On 2022/6/28 17:10, Ethan Zhao wrote:
Hi, Baolu

在 2022/6/28 14:28, Baolu Lu 写道:
Hi Ethan,

On 2022/6/27 21:03, Ethan Zhao wrote:

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);
-    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

No. This is not the iommu group. It's page request group defined by the
PCI SIG spec. Multiple page requests could be put in a group with a
same group id. All page requests in a group could be responded to device
in one shot.

Thanks your explaination, understand the concept of PCIe PRG.  I meant

do we still have the necessity to mention the "group" here in the name

iopf_handle_group(),  which one is better ? iopf_handle_prg() or

iopf_handler(),  perhaps none of them ? :)

Oh! Sorry for the misunderstanding.

I have no strong feeling to change this naming. :-) All the names
express what the helper does. Jean is the author of this framework. If
he has the same idea as you, I don't mind renaming it in this patch.

Best regards,
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