On Wed, 14 Jun 2017 15:23:02 -0700 Jacob Pan <[email protected]> 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 <[email protected]> > Signed-off-by: Ashok Raj <[email protected]> > --- > 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". > + return -EINVAL; > + } > + dev = &pdev->dev; Leaks pdev reference. Both normal and error path. > + } > + > + 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) {
