| Message ID | 20230327232138.1490712-2-jacob.jun.pan@linux.intel.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Re-enable IDXD kernel workqueue under DMA API | expand |
On 3/28/23 7:21 AM, Jacob Pan wrote: > Supervisor Request Enable (SRE) bit in a PASID entry is for permission > checking on DMA requests. When SRE = 0, DMA with supervisor privilege > will be blocked. However, for in-kernel DMA this is not necessary in that > we are targeting kernel memory anyway. There's no need to differentiate > user and kernel for in-kernel DMA. > > Let's use non-privileged (user) permission for all PASIDs used in kernel, > it will be consistent with DMA without PASID (RID_PASID) as well. > > Signed-off-by: Jacob Pan<jacob.jun.pan@linux.intel.com> Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com> Best regards, baolu
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c index 0768dcae90fd..9f737ef55463 100644 --- a/drivers/iommu/intel/iommu.c +++ b/drivers/iommu/intel/iommu.c @@ -2338,8 +2338,6 @@ static int domain_setup_first_level(struct intel_iommu *iommu, if (level != 4 && level != 5) return -EINVAL; - if (pasid != PASID_RID2PASID) - flags |= PASID_FLAG_SUPERVISOR_MODE; if (level == 5) flags |= PASID_FLAG_FL5LP;
Supervisor Request Enable (SRE) bit in a PASID entry is for permission checking on DMA requests. When SRE = 0, DMA with supervisor privilege will be blocked. However, for in-kernel DMA this is not necessary in that we are targeting kernel memory anyway. There's no need to differentiate user and kernel for in-kernel DMA. Let's use non-privileged (user) permission for all PASIDs used in kernel, it will be consistent with DMA without PASID (RID_PASID) as well. Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> --- drivers/iommu/intel/iommu.c | 2 -- 1 file changed, 2 deletions(-)