On Mon, 14 May 2018 14:39:51 +0800 Lu Baolu <baolu...@linux.intel.com> wrote:
> Hi, > > On 05/12/2018 04:54 AM, Jacob Pan wrote: > > IO page faults can be handled outside IOMMU subsystem. For an > > example, when nested translation is turned on and guest owns the > > first level page tables, device page request can be forwared > > to the guest for handling faults. As the page response returns > > by the guest, IOMMU driver on the host need to process the > > response which informs the device and completes the page request > > transaction. > > > > This patch introduces generic API function for page response > > passing from the guest or other in-kernel users. The definitions of > > the generic data is based on PCI ATS specification not limited to > > any vendor. > > > > Signed-off-by: Jean-Philippe Brucker <jean-philippe.bruc...@arm.com> > > Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com> > > Link: https://lkml.org/lkml/2017/12/7/1725 > > --- > > drivers/iommu/iommu.c | 45 > > +++++++++++++++++++++++++++++++++++++++++++++ include/linux/iommu.h > > | 43 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, > > 88 insertions(+) > > > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > > index b3f9daf..02fed3e 100644 > > --- a/drivers/iommu/iommu.c > > +++ b/drivers/iommu/iommu.c > > @@ -1533,6 +1533,51 @@ int iommu_sva_invalidate(struct iommu_domain > > *domain, } > > EXPORT_SYMBOL_GPL(iommu_sva_invalidate); > > > > +int iommu_page_response(struct device *dev, > > + struct page_response_msg *msg) > > +{ > > + struct iommu_param *param = dev->iommu_param; > > + int ret = -EINVAL; > > + struct iommu_fault_event *evt; > > + struct iommu_domain *domain = > > iommu_get_domain_for_dev(dev); + > > + if (!domain || !domain->ops->page_response) > > + return -ENODEV; > > + > > + /* > > + * Device iommu_param should have been allocated when > > device is > > + * added to its iommu_group. > > + */ > > + if (!param || !param->fault_param) > > + return -EINVAL; > > + > > + /* Only send response if there is a fault report pending */ > > + mutex_lock(¶m->fault_param->lock); > > + if (list_empty(¶m->fault_param->faults)) { > > + pr_warn("no pending PRQ, drop response\n"); > > + goto done_unlock; > > + } > > + /* > > + * Check if we have a matching page request pending to > > respond, > > + * otherwise return -EINVAL > > + */ > > + list_for_each_entry(evt, ¶m->fault_param->faults, > > list) { > > + if (evt->pasid == msg->pasid && > > + msg->page_req_group_id == > > evt->page_req_group_id) { > > + msg->private_data = evt->iommu_private; > > + ret = domain->ops->page_response(dev, msg); > > + list_del(&evt->list); > > + kfree(evt); > > + break; > > + } > > + } > > Are above two checks duplicated? We won't find a matching > request if the list is empty. And we need to printk a message > if we can't find the matching request. > sorry about the delay. I am not sure which two checks, we only search for pending page request if the list is not empty. Yes, it is a good idea to print out warning if the page response has no match request. > Best regards, > Lu Baolu > > [...] > [Jacob Pan] _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
