hisi_acc_vfio_pci: fix VF reset timeout issue

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: b0eed08 ("hisi_acc_vfio_pci: Add support for VFIO live migration")
Signed-off-by: Weili Qian <qianweili@huawei.com>
Link: https://lore.kernel.org/r/20260122020205.2884497-2-liulongfang@huawei.com
Signed-off-by: Alex Williamson <alex@shazbot.org>

Author: Weili Qian

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,
 };

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.