[RFC PATCH v2 6/6] vfio: Add nested IOPF support
Shenming Lu
lushenming at huawei.com
Tue Mar 9 06:22:07 GMT 2021
To set up nested mode, drivers such as vfio_pci have 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 combined one) via
flags (set IOPF_REPORT_NESTED_L1_CONCERNED), and further deliver
the received stage 1 faults in the handler to the guest through
a newly added vfio_device_ops callback.
Signed-off-by: Shenming Lu <lushenming at huawei.com>
---
drivers/vfio/vfio.c | 83 +++++++++++++++++++++++++++++++++
drivers/vfio/vfio_iommu_type1.c | 37 +++++++++++++++
include/linux/vfio.h | 9 ++++
3 files changed, 129 insertions(+)
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 77b29bbd3027..c6a01d947d0d 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -2389,6 +2389,89 @@ int vfio_iommu_dev_fault_handler(struct iommu_fault *fault, void *data)
}
EXPORT_SYMBOL_GPL(vfio_iommu_dev_fault_handler);
+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_hdlr_nested))
+ ret = driver->ops->unregister_hdlr_nested(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);
+
+/*
+ * Register/Update the VFIO page fault 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_hdlr_nested))
+ ret = driver->ops->register_hdlr_nested(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_transfer_dev_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_dev_fault);
+
/**
* Module/class support
*/
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 8d14ced649a6..62ad4a47de4a 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -3581,6 +3581,13 @@ static int vfio_iommu_type1_dma_map_iopf(void *iommu_data,
enum iommu_page_response_code status = IOMMU_PAGE_RESP_INVALID;
struct iommu_page_response resp = {0};
+ /*
+ * When configured in nested mode, further deliver
+ * stage/level 1 faults to the guest.
+ */
+ if (iommu->nesting && !(fault->prm.flags & IOMMU_FAULT_PAGE_REQUEST_L2))
+ return vfio_transfer_dev_fault(dev, fault);
+
mutex_lock(&iommu->lock);
dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
@@ -3654,6 +3661,34 @@ static int vfio_iommu_type1_dma_map_iopf(void *iommu_data,
return 0;
}
+static int vfio_iommu_type1_register_hdlr_nested(void *iommu_data,
+ struct device *dev)
+{
+ struct vfio_iommu *iommu = iommu_data;
+
+ if (iommu->iopf_enabled)
+ return iommu_update_device_fault_handler(dev, ~0,
+ IOPF_REPORT_NESTED_L1_CONCERNED);
+ else
+ return iommu_register_device_fault_handler(dev,
+ vfio_iommu_dev_fault_handler,
+ IOPF_REPORT_NESTED |
+ IOPF_REPORT_NESTED_L1_CONCERNED,
+ dev);
+}
+
+static int vfio_iommu_type1_unregister_hdlr_nested(void *iommu_data,
+ struct device *dev)
+{
+ struct vfio_iommu *iommu = iommu_data;
+
+ if (iommu->iopf_enabled)
+ return iommu_update_device_fault_handler(dev,
+ ~IOPF_REPORT_NESTED_L1_CONCERNED, 0);
+ else
+ return iommu_unregister_device_fault_handler(dev);
+}
+
static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
.name = "vfio-iommu-type1",
.owner = THIS_MODULE,
@@ -3670,6 +3705,8 @@ static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
.group_iommu_domain = vfio_iommu_type1_group_iommu_domain,
.notify = vfio_iommu_type1_notify,
.dma_map_iopf = vfio_iommu_type1_dma_map_iopf,
+ .register_hdlr_nested = vfio_iommu_type1_register_hdlr_nested,
+ .unregister_hdlr_nested = vfio_iommu_type1_unregister_hdlr_nested,
};
static int __init vfio_iommu_type1_init(void)
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 73af317a4343..60e935e4851b 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -29,6 +29,7 @@
* @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 faults to the guest for nested mode.
*/
struct vfio_device_ops {
char *name;
@@ -43,6 +44,7 @@ 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);
@@ -102,6 +104,10 @@ struct vfio_iommu_driver_ops {
int (*dma_map_iopf)(void *iommu_data,
struct iommu_fault *fault,
struct device *dev);
+ int (*register_hdlr_nested)(void *iommu_data,
+ struct device *dev);
+ int (*unregister_hdlr_nested)(void *iommu_data,
+ struct device *dev);
};
extern int vfio_register_iommu_driver(const struct vfio_iommu_driver_ops *ops);
@@ -164,6 +170,9 @@ struct kvm;
extern void vfio_group_set_kvm(struct vfio_group *group, struct kvm *kvm);
extern int vfio_iommu_dev_fault_handler(struct iommu_fault *fault, void *data);
+extern int vfio_iommu_dev_fault_handler_unregister_nested(struct device *dev);
+extern int vfio_iommu_dev_fault_handler_register_nested(struct device *dev);
+extern int vfio_transfer_dev_fault(struct device *dev, struct iommu_fault *fault);
/*
* Sub-module helpers
--
2.19.1
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