On Tue, Oct 10, 2023 at 11:11 AM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> Some buggy devices, the common cfg size may not match the features.
>
> This patch checks the common cfg size for the
> features(VIRTIO_F_NOTIF_CONFIG_DATA, VIRTIO_F_RING_RESET). When the
> common cfg size does not match the corresponding feature, we fail the
> probe and print error message.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_pci_modern.c | 36 ++++++++++++++++++++++++++
> drivers/virtio/virtio_pci_modern_dev.c | 2 +-
> include/linux/virtio_pci_modern.h | 1 +
> 3 files changed, 38 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index d6bb68ba84e5..6a8f5ff05636 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -39,6 +39,39 @@ static void vp_transport_features(struct virtio_device *vdev, u64 features)
> __virtio_set_bit(vdev, VIRTIO_F_RING_RESET);
> }
>
> +static int __vp_check_common_size_one_feature(struct virtio_device *vdev, u32 fbit,
> + u32 offset, const char *fname)
> +{
> + struct virtio_pci_device *vp_dev = to_vp_device(vdev);
> +
> + if (!__virtio_test_bit(vdev, fbit))
> + return 0;
> +
> + if (likely(vp_dev->mdev.common_len >= offset))
> + return 0;
> +
> + dev_err(&vdev->dev,
> + "virtio: common cfg size(%ld) does not match the feature %s\n",
> + vp_dev->mdev.common_len, fname);
> +
> + return -EINVAL;
> +}
> +
> +#define vp_check_common_size_one_feature(vdev, fbit, field) \
> + __vp_check_common_size_one_feature(vdev, fbit, \
> + offsetofend(struct virtio_pci_modern_common_cfg, field), #fbit)
> +
> +static int vp_check_common_size(struct virtio_device *vdev)
> +{
> + if (vp_check_common_size_one_feature(vdev, VIRTIO_F_NOTIF_CONFIG_DATA, queue_notify_data))
> + return -EINVAL;
> +
> + if (vp_check_common_size_one_feature(vdev, VIRTIO_F_RING_RESET, queue_reset))
> + return -EINVAL;
Do we need to at least check the offset of the queue_device as well here?
Thanks
> +
> + return 0;
> +}
> +
> /* virtio config->finalize_features() implementation */
> static int vp_finalize_features(struct virtio_device *vdev)
> {
> @@ -57,6 +90,9 @@ static int vp_finalize_features(struct virtio_device *vdev)
> return -EINVAL;
> }
>
> + if (vp_check_common_size(vdev))
> + return -EINVAL;
> +
> vp_modern_set_features(&vp_dev->mdev, vdev->features);
>
> return 0;
> diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
> index 9cb601e16688..33f319da1558 100644
> --- a/drivers/virtio/virtio_pci_modern_dev.c
> +++ b/drivers/virtio/virtio_pci_modern_dev.c
> @@ -292,7 +292,7 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
> mdev->common = vp_modern_map_capability(mdev, common,
> sizeof(struct virtio_pci_common_cfg), 4,
> 0, sizeof(struct virtio_pci_modern_common_cfg),
> - NULL, NULL);
> + &mdev->common_len, NULL);
> if (!mdev->common)
> goto err_map_common;
> mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
> diff --git a/include/linux/virtio_pci_modern.h b/include/linux/virtio_pci_modern.h
> index 067ac1d789bc..edf62bae0474 100644
> --- a/include/linux/virtio_pci_modern.h
> +++ b/include/linux/virtio_pci_modern.h
> @@ -28,6 +28,7 @@ struct virtio_pci_modern_device {
> /* So we can sanity-check accesses. */
> size_t notify_len;
> size_t device_len;
> + size_t common_len;
>
> /* Capability for when we need to map notifications per-vq. */
> int notify_map_cap;
> --
> 2.32.0.3.g01195cf9f
>
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