Re: [Qemu-devel] [PATCH v3] net: e1000e: fix an infinite loop issue

[Dmitry Fleytman]

Reviewed-by: Dmitry Fleytman <address@hidden>

> On 10 Feb 2017, at 04:19 AM, Li Qiang <address@hidden> wrote:
> 
> This issue is like the issue in e1000 network card addressed in
> this commit:
> e1000: eliminate infinite loops on out-of-bounds transfer start.
> 
> Signed-off-by: Li Qiang <address@hidden>
> ---
> 
> Change since v2:
> fix error in e1000e_ring_empty
> eliminate unnecessory detect code in loop
> 
> Changes since v1:
> make wraparound detect in e1000e_ring_empty
> 
> hw/net/e1000e_core.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/net/e1000e_core.c b/hw/net/e1000e_core.c
> index 2b11499..dc94188 100644
> --- a/hw/net/e1000e_core.c
> +++ b/hw/net/e1000e_core.c
> @@ -806,7 +806,8 @@ typedef struct E1000E_RingInfo_st {
> static inline bool
> e1000e_ring_empty(E1000ECore *core, const E1000E_RingInfo *r)
> {
> -    return core->mac[r->dh] == core->mac[r->dt];
> +    return core->mac[r->dh] == core->mac[r->dt] ||
> +                core->mac[r->dt] >= core->mac[r->dlen] / E1000_RING_DESC_LEN;
> }
> 
> static inline uint64_t
> @@ -1522,6 +1523,10 @@ e1000e_write_packet_to_guest(E1000ECore *core, struct 
> NetRxPkt *pkt,
>             desc_size = core->rx_desc_buf_size;
>         }
> 
> +        if (e1000e_ring_empty(core, rxi)) {
> +            return;
> +        }
> +
>         base = e1000e_ring_head_descr(core, rxi);
> 
>         pci_dma_read(d, base, &desc, core->rx_desc_len);
> -- 
> 1.8.3.1
>