[PATCH v8 08/10] iommu/amd: Modify clear_dte_entry() to avoid in-place update

Suravee Suthikulpanit
2024-10-31T18:43:40Z

By reusing the make_clear_dte() and update_dte256().

Also, there is no need to set TV bit for non-SNP system when clearing DTE
for blocked domain, and no longer need to apply erratum 63 in clear_dte()
since it is already stored in struct ivhd_dte_flags and apply in
set_dte_entry().

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
drivers/iommu/amd/iommu.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 1262ea7150f6..f0ae0d7734b5 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2111,19 +2111,16 @@ static void set_dte_entry(struct amd_iommu *iommu,
}
}

-static void clear_dte_entry(struct amd_iommu *iommu, u16 devid)
+/*
+ * Clear DMA-remap related flags to block all DMA (blockeded domain)
+ */
+static void clear_dte_entry(struct amd_iommu *iommu, struct iommu_dev_data *dev_data)
{
- struct dev_table_entry *dev_table = get_dev_table(iommu);
-
- /* remove entry from the device table seen by the hardware */
- dev_table[devid].data[0] = DTE_FLAG_V;
-
- if (!amd_iommu_snp_en)
- dev_table[devid].data[0] |= DTE_FLAG_TV;
-
- dev_table[devid].data[1] &= DTE_FLAG_MASK;
+ struct dev_table_entry new = {};
+ struct dev_table_entry *dte = &get_dev_table(iommu)[dev_data->devid];

- amd_iommu_apply_erratum_63(iommu, devid);
+ make_clear_dte(dev_data, dte, &new);
+ update_dte256(iommu, dev_data, &new);
}

/* Update and flush DTE for the given device */
@@ -2134,7 +2131,7 @@ static void dev_update_dte(struct iommu_dev_data *dev_data, bool set)
if (set)
set_dte_entry(iommu, dev_data);
else
- clear_dte_entry(iommu, dev_data->devid);
+ clear_dte_entry(iommu, dev_data);

clone_aliases(iommu, dev_data->dev);
device_flush_dte(dev_data);
--
2.34.1