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Re: [Qemu-devel] [PATCH] NetKVM: fix for indirectc mode when vring is fu
From: |
Yan Vugenfirer |
Subject: |
Re: [Qemu-devel] [PATCH] NetKVM: fix for indirectc mode when vring is full |
Date: |
Sun, 14 Dec 2014 15:30:21 +0200 |
Thanks!
The fix is correct, but I am not sure this patch is needed.
This is a frozen part of the code with XP and Windows 2003 support for NetKVM
only.
The library that is used for newer OSes and other drivers has this fix:
https://github.com/YanVugenfirer/kvm-guest-drivers-windows/commit/264f1b6c86f5eeca5e2c9fbd24e3de8dbd0bee1d
In the NetKVM driver code itself we are testing for those conditions before
calling to add_buf (check ParaNdis_DoSubmitPacket function in
https://github.com/YanVugenfirer/kvm-guest-drivers-windows/blob/stable/NetKVM/NDIS5/Common/ParaNdis-Common.c#L1528).
Best regads,
Yan.
> On Dec 10, 2014, at 9:28 AM, Ting Wang <address@hidden> wrote:
>
> In function vring_add_indirect, there is no limiti
> about free entry in vring. If vring is full,
> vq->num_free will be less than zero, and
> the address of vq->vring.desc becomes illegal.
>
> Signed-off-by: Ting Wang <address@hidden>
> ---
> NetKVM/NDIS5/VirtIO/VirtIORing.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/NetKVM/NDIS5/VirtIO/VirtIORing.c
> b/NetKVM/NDIS5/VirtIO/VirtIORing.c
> index 90ace4c..0f3783c 100644
> --- a/NetKVM/NDIS5/VirtIO/VirtIORing.c
> +++ b/NetKVM/NDIS5/VirtIO/VirtIORing.c
> @@ -150,7 +150,7 @@ static int vring_add_buf(struct virtqueue *_vq,
> return -1;
> }
>
> - if (va_indirect)
> + if (va_indirect && (out + in) > 1 && vq->num_free)
> {
> int ret = vring_add_indirect(_vq, sg, out, in, va_indirect,
> phys_indirect);
> if (ret >= 0)
> --
> 1.8.5
>
>