On Fri, 9 Apr 2021 11:44:20 +0800 Shenming Lu <[email protected]> wrote:
> To set up nested mode, drivers such as vfio_pci need to register a > handler to receive stage/level 1 faults from the IOMMU, but since > currently each device can only have one iommu dev fault handler, > and if stage 2 IOPF is already enabled (VFIO_IOMMU_ENABLE_IOPF), > we choose to update the registered handler (a consolidated one) via > flags (set FAULT_REPORT_NESTED_L1), and further deliver the received > stage 1 faults in the handler to the guest through a newly added > vfio_device_ops callback. Are there proposed in-kernel drivers that would use any of these symbols? > Signed-off-by: Shenming Lu <[email protected]> > --- > drivers/vfio/vfio.c | 81 +++++++++++++++++++++++++++++++++ > drivers/vfio/vfio_iommu_type1.c | 49 +++++++++++++++++++- > include/linux/vfio.h | 12 +++++ > 3 files changed, 141 insertions(+), 1 deletion(-) > > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index 44c8dfabf7de..4245f15914bf 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -2356,6 +2356,87 @@ struct iommu_domain *vfio_group_iommu_domain(struct > vfio_group *group) > } > EXPORT_SYMBOL_GPL(vfio_group_iommu_domain); > > +/* > + * Register/Update the VFIO IOPF handler to receive > + * nested stage/level 1 faults. > + */ > +int vfio_iommu_dev_fault_handler_register_nested(struct device *dev) > +{ > + struct vfio_container *container; > + struct vfio_group *group; > + struct vfio_iommu_driver *driver; > + int ret; > + > + if (!dev) > + return -EINVAL; > + > + group = vfio_group_get_from_dev(dev); > + if (!group) > + return -ENODEV; > + > + ret = vfio_group_add_container_user(group); > + if (ret) > + goto out; > + > + container = group->container; > + driver = container->iommu_driver; > + if (likely(driver && driver->ops->register_handler)) > + ret = driver->ops->register_handler(container->iommu_data, dev); > + else > + ret = -ENOTTY; > + > + vfio_group_try_dissolve_container(group); > + > +out: > + vfio_group_put(group); > + return ret; > +} > +EXPORT_SYMBOL_GPL(vfio_iommu_dev_fault_handler_register_nested); > + > +int vfio_iommu_dev_fault_handler_unregister_nested(struct device *dev) > +{ > + struct vfio_container *container; > + struct vfio_group *group; > + struct vfio_iommu_driver *driver; > + int ret; > + > + if (!dev) > + return -EINVAL; > + > + group = vfio_group_get_from_dev(dev); > + if (!group) > + return -ENODEV; > + > + ret = vfio_group_add_container_user(group); > + if (ret) > + goto out; > + > + container = group->container; > + driver = container->iommu_driver; > + if (likely(driver && driver->ops->unregister_handler)) > + ret = driver->ops->unregister_handler(container->iommu_data, > dev); > + else > + ret = -ENOTTY; > + > + vfio_group_try_dissolve_container(group); > + > +out: > + vfio_group_put(group); > + return ret; > +} > +EXPORT_SYMBOL_GPL(vfio_iommu_dev_fault_handler_unregister_nested); > + > +int vfio_transfer_iommu_fault(struct device *dev, struct iommu_fault *fault) > +{ > + struct vfio_device *device = dev_get_drvdata(dev); > + > + if (unlikely(!device->ops->transfer)) > + return -EOPNOTSUPP; > + > + return device->ops->transfer(device->device_data, fault); > +} > +EXPORT_SYMBOL_GPL(vfio_transfer_iommu_fault); > + > /** > * Module/class support > */ > diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > index ba2b5a1cf6e9..9d1adeddb303 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -3821,13 +3821,32 @@ static int vfio_iommu_type1_dma_map_iopf(struct > iommu_fault *fault, void *data) > struct vfio_batch batch; > struct vfio_range *range; > dma_addr_t iova = ALIGN_DOWN(fault->prm.addr, PAGE_SIZE); > - int access_flags = 0; > + int access_flags = 0, nested; > size_t premap_len, map_len, mapped_len = 0; > unsigned long bit_offset, vaddr, pfn, i, npages; > int ret; > enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID; > struct