Messages in this thread | | | Date | Tue, 28 Jun 2022 14:28:14 +0800 | Subject | Re: [PATCH v9 10/11] iommu: Per-domain I/O page fault handling | From | Baolu Lu <> |
| |
Hi Ethan,
On 2022/6/27 21:03, Ethan Zhao wrote: > 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
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.
Best regards, baolu
> > 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)) >
| |