Re: [PATCH v2 5/8] vfio/iommufd: Add IOMMU_HWPT_GET_DIRTY_BITMAP_NO_CLEAR flag support

Mon, 20 Oct 2025 05:40:04 -0700 

On 2025/10/17 16:22, Zhenzhong Duan wrote:

Pass IOMMU_HWPT_GET_DIRTY_BITMAP_NO_CLEAR when doing the last dirty
bitmap query right before unmap, no PTEs flushes. This accelerates the
query without issue because unmap will tear down the mapping anyway.

Co-developed-by: Joao Martins <[email protected]>
Signed-off-by: Joao Martins <[email protected]>
Signed-off-by: Zhenzhong Duan <[email protected]>
Tested-by: Xudong Hao <[email protected]>
Tested-by: Giovannio Cabiddu <[email protected]>
---
  include/system/iommufd.h | 2 +-
  backends/iommufd.c       | 5 +++--
  hw/vfio/iommufd.c        | 5 +++--
  backends/trace-events    | 2 +-
  4 files changed, 8 insertions(+), 6 deletions(-)


Reviewed-by: Yi Liu <[email protected]>


diff --git a/include/system/iommufd.h b/include/system/iommufd.h
index a659f36a20..767a8e4cb6 100644
--- a/include/system/iommufd.h
+++ b/include/system/iommufd.h
@@ -64,7 +64,7 @@ bool iommufd_backend_set_dirty_tracking(IOMMUFDBackend *be, 
uint32_t hwpt_id,
  bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be, uint32_t hwpt_id,
                                        uint64_t iova, ram_addr_t size,
                                        uint64_t page_size, uint64_t *data,
-                                      Error **errp);
+                                      uint64_t flags, Error **errp);
  bool iommufd_backend_invalidate_cache(IOMMUFDBackend *be, uint32_t id,
                                        uint32_t data_type, uint32_t entry_len,
                                        uint32_t *entry_num, void *data,
diff --git a/backends/iommufd.c b/backends/iommufd.c
index fdfb7c9d67..086bd67aea 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -361,7 +361,7 @@ bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be,
                                        uint32_t hwpt_id,
                                        uint64_t iova, ram_addr_t size,
                                        uint64_t page_size, uint64_t *data,
-                                      Error **errp)
+                                      uint64_t flags, Error **errp)
  {
      int ret;
      struct iommu_hwpt_get_dirty_bitmap get_dirty_bitmap = {
@@ -371,11 +371,12 @@ bool iommufd_backend_get_dirty_bitmap(IOMMUFDBackend *be,
          .length = size,
          .page_size = page_size,
          .data = (uintptr_t)data,
+        .flags = flags,
      };
ret = ioctl(be->fd, IOMMU_HWPT_GET_DIRTY_BITMAP, &get_dirty_bitmap); 
      trace_iommufd_backend_get_dirty_bitmap(be->fd, hwpt_id, iova, size,
-                                           page_size, ret ? errno : 0);
+                                           flags, page_size, ret ? errno : 0);
      if (ret) {
          error_setg_errno(errp, errno,
                           "IOMMU_HWPT_GET_DIRTY_BITMAP (iova: 0x%"HWADDR_PRIx
diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 6457cef344..937b80340c 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -74,7 +74,8 @@ static int iommufd_cdev_unmap(const VFIOContainer *bcontainer,
      if (iotlb && vfio_container_dirty_tracking_is_started(bcontainer)) {
          if (!vfio_container_devices_dirty_tracking_is_supported(bcontainer) &&
              bcontainer->dirty_pages_supported) {
-            ret = vfio_container_query_dirty_bitmap(bcontainer, iova, size, 0,
+            ret = vfio_container_query_dirty_bitmap(bcontainer, iova, size,
+                                                    
IOMMU_HWPT_GET_DIRTY_BITMAP_NO_CLEAR,
                                                      iotlb->translated_addr,
                                                      &local_err);
              if (ret) {
@@ -224,7 +225,7 @@ static int iommufd_query_dirty_bitmap(const VFIOContainer 
*bcontainer,
          if (!iommufd_backend_get_dirty_bitmap(container->be, hwpt->hwpt_id,
                                                iova, size, page_size,
                                                (uint64_t *)vbmap->bitmap,
-                                              errp)) {
+                                              backend_flag, errp)) {
              return -EINVAL;
          }
      }
diff --git a/backends/trace-events b/backends/trace-events
index 56132d3fd2..e1992ba12f 100644
--- a/backends/trace-events
+++ b/backends/trace-events
@@ -19,5 +19,5 @@ iommufd_backend_alloc_ioas(int iommufd, uint32_t ioas) " 
iommufd=%d ioas=%d"
  iommufd_backend_alloc_hwpt(int iommufd, uint32_t dev_id, uint32_t pt_id, uint32_t flags, uint32_t 
hwpt_type, uint32_t len, uint64_t data_ptr, uint32_t out_hwpt_id, int ret) " iommufd=%d 
dev_id=%u pt_id=%u flags=0x%x hwpt_type=%u len=%u data_ptr=0x%"PRIx64" out_hwpt=%u 
(%d)"
  iommufd_backend_free_id(int iommufd, uint32_t id, int ret) " iommufd=%d id=%d 
(%d)"
  iommufd_backend_set_dirty(int iommufd, uint32_t hwpt_id, bool start, int ret) " 
iommufd=%d hwpt=%u enable=%d (%d)"
-iommufd_backend_get_dirty_bitmap(int iommufd, uint32_t hwpt_id, uint64_t iova, uint64_t size, uint64_t page_size, int 
ret) " iommufd=%d hwpt=%u iova=0x%"PRIx64" size=0x%"PRIx64" page_size=0x%"PRIx64" 
(%d)"
+iommufd_backend_get_dirty_bitmap(int iommufd, uint32_t hwpt_id, uint64_t iova, uint64_t size, uint64_t flags, uint64_t 
page_size, int ret) " iommufd=%d hwpt=%u iova=0x%"PRIx64" size=0x%"PRIx64" flags=0x%"PRIx64" 
page_size=0x%"PRIx64" (%d)"
  iommufd_backend_invalidate_cache(int iommufd, uint32_t id, uint32_t data_type, uint32_t 
entry_len, uint32_t entry_num, uint32_t done_num, uint64_t data_ptr, int ret) " iommufd=%d 
id=%u data_type=%u entry_len=%u entry_num=%u done_num=%u data_ptr=0x%"PRIx64" (%d)"

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