[PATCH v2 2/3] memory: Allow a MemoryRegion to be marked no_vhost

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

Allow a memory region to be marked as 'no_vhost' and
exclude that region from vhost's list build.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 hw/virtio/vhost.c     |  3 ++-
 include/exec/memory.h | 21 +++++++++++++++++++++
 memory.c              | 15 +++++++++++++++
 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 774d87d98e..462498bfe6 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -402,7 +402,8 @@ static bool vhost_section(struct vhost_dev *dev, MemoryRegionSection *section)
     bool log_dirty = memory_region_get_dirty_log_mask(section->mr) &
                      ~(1 << DIRTY_MEMORY_MIGRATION);
     result = memory_region_is_ram(section->mr) &&
-        !memory_region_is_rom(section->mr);
+             !memory_region_is_rom(section->mr) &&
+             !memory_region_get_no_vhost(section->mr);
 
     /* Vhost doesn't handle any block which is doing dirty-tracking other
      * than migration; this typically fires on VGA areas.
diff --git a/include/exec/memory.h b/include/exec/memory.h
index aef8123d48..f475c06d63 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -394,6 +394,7 @@ struct MemoryRegion {
     bool ram_device;
     bool enabled;
     bool warning_printed; /* For reservations */
+    bool no_vhost;
     uint8_t vga_logging_count;
     MemoryRegion *alias;
     hwaddr alias_offset;
@@ -1625,6 +1626,26 @@ void memory_region_set_readonly(MemoryRegion *mr, bool readonly);
  */
 void memory_region_set_nonvolatile(MemoryRegion *mr, bool nonvolatile);
 
+/**
+ * memory_region_set_no_vhost: Make vhost ignore a memory region
+ *
+ * Makes vhost ignore a memory region, useful if it isn't real
+ * DMAble memory and is at inconvenient addresses
+ *
+ * @mr: the region being updated.
+ * @no_vhost: true to ignore
+ */
+void memory_region_set_no_vhost(MemoryRegion *mr, bool no_vhost);
+
+/**
+ * memory_region_set_no_vhost: Test if memory region is marked no vhost
+ *
+ * Test if the no_vhost flag is set on the memory region
+ *
+ * @mr: the region being tested.
+ */
+bool memory_region_get_no_vhost(const MemoryRegion *mr);
+
 /**
  * memory_region_rom_device_set_romd: enable/disable ROMD mode
  *
diff --git a/memory.c b/memory.c
index d7b9bb6951..9371998e30 100644
--- a/memory.c
+++ b/memory.c
@@ -2136,6 +2136,21 @@ void memory_region_set_nonvolatile(MemoryRegion *mr, bool nonvolatile)
     }
 }
 
+void memory_region_set_no_vhost(MemoryRegion *mr, bool no_vhost)
+{
+    if (mr->no_vhost != no_vhost) {
+        memory_region_transaction_begin();
+        mr->no_vhost = no_vhost;
+        memory_region_update_pending |= mr->enabled;
+        memory_region_transaction_commit();
+    }
+}
+
+bool memory_region_get_no_vhost(const MemoryRegion *mr)
+{
+    return mr->no_vhost;
+}
+
 void memory_region_rom_device_set_romd(MemoryRegion *mr, bool romd_mode)
 {
     if (mr->romd_mode != romd_mode) {
-- 
2.24.1