On Wed, Jun 02, 2021 at 10:15:34AM +0800, Jason Wang wrote:
> This patch introduce a helper to get driver/guest features from the
> device.
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Reviewed-by: Eli Cohen <elic@xxxxxxxxxx>
> ---
> drivers/virtio/virtio_pci_modern_dev.c | 21 +++++++++++++++++++++
> include/linux/virtio_pci_modern.h | 1 +
> 2 files changed, 22 insertions(+)
>
> diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
> index 54f297028586..e11ed748e661 100644
> --- a/drivers/virtio/virtio_pci_modern_dev.c
> +++ b/drivers/virtio/virtio_pci_modern_dev.c
> @@ -383,6 +383,27 @@ u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev)
> }
> EXPORT_SYMBOL_GPL(vp_modern_get_features);
>
> +/*
> + * vp_modern_get_driver_features - get driver features from device
> + * @mdev: the modern virtio-pci device
> + *
> + * Returns the driver features read from the device
> + */
> +u64 vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev)
> +{
> + struct virtio_pci_common_cfg __iomem *cfg = mdev->common;
> +
> + u64 features;
> +
> + vp_iowrite32(0, &cfg->guest_feature_select);
> + features = vp_ioread32(&cfg->guest_feature);
> + vp_iowrite32(1, &cfg->guest_feature_select);
> + features |= ((u64)vp_ioread32(&cfg->guest_feature) << 32);
> +
> + return features;
> +}
> +EXPORT_SYMBOL_GPL(vp_modern_get_driver_features);
> +
> /*
> * vp_modern_set_features - set features to device
> * @mdev: the modern virtio-pci device
> diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
> index 6a95b58fd0f4..eb2bd9b4077d 100644
> --- a/include/linux/virtio_pci_modern.h
> +++ b/include/linux/virtio_pci_modern.h
> @@ -79,6 +79,7 @@ static inline void vp_iowrite64_twopart(u64 val,
> }
>
> u64 vp_modern_get_features(struct virtio_pci_modern_device *mdev);
> +u64 vp_modern_get_driver_features(struct virtio_pci_modern_device *mdev);
> void vp_modern_set_features(struct virtio_pci_modern_device *mdev,
> u64 features);
> u32 vp_modern_generation(struct virtio_pci_modern_device *mdev);
> --
> 2.25.1
>
