",
         .help       = "show memory tree (-f: dump flat view for address spaces;"
-                      "-d: dump dispatch tree, valid with -f only)",
+                      "-d: dump dispatch tree, valid with -f only);"
+                      "-o: dump region owners/parents",
         .cmd        = hmp_info_mtree,
     },
 
-- 
2.11.0

Re: [Qemu-devel] [PATCH qemu v3 1/2] object: Handle objects with no parents

[Paolo Bonzini]

On 30/05/2018 09:17, Alexey Kardashevskiy wrote:
> At the moment object_get_canonical_path() crashes if the object or one
> of its parents does not have a parent, for example, a KVM accelerator
> object.
> 
> This adds a check for obj!=NULL in a loop to prevent the crash.
> In order not to return a wrong path, this checks for currently resolved
> partial path and does not add a leading slash to tell the reader that
> the path is partial as the owner object is detached.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
> 
> I have not tested the case with obj==NULL and path!=NULL as this is
> for objects which have parents which are not attached to the root
> and we do not have such objects in current QEMU afaict but I kept it
> just in case.
> 
> ---
> Changes:
> v3:
> * do not check for obj->parent
> * return NULL or incomplete path depending on the situation
> ---
>  qom/object.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/qom/object.c b/qom/object.c
> index 0fc9720..05138ba 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -1669,7 +1669,7 @@ gchar *object_get_canonical_path(Object *obj)
>      Object *root = object_get_root();
>      char *newpath, *path = NULL;
>  
> -    while (obj != root) {
> +    while (obj && obj != root) {
>          char *component = object_get_canonical_path_component(obj);
>  
>          if (path) {
> @@ -1684,7 +1684,13 @@ gchar *object_get_canonical_path(Object *obj)
>          obj = obj->parent;
>      }
>  
> -    newpath = g_strdup_printf("/%s", path ? path : "");
> +    if (obj && path) {
> +        newpath = g_strdup_printf("/%s", path);
> +    } else if (path) {
> +        newpath = g_strdup(path);
> +    } else {
> +        newpath = NULL;
> +    }
>      g_free(path);
>  
>      return newpath;

I think this is still wrong, as you wouldn't be able to get back these
objects later (e.g. by assigning the result to a link<> property).  I've
posted an alternative patch.

Paolo