[Qemu-devel] [RESEND PATCH for-3.1] hw/arm/sysbus-fdt: Only call match_fn callback if the type matches

[Qemu-devel] [RESEND PATCH for-3.1] hw/arm/sysbus-fdt: Only call match_fn callback if the type matches

[Eric Auger]

Commit af7d64ede0b9 (hw/arm/sysbus-fdt: Allow device matching with DT
compatible value) introduced a match_fn callback which gets called
for each registered combo to check whether a sysbus device can be
dynamically instantiated. However the callback gets called even if
the device type does not match the binding combo typename field.

Let's change the add_fdt_node() logic so that we first check the
type and if the match_fn callback is defined, then we also call it.

Binding combos only requesting a type check do not define the
match_fn callback.

Fixes: af7d64ede0b9 (hw/arm/sysbus-fdt: Allow device matching with
DT compatible value)

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reported-by: Thomas Huth <thuth@redhat.com>
---
 hw/arm/sysbus-fdt.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/hw/arm/sysbus-fdt.c b/hw/arm/sysbus-fdt.c
index 0e24c803a1..a44cf7f255 100644
--- a/hw/arm/sysbus-fdt.c
+++ b/hw/arm/sysbus-fdt.c
@@ -449,7 +449,7 @@ static bool type_match(SysBusDevice *sbdev, const BindingEntry *entry)
     return !strcmp(object_get_typename(OBJECT(sbdev)), entry->typename);
 }
 
-#define TYPE_BINDING(type, add_fn) {(type), NULL, (add_fn), type_match}
+#define TYPE_BINDING(type, add_fn) {(type), NULL, (add_fn), NULL}
 
 /* list of supported dynamic sysbus bindings */
 static const BindingEntry bindings[] = {
@@ -481,10 +481,18 @@ static void add_fdt_node(SysBusDevice *sbdev, void *opaque)
     for (i = 0; i < ARRAY_SIZE(bindings); i++) {
         const BindingEntry *iter = &bindings[i];
 
-        if (iter->match_fn(sbdev, iter)) {
-            ret = iter->add_fn(sbdev, opaque);
-            assert(!ret);
-            return;
+        if (type_match(sbdev, iter)) {
+            if (iter->match_fn) {
+                if (iter->match_fn(sbdev, iter)) {
+                    ret = iter->add_fn(sbdev, opaque);
+                    assert(!ret);
+                    return;
+                }
+            } else {
+                ret = iter->add_fn(sbdev, opaque);
+                assert(!ret);
+                return;
+            }
         }
     }
     error_report("Device %s can not be dynamically instantiated",
-- 
2.17.2

Re: [Qemu-devel] [RESEND PATCH for-3.1] hw/arm/sysbus-fdt: Only call match_fn callback if the type matches

[Peter Maydell]

On 5 November 2018 at 15:35, Eric Auger <eric.auger@redhat.com> wrote:
> Commit af7d64ede0b9 (hw/arm/sysbus-fdt: Allow device matching with DT
> compatible value) introduced a match_fn callback which gets called
> for each registered combo to check whether a sysbus device can be
> dynamically instantiated. However the callback gets called even if
> the device type does not match the binding combo typename field.
>
> Let's change the add_fdt_node() logic so that we first check the
> type and if the match_fn callback is defined, then we also call it.
>
> Binding combos only requesting a type check do not define the
> match_fn callback.
>
> Fixes: af7d64ede0b9 (hw/arm/sysbus-fdt: Allow device matching with
> DT compatible value)
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> Reported-by: Thomas Huth <thuth@redhat.com>
> ---
>  hw/arm/sysbus-fdt.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/hw/arm/sysbus-fdt.c b/hw/arm/sysbus-fdt.c
> index 0e24c803a1..a44cf7f255 100644
> --- a/hw/arm/sysbus-fdt.c
> +++ b/hw/arm/sysbus-fdt.c
> @@ -449,7 +449,7 @@ static bool type_match(SysBusDevice *sbdev, const BindingEntry *entry)
>      return !strcmp(object_get_typename(OBJECT(sbdev)), entry->typename);
>  }
>
> -#define TYPE_BINDING(type, add_fn) {(type), NULL, (add_fn), type_match}
> +#define TYPE_BINDING(type, add_fn) {(type), NULL, (add_fn), NULL}
>
>  /* list of supported dynamic sysbus bindings */
>  static const BindingEntry bindings[] = {
> @@ -481,10 +481,18 @@ static void add_fdt_node(SysBusDevice *sbdev, void *opaque)
>      for (i = 0; i < ARRAY_SIZE(bindings); i++) {
>          const BindingEntry *iter = &bindings[i];
>
> -        if (iter->match_fn(sbdev, iter)) {
> -            ret = iter->add_fn(sbdev, opaque);
> -            assert(!ret);
> -            return;
> +        if (type_match(sbdev, iter)) {
> +            if (iter->match_fn) {
> +                if (iter->match_fn(sbdev, iter)) {

"if (!iter->match_fn || iter->match_fn(sbdev, iter)) {"

would let you avoid duplicating the code in the body
of this if and the else clause later.

(Or you could have a match_always() function that always
returns true instead of having to special case NULL.)

> +                    ret = iter->add_fn(sbdev, opaque);
> +                    assert(!ret);
> +                    return;
> +                }
> +            } else {
> +                ret = iter->add_fn(sbdev, opaque);
> +                assert(!ret);
> +                return;
> +            }
>          }

thanks
-- PMM