If we detach group during dirty page tracking, we shouldn't remove
vfio_dma, because dirty log will lose.

But we don't prevent unmap_unpin_all in vfio_iommu_release, because
under normal procedure, dirty tracking has been stopped.

Fixes: d6a4c185660c ("vfio iommu: Implementation of ioctl for dirty pages 
tracking")
Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com>
---
 drivers/vfio/vfio_iommu_type1.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 26b7eb2a5cfc..9776a059904d 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -2373,7 +2373,12 @@ static void vfio_iommu_type1_detach_group(void 
*iommu_data,
                        if (list_empty(&iommu->external_domain->group_list)) {
                                vfio_sanity_check_pfn_list(iommu);
 
-                               if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
+                               /*
+                                * During dirty page tracking, we can't remove
+                                * vfio_dma because dirty log will lose.
+                                */
+                               if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) &&
+                                   !iommu->dirty_page_tracking)
                                        vfio_iommu_unmap_unpin_all(iommu);
 
                                kfree(iommu->external_domain);
@@ -2406,10 +2411,15 @@ static void vfio_iommu_type1_detach_group(void 
*iommu_data,
                 * iommu and external domain doesn't exist, then all the
                 * mappings go away too. If it's the last domain with iommu and
                 * external domain exist, update accounting
+                *
+                * Note: During dirty page tracking, we can't remove vfio_dma
+                * because dirty log will lose. Just update accounting is a good
+                * choice.
                 */
                if (list_empty(&domain->group_list)) {
                        if (list_is_singular(&iommu->domain_list)) {
-                               if (!iommu->external_domain)
+                               if (!iommu->external_domain &&
+                                   !iommu->dirty_page_tracking)
                                        vfio_iommu_unmap_unpin_all(iommu);
                                else
                                        vfio_iommu_unmap_unpin_reaccount(iommu);
-- 
2.19.1

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