regions can be bypassed, because corresponding DMA mappings are readonly
and never become dirty.
This can optimize dirty tracking a bit for passthrough device.
Signed-off-by: Zhenzhong Duan <[email protected]>
---
hw/vfio/listener.c | 46 +++++++++++++++++++++++++++++++++-----------
hw/vfio/trace-events | 1 +
2 files changed, 36 insertions(+), 11 deletions(-)
diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
index 3b48f6796c..ca2377d860 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 +502,7 @@ 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, false, "region_add")) {
return;
}
@@ -663,7 +668,7 @@ 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, false, "region_del")) {
return;
}
@@ -722,11 +727,11 @@ static void
vfio_listener_region_del(MemoryListener *listener,
}
/*
- * Fake an IOTLB entry for identity mapping which is needed by
dirty
- * tracking. In fact, in unmap_bitmap, only translated_addr field is
- * used to set dirty bitmap.
+ * Fake an IOTLB entry for writable identity mapping which is
needed
+ * by dirty tracking. In fact, in unmap_bitmap, only
translated_addr
+ * field is used to set dirty bitmap.
*/
- if (!memory_region_is_iommu(section->mr)) {
+ if (!memory_region_is_iommu(section->mr)
&& !section->readonly) {
entry.iova = iova;
entry.translated_addr = iova;
iotlb = &entry;
@@ -834,7 +839,8 @@ static void
vfio_dirty_tracking_update(MemoryListener *listener,
container_of(listener, VFIODirtyRangesListener, listener);
hwaddr iova, end;
- if (!vfio_listener_valid_section(section, "tracking_update") ||
+ /* Bypass readonly section as it never becomes dirty */
+ if (!vfio_listener_valid_section(section, true, "tracking_update") ||
!vfio_get_section_iova_range(dirty->bcontainer, section,
&iova, &end, NULL)) {
return;
@@ -1093,6 +1099,19 @@ static void
vfio_iommu_map_dirty_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
if (!mr) {
goto out_unlock;
}
+
+ /*
+ * The mapping is readonly when either it's a readonly mapping in guest
+ * or mapped target is readonly, bypass it for dirty tracking as it
+ * never becomes dirty.
+ */
+ if (!(iotlb->perm & IOMMU_WO) || mr->readonly) {
