[PATCH-for-5.2] memory: Add trace events to audit MemoryRegionOps fields

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Add trace events to audit MemoryRegionOps field such:
 - are all the valid/impl fields provided?
 - is the region a power of two?

These cases are accepted, but it is interesting to list them.

Example:

  $ qemu-system-i386 -S -trace memory_region_io_check\*
  memory_region_io_check_odd_size mr name:'dma-page' size:0x3
  memory_region_io_check_access_size_incomplete mr name:'acpi-tmr' min/max:[valid:1/4 impl:4/0]
  memory_region_io_check_access_size_incomplete mr name:'acpi-evt' min/max:[valid:1/2 impl:2/0]
  memory_region_io_check_access_size_incomplete mr name:'acpi-cnt' min/max:[valid:1/2 impl:2/0]

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
Based-on: <20200805130221.24487-1-philmd@redhat.com>
          "softmmu: Add missing trace-events file"
---
 softmmu/memory.c     | 11 +++++++++++
 softmmu/trace-events |  2 ++
 2 files changed, 13 insertions(+)

diff --git a/softmmu/memory.c b/softmmu/memory.c
index d030eb6f7c..daa0daf2a8 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -1488,6 +1488,17 @@ void memory_region_init_io(MemoryRegion *mr,
     mr->ops = ops ? ops : &unassigned_mem_ops;
     mr->opaque = opaque;
     mr->terminates = true;
+    if (size != UINT64_MAX && !is_power_of_2(size)) {
+        trace_memory_region_io_check_odd_size(name, size);
+    }
+    if (ops && (!ops->impl.min_access_size || !ops->impl.max_access_size ||
+                !ops->valid.min_access_size || !ops->valid.max_access_size)) {
+        trace_memory_region_io_check_access_size_incomplete(name,
+                mr->ops->valid.min_access_size,
+                mr->ops->valid.max_access_size,
+                mr->ops->impl.min_access_size,
+                mr->ops->impl.max_access_size);
+    }
 }
 
 void memory_region_init_ram_nomigrate(MemoryRegion *mr,
diff --git a/softmmu/trace-events b/softmmu/trace-events
index b80ca042e1..00eb316aef 100644
--- a/softmmu/trace-events
+++ b/softmmu/trace-events
@@ -18,6 +18,8 @@ memory_region_ram_device_write(int cpu_index, void *mr, uint64_t addr, uint64_t
 flatview_new(void *view, void *root) "%p (root %p)"
 flatview_destroy(void *view, void *root) "%p (root %p)"
 flatview_destroy_rcu(void *view, void *root) "%p (root %p)"
+memory_region_io_check_odd_size(const char *name, uint64_t size) "mr name:'%s' size:0x%"PRIx64
+memory_region_io_check_access_size_incomplete(const char *name, unsigned vmin, unsigned vmax, unsigned imin, unsigned imax) "mr name:'%s' min/max:[valid:%u/%u impl:%u/%u]"
 
 # vl.c
 vm_state_notify(int running, int reason, const char *reason_str) "running %d reason %d (%s)"
-- 
2.21.3