iommu_page_response resp = {0}; > > + if (vfio_dev_domian_nested(dev, &nested)) > + return -ENODEV; > + > + /* > + * When configured in nested mode, further deliver the > + * stage/level 1 faults to the guest. > + */ > + if (nested) { > + bool l2; > + > + if (fault->type == IOMMU_FAULT_PAGE_REQ) > + l2 = fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_L2; > + if (fault->type == IOMMU_FAULT_DMA_UNRECOV) > + l2 = fault->event.flags & IOMMU_FAULT_UNRECOV_L2; > + > + if (!l2) > + return vfio_transfer_iommu_fault(dev, fault); > + } > + > if (fault->type != IOMMU_FAULT_PAGE_REQ) > return -EOPNOTSUPP; > > @@ -4201,6 +4220,32 @@ static void vfio_iommu_type1_notify(void *iommu_data, > wake_up_all(&iommu->vaddr_wait); > } > > +static int vfio_iommu_type1_register_handler(void *iommu_data, > + struct device *dev) > +{ > + struct vfio_iommu *iommu = iommu_data; > + > + if (iommu->iopf_enabled) > + return iommu_update_device_fault_handler(dev, ~0, > + FAULT_REPORT_NESTED_L1); > + else > + return iommu_register_device_fault_handler(dev, > + vfio_iommu_type1_dma_map_iopf, > + FAULT_REPORT_NESTED_L1, dev); > +} > + > +static int vfio_iommu_type1_unregister_handler(void *iommu_data, > + struct device *dev) > +{ > + struct vfio_iommu *iommu = iommu_data; > + > + if (iommu->iopf_enabled) > + return iommu_update_device_fault_handler(dev, > + ~FAULT_REPORT_NESTED_L1, 0); > + else > + return iommu_unregister_device_fault_handler(dev); > +} The path through vfio to register this is pretty ugly, but I don't see any reason for the the update interfaces here, the previously registered handler just changes its behavior. > + > static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = { > .name = "vfio-iommu-type1", > .owner = THIS_MODULE, > @@ -4216,6 +4261,8 @@ static const struct vfio_iommu_driver_ops > vfio_iommu_driver_ops_type1 = { > .dma_rw = vfio_iommu_type1_dma_rw, > .group_iommu_domain = vfio_iommu_type1_group_iommu_domain, > .notify = vfio_iommu_type1_notify, > + .register_handler = vfio_iommu_type1_register_handler, > + .unregister_handler = vfio_iommu_type1_unregister_handler, > }; > > static int __init vfio_iommu_type1_init(void) > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index a7b426d579df..4621d8f0395d 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -29,6 +29,8 @@ > * @match: Optional device name match callback (return: 0 for no-match, >0 > for > * match, -errno for abort (ex. match with insufficient or incorrect > * additional args) > + * @transfer: Optional. Transfer the received stage/level 1 faults to the > guest > + * for nested mode. > */ > struct vfio_device_ops { > char *name; > @@ -43,6 +45,7 @@ struct vfio_device_ops { > int (*mmap)(void *device_data, struct vm_area_struct *vma); > void (*request)(void *device_data, unsigned int count); > int (*match)(void *device_data, char *buf); > + int (*transfer)(void *device_data, struct iommu_fault *fault); > }; > > extern struct iommu_group *vfio_iommu_group_get(struct device *dev); > @@ -100,6 +103,10 @@ struct vfio_iommu_driver_ops { > struct iommu_group *group); > void (*notify)(void *iommu_data, > enum vfio_iommu_notify_type event); > + int (*register_handler)(void *iommu_data, > + struct device *dev); > + int (*unregister_handler)(void *iommu_data, > + struct device *dev); > }; > > extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops > *ops); > @@ -161,6 +168,11 @@ extern int vfio_unregister_notifier(struct device *dev, > struct kvm; > extern void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm); > > +extern int vfio_iommu_dev_fault_handler_register_nested(struct device *dev); > +extern int vfio_iommu_dev_fault_handler_unregister_nested(struct device > *dev); > +extern int vfio_transfer_iommu_fault(struct device *dev, > + struct iommu_fault *fault); > + > /* > * Sub-module helpers > */ _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
