Messages in this thread | | | Date | Mon, 27 Jun 2022 21:03:52 +0800 | Subject | Re: [PATCH v9 10/11] iommu: Per-domain I/O page fault handling | From | Ethan Zhao <> |
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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.lu@linux.intel.com> > Reviewed-by: Jean-Philippe Brucker <jean-philippe@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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