-----Original Message----- From: liulongfang <liulongfang@huawei.com> Sent: Friday, April 11, 2025 4:59 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 v7 5/6] hisi_acc_vfio_pci: bugfix live migration function without VF device driver

If the VF device driver is not loaded in the Guest OS and we attempt to perform device data migration, the address of the migrated data 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.

Fixes: b0eed085903e ("hisi_acc_vfio_pci: Add support for VFIO live migration") Signed-off-by: Longfang Liu <liulongfang@huawei.com> Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> --- .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 22 +++++++++++++------ 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c index cadc82419dca..d12a350440d3 100644 --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c @@ -426,13 +426,6 @@ static int vf_qm_check_match(struct hisi_acc_vf_core_device *hisi_acc_vdev, return -EINVAL; }

- ret = qm_write_regs(vf_qm, QM_VF_STATE, &vf_data->vf_qm_state, 1); - if (ret) { - dev_err(dev, "failed to write QM_VF_STATE\n"); - return ret; - } - - hisi_acc_vdev->vf_qm_state = vf_data->vf_qm_state; hisi_acc_vdev->match_done = true; return 0; } @@ -498,6 +491,20 @@ static int vf_qm_load_data(struct hisi_acc_vf_core_device *hisi_acc_vdev, if (migf->total_length < sizeof(struct acc_vf_data)) return -EINVAL;

+ if (!vf_data->eqe_dma || !vf_data->aeqe_dma || + !vf_data->sqc_dma || !vf_data->cqc_dma) { + dev_info(dev, "resume dma addr is NULL!\n"); + hisi_acc_vdev->vf_qm_state = QM_NOT_READY; + return 0; + }

I am still not fully understood why we need the above check. The only case as far as I can think of where this will happen is when the source VM Guest has not loaded the ACC driver. And we do take care of that already using vf_qm_state and checking total_length == QM_MATCH_SIZE. Have you seen this happening in any other scenario during your tests? Thanks, Shameer

+ + ret = qm_write_regs(qm, QM_VF_STATE, &vf_data->vf_qm_state, 1); + if (ret) { + dev_err(dev, "failed to write QM_VF_STATE\n"); + return -EINVAL; + } + hisi_acc_vdev->vf_qm_state = vf_data->vf_qm_state; + qm->eqe_dma = vf_data->eqe_dma; qm->aeqe_dma = vf_data->aeqe_dma; qm->sqc_dma = vf_data->sqc_dma; @@ -1531,6 +1538,7 @@ static int hisi_acc_vfio_pci_migrn_init_dev(struct vfio_device *core_vdev) hisi_acc_vdev->vf_id = pci_iov_vf_id(pdev) + 1; hisi_acc_vdev->pf_qm = pf_qm; hisi_acc_vdev->vf_dev = pdev; + hisi_acc_vdev->vf_qm_state = QM_NOT_READY; mutex_init(&hisi_acc_vdev->state_mutex); mutex_init(&hisi_acc_vdev->open_mutex);

-- 2.24.0