On Thu, 22 Jun 2017 16:53:58 -0600 Alex Williamson <alex.william...@redhat.com> wrote:
> On Wed, 14 Jun 2017 15:23:02 -0700 > Jacob Pan <jacob.jun....@linux.intel.com> wrote: > > > If the source device of a page request has its PASID table pointer > > bond to a guest, the first level page tables are owned by the guest. > > In this case, we shall let guest OS to manage page fault. > > > > This patch uses the IOMMU fault notification API to send > > notifications, possibly via VFIO, to the guest OS. Once guest pages > > are fault in, guest will issue page response which will be passed > > down via the invalidation passdown APIs. > > > > Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com> > > Signed-off-by: Ashok Raj <ashok....@intel.com> > > --- > > drivers/iommu/intel-svm.c | 81 > > ++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 80 > > insertions(+), 1 deletion(-) > > > > diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c > > index 23c4276..d1d2d23 100644 > > --- a/drivers/iommu/intel-svm.c > > +++ b/drivers/iommu/intel-svm.c > > @@ -525,6 +525,80 @@ static bool access_error(struct vm_area_struct > > *vma, struct page_req_dsc *req) return (requested & > > ~vma->vm_flags) != 0; } > > > > +static int prq_to_iommu_prot(struct page_req_dsc *req) > > +{ > > + int prot = 0; > > + > > + if (req->rd_req) > > + prot |= IOMMU_READ; > > + if (req->wr_req) > > + prot |= IOMMU_WRITE; > > + if (req->exe_req) > > + prot |= IOMMU_EXEC; > > + if (req->priv_req) > > + prot |= IOMMU_PRIV; > > + > > + return prot; > > +} > > + > > +static int intel_svm_prq_notify(struct device *dev, struct > > page_req_dsc *desc) +{ > > + int ret = 0; > > + struct iommu_fault_event *event; > > + struct pci_dev *pdev; > > + struct device_domain_info *info; > > + unsigned long buf_offset; > > + > > + /** > > + * If caller does not provide struct device, this is the > > case where > > + * guest PASID table is bond to the device. So we need to > > retrieve > > + * struct device from the page request deescriptor then > > proceed. > > + */ > > + if (!dev) { > > + pdev = pci_get_bus_and_slot(desc->bus, > > desc->devfn); > > + if (!pdev) { > > + pr_err("No PCI device found for PRQ > > [%02x:%02x.%d]\n", > > + desc->bus, PCI_SLOT(desc->devfn), > > + PCI_FUNC(desc->devfn)); > > + return -ENODEV; > > + } > > + /** > > + * Make sure PASID table pointer is bond to guest, > > if yes notify > > + * handler in the guest, e.g. via VFIO. > > + */ > > + info = pdev->dev.archdata.iommu; > > + if (!info || !info->pasid_tbl_bond) { > > + pr_debug("PRQ device pasid table not > > bond.\n"); > > I can "bond" two things together, they are then "bound". > will fix that :) > > + return -EINVAL; > > + } > > + dev = &pdev->dev; > > Leaks pdev reference. Both normal and error path. > I guess you are referring to ref count in pci_get_bus_and_slot()? I did look at the code, it does not seem to do the count increment. Perhaps the comment is stale? * pointer to its data structure. The caller must decrement the * reference count by calling pci_dev_put(). If no device is found, * %NULL is returned. */ struct pci_dev *pci_get_domain_bus_and_slot(int domain, unsigned int bus, unsigned int devfn) { struct pci_dev *dev = NULL; for_each_pci_dev(dev) { if (pci_domain_nr(dev->bus) == domain && (dev->bus->number == bus && dev->devfn == devfn)) return dev; } return NULL; } EXPORT_SYMBOL(pci_get_domain_bus_and_slot); > > + } > > + > > + pr_debug("Notify PRQ device [%02x:%02x.%d]\n", > > + desc->bus, PCI_SLOT(desc->devfn), > > + PCI_FUNC(desc->devfn)); > > + event = kzalloc(sizeof(*event) + sizeof(*desc), > > GFP_KERNEL); > > + if (!event) > > + return -ENOMEM; > > + > > + get_device(dev); > > + /* Fill in event data for device specific processing */ > > + event->dev = dev; > > + buf_offset = offsetofend(struct iommu_fault_event, length); > > + memcpy(buf_offset + event, desc, sizeof(*desc)); > > + event->addr = desc->addr; > > + event->pasid = desc->pasid; > > + event->prot = prq_to_iommu_prot(desc); > > + event->length = sizeof(*desc); > > + event->flags = IOMMU_FAULT_PAGE_REQ; > > + > > + ret = iommu_fault_notifier_call_chain(event); > > + put_device(dev); > > + kfree(event); > > + > > + return ret; > > +} > > + > > static irqreturn_t prq_event_thread(int irq, void *d) > > { > > struct intel_iommu *iommu = d; > > @@ -548,7 +622,12 @@ static irqreturn_t prq_event_thread(int irq, > > void *d) handled = 1; > > > > req = &iommu->prq[head / sizeof(*req)]; > > - > > + /** > > + * If prq is to be handled outside iommu driver > > via receiver of > > + * the fault notifiers, we skip the page response > > here. > > + */ > > + if (!intel_svm_prq_notify(NULL, req)) > > + continue; > > result = QI_RESP_FAILURE; > > address = (u64)req->addr << VTD_PAGE_SHIFT; > > if (!req->pasid_present) { > [Jacob Pan]