Hi,

在 2022/6/21 22:43, Lu Baolu 写道:
Tweak the I/O page fault handling framework to route the page faults to
the domain and call the page fault handler retrieved from the domain.
This makes the I/O page fault handling framework possible to serve more
usage scenarios as long as they have an IOMMU domain and install a page
fault handler in it. Some unused functions are also removed to avoid
dead code.

The iommu_get_domain_for_dev_pasid() which retrieves attached domain
for a {device, PASID} pair is used. It will be used by the page fault
handling framework which knows {device, PASID} reported from the iommu
driver. We have a guarantee that the SVA domain doesn't go away during
IOPF handling, because unbind() waits for pending faults with
iopf_queue_flush_dev() before freeing the domain. Hence, there's no need
to synchronize life cycle of the iommu domains between the unbind() and
the interrupt threads.

Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-phili...@linaro.org>
---
  drivers/iommu/io-pgfault.c | 64 +++++---------------------------------
  1 file changed, 7 insertions(+), 57 deletions(-)

diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
index aee9e033012f..4f24ec703479 100644
--- a/drivers/iommu/io-pgfault.c
+++ b/drivers/iommu/io-pgfault.c
@@ -69,69 +69,18 @@ static int iopf_complete_group(struct device *dev, struct 
iopf_fault *iopf,
        return iommu_page_response(dev, &resp);
  }
-static enum iommu_page_response_code
-iopf_handle_single(struct iopf_fault *iopf)
-{
-       vm_fault_t ret;
-       struct mm_struct *mm;
-       struct vm_area_struct *vma;
-       unsigned int access_flags = 0;
-       unsigned int fault_flags = FAULT_FLAG_REMOTE;
-       struct iommu_fault_page_request *prm = &iopf->fault.prm;
-       enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
-
-       if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID))
-               return status;
-
-       mm = iommu_sva_find(prm->pasid);
-       if (IS_ERR_OR_NULL(mm))
-               return status;
-
-       mmap_read_lock(mm);
-
-       vma = find_extend_vma(mm, prm->addr);
-       if (!vma)
-               /* Unmapped area */
-               goto out_put_mm;
-
-       if (prm->perm & IOMMU_FAULT_PERM_READ)
-               access_flags |= VM_READ;
-
-       if (prm->perm & IOMMU_FAULT_PERM_WRITE) {
-               access_flags |= VM_WRITE;
-               fault_flags |= FAULT_FLAG_WRITE;
-       }
-
-       if (prm->perm & IOMMU_FAULT_PERM_EXEC) {
-               access_flags |= VM_EXEC;
-               fault_flags |= FAULT_FLAG_INSTRUCTION;
-       }
-
-       if (!(prm->perm & IOMMU_FAULT_PERM_PRIV))
-               fault_flags |= FAULT_FLAG_USER;
-
-       if (access_flags & ~vma->vm_flags)
-               /* Access fault */
-               goto out_put_mm;
-
-       ret = handle_mm_fault(vma, prm->addr, fault_flags, NULL);
-       status = ret & VM_FAULT_ERROR ? IOMMU_PAGE_RESP_INVALID :
-               IOMMU_PAGE_RESP_SUCCESS;
-
-out_put_mm:
-       mmap_read_unlock(mm);
-       mmput(mm);
-
-       return status;
-}
-

Once the iopf_handle_single() is removed, the name of iopf_handle_group() looks a little weired

and confused, does this group mean the iommu group (domain) ? while I take some minutes to

look into the code, oh, means a batch / list / queue  of iopfs , and iopf_handle_group() becomes a

generic iopf_handler() .

Doe it make sense to revise the names of iopf_handle_group(), iopf_complete_group,  iopf_group in

this patch set ?


Thanks,

Ethan

  static void iopf_handle_group(struct work_struct *work)
  {
        struct iopf_group *group;
+       struct iommu_domain *domain;
        struct iopf_fault *iopf, *next;
        enum iommu_page_response_code status = IOMMU_PAGE_RESP_SUCCESS;
group = container_of(work, struct iopf_group, work);
+       domain = iommu_get_domain_for_dev_pasid(group->dev,
+                               group->last_fault.fault.prm.pasid);
+       if (!domain || !domain->iopf_handler)
+               status = IOMMU_PAGE_RESP_INVALID;
list_for_each_entry_safe(iopf, next, &group->faults, list) {
                /*
@@ -139,7 +88,8 @@ static void iopf_handle_group(struct work_struct *work)
                 * faults in the group if there is an error.
                 */
                if (status == IOMMU_PAGE_RESP_SUCCESS)
-                       status = iopf_handle_single(iopf);
+                       status = domain->iopf_handler(&iopf->fault,
+                                                     domain->fault_data);
if (!(iopf->fault.prm.flags &
                      IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE))

--
"firm, enduring, strong, and long-lived"

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