When bypass_ro is true, readonly memory section is bypassed from mapping
in the container.

This is a preparing patch to workaround Intel ERRATA_772415, see changelog
in next patch for details about the errata.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
---
 include/hw/vfio/vfio-container.h |  1 +
 hw/vfio/listener.c               | 21 ++++++++++++++-------
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/include/hw/vfio/vfio-container.h b/include/hw/vfio/vfio-container.h
index 9f6e8cedfc..a7d5c5ed67 100644
--- a/include/hw/vfio/vfio-container.h
+++ b/include/hw/vfio/vfio-container.h
@@ -52,6 +52,7 @@ struct VFIOContainer {
     QLIST_HEAD(, VFIODevice) device_list;
     GList *iova_ranges;
     NotifierWithReturn cpr_reboot_notifier;
+    bool bypass_ro;
 };
 
 #define TYPE_VFIO_IOMMU "vfio-iommu"
diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index 2109101158..0862b2b834 100644
--- a/hw/vfio/listener.c
+++ b/hw/vfio/listener.c
@@ -76,8 +76,13 @@ static bool vfio_log_sync_needed(const VFIOContainer *bcontainer)
     return true;
 }
 
-static bool vfio_listener_skipped_section(MemoryRegionSection *section)
+static bool vfio_listener_skipped_section(MemoryRegionSection *section,
+                                          bool bypass_ro)
 {
+    if (bypass_ro && section->readonly) {
+        return true;
+    }
+
     return (!memory_region_is_ram(section->mr) &&
             !memory_region_is_iommu(section->mr)) ||
            memory_region_is_protected(section->mr) ||
@@ -368,9 +373,9 @@ static bool vfio_known_safe_misalignment(MemoryRegionSection *section)
 }
 
 static bool vfio_listener_valid_section(MemoryRegionSection *section,
-                                        const char *name)
+                                        bool bypass_ro, const char *name)
 {
-    if (vfio_listener_skipped_section(section)) {
+    if (vfio_listener_skipped_section(section, bypass_ro)) {
         trace_vfio_listener_region_skip(name,
                 section->offset_within_address_space,
                 section->offset_within_address_space +
@@ -497,7 +502,8 @@ void vfio_container_region_add(VFIOContainer *bcontainer,
     int ret;
     Error *err = NULL;
 
-    if (!vfio_listener_valid_section(section, "region_add")) {
+    if (!vfio_listener_valid_section(section, bcontainer->bypass_ro,
+                                     "region_add")) {
         return;
     }
 
@@ -663,7 +669,8 @@ static void vfio_listener_region_del(MemoryListener *listener,
     int ret;
     bool try_unmap = true;
 
-    if (!vfio_listener_valid_section(section, "region_del")) {
+    if (!vfio_listener_valid_section(section, bcontainer->bypass_ro,
+                                     "region_del")) {
         return;
     }
 
@@ -821,7 +828,7 @@ static void vfio_dirty_tracking_update(MemoryListener *listener,
         container_of(listener, VFIODirtyRangesListener, listener);
     hwaddr iova, end;
 
-    if (!vfio_listener_valid_section(section, "tracking_update") ||
+    if (!vfio_listener_valid_section(section, false, "tracking_update") ||
         !vfio_get_section_iova_range(dirty->bcontainer, section,
                                      &iova, &end, NULL)) {
         return;
@@ -1215,7 +1222,7 @@ static void vfio_listener_log_sync(MemoryListener *listener,
     int ret;
     Error *local_err = NULL;
 
-    if (vfio_listener_skipped_section(section)) {
+    if (vfio_listener_skipped_section(section, false)) {
         return;
     }
 
-- 
2.47.1