Re: [PATCH] vfio/pci: add support for VF token

[Cédric Le Goater]

On 3/20/23 08:35, Minwoo Im wrote:
> VF token was introduced [1] to kernel vfio-pci along with SR-IOV
> support [2].  This patch adds support VF token among PF and VF(s). To
> passthu PCIe VF to a VM, kernel >= v5.7 needs this.
>
> It can be configured with UUID like:
>
>    -device vfio-pci,host=DDDD:BB:DD:F,vf-token=<uuid>,...
>
> [1] 
> https://lore.kernel.org/linux-pci/158396393244.5601.10297430724964025753.stgit@gimli.home/
> [2] 
> https://lore.kernel.org/linux-pci/158396044753.5601.14804870681174789709.stgit@gimli.home/
>
> Cc: Alex Williamson <alex.williamson@redhat.com>
> Signed-off-by: Minwoo Im <minwoo.im@samsung.com>
> Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
> ---
>   hw/vfio/pci.c | 13 ++++++++++++-
>   hw/vfio/pci.h |  1 +
>   2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index ec9a854361..cf27f28936 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2856,6 +2856,8 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>       int groupid;
>       int i, ret;
>       bool is_mdev;
> +    char uuid[UUID_FMT_LEN];
> +    char *name;
>   
>       if (!vbasedev->sysfsdev) {
>           if (!(~vdev->host.domain || ~vdev->host.bus ||
> @@ -2936,7 +2938,15 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
>           goto error;
>       }
>   
> -    ret = vfio_get_device(group, vbasedev->name, vbasedev, errp);
> +    if (!qemu_uuid_is_null(&vdev->vf_token)) {
> +        qemu_uuid_unparse(&vdev->vf_token, uuid);
> +        name = g_strdup_printf("%s vf_token=%s", vbasedev->name, uuid);
> +    } else {
> +        name = vbasedev->name;
> +    }
> +
> +    ret = vfio_get_device(group, name, vbasedev, errp);
> +    g_free(name);
>       if (ret) {
>           vfio_put_group(group);
>           goto error;

Shouldn't we set the VF token in the kernel also ? See this QEMU implementation

  https://lore.kernel.org/lkml/20200204161737.34696b91@w520.home/

May be I misunderstood.

Thanks,

C.

> @@ -3268,6 +3278,7 @@ static void vfio_instance_init(Object *obj)
>   
>   static Property vfio_pci_dev_properties[] = {
>       DEFINE_PROP_PCI_HOST_DEVADDR("host", VFIOPCIDevice, host),
> +    DEFINE_PROP_UUID_NODEFAULT("vf-token", VFIOPCIDevice, vf_token),
>       DEFINE_PROP_STRING("sysfsdev", VFIOPCIDevice, vbasedev.sysfsdev),
>       DEFINE_PROP_ON_OFF_AUTO("x-pre-copy-dirty-page-tracking", VFIOPCIDevice,
>                               vbasedev.pre_copy_dirty_page_tracking,
> diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
> index 177abcc8fb..2674476d6c 100644
> --- a/hw/vfio/pci.h
> +++ b/hw/vfio/pci.h
> @@ -137,6 +137,7 @@ struct VFIOPCIDevice {
>       VFIOVGA *vga; /* 0xa0000, 0x3b0, 0x3c0 */
>       void *igd_opregion;
>       PCIHostDeviceAddress host;
> +    QemuUUID vf_token;
>       EventNotifier err_notifier;
>       EventNotifier req_notifier;
>       int (*resetfn)(struct VFIOPCIDevice *);