[Qemu-devel] [PATCH] memory: call begin, log_start and commit when registering a new listener

[Qemu-devel] [PATCH] memory: call begin, log_start and commit when registering a new listener

[Paolo Bonzini]

This ensures that cpu_reload_memory_map() is called as soon as
tcg_cpu_address_space_init() is called, and before cpu->memory_dispatch
is used.  qemu-system-s390x never changes the address spaces after
tcg_cpu_address_space_init() is called, and thus tcg_commit() is never
called.  This causes a SIGSEGV.

Reported-by: Philipp Kern <pkern@debian.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Fixes: 0a1c71cec63e95f9b8d0dc96d049d2daa00c5210
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 memory.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/memory.c b/memory.c
index 2eb1597..c435c88 100644
--- a/memory.c
+++ b/memory.c
@@ -2036,6 +2036,9 @@ static void listener_add_address_space(MemoryListener *listener,
         return;
     }
 
+    if (listener->begin) {
+        listener->begin(listener);
+    }
     if (global_dirty_log) {
         if (listener->log_global_start) {
             listener->log_global_start(listener);
@@ -2052,10 +2055,16 @@ static void listener_add_address_space(MemoryListener *listener,
             .offset_within_address_space = int128_get64(fr->addr.start),
             .readonly = fr->readonly,
         };
+        if (fr->dirty_log_mask && listener->log_start) {
+            listener->log_start(listener, &section, 0, fr->dirty_log_mask);
+        }
         if (listener->region_add) {
             listener->region_add(listener, &section);
         }
     }
+    if (listener->commit) {
+        listener->commit(listener);
+    }
     flatview_unref(view);
 }
 
-- 
2.5.0

Re: [Qemu-devel] [PATCH] memory: call begin, log_start and commit when registering a new listener

[Peter Maydell]

On 2 November 2015 at 08:24, Paolo Bonzini <pbonzini@redhat.com> wrote:
> This ensures that cpu_reload_memory_map() is called as soon as
> tcg_cpu_address_space_init() is called, and before cpu->memory_dispatch
> is used.  qemu-system-s390x never changes the address spaces after
> tcg_cpu_address_space_init() is called, and thus tcg_commit() is never
> called.  This causes a SIGSEGV.
>
> Reported-by: Philipp Kern <pkern@debian.org>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Fixes: 0a1c71cec63e95f9b8d0dc96d049d2daa00c5210
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

This is how I expected the memory listener API to work when I wrote
the exec.c change, anyway :-)

thanks
-- PMM