From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
As sections are reported by the listener to the _nop and _add
methods, add them to the temporary section list but now merge them
with the previous section if the new one abuts and the backend allows.
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
hw/virtio/trace-events | 2 ++
hw/virtio/vhost.c | 70 +++++++++++++++++++++++++++++++++++++++++++-------
2 files changed, 63 insertions(+), 9 deletions(-)
diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events
index 4a493bcd46..0e63c8739d 100644
--- a/hw/virtio/trace-events
+++ b/hw/virtio/trace-events
@@ -1,6 +1,8 @@
# See docs/devel/tracing.txt for syntax documentation.
# hw/virtio/vhost.c
+vhost_region_add_section(const char *name, uint64_t gpa, uint64_t size,
uint64_t host) "%s: 0x%"PRIx64"+0x%"PRIx64" @ 0x%"PRIx64
+vhost_region_add_section_abut(const char *name, uint64_t new_size) "%s:
0x%"PRIx64
vhost_section(const char *name, int r) "%s:%d"
# hw/virtio/virtio.c
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 18611f0d40..57d15acd2b 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -709,14 +709,65 @@ out:
return;
}
-static void vhost_add_section(struct vhost_dev *dev,
- MemoryRegionSection *section)
+/* Adds the section data to the tmp_section structure.
+ * It relies on the listener calling us in memory address order
+ * and for each region (via the _add and _nop methods) to
+ * join neighbours.
+ */
+static void vhost_region_add_section(struct vhost_dev *dev,
+ MemoryRegionSection *section)
{
- ++dev->n_tmp_sections;
- dev->tmp_sections = g_renew(MemoryRegionSection, dev->tmp_sections,
- dev->n_tmp_sections);
- dev->tmp_sections[dev->n_tmp_sections - 1] = *section;
- memory_region_ref(section->mr);
+ bool need_add = true;
+ uint64_t mrs_size = int128_get64(section->size);
+ uint64_t mrs_gpa = section->offset_within_address_space;
+ uintptr_t mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
+ section->offset_within_region;
+
+ trace_vhost_region_add_section(section->mr->name, mrs_gpa, mrs_size,
+ mrs_host);
+
+ if (dev->n_tmp_sections) {
+ /* Since we already have at least one section, lets see if
+ * this extends it; since we're scanning in order, we only
+ * have to look at the last one, and the FlatView that calls
+ * us shouldn't have overlaps.
+ */
+ MemoryRegionSection *prev_sec = dev->tmp_sections +
+ (dev->n_tmp_sections - 1);
+ uint64_t prev_gpa_start = prev_sec->offset_within_address_space;
+ uint64_t prev_size = int128_get64(prev_sec->size);
+ uint64_t prev_gpa_end = range_get_last(prev_gpa_start, prev_size);
+ uint64_t prev_host_start =
+ (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr) +
+ prev_sec->offset_within_region;
+ uint64_t prev_host_end = range_get_last(prev_host_start, prev_size);
+
+ if (prev_gpa_end + 1 == mrs_gpa &&
+ prev_host_end + 1 == mrs_host &&
+ section->mr == prev_sec->mr &&
+ (!dev->vhost_ops->vhost_backend_can_merge ||
+ dev->vhost_ops->vhost_backend_can_merge(dev,
+ mrs_host, mrs_size,
+ prev_host_start, prev_size))) {
+ /* The two sections abut */
+ need_add = false;
+ prev_sec->size = int128_add(prev_sec->size, section->size);
+ trace_vhost_region_add_section_abut(section->mr->name,
+ mrs_size + prev_size);
+ }
+ }
+
+ if (need_add) {
+ ++dev->n_tmp_sections;
+ dev->tmp_sections = g_renew(MemoryRegionSection, dev->tmp_sections,
+ dev->n_tmp_sections);
+ dev->tmp_sections[dev->n_tmp_sections - 1] = *section;
+ /* The flatview isn't stable and we don't use it, making it NULL
+ * means we can memcmp the list.
+ */
+ dev->tmp_sections[dev->n_tmp_sections - 1].fv = NULL;
+ memory_region_ref(section->mr);
+ }
}
static void vhost_region_add(MemoryListener *listener,
@@ -728,11 +779,12 @@ static void vhost_region_add(MemoryListener *listener,
if (!vhost_section(section)) {
return;
}
+ vhost_region_add_section(dev, section);
- vhost_add_section(dev, section);
vhost_set_memory(listener, section, true);
}
+/* Called on regions that have not changed */
static void vhost_region_nop(MemoryListener *listener,
MemoryRegionSection *section)
{
@@ -743,7 +795,7 @@ static void vhost_region_nop(MemoryListener *listener,
return;
}
- vhost_add_section(dev, section);
+ vhost_region_add_section(dev, section);
}
static void vhost_region_del(MemoryListener *listener,
--
2.14.3
