[PATCH 20/20] iommu/vt-d: Remove domain_update_iommu_superpage()

Lu Baolu
2024-05-29T05:36:43Z

The requirement for consistent super page support across all the IOMMU
hardware in the system has been removed. In the past, if a new IOMMU
was hot-added and lacked consistent super page capability, the hot-add
process would be aborted. However, with the updated attachment semantics,
it is now permissible for the super page capability to vary among
different IOMMU hardware units.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/iommu.c | 39 +------------------------------------
1 file changed, 1 insertion(+), 38 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 74e005b1c4b4..660d2b6c531b 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -366,36 +366,6 @@ static bool iommu_paging_structure_coherency(struct intel_iommu *iommu)
ecap_smpwc(iommu->ecap) : ecap_coherent(iommu->ecap);
}

-static int domain_update_iommu_superpage(struct dmar_domain *domain,
- struct intel_iommu *skip)
-{
- struct dmar_drhd_unit *drhd;
- struct intel_iommu *iommu;
- int mask = 0x3;
-
- if (!intel_iommu_superpage)
- return 0;
-
- /* set iommu_superpage to the smallest common denominator */
- rcu_read_lock();
- for_each_active_iommu(iommu, drhd) {
- if (iommu != skip) {
- if (domain && domain->use_first_level) {
- if (!cap_fl1gp_support(iommu->cap))
- mask = 0x1;
- } else {
- mask &= cap_super_page_val(iommu->cap);
- }
-
- if (!mask)
- break;
- }
- }
- rcu_read_unlock();
-
- return fls(mask);
-}
-
/* Return the super pagesize bitmap if supported. */
static unsigned long domain_super_pgsize_bitmap(struct dmar_domain *domain)
{
@@ -2845,8 +2815,8 @@ int dmar_parse_one_satc(struct acpi_dmar_header *hdr, void *arg)

static int intel_iommu_add(struct dmar_drhd_unit *dmaru)
{
- int sp, ret;
struct intel_iommu *iommu = dmaru->iommu;
+ int ret;

ret = intel_cap_audit(CAP_AUDIT_HOTPLUG_DMAR, iommu);
if (ret)
@@ -2858,13 +2828,6 @@ static int intel_iommu_add(struct dmar_drhd_unit *dmaru)
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",
- iommu->name);
- return -ENXIO;
- }
-
/*
* Disable translation if already enabled prior to OS handover.
*/
--
2.34.1