Re: [Qemu-devel] [PATCH v2] target/s390x: Fix broken user mode

[Philippe Mathieu-Daudé]

Hi Stefan, Richard.

On 03/16/2017 10:28 AM, David Hildenbrand wrote:

On 02.03.2017 20:56, David Hildenbrand wrote:

Am 30.01.2017 um 14:15 schrieb Stefan Weil:

Returning NULL from get_max_cpu_model results in a SIGSEGV runtime error.

Signed-off-by: Stefan Weil <s...@weilnetz.de>
---

v2: Re-sent as v1 was damaged by my mailer.

This is also broken in Debian.

In addition, there is no default CPU ("any"), so binfmt and related
actions currently don't work. I hacked my local installation by
duplicating the "qemu" cpu definition for "any", but maybe there is
a better solution.

That should then already work.

Regards
Stefan

 target/s390x/cpu_models.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/target/s390x/cpu_models.c b/target/s390x/cpu_models.c
index 2a894ee..6e34763 100644
--- a/target/s390x/cpu_models.c
+++ b/target/s390x/cpu_models.c
@@ -660,7 +660,6 @@ static void check_compatibility(const S390CPUModel 
*max_model,

 static S390CPUModel *get_max_cpu_model(Error **errp)
 {
-#ifndef CONFIG_USER_ONLY
     static S390CPUModel max_model;
     static bool cached;

@@ -680,7 +679,6 @@ static S390CPUModel *get_max_cpu_model(Error **errp)
         cached = true;
         return &max_model;
     }
-#endif
     return NULL;
 }

I thought this was already picked up for stable...
But looks like only the "any" model fixup got.

So

Acked-by: David Hildenbrand <da...@redhat.com>

Ping, can somebody please pick this up?

I see at least two possible changes:

the nasty one to catch bug:

@@ -681,7 +681,7 @@ static S390CPUModel *get_max_cpu_model(Error **errp)
         return &max_model;
     }
 #endif
-    return NULL;
+    abort();
 }

and the nicer one to avoid SIGSEGV:

@@ -734,8 +734,10 @@ void s390_realize_cpu_model(CPUState *cs, Error **errp)
     }

     max_model = get_max_cpu_model(errp);
-    if (*errp) {
-        error_prepend(errp, "CPU models are not available: ");
+    if (max_model == NULL) {
+        if (*errp) {
+            error_prepend(errp, "CPU models are not available: ");
+        } else {
+            error_setg(errp, "CPU models are not available");
+        }
         return;
     }