Messages in this thread | | | Date | Sat, 23 Jul 2022 11:33:34 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v10 10/12] iommu: Prepare IOMMU domain for IOPF |
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On Tue, Jul 05, 2022 at 01:07:08PM +0800, Lu Baolu wrote: > This adds some mechanisms around the iommu_domain so that the I/O page > fault handling framework could route a page fault to the domain and > call the fault handler from it. > > Add pointers to the page fault handler and its private data in struct > iommu_domain. The fault handler will be called with the private data > as a parameter once a page fault is routed to the domain. Any kernel > component which owns an iommu domain could install handler and its > private parameter so that the page fault could be further routed and > handled. > > This also prepares the SVA implementation to be the first consumer of > the per-domain page fault handling model. The I/O page fault handler > for SVA is copied to the SVA file with mmget_not_zero() added before > mmap_read_lock(). > > Suggested-by: Jean-Philippe Brucker <jean-philippe@linaro.org> > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org> > Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org> > Tested-by: Tony Zhu <tony.zhu@intel.com> > --- > include/linux/iommu.h | 3 ++ > drivers/iommu/iommu-sva-lib.h | 8 +++++ > drivers/iommu/io-pgfault.c | 7 +++++ > drivers/iommu/iommu-sva-lib.c | 58 +++++++++++++++++++++++++++++++++++ > drivers/iommu/iommu.c | 4 +++ > 5 files changed, 80 insertions(+) > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index ae0cfca064e6..47610f21d451 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -105,6 +105,9 @@ struct iommu_domain { > unsigned long pgsize_bitmap; /* Bitmap of page sizes in use */ > struct iommu_domain_geometry geometry; > struct iommu_dma_cookie *iova_cookie; > + enum iommu_page_response_code (*iopf_handler)(struct iommu_fault *fault, > + void *data); > + void *fault_data; > union { > struct { > iommu_fault_handler_t handler;
Why do we need two falut callbacks? The only difference is that one is recoverable and the other is not, right?
Can we run both down the same op?
> +/* > + * I/O page fault handler for SVA > + */ > +enum iommu_page_response_code > +iommu_sva_handle_iopf(struct iommu_fault *fault, void *data) > +{ > + vm_fault_t ret; > + struct vm_area_struct *vma; > + struct mm_struct *mm = data; > + unsigned int access_flags = 0; > + unsigned int fault_flags = FAULT_FLAG_REMOTE; > + struct iommu_fault_page_request *prm = &fault->prm; > + enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID; > + > + if (!(prm->flags & IOMMU_FAULT_PAGE_REQUEST_PASID_VALID)) > + return status; > + > + if (IS_ERR_OR_NULL(mm) || !mmget_not_zero(mm))
Do not use IS_ERR_ON_NULL. mm should never be null here since the fault handler should have been removed from the domain before the fault_data is changed.
Jason
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