RE: [PATCH v2 1/5] hisi_acc_vfio_pci: fix XQE dma address error

Shameerali Kolothum Thodi
2024-12-19T10:01:07Z

> -----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 1/5] hisi_acc_vfio_pci: fix XQE dma address error
>
> The dma addresses of EQE and AEQE are wrong after migration and
> results in guest kernel-mode encryption services failure.
> Comparing the definition of hardware registers, we found that
> there was an error when the data read from the register was
> combined into an address. Therefore, the address combination
> sequence needs to be corrected.
>
> Even after fixing the above problem, we still have an issue
> where the Guest from an old kernel can get migrated to
> new kernel and may result in wrong data.
>
> In order to ensure that the address is correct after migration,
> if an old magic number is detected, the dma address needs to be
> updated.
>
> 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 | 34 +++++++++++++++----
> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h | 9 ++++-
> 2 files changed, 36 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 451c639299eb..8518efea3a52 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -350,6 +350,27 @@ static int vf_qm_func_stop(struct hisi_qm *qm)
> return hisi_qm_mb(qm, QM_MB_CMD_PAUSE_QM, 0, 0, 0);
> }
>
> +static int vf_qm_magic_check(struct acc_vf_data *vf_data)
> +{
> + switch (vf_data->acc_magic) {
> + case ACC_DEV_MAGIC_V2:
> + break;
> + case ACC_DEV_MAGIC_V1:
> + /* Correct dma address */
> + vf_data->eqe_dma = vf_data-
> >qm_eqc_dw[QM_XQC_ADDR_HIGH];
> + vf_data->eqe_dma <<= QM_XQC_ADDR_OFFSET;
> + vf_data->eqe_dma |= vf_data-
> >qm_eqc_dw[QM_XQC_ADDR_LOW];
> + vf_data->aeqe_dma = vf_data-
> >qm_aeqc_dw[QM_XQC_ADDR_HIGH];
> + vf_data->aeqe_dma <<= QM_XQC_ADDR_OFFSET;
> + vf_data->aeqe_dma |= vf_data-
> >qm_aeqc_dw[QM_XQC_ADDR_LOW];
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> static int vf_qm_check_match(struct hisi_acc_vf_core_device
> *hisi_acc_vdev,
> struct hisi_acc_vf_migration_file *migf)
> {
> @@ -363,7 +384,8 @@ static int vf_qm_check_match(struct
> hisi_acc_vf_core_device *hisi_acc_vdev,
> if (migf->total_length < QM_MATCH_SIZE || hisi_acc_vdev-
> >match_done)
> return 0;
>
> - if (vf_data->acc_magic != ACC_DEV_MAGIC) {
> + ret = vf_qm_magic_check(vf_data);
> + if (ret) {
> dev_err(dev, "failed to match ACC_DEV_MAGIC\n");
> return -EINVAL;
> }
> @@ -418,7 +440,7 @@ static int vf_qm_get_match_data(struct
> hisi_acc_vf_core_device *hisi_acc_vdev,
> int vf_id = hisi_acc_vdev->vf_id;
> int ret;
>
> - vf_data->acc_magic = ACC_DEV_MAGIC;
> + vf_data->acc_magic = ACC_DEV_MAGIC_V2;
> /* Save device id */
> vf_data->dev_id = hisi_acc_vdev->vf_dev->device;
>
> @@ -496,12 +518,12 @@ static int vf_qm_read_data(struct hisi_qm
> *vf_qm, struct acc_vf_data *vf_data)
> return -EINVAL;
>
> /* Every reg is 32 bit, the dma address is 64 bit. */
> - vf_data->eqe_dma = vf_data->qm_eqc_dw[1];
> + vf_data->eqe_dma = vf_data->qm_eqc_dw[QM_XQC_ADDR_HIGH];
> vf_data->eqe_dma <<= QM_XQC_ADDR_OFFSET;
> - vf_data->eqe_dma |= vf_data->qm_eqc_dw[0];
> - vf_data->aeqe_dma = vf_data->qm_aeqc_dw[1];
> + vf_data->eqe_dma |= vf_data->qm_eqc_dw[QM_XQC_ADDR_LOW];
> + vf_data->aeqe_dma = vf_data-
> >qm_aeqc_dw[QM_XQC_ADDR_HIGH];
> vf_data->aeqe_dma <<= QM_XQC_ADDR_OFFSET;
> - vf_data->aeqe_dma |= vf_data->qm_aeqc_dw[0];
> + vf_data->aeqe_dma |= vf_data-
> >qm_aeqc_dw[QM_XQC_ADDR_LOW];
>
> /* Through SQC_BT/CQC_BT to get sqc and cqc address */
> ret = qm_get_sqc(vf_qm, &vf_data->sqc_dma);
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> index 245d7537b2bc..2afce68f5a34 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.h
> @@ -39,6 +39,9 @@
> #define QM_REG_ADDR_OFFSET 0x0004
>
> #define QM_XQC_ADDR_OFFSET 32U
> +#define QM_XQC_ADDR_LOW 0x1
> +#define QM_XQC_ADDR_HIGH 0x2
> +
> #define QM_VF_AEQ_INT_MASK 0x0004
> #define QM_VF_EQ_INT_MASK 0x000c
> #define QM_IFC_INT_SOURCE_V 0x0020
> @@ -50,10 +53,14 @@
> #define QM_EQC_DW0 0X8000
> #define QM_AEQC_DW0 0X8020
>
> +enum acc_magic_num {
> + ACC_DEV_MAGIC_V1 = 0XCDCDCDCDFEEDAACC,
> + ACC_DEV_MAGIC_V2 = 0xAACCFEEDDECADEDE,

I think we have discussed this before that having some kind of
version info embed into magic_num will be beneficial going
forward. ie, may be use the last 4 bytes for denoting version.

ACC_DEV_MAGIC_V2 = 0xAACCFEEDDECA0002

The reason being, otherwise we have to come up with a random
magic each time when a fix like this is required in future.

Thanks,
Shameer