[PATCH v1] iommu/vt-d: Remove the redundant logic in first_level_by_default()

[Wei Wang <wei.w.wang@intel.com>]

This original implementation included redundant logic to determine whether
first-stage translation should be used by default. Simplify it and
preserve the original behavior:
- Returns false in legacy mode (no scalable mode support).
- Defaults to first-level translation when both FLTS and SLTS are
  supported.

Signed-off-by: Wei Wang <wei.w.wang@intel.com>
---
 drivers/iommu/intel/iommu.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index cb0b993bebb4..228da47ab7cd 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1366,15 +1366,7 @@ static void free_dmar_iommu(struct intel_iommu *iommu)
  */
 static bool first_level_by_default(struct intel_iommu *iommu)
 {
-	/* Only SL is available in legacy mode */
-	if (!sm_supported(iommu))
-		return false;
-
-	/* Only level (either FL or SL) is available, just use it */
-	if (ecap_flts(iommu->ecap) ^ ecap_slts(iommu->ecap))
-		return ecap_flts(iommu->ecap);
-
-	return true;
+	return sm_supported(iommu) && ecap_flts(iommu->ecap);
 }
 
 int domain_attach_iommu(struct dmar_domain *domain, struct intel_iommu *iommu)
-- 
2.43.0