> -----Original Message-----
> From: liulongfang <liulongfang@xxxxxxxxxx>
> Sent: Monday, June 30, 2025 9:54 AM
> To: alex.williamson@xxxxxxxxxx; jgg@xxxxxxxxxx; Shameerali Kolothum
> Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>; Jonathan Cameron
> <jonathan.cameron@xxxxxxxxxx>
> Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> linuxarm@xxxxxxxxxxxxx; liulongfang <liulongfang@xxxxxxxxxx>
> Subject: [PATCH v5 1/3] migration: update BAR space size
>
> On new platforms greater than QM_HW_V3, the live migration
> configuration
> region is moved from VF to PF. The VF's own configuration space is
> restored to the complete 64KB, and there is no need to divide the
> size of the BAR configuration space equally.
>
> Signed-off-by: Longfang Liu <liulongfang@xxxxxxxxxx>
> ---
See one minor comment below.
LGTM:
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
> .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 36 ++++++++++++++-----
> 1 file changed, 27 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 2149f49aeec7..1ddc9dbadb70 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -1250,6 +1250,28 @@ static struct hisi_qm *hisi_acc_get_pf_qm(struct
> pci_dev *pdev)
> return !IS_ERR(pf_qm) ? pf_qm : NULL;
> }
>
> +static size_t hisi_acc_get_resource_len(struct vfio_pci_core_device *vdev,
> + unsigned int index)
> +{
> + struct hisi_acc_vf_core_device *hisi_acc_vdev =
> + hisi_acc_drvdata(vdev->pdev);
> +
> + /*
> + * On the old QM_HW_V3 device, the ACC VF device BAR2
> + * region encompasses both functional register space
> + * and migration control register space.
> + * only the functional region should be report to Guest.
> + *
> + * On the new HW device, the migration control register
> + * has been moved to the PF device BAR2 region.
> + * The VF device BAR2 is entirely functional register space.
> + */
Nit: May be move the above comment about new HW to the below
check is better.
> + if (hisi_acc_vdev->pf_qm->ver == QM_HW_V3)
> + return (pci_resource_len(vdev->pdev, index) >> 1);
> +
> + return pci_resource_len(vdev->pdev, index);
> +}
> +
> static int hisi_acc_pci_rw_access_check(struct vfio_device *core_vdev,
> size_t count, loff_t *ppos,
> size_t *new_count)
> @@ -1260,8 +1282,9 @@ static int hisi_acc_pci_rw_access_check(struct
> vfio_device *core_vdev,
>
> if (index == VFIO_PCI_BAR2_REGION_INDEX) {
> loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
> - resource_size_t end = pci_resource_len(vdev->pdev, index) /
> 2;
> + resource_size_t end;
>
> + end = hisi_acc_get_resource_len(vdev, index);
> /* Check if access is for migration control region */
> if (pos >= end)
> return -EINVAL;
> @@ -1282,8 +1305,9 @@ static int hisi_acc_vfio_pci_mmap(struct
> vfio_device *core_vdev,
> index = vma->vm_pgoff >> (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT);
> if (index == VFIO_PCI_BAR2_REGION_INDEX) {
> u64 req_len, pgoff, req_start;
> - resource_size_t end = pci_resource_len(vdev->pdev, index) /
> 2;
> + resource_size_t end;
>
> + end = hisi_acc_get_resource_len(vdev, index);
> req_len = vma->vm_end - vma->vm_start;
> pgoff = vma->vm_pgoff &
> ((1U << (VFIO_PCI_OFFSET_SHIFT - PAGE_SHIFT)) - 1);
> @@ -1330,7 +1354,6 @@ static long hisi_acc_vfio_pci_ioctl(struct
> vfio_device *core_vdev, unsigned int
> if (cmd == VFIO_DEVICE_GET_REGION_INFO) {
> struct vfio_pci_core_device *vdev =
> container_of(core_vdev, struct vfio_pci_core_device,
> vdev);
> - struct pci_dev *pdev = vdev->pdev;
> struct vfio_region_info info;
> unsigned long minsz;
>
> @@ -1345,12 +1368,7 @@ static long hisi_acc_vfio_pci_ioctl(struct
> vfio_device *core_vdev, unsigned int
> if (info.index == VFIO_PCI_BAR2_REGION_INDEX) {
> info.offset =
> VFIO_PCI_INDEX_TO_OFFSET(info.index);
>
> - /*
> - * ACC VF dev BAR2 region consists of both
> functional
> - * register space and migration control register
> space.
> - * Report only the functional region to Guest.
> - */
> - info.size = pci_resource_len(pdev, info.index) / 2;
> + info.size = hisi_acc_get_resource_len(vdev,
> info.index);
>
> info.flags = VFIO_REGION_INFO_FLAG_READ |
> VFIO_REGION_INFO_FLAG_WRITE |
> --
> 2.24.0
