-----Original Message----- From: liulongfang liulongfang@huawei.com Sent: Thursday, December 19, 2024 9:18 AM To: alex.williamson@redhat.com; jgg@nvidia.com; Shameerali Kolothum Thodi shameerali.kolothum.thodi@huawei.com; Jonathan Cameron jonathan.cameron@huawei.com Cc: kvm@vger.kernel.org; linux-kernel@vger.kernel.org; linuxarm@openeuler.org; liulongfang liulongfang@huawei.com Subject: [PATCH v2 5/5] hisi_acc_vfio_pci: bugfix live migration function without VF device driver

If the driver of the VF device is not loaded in the Guest OS, then perform device data migration. The migrated data address will be NULL. The live migration recovery operation on the destination side will access a null address value, which will cause access errors.

Therefore, live migration of VMs without added VF device drivers does not require device data migration. In addition, when the queue address data obtained by the destination is empty, device queue recovery processing will not be performed.

Signed-off-by: Longfang Liu liulongfang@huawei.com

Why this doesn't need a Fixes tag?

---

drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c index 8d9e07ebf4fd..9a5f7e9bc695 100644 --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c @@ -436,6 +436,7 @@ static int vf_qm_get_match_data(struct hisi_acc_vf_core_device *hisi_acc_vdev, struct acc_vf_data *vf_data) { struct hisi_qm *pf_qm = hisi_acc_vdev->pf_qm;

• struct hisi_qm *vf_qm = &hisi_acc_vdev->vf_qm; struct device *dev = &pf_qm->pdev->dev; int vf_id = hisi_acc_vdev->vf_id; int ret;

@@ -460,6 +461,13 @@ static int vf_qm_get_match_data(struct hisi_acc_vf_core_device *hisi_acc_vdev, return ret; }

• /* Get VF driver insmod state */
• ret = qm_read_regs(vf_qm, QM_VF_STATE, &vf_data->vf_qm_state,

1);

• if (ret) {

• dev_err(dev, "failed to read QM_VF_STATE!\n");
  

• return ret;
  

• }
• return 0;

}

@@ -499,6 +507,12 @@ static int vf_qm_load_data(struct hisi_acc_vf_core_device *hisi_acc_vdev, qm->qp_base = vf_data->qp_base; qm->qp_num = vf_data->qp_num;

• if (!vf_data->eqe_dma || !vf_data->aeqe_dma ||

•    !vf_data->sqc_dma || !vf_data->cqc_dma) {
  

• dev_err(dev, "resume dma addr is NULL!\n");
  

• return -EINVAL;
  

• }

So this is to cover the corner case where the Guest has loaded the driver (QM_READY set) but not configured the DMA address? When this will happen? I thought we are setting QM_READY in guest after all configurations.

Thanks, Shameer