Re: [PATCH v5 5/5] hisi_acc_vfio_pci: bugfix live migration function without VF device driver

liulongfang
2025-03-18T06:20:35Z

On 2025/3/14 16:11, Shameerali Kolothum Thodi wrote:
>
>
>> -----Original Message-----
>> From: liulongfang <liulongfang@huawei.com>
>> Sent: Thursday, March 13, 2025 7:20 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 v5 5/5] 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>
>> ---
>> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 25 +++++++++++++------
>> 1 file changed, 18 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..44fa2d16bbcc 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 +491,13 @@ 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;
>>
>> + 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;
>> @@ -506,6 +506,12 @@ 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;
>> + }
>> +
>> ret = qm_set_regs(qm, vf_data);
>> if (ret) {
>> dev_err(dev, "set VF regs failed\n");
>> @@ -726,8 +732,12 @@ static int hisi_acc_vf_load_state(struct
>> hisi_acc_vf_core_device *hisi_acc_vdev)
>> {
>> struct device *dev = &hisi_acc_vdev->vf_dev->dev;
>> struct hisi_acc_vf_migration_file *migf = hisi_acc_vdev-
>>> resuming_migf;
>> + struct acc_vf_data *vf_data = &migf->vf_data;
>> int ret;
>>
>> + if (vf_data->vf_qm_state != QM_READY)
>> + return 0;
>
> I don't think we need to check the above. In vf_qm_satte_save(),
> If vf_qm_state != QM_READY, we set the
> migf->total_length = QM_MATCH_SIZE.
>
> Hence it will return 0 in the below vf_qm_load_data() anyway.
>

After removing this judgment code, the live migration function works normally
without loading the VM driver.
I will remove this judgment in the next version.

Thanks.
Longfang.

> With that corrected,
>
> Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
>
> Thanks,
> Shameer
>
>> +
>> /* Recover data to VF */
>> ret = vf_qm_load_data(hisi_acc_vdev, migf);
>> if (ret) {
>> @@ -1531,6 +1541,7 @@ 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
>
> .
>