[Intel-wired-lan] [next-queue PATCH] ixgbevf: Fix coexistence of malicious driver detection with XDP

[Intel-wired-lan] [next-queue PATCH] ixgbevf: Fix coexistence of malicious driver detection with XDP

[Alexander Duyck]

In the case of the VF driver it is supposed to provide a context descriptor
that allows us to provide information about the header offsets inside of
the frame. However in the case of XDP we don't really have any of that
information since the data is minimally processed. As a result we were
seeing malicious driver detection (MDD) events being triggered when the PF
had that functionality enabled.

To address this I have added a bit of new code that will "prime" the XDP
ring by providing one context descriptor that assumes the minimal setup of
an Ethernet frame which is an L2 header length of 14. With just that we can
provide enough information to make the hardware happy so that we don't
trigger MDD events.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---
 drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      |    1 +
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |   36 +++++++++++++++++----
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
index 70c7568..56a1031 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
@@ -76,6 +76,7 @@ enum ixgbevf_ring_state_t {
 	__IXGBEVF_TX_DETECT_HANG,
 	__IXGBEVF_HANG_CHECK_ARMED,
 	__IXGBEVF_TX_XDP_RING,
+	__IXGBEVF_TX_XDP_RING_PRIMED,
 };
 
 #define ring_is_xdp(ring) \
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index c298614..e2a8a03 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
@@ -991,24 +991,45 @@ static int ixgbevf_xmit_xdp_ring(struct ixgbevf_ring *ring,
 		return IXGBEVF_XDP_CONSUMED;
 
 	/* record the location of the first descriptor for this packet */
-	tx_buffer = &ring->tx_buffer_info[ring->next_to_use];
-	tx_buffer->bytecount = len;
-	tx_buffer->gso_segs = 1;
-	tx_buffer->protocol = 0;
-
 	i = ring->next_to_use;
-	tx_desc = IXGBEVF_TX_DESC(ring, i);
+	tx_buffer = &ring->tx_buffer_info[i];
 
 	dma_unmap_len_set(tx_buffer, len, len);
 	dma_unmap_addr_set(tx_buffer, dma, dma);
 	tx_buffer->data = xdp->data;
-	tx_desc->read.buffer_addr = cpu_to_le64(dma);
+	tx_buffer->bytecount = len;
+	tx_buffer->gso_segs = 1;
+	tx_buffer->protocol = 0;
+
+	/* Populate minimal context descriptor that will provide for the
+	 * fact that we are expected to process Ethernet frames.
+	 */
+	if (!test_bit(__IXGBEVF_TX_XDP_RING_PRIMED, &ring->state)) {
+		struct ixgbe_adv_tx_context_desc *context_desc;
+
+		set_bit(__IXGBEVF_TX_XDP_RING_PRIMED, &ring->state);
+
+		context_desc = IXGBEVF_TX_CTXTDESC(ring, 0);
+		context_desc->vlan_macip_lens	=
+			cpu_to_le32(ETH_HLEN << IXGBE_ADVTXD_MACLEN_SHIFT);
+		context_desc->seqnum_seed	= 0;
+		context_desc->type_tucmd_mlhl	=
+			cpu_to_le32(IXGBE_TXD_CMD_DEXT |
+				    IXGBE_ADVTXD_DTYP_CTXT);
+		context_desc->mss_l4len_idx	= 0;
+
+		i = 1;
+	}
 
 	/* put descriptor type bits */
 	cmd_type = IXGBE_ADVTXD_DTYP_DATA |
 		   IXGBE_ADVTXD_DCMD_DEXT |
 		   IXGBE_ADVTXD_DCMD_IFCS;
 	cmd_type |= len | IXGBE_TXD_CMD;
+
+	tx_desc = IXGBEVF_TX_DESC(ring, i);
+	tx_desc->read.buffer_addr = cpu_to_le64(dma);
+
 	tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);
 	tx_desc->read.olinfo_status =
 			cpu_to_le32((len << IXGBE_ADVTXD_PAYLEN_SHIFT) |
@@ -1688,6 +1709,7 @@ static void ixgbevf_configure_tx_ring(struct ixgbevf_adapter *adapter,
 	       sizeof(struct ixgbevf_tx_buffer) * ring->count);
 
 	clear_bit(__IXGBEVF_HANG_CHECK_ARMED, &ring->state);
+	clear_bit(__IXGBEVF_TX_XDP_RING_PRIMED, &ring->state);
 
 	IXGBE_WRITE_REG(hw, IXGBE_VFTXDCTL(reg_idx), txdctl);
 

