Messages in this thread | | | Date | Sun, 31 Jul 2022 21:47:44 +0800 | Subject | Re: [PATCH v10 10/12] iommu: Prepare IOMMU domain for IOPF | From | Baolu Lu <> |
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On 2022/7/31 20:50, Yi Liu wrote: > On 2022/7/5 13:07, 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; >> diff --git a/drivers/iommu/iommu-sva-lib.h >> b/drivers/iommu/iommu-sva-lib.h >> index 8909ea1094e3..1b3ace4b5863 100644 >> --- a/drivers/iommu/iommu-sva-lib.h >> +++ b/drivers/iommu/iommu-sva-lib.h >> @@ -26,6 +26,8 @@ int iopf_queue_flush_dev(struct device *dev); >> struct iopf_queue *iopf_queue_alloc(const char *name); >> void iopf_queue_free(struct iopf_queue *queue); >> int iopf_queue_discard_partial(struct iopf_queue *queue); >> +enum iommu_page_response_code >> +iommu_sva_handle_iopf(struct iommu_fault *fault, void *data); >> #else /* CONFIG_IOMMU_SVA */ >> static inline int iommu_queue_iopf(struct iommu_fault *fault, void >> *cookie) >> @@ -63,5 +65,11 @@ static inline int iopf_queue_discard_partial(struct >> iopf_queue *queue) >> { >> return -ENODEV; >> } >> + >> +static inline enum iommu_page_response_code >> +iommu_sva_handle_iopf(struct iommu_fault *fault, void *data) >> +{ >> + return IOMMU_PAGE_RESP_INVALID; >> +} >> #endif /* CONFIG_IOMMU_SVA */ >> #endif /* _IOMMU_SVA_LIB_H */ >> diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c >> index 1df8c1dcae77..aee9e033012f 100644 >> --- a/drivers/iommu/io-pgfault.c >> +++ b/drivers/iommu/io-pgfault.c >> @@ -181,6 +181,13 @@ static void iopf_handle_group(struct work_struct >> *work) >> * request completes, outstanding faults will have been dealt with >> by the time >> * the PASID is freed. >> * >> + * Any valid page fault will be eventually routed to an iommu domain >> and the >> + * page fault handler installed there will get called. The users of this >> + * handling framework should guarantee that the iommu domain could >> only be >> + * freed after the device has stopped generating page faults (or the >> iommu >> + * hardware has been set to block the page faults) and the pending >> page faults >> + * have been flushed. >> + * >> * Return: 0 on success and <0 on error. >> */ >> int iommu_queue_iopf(struct iommu_fault *fault, void *cookie) >> diff --git a/drivers/iommu/iommu-sva-lib.c >> b/drivers/iommu/iommu-sva-lib.c >> index 751366980232..536d34855c74 100644 >> --- a/drivers/iommu/iommu-sva-lib.c >> +++ b/drivers/iommu/iommu-sva-lib.c >> @@ -167,3 +167,61 @@ u32 iommu_sva_get_pasid(struct iommu_sva *handle) >> return domain->mm->pasid; >> } >> EXPORT_SYMBOL_GPL(iommu_sva_get_pasid); >> + >> +/* >> + * 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)) > > is it possible to be ERR or NULL? The mm life circle should have been > guaranteed by the mmgrab() in iommu_sva_domain_alloc(). Perhaps coding > issue if it happens. :-)
Updated. Thanks!
Best regards, baolu
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