[PATCH 7/9] iommu/vt-d: Clean up unused PASID updating functions

Lu Baolu
2021-10-14T05:43:01Z

From: Fenghua Yu <fenghua.yu@intel.com>

update_pasid() and its call chain are currently unused in the tree because
Thomas disabled the ENQCMD feature. The feature will be re-enabled shortly
using a different approach and update_pasid() and its call chain will not
be used in the new approach.

Remove the useless functions.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20210920192349.2602141-1-fenghua.yu@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
arch/x86/include/asm/fpu/api.h | 2 --
drivers/iommu/intel/svm.c | 24 +-----------------------
2 files changed, 1 insertion(+), 25 deletions(-)

diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index 23bef08a8388..ca4d0dee1ecd 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -106,6 +106,4 @@ extern int cpu_has_xfeatures(u64 xfeatures_mask, const char **feature_name);
*/
#define PASID_DISABLED 0

-static inline void update_pasid(void) { }
-
#endif /* _ASM_X86_FPU_API_H */
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 0c228787704f..5b5d69b04fcc 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -505,21 +505,6 @@ int intel_svm_unbind_gpasid(struct device *dev, u32 pasid)
return ret;
}

-static void _load_pasid(void *unused)
-{
- update_pasid();
-}
-
-static void load_pasid(struct mm_struct *mm, u32 pasid)
-{
- mutex_lock(&mm->context.lock);
-
- /* Update PASID MSR on all CPUs running the mm's tasks. */
- on_each_cpu_mask(mm_cpumask(mm), _load_pasid, NULL, true);
-
- mutex_unlock(&mm->context.lock);
-}
-
static int intel_svm_alloc_pasid(struct device *dev, struct mm_struct *mm,
unsigned int flags)
{
@@ -614,10 +599,6 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
if (ret)
goto free_sdev;

- /* The newly allocated pasid is loaded to the mm. */
- if (!(flags & SVM_FLAG_SUPERVISOR_MODE) && list_empty(&svm->devs))
- load_pasid(mm, svm->pasid);
-
list_add_rcu(&sdev->list, &svm->devs);
success:
return &sdev->sva;
@@ -670,11 +651,8 @@ static int intel_svm_unbind_mm(struct device *dev, u32 pasid)
kfree_rcu(sdev, rcu);

if (list_empty(&svm->devs)) {
- if (svm->notifier.ops) {
+ if (svm->notifier.ops)
mmu_notifier_unregister(&svm->notifier, mm);
- /* Clear mm's pasid. */
- load_pasid(mm, PASID_DISABLED);
- }
pasid_private_remove(svm->pasid);
/* We mandate that no page faults may be outstanding
* for the PASID when intel_svm_unbind_mm() is called.