[Intel-wired-lan] [next-queue PATCH] ixgbevf: Fix coexistence of malicious driver detection with XDP

[Shannon Nelson]

On 5/22/2018 8:44 AM, Alexander Duyck wrote:
> In the case of the VF driver it is supposed to provide a context descriptor
> that allows us to provide information about the header offsets inside of
> the frame. However in the case of XDP we don't really have any of that
> information since the data is minimally processed. As a result we were
> seeing malicious driver detection (MDD) events being triggered when the PF
> had that functionality enabled.
> 
> To address this I have added a bit of new code that will "prime" the XDP
> ring by providing one context descriptor that assumes the minimal setup of
> an Ethernet frame which is an L2 header length of 14. With just that we can
> provide enough information to make the hardware happy so that we don't
> trigger MDD events.
> 
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
> ---
>   drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      |    1 +
>   drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |   36 +++++++++++++++++----
>   2 files changed, 30 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
> index 70c7568..56a1031 100644
> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
> @@ -76,6 +76,7 @@ enum ixgbevf_ring_state_t {
>   	__IXGBEVF_TX_DETECT_HANG,
>   	__IXGBEVF_HANG_CHECK_ARMED,
>   	__IXGBEVF_TX_XDP_RING,
> +	__IXGBEVF_TX_XDP_RING_PRIMED,
>   };
>   
>   #define ring_is_xdp(ring) \
> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> index c298614..e2a8a03 100644
> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
> @@ -991,24 +991,45 @@ static int ixgbevf_xmit_xdp_ring(struct ixgbevf_ring *ring,
>   		return IXGBEVF_XDP_CONSUMED;
>   
>   	/* record the location of the first descriptor for this packet */
> -	tx_buffer = &ring->tx_buffer_info[ring->next_to_use];
> -	tx_buffer->bytecount = len;
> -	tx_buffer->gso_segs = 1;
> -	tx_buffer->protocol = 0;
> -
>   	i = ring->next_to_use;
> -	tx_desc = IXGBEVF_TX_DESC(ring, i);
> +	tx_buffer = &ring->tx_buffer_info[i];
>   
>   	dma_unmap_len_set(tx_buffer, len, len);
>   	dma_unmap_addr_set(tx_buffer, dma, dma);
>   	tx_buffer->data = xdp->data;
> -	tx_desc->read.buffer_addr = cpu_to_le64(dma);
> +	tx_buffer->bytecount = len;
> +	tx_buffer->gso_segs = 1;
> +	tx_buffer->protocol = 0;
> +
> +	/* Populate minimal context descriptor that will provide for the
> +	 * fact that we are expected to process Ethernet frames.
> +	 */
> +	if (!test_bit(__IXGBEVF_TX_XDP_RING_PRIMED, &ring->state)) {
> +		struct ixgbe_adv_tx_context_desc *context_desc;
> +
> +		set_bit(__IXGBEVF_TX_XDP_RING_PRIMED, &ring->state);
> +
> +		context_desc = IXGBEVF_TX_CTXTDESC(ring, 0);
> +		context_desc->vlan_macip_lens	=
> +			cpu_to_le32(ETH_HLEN << IXGBE_ADVTXD_MACLEN_SHIFT);
> +		context_desc->seqnum_seed	= 0;
> +		context_desc->type_tucmd_mlhl	=
> +			cpu_to_le32(IXGBE_TXD_CMD_DEXT |
> +				    IXGBE_ADVTXD_DTYP_CTXT);
> +		context_desc->mss_l4len_idx	= 0;
> +
> +		i = 1;

This setting of i looks odd to me.  If i is the index of the next Tx 
descriptor to be used, why are hard coding it to 1 here?  If this bit of 
code is only run the first time after the ring has been configured, then 
next_to_use was 0, and the data is in tx_buffer_info[0], but now 
tx_desc[1] will be filled in?  Or am I misreading this?

