On Mon, Sep 25, 2023 at 11:58 AM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
>
> Now, the function vp_modern_map_capability() takes the size parameter,
> which corresponds to the size of virtio_pci_common_cfg. As a result, the
> pci_iomap_range() function maps the memory area for
> virtio_pci_common_cfg.
>
> However, if the _F_RING_RESET is negotiated, the extra items will be
> used. Therefore, we need to use the size of virtio_pci_modre_common_cfg
> to map more space.
>
> Meanwhile, I have introduced a new variable called common_len in the
> mdev. This allows us to check common_len when accessing the new item of
> virtio_pci_modre_common_cfg.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> ---
> drivers/virtio/virtio_pci_modern_dev.c | 8 ++++++--
> include/linux/virtio_pci_modern.h | 1 +
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/virtio/virtio_pci_modern_dev.c b/drivers/virtio/virtio_pci_modern_dev.c
> index aad7d9296e77..ef6667de1b38 100644
> --- a/drivers/virtio/virtio_pci_modern_dev.c
> +++ b/drivers/virtio/virtio_pci_modern_dev.c
> @@ -291,8 +291,8 @@ int vp_modern_probe(struct virtio_pci_modern_device *mdev)
> err = -EINVAL;
> mdev->common = vp_modern_map_capability(mdev, common,
> sizeof(struct virtio_pci_common_cfg), 4,
> - 0, sizeof(struct virtio_pci_common_cfg),
> - NULL, NULL);
> + 0, sizeof(struct virtio_pci_modern_common_cfg),
> + &mdev->common_len, NULL);
> if (!mdev->common)
> goto err_map_common;
> mdev->isr = vp_modern_map_capability(mdev, isr, sizeof(u8), 1,
> @@ -493,6 +493,8 @@ int vp_modern_get_queue_reset(struct virtio_pci_modern_device *mdev, u16 index)
> {
> struct virtio_pci_modern_common_cfg __iomem *cfg;
>
> + BUG_ON(mdev->common_len < offsetofend(struct virtio_pci_modern_common_cfg, queue_reset));
Instead of using BUG for buggy hardware, why not simply fail the probe
in this case?
Thanks
> +
> cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
>
> vp_iowrite16(index, &cfg->cfg.queue_select);
> @@ -509,6 +511,8 @@ void vp_modern_set_queue_reset(struct virtio_pci_modern_device *mdev, u16 index)
> {
> struct virtio_pci_modern_common_cfg __iomem *cfg;
>
> + BUG_ON(mdev->common_len < offsetofend(struct virtio_pci_modern_common_cfg, queue_reset));
> +
> cfg = (struct virtio_pci_modern_common_cfg __iomem *)mdev->common;
>
> vp_iowrite16(index, &cfg->cfg.queue_select);
> 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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