[PATCH v3] vfio : add aer process

[Zhou Jie]

During aer err occurs and resume do following to
protect device from being accessed.
1. Make config space read only.
2. Disable INTx/MSI Interrupt.
3. Do nothing for bar regions.

Signed-off-by: Zhou Jie <zhoujie2011@xxxxxxxxxxxxxx>
---
v2-v3:
   1. Call init_completion() in vfio_pci_probe.
   2. Call reinit_completion() in vfio_pci_aer_err_detected.
   3. Remove unnecessary brackets.

v1-v2:
   1. Add aer process to vfio driver.

 drivers/vfio/pci/vfio_pci.c         | 48 +++++++++++++++++++++++++++++++++++++
 drivers/vfio/pci/vfio_pci_private.h |  2 ++
 include/uapi/linux/vfio.h           |  2 ++
 3 files changed, 52 insertions(+)

diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index d624a52..4c246a1 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -648,6 +648,15 @@ static long vfio_pci_ioctl(void *device_data,
 	struct vfio_pci_device *vdev = device_data;
 	unsigned long minsz;
 
+	if (vdev->aer_error_in_progress && (cmd == VFIO_DEVICE_SET_IRQS ||
+	    cmd == VFIO_DEVICE_RESET || cmd == VFIO_DEVICE_PCI_HOT_RESET)) {
+		int ret;
+		ret = wait_for_completion_interruptible(
+			&vdev->aer_error_completion);
+		if (ret)
+			return ret;
+	}
+
 	if (cmd == VFIO_DEVICE_GET_INFO) {
 		struct vfio_device_info info;
 
@@ -664,6 +673,10 @@ static long vfio_pci_ioctl(void *device_data,
 		if (vdev->reset_works)
 			info.flags |= VFIO_DEVICE_FLAGS_RESET;
 
+		info.flags |= VFIO_DEVICE_FLAGS_AERPROCESS;
+		if (vdev->aer_error_in_progress)
+			info.flags |= VFIO_DEVICE_FLAGS_INAERPROCESS;
+
 		info.num_regions = VFIO_PCI_NUM_REGIONS + vdev->num_regions;
 		info.num_irqs = VFIO_PCI_NUM_IRQS;
 
@@ -1070,6 +1083,13 @@ static ssize_t vfio_pci_rw(void *device_data, char __user *buf,
 
 	switch (index) {
 	case VFIO_PCI_CONFIG_REGION_INDEX:
+		if (vdev->aer_error_in_progress && iswrite) {
+			int ret;
+			ret = wait_for_completion_interruptible(
+				&vdev->aer_error_completion);
+			if (ret)
+				return ret;
+		}
 		return vfio_pci_config_rw(vdev, buf, count, ppos, iswrite);
 
 	case VFIO_PCI_ROM_REGION_INDEX:
@@ -1228,6 +1248,7 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	vdev->irq_type = VFIO_PCI_NUM_IRQS;
 	mutex_init(&vdev->igate);
 	spin_lock_init(&vdev->irqlock);
+	init_completion(&vdev->aer_error_completion);
 
 	ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
 	if (ret) {
@@ -1300,6 +1321,11 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
 
 	mutex_lock(&vdev->igate);
 
+	vdev->aer_error_in_progress = true;
+	reinit_completion(&vdev->aer_error_completion);
+	vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
+				VFIO_IRQ_SET_ACTION_TRIGGER,
+				vdev->irq_type, 0, 0, NULL);
 	if (vdev->err_trigger)
 		eventfd_signal(vdev->err_trigger, 1);
 
@@ -1310,8 +1336,30 @@ static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
 	return PCI_ERS_RESULT_CAN_RECOVER;
 }
 
+static void vfio_pci_aer_resume(struct pci_dev *pdev)
+{
+	struct vfio_pci_device *vdev;
+	struct vfio_device *device;
+
+	device = vfio_device_get_from_dev(&pdev->dev);
+	if (device == NULL)
+		return;
+
+	vdev = vfio_device_data(device);
+	if (vdev == NULL) {
+		vfio_device_put(device);
+		return;
+	}
+
+	vdev->aer_error_in_progress = false;
+	complete_all(&vdev->aer_error_completion);
+
+	vfio_device_put(device);
+}
+
 static const struct pci_error_handlers vfio_err_handlers = {
 	.error_detected = vfio_pci_aer_err_detected,
+	.resume         = vfio_pci_aer_resume,
 };
 
 static struct pci_driver vfio_pci_driver = {
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 2128de8..7430d92 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -91,6 +91,8 @@ struct vfio_pci_device {
 	bool			has_vga;
 	bool			needs_reset;
 	bool			nointx;
+	bool			aer_error_in_progress;
+	struct completion	aer_error_completion;
 	struct pci_saved_state	*pci_saved_state;
 	int			refcnt;
 	struct eventfd_ctx	*err_trigger;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 255a211..59b9cf6 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -198,6 +198,8 @@ struct vfio_device_info {
 #define VFIO_DEVICE_FLAGS_PCI	(1 << 1)	/* vfio-pci device */
 #define VFIO_DEVICE_FLAGS_PLATFORM (1 << 2)	/* vfio-platform device */
 #define VFIO_DEVICE_FLAGS_AMBA  (1 << 3)	/* vfio-amba device */
+#define VFIO_DEVICE_FLAGS_AERPROCESS  (1 << 4)	/* support aer error progress */
+#define VFIO_DEVICE_FLAGS_INAERPROCESS  (1 << 5)/* status in aer error progress */
 	__u32	num_regions;	/* Max region index + 1 */
 	__u32	num_irqs;	/* Max IRQ index + 1 */
 };
-- 
1.8.3.1