[PATCH v4 3/4] iommu/vt-d: Remove domain_update_iommu_snooping()

Lu Baolu
2022-05-08T12:38:47Z

The IOMMU force snooping capability is not required to be consistent
among all the IOMMUs anymore. Remove force snooping capability check
in the IOMMU hot-add path and domain_update_iommu_snooping() becomes
a dead code now.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
drivers/iommu/intel/iommu.c | 34 +---------------------------------
1 file changed, 1 insertion(+), 33 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 048ebfbd5fcb..444d51a18c93 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -533,33 +533,6 @@ static void domain_update_iommu_coherency(struct dmar_domain *domain)
rcu_read_unlock();
}

-static bool domain_update_iommu_snooping(struct intel_iommu *skip)
-{
- struct dmar_drhd_unit *drhd;
- struct intel_iommu *iommu;
- bool ret = true;
-
- rcu_read_lock();
- for_each_active_iommu(iommu, drhd) {
- if (iommu != skip) {
- /*
- * If the hardware is operating in the scalable mode,
- * the snooping control is always supported since we
- * always set PASID-table-entry.PGSNP bit if the domain
- * is managed outside (UNMANAGED).
- */
- if (!sm_supported(iommu) &&
- !ecap_sc_support(iommu->ecap)) {
- ret = false;
- break;
- }
- }
- }
- rcu_read_unlock();
-
- return ret;
-}
-
static int domain_update_iommu_superpage(struct dmar_domain *domain,
struct intel_iommu *skip)
{
@@ -3606,12 +3579,7 @@ static int intel_iommu_add(struct dmar_drhd_unit *dmaru)
iommu->name);
return -ENXIO;
}
- if (!ecap_sc_support(iommu->ecap) &&
- domain_update_iommu_snooping(iommu)) {
- pr_warn("%s: Doesn't support snooping.\n",
- iommu->name);
- return -ENXIO;
- }
+
sp = domain_update_iommu_superpage(NULL, iommu) - 1;
if (sp >= 0 && !(cap_super_page_val(iommu->cap) & (1 << sp))) {
pr_warn("%s: Doesn't support large page.\n",
--
2.25.1