[PATCH v2 1/4] hisi_acc_vfio_pci: fix VF reset timeout issue

[Longfang Liu <liulongfang@huawei.com>]

From: Weili Qian <qianweili@huawei.com>

If device error occurs during live migration, qemu will
reset the VF. At this time, VF reset and device reset are performed
simultaneously. The VF reset will timeout. Therefore, the QM_RESETTING
flag is used to ensure that VF reset and device reset are performed
serially.

Fixes: b0eed085903e ("hisi_acc_vfio_pci: Add support for VFIO live migration")
Signed-off-by: Weili Qian <qianweili@huawei.com>
---
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c    | 24 +++++++++++++++++++
 .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h    |  2 ++
 2 files changed, 26 insertions(+)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index cf45f6370c36..d1e8053640a9 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -1188,9 +1188,32 @@ hisi_acc_vfio_pci_get_device_state(struct vfio_device *vdev,
 	return 0;
 }
 
+static void hisi_acc_vf_pci_reset_prepare(struct pci_dev *pdev)
+{
+	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);
+	struct hisi_qm *qm = hisi_acc_vdev->pf_qm;
+	struct device *dev = &qm->pdev->dev;
+	u32 delay = 0;
+
+	/* All reset requests need to be queued for processing */
+	while (test_and_set_bit(QM_RESETTING, &qm->misc_ctl)) {
+		msleep(1);
+		if (++delay > QM_RESET_WAIT_TIMEOUT) {
+			dev_err(dev, "reset prepare failed\n");
+			return;
+		}
+	}
+
+	hisi_acc_vdev->set_reset_flag = true;
+}
+
 static void hisi_acc_vf_pci_aer_reset_done(struct pci_dev *pdev)
 {
 	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);
+	struct hisi_qm *qm = hisi_acc_vdev->pf_qm;
+
+	if (hisi_acc_vdev->set_reset_flag)
+		clear_bit(QM_RESETTING, &qm->misc_ctl);
 
 	if (hisi_acc_vdev->core_device.vdev.migration_flags !=
 				VFIO_MIGRATION_STOP_COPY)
@@ -1734,6 +1757,7 @@ static const struct pci_device_id hisi_acc_vfio_pci_table[] = {
 MODULE_DEVICE_TABLE(pci, hisi_acc_vfio_pci_table);
 
 static const struct pci_error_handlers hisi_acc_vf_err_handlers = {
+	.reset_prepare = hisi_acc_vf_pci_reset_prepare,
 	.reset_done = hisi_acc_vf_pci_aer_reset_done,
 	.error_detected = vfio_pci_core_aer_err_detected,
 };
diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
index cd55eba64dfb..a3d91a31e3d8 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
@@ -27,6 +27,7 @@
 
 #define ERROR_CHECK_TIMEOUT		100
 #define CHECK_DELAY_TIME		100
+#define QM_RESET_WAIT_TIMEOUT  60000
 
 #define QM_SQC_VFT_BASE_SHIFT_V2	28
 #define QM_SQC_VFT_BASE_MASK_V2		GENMASK(15, 0)
@@ -128,6 +129,7 @@ struct hisi_acc_vf_migration_file {
 struct hisi_acc_vf_core_device {
 	struct vfio_pci_core_device core_device;
 	u8 match_done;
+	bool set_reset_flag;
 	/*
 	 * io_base is only valid when dev_opened is true,
 	 * which is protected by open_mutex.
-- 
2.33.0