Re: [PATCH] net/virtio: remove address width limit for modern devices

[Maxime Coquelin <maxime.coquelin@redhat.com>]

Hi David,

On 3/9/23 15:36, David Marchand wrote:
> Modern devices don't have the same limitation as legacy devices, because
> vring addresses are not configured using a 32-bit register.
> 

Do we want to backport it? This is a bug in my opinion.

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks!
Maxime


> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>   drivers/net/virtio/virtio_pci.c | 28 ++++++++--------------------
>   1 file changed, 8 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_pci.c b/drivers/net/virtio/virtio_pci.c
> index 9cf4d760b4..29eb739b04 100644
> --- a/drivers/net/virtio/virtio_pci.c
> +++ b/drivers/net/virtio/virtio_pci.c
> @@ -33,22 +33,6 @@
>   
>   struct virtio_pci_internal virtio_pci_internal[RTE_MAX_ETHPORTS];
>   
> -static inline int
> -check_vq_phys_addr_ok(struct virtqueue *vq)
> -{
> -	/* Virtio PCI device VIRTIO_PCI_QUEUE_PF register is 32bit,
> -	 * and only accepts 32 bit page frame number.
> -	 * Check if the allocated physical memory exceeds 16TB.
> -	 */
> -	if ((vq->vq_ring_mem + vq->vq_ring_size - 1) >>
> -			(VIRTIO_PCI_QUEUE_ADDR_SHIFT + 32)) {
> -		PMD_INIT_LOG(ERR, "vring address shouldn't be above 16TB!");
> -		return 0;
> -	}
> -
> -	return 1;
> -}
> -
>   #define PCI_MSIX_ENABLE 0x8000
>   
>   static enum virtio_msix_status
> @@ -273,8 +257,15 @@ legacy_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
>   {
>   	uint32_t src;
>   
> -	if (!check_vq_phys_addr_ok(vq))
> +	/* Virtio PCI device VIRTIO_PCI_QUEUE_PFN register is 32bit,
> +	 * and only accepts 32 bit page frame number.
> +	 * Check if the allocated physical memory exceeds 16TB.
> +	 */
> +	if ((vq->vq_ring_mem + vq->vq_ring_size - 1) >>
> +			(VIRTIO_PCI_QUEUE_ADDR_SHIFT + 32)) {
> +		PMD_INIT_LOG(ERR, "vring address shouldn't be above 16TB!");
>   		return -1;
> +	}
>   
>   	rte_pci_ioport_write(VTPCI_IO(hw), &vq->vq_queue_index, 2,
>   		VIRTIO_PCI_QUEUE_SEL);
> @@ -476,9 +467,6 @@ modern_setup_queue(struct virtio_hw *hw, struct virtqueue *vq)
>   	uint64_t desc_addr, avail_addr, used_addr;
>   	uint16_t notify_off;
>   
> -	if (!check_vq_phys_addr_ok(vq))
> -		return -1;
> -
>   	desc_addr = vq->vq_ring_mem;
>   	avail_addr = desc_addr + vq->vq_nentries * sizeof(struct vring_desc);
>   	used_addr = RTE_ALIGN_CEIL(avail_addr + offsetof(struct vring_avail,