[PATCH v2 2/2] vfio/common: Add trace point when a MMIO RAM section less than PAGE_SIZE

[Kunkun Jiang]

The MSI-X structures of some devices and other non-MSI-X structures
are in the same BAR. They may share one host page, especially in the
case of large page granularity, such as 64K.

For example, MSIX-Table size of 82599 NIC is 0x30 and the offset in
Bar 3(size 64KB) is 0x0. If host page size is 64KB.
vfio_listener_region_add() will be called to map the remaining range
(0x30-0xffff). And it will return early at
'int128_ge((int128_make64(iova), llend))' and hasn't any message.
Let's add a trace point to informed users like commit 5c08600547c0
("vfio: Use a trace point when a RAM section cannot be DMA mapped")
did.

Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
---
 hw/vfio/common.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 8728d4d5c2..2fc6213c0f 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -892,6 +892,13 @@ static void vfio_listener_region_add(MemoryListener 
*listener,
     llend = int128_and(llend, int128_exts64(qemu_real_host_page_mask));
 
     if (int128_ge(int128_make64(iova), llend)) {
+        if (memory_region_is_ram_device(section->mr)) {
+            trace_vfio_listener_region_add_no_dma_map(
+                memory_region_name(section->mr),
+                section->offset_within_address_space,
+                int128_getlo(section->size),
+                qemu_real_host_page_size);
+        }
         return;
     }
     end = int128_get64(int128_sub(llend, int128_one()));
-- 
2.23.0