On 10/24/25 10:43 AM, Zhenzhong Duan wrote:
> When doing ditry tracking or calculating dirty tracking range, readonly
dirty tracking or when ...
> 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 | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/hw/vfio/listener.c b/hw/vfio/listener.c
> index 0862b2b834..cbd86c79af 100644
> --- a/hw/vfio/listener.c
> +++ b/hw/vfio/listener.c
> @@ -828,7 +828,8 @@ static void vfio_dirty_tracking_update(MemoryListener
> *listener,
> container_of(listener, VFIODirtyRangesListener, listener);
> hwaddr iova, end;
>
> - if (!vfio_listener_valid_section(section, false, "tracking_update") ||
> + /* Bypass readonly section as it never become dirty */
> + if (!vfio_listener_valid_section(section, true, "tracking_update") ||
> !vfio_get_section_iova_range(dirty->bcontainer, section,
> &iova, &end, NULL)) {
> return;
> @@ -1087,6 +1088,12 @@ static void vfio_iommu_map_dirty_notify(IOMMUNotifier
> *n, IOMMUTLBEntry *iotlb)
> if (!mr) {
> goto out_unlock;
> }
> +
> + if (!(iotlb->perm & IOMMU_WO) || mr->readonly) {
> + rcu_read_unlock();
> + return;
This change is less obvsious compared to the others. Might be worth
explaining why you add it.
> + }
> +
> translated_addr = memory_region_get_ram_addr(mr) + xlat;
>
> ret = vfio_container_query_dirty_bitmap(bcontainer, iova,
> iotlb->addr_mask + 1,
> @@ -1222,7 +1229,7 @@ static void vfio_listener_log_sync(MemoryListener
> *listener,
> int ret;
> Error *local_err = NULL;
>
> - if (vfio_listener_skipped_section(section, false)) {
> + if (vfio_listener_skipped_section(section, true)) {
the false -> true change might be squashed into the 18/23 patch while
explainig why you set this value.
Eric
> return;
> }
>
