Re: [PATCH v6 1/5] hisi_acc_vfio_pci: fix XQE dma address error

From: Alex Williamson
Date: Fri Mar 28 2025 - 10:09:02 EST

On Fri, 28 Mar 2025 16:04:17 +0800
liulongfang <liulongfang@xxxxxxxxxx> wrote:

> on 2025/3/21 23:51, Alex Williamson wrote:
> > On Tue, 18 Mar 2025 14:45:44 +0800
> > Longfang Liu <liulongfang@xxxxxxxxxx> wrote:
> >
> >> 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@xxxxxxxxxx>
> >> Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
> >> ---
> >> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 41 ++++++++++++++++---
> >> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.h | 14 ++++++-
> >> 2 files changed, 47 insertions(+), 8 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..304dbdfa0e95 100644
> >> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> >> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> >> @@ -350,6 +350,32 @@ 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_version_check(struct acc_vf_data *vf_data, struct device *dev)
> >> +{
> >> + switch (vf_data->acc_magic) {
> >> + case ACC_DEV_MAGIC_V2:
> >> + if (vf_data->major_ver != ACC_DRV_MAJOR_VER) {
> >> + dev_info(dev, "migration driver version<%u.%u> not match!\n",
> >> + vf_data->major_ver, vf_data->minor_ver);
> >> + return -EINVAL;
> >> + }
> >> + 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 +389,8 @@ 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_version_check(vf_data, dev);
> >> + if (ret) {
> >> dev_err(dev, "failed to match ACC_DEV_MAGIC\n");
> >> return -EINVAL;
> >> }
> >
> > Nit, we store the return value here, but never use it beyond testing
> > non-zero. This is a pattern throughout this driver that should be
> > fixed (maybe in a future series). We should return the errno from the
> > sub-function rather than overriding it unless we have a specific reason
> > to do otherwise. Thanks,
> >
>
> You've raised a point that seems to apply in multiple places.
> Could this be addressed in a future bugfix patch?

Yes, I've noted that above. Thanks,

Alex

> >> @@ -418,7 +445,9 @@ 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;
> >> + vf_data->major_ver = ACC_DRV_MAJOR_VER;
> >> + vf_data->minor_ver = ACC_DRV_MINOR_VER;
> >> /* Save device id */
> >> vf_data->dev_id = hisi_acc_vdev->vf_dev->device;
> >>
> >> @@ -496,12 +525,12 @@ 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..91002ceeebc1 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 +53,15 @@
> >> #define QM_EQC_DW0 0X8000
> >> #define QM_AEQC_DW0 0X8020
> >>
> >> +#define ACC_DRV_MAJOR_VER 1
> >> +#define ACC_DRV_MINOR_VER 0
> >> +
> >> +#define ACC_DEV_MAGIC_V1 0XCDCDCDCDFEEDAACC
> >> +#define ACC_DEV_MAGIC_V2 0xAACCFEEDDECADEDE
> >> +
> >> struct acc_vf_data {
> >> #define QM_MATCH_SIZE offsetofend(struct acc_vf_data, qm_rsv_state)
> >> /* QM match information */
> >> -#define ACC_DEV_MAGIC 0XCDCDCDCDFEEDAACC
> >> u64 acc_magic;
> >> u32 qp_num;
> >> u32 dev_id;
> >> @@ -61,7 +69,9 @@ struct acc_vf_data {
> >> u32 qp_base;
> >> u32 vf_qm_state;
> >> /* QM reserved match information */
> >> - u32 qm_rsv_state[3];
> >> + u16 major_ver;
> >> + u16 minor_ver;
> >> + u32 qm_rsv_state[2];
> >>
> >> /* QM RW regs */
> >> u32 aeq_int_mask;
> >
> >
> >
> > .
> >
>