[PATCH v4 4/6] vfio/spapr: Always clear TCEs before unsetting the window
From: Shivaprasad G Bhat <hidden>
Date: 2024-06-24 12:39:25
Also in:
kvm, lkml
Subsystem:
ibm power vfio support, the rest, vfio driver · Maintainers:
Timothy Pearson, Linus Torvalds, Alex Williamson
The PAPR expects the TCE table to have no entries at the time of unset window(i.e. remove-pe). The TCE clear right now is done before freeing the iommu table. On pSeries, the unset window makes those entries inaccessible to the OS and the H_PUT/GET calls fail on them with H_CONSTRAINED. On PowerNV, this has no side effect as the TCE clear can be done before the DMA window removal as well. Signed-off-by: Shivaprasad G Bhat <redacted> --- drivers/vfio/vfio_iommu_spapr_tce.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index a94ec6225d31..5f9e7e477078 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c@@ -364,7 +364,6 @@ static void tce_iommu_release(void *iommu_data) if (!tbl) continue; - tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size); tce_iommu_free_table(container, tbl); }
@@ -720,6 +719,8 @@ static long tce_iommu_remove_window(struct tce_container *container, BUG_ON(!tbl->it_size); + tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size); + /* Detach groups from IOMMUs */ list_for_each_entry(tcegrp, &container->group_list, next) { table_group = iommu_group_get_iommudata(tcegrp->grp);
@@ -738,7 +739,6 @@ static long tce_iommu_remove_window(struct tce_container *container, } /* Free table */ - tce_iommu_clear(container, tbl, tbl->it_offset, tbl->it_size); tce_iommu_free_table(container, tbl); container->tables[num] = NULL;
@@ -1197,9 +1197,14 @@ static void tce_iommu_release_ownership(struct tce_container *container, return; } - for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) - if (container->tables[i]) + for (i = 0; i < IOMMU_TABLE_GROUP_MAX_TABLES; ++i) { + if (container->tables[i]) { + tce_iommu_clear(container, container->tables[i], + container->tables[i]->it_offset, + container->tables[i]->it_size); table_group->ops->unset_window(table_group, i); + } + } } static long tce_iommu_take_ownership(struct tce_container *container,