[PATCH 3/7] iommu/vt-d: Add blocking domain support

Lu Baolu
2022-11-22T00:37:17Z

The Intel IOMMU hardwares support blocking DMA transactions by clearing
the translation table entries. This implements a real blocking domain to
avoid using an empty UNMANAGED domain. The detach_dev callback of the
domain ops is not used in any path. Remove it to avoid dead code as well.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20221118132451.114406-4-baolu.lu@linux.intel.com
---
drivers/iommu/intel/iommu.c | 26 ++++++++++++++++++--------
1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 1c1a52d1a818..603332740bc3 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -278,6 +278,7 @@ static LIST_HEAD(dmar_satc_units);
list_for_each_entry(rmrr, &dmar_rmrr_units, list)

static void device_block_translation(struct device *dev);
+static void intel_iommu_domain_free(struct iommu_domain *domain);

int dmar_disabled = !IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_ON);
int intel_iommu_sm = IS_ENABLED(CONFIG_INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON);
@@ -4162,12 +4163,28 @@ static int md_domain_init(struct dmar_domain *domain, int guest_width)
return 0;
}

+static int blocking_domain_attach_dev(struct iommu_domain *domain,
+ struct device *dev)
+{
+ device_block_translation(dev);
+ return 0;
+}
+
+static struct iommu_domain blocking_domain = {
+ .ops = &(const struct iommu_domain_ops) {
+ .attach_dev = blocking_domain_attach_dev,
+ .free = intel_iommu_domain_free
+ }
+};
+
static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)
{
struct dmar_domain *dmar_domain;
struct iommu_domain *domain;

switch (type) {
+ case IOMMU_DOMAIN_BLOCKED:
+ return &blocking_domain;
case IOMMU_DOMAIN_DMA:
case IOMMU_DOMAIN_DMA_FQ:
case IOMMU_DOMAIN_UNMANAGED:
@@ -4202,7 +4219,7 @@ static struct iommu_domain *intel_iommu_domain_alloc(unsigned type)

static void intel_iommu_domain_free(struct iommu_domain *domain)
{
- if (domain != &si_domain->domain)
+ if (domain != &si_domain->domain && domain != &blocking_domain)
domain_exit(to_dmar_domain(domain));
}

@@ -4272,12 +4289,6 @@ static int intel_iommu_attach_device(struct iommu_domain *domain,
return domain_add_dev_info(to_dmar_domain(domain), dev);
}

-static void intel_iommu_detach_device(struct iommu_domain *domain,
- struct device *dev)
-{
- dmar_remove_one_dev_info(dev);
-}
-
static int intel_iommu_map(struct iommu_domain *domain,
unsigned long iova, phys_addr_t hpa,
size_t size, int iommu_prot, gfp_t gfp)
@@ -4785,7 +4796,6 @@ const struct iommu_ops intel_iommu_ops = {
#endif
.default_domain_ops = &(const struct iommu_domain_ops) {
.attach_dev = intel_iommu_attach_device,
- .detach_dev = intel_iommu_detach_device,
.map_pages = intel_iommu_map_pages,
.unmap_pages = intel_iommu_unmap_pages,
.iotlb_sync_map = intel_iommu_iotlb_sync_map,
--
2.34.1