[Qemu-devel] [PATCH] NetKVM: fix for indirectc mode when vring is full

[Qemu-devel] [PATCH] NetKVM: fix for indirectc mode when vring is full

[Ting Wang]

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 <kathy.wangting@huawei.com>
---
 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

Re: [Qemu-devel] [PATCH] NetKVM: fix for indirectc mode when vring is full

[Yan Vugenfirer]

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 <kathy.wangting@huawei.com> 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 <kathy.wangting@huawei.com>
> ---
> 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
> 
> 

Re: [Qemu-devel] [PATCH] NetKVM: fix for indirectc mode when vring is full

[Wangting (Kathy)]

okay, thank you, I think it is better for net and other feature with one virtio code set like linux.

On 2014-12-14 21:30, Yan Vugenfirer wrote:
> 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 <kathy.wangting@huawei.com> 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 <kathy.wangting@huawei.com>
>> ---
>> 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
>>
>>
> 
> 
> .
>