memory: Export a helper to get intersection of a MemoryRegionSection with a given range

Rename the helper to memory_region_section_intersect_range() to make it
more generic. Meanwhile, define the @end as Int128 and replace the
related operations with Int128_* format since the helper is exported as
a wider API.

Suggested-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Alexey Kardashevskiy <aik@amd.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@amd.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Link: https://lore.kernel.org/r/20250612082747.51539-2-chenyi.qiang@intel.com
Signed-off-by: Peter Xu <peterx@redhat.com>

1 files changed, 5 insertions, 27 deletions

diff --git a/hw/virtio/virtio-mem.c b/hw/virtio/virtio-mem.c
index a3d1a67..b3c126e 100644
--- a/hw/virtio/virtio-mem.c
+++ b/hw/virtio/virtio-mem.c
@@ -244,28 +244,6 @@ static int virtio_mem_for_each_plugged_range(VirtIOMEM *vmem, void *arg,
     return ret;
 }
 
-/*
- * Adjust the memory section to cover the intersection with the given range.
- *
- * Returns false if the intersection is empty, otherwise returns true.
- */
-static bool virtio_mem_intersect_memory_section(MemoryRegionSection *s,
-                                                uint64_t offset, uint64_t size)
-{
-    uint64_t start = MAX(s->offset_within_region, offset);
-    uint64_t end = MIN(s->offset_within_region + int128_get64(s->size),
-                       offset + size);
-
-    if (end <= start) {
-        return false;
-    }
-
-    s->offset_within_address_space += start - s->offset_within_region;
-    s->offset_within_region = start;
-    s->size = int128_make64(end - start);
-    return true;
-}
-
 typedef int (*virtio_mem_section_cb)(MemoryRegionSection *s, void *arg);
 
 static int virtio_mem_for_each_plugged_section(const VirtIOMEM *vmem,
@@ -287,7 +265,7 @@ static int virtio_mem_for_each_plugged_section(const VirtIOMEM *vmem,
                                       first_bit + 1) - 1;
         size = (last_bit - first_bit + 1) * vmem->block_size;
 
-        if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
+        if (!memory_region_section_intersect_range(&tmp, offset, size)) {
             break;
         }
         ret = cb(&tmp, arg);
@@ -319,7 +297,7 @@ static int virtio_mem_for_each_unplugged_section(const VirtIOMEM *vmem,
                                  first_bit + 1) - 1;
         size = (last_bit - first_bit + 1) * vmem->block_size;
 
-        if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
+        if (!memory_region_section_intersect_range(&tmp, offset, size)) {
             break;
         }
         ret = cb(&tmp, arg);
@@ -355,7 +333,7 @@ static void virtio_mem_notify_unplug(VirtIOMEM *vmem, uint64_t offset,
     QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
         MemoryRegionSection tmp = *rdl->section;
 
-        if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
+        if (!memory_region_section_intersect_range(&tmp, offset, size)) {
             continue;
         }
         rdl->notify_discard(rdl, &tmp);
@@ -371,7 +349,7 @@ static int virtio_mem_notify_plug(VirtIOMEM *vmem, uint64_t offset,
     QLIST_FOREACH(rdl, &vmem->rdl_list, next) {
         MemoryRegionSection tmp = *rdl->section;
 
-        if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
+        if (!memory_region_section_intersect_range(&tmp, offset, size)) {
             continue;
         }
         ret = rdl->notify_populate(rdl, &tmp);
@@ -388,7 +366,7 @@ static int virtio_mem_notify_plug(VirtIOMEM *vmem, uint64_t offset,
             if (rdl2 == rdl) {
                 break;
             }
-            if (!virtio_mem_intersect_memory_section(&tmp, offset, size)) {
+            if (!memory_region_section_intersect_range(&tmp, offset, size)) {
                 continue;
             }
             rdl2->notify_discard(rdl2, &tmp);