sln

> +	}
>   
>   	/* put descriptor type bits */
>   	cmd_type = IXGBE_ADVTXD_DTYP_DATA |
>   		   IXGBE_ADVTXD_DCMD_DEXT |
>   		   IXGBE_ADVTXD_DCMD_IFCS;
>   	cmd_type |= len | IXGBE_TXD_CMD;
> +
> +	tx_desc = IXGBEVF_TX_DESC(ring, i);
> +	tx_desc->read.buffer_addr = cpu_to_le64(dma);
> +
>   	tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);
>   	tx_desc->read.olinfo_status =
>   			cpu_to_le32((len << IXGBE_ADVTXD_PAYLEN_SHIFT) |
> @@ -1688,6 +1709,7 @@ static void ixgbevf_configure_tx_ring(struct ixgbevf_adapter *adapter,
>   	       sizeof(struct ixgbevf_tx_buffer) * ring->count);
>   
>   	clear_bit(__IXGBEVF_HANG_CHECK_ARMED, &ring->state);
> +	clear_bit(__IXGBEVF_TX_XDP_RING_PRIMED, &ring->state);
>   
>   	IXGBE_WRITE_REG(hw, IXGBE_VFTXDCTL(reg_idx), txdctl);
>   
> 
> _______________________________________________
> Intel-wired-lan mailing list
> Intel-wired-lan at osuosl.org
> https://lists.osuosl.org/mailman/listinfo/intel-wired-lan
> 

[Intel-wired-lan] [next-queue PATCH] ixgbevf: Fix coexistence of malicious driver detection with XDP

[Alexander Duyck]

On Tue, May 22, 2018 at 10:02 AM, Shannon Nelson
<shannon.nelson@oracle.com> wrote:
> On 5/22/2018 8:44 AM, Alexander Duyck wrote:
>>
>> In the case of the VF driver it is supposed to provide a context
>> descriptor
>> that allows us to provide information about the header offsets inside of
>> the frame. However in the case of XDP we don't really have any of that
>> information since the data is minimally processed. As a result we were
>> seeing malicious driver detection (MDD) events being triggered when the PF
>> had that functionality enabled.
>>
>> To address this I have added a bit of new code that will "prime" the XDP
>> ring by providing one context descriptor that assumes the minimal setup of
>> an Ethernet frame which is an L2 header length of 14. With just that we
>> can
>> provide enough information to make the hardware happy so that we don't
>> trigger MDD events.
>>
>> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
>> ---
>>   drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      |    1 +
>>   drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |   36
>> +++++++++++++++++----
>>   2 files changed, 30 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
>> b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
>> index 70c7568..56a1031 100644
>> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
>> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf.h
>> @@ -76,6 +76,7 @@ enum ixgbevf_ring_state_t {
>>         __IXGBEVF_TX_DETECT_HANG,
>>         __IXGBEVF_HANG_CHECK_ARMED,
>>         __IXGBEVF_TX_XDP_RING,
>> +       __IXGBEVF_TX_XDP_RING_PRIMED,
>>   };
>>     #define ring_is_xdp(ring) \
>> diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
>> b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
>> index c298614..e2a8a03 100644
>> --- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
>> +++ b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
>> @@ -991,24 +991,45 @@ static int ixgbevf_xmit_xdp_ring(struct ixgbevf_ring
>> *ring,
>>                 return IXGBEVF_XDP_CONSUMED;
>>         /* record the location of the first descriptor for this packet */
>> -       tx_buffer = &ring->tx_buffer_info[ring->next_to_use];
>> -       tx_buffer->bytecount = len;
>> -       tx_buffer->gso_segs = 1;
>> -       tx_buffer->protocol = 0;
>> -
>>         i = ring->next_to_use;
>> -       tx_desc = IXGBEVF_TX_DESC(ring, i);
>> +       tx_buffer = &ring->tx_buffer_info[i];
>>         dma_unmap_len_set(tx_buffer, len, len);
>>         dma_unmap_addr_set(tx_buffer, dma, dma);
>>         tx_buffer->data = xdp->data;
>> -       tx_desc->read.buffer_addr = cpu_to_le64(dma);
>> +       tx_buffer->bytecount = len;
>> +       tx_buffer->gso_segs = 1;
>> +       tx_buffer->protocol = 0;
>> +
>> +       /* Populate minimal context descriptor that will provide for the
>> +        * fact that we are expected to process Ethernet frames.
>> +        */
>> +       if (!test_bit(__IXGBEVF_TX_XDP_RING_PRIMED, &ring->state)) {
>> +               struct ixgbe_adv_tx_context_desc *context_desc;
>> +
>> +               set_bit(__IXGBEVF_TX_XDP_RING_PRIMED, &ring->state);
>> +
>> +               context_desc = IXGBEVF_TX_CTXTDESC(ring, 0);
>> +               context_desc->vlan_macip_lens   =
>> +                       cpu_to_le32(ETH_HLEN <<
>> IXGBE_ADVTXD_MACLEN_SHIFT);
>> +               context_desc->seqnum_seed       = 0;
>> +               context_desc->type_tucmd_mlhl   =
>> +                       cpu_to_le32(IXGBE_TXD_CMD_DEXT |
>> +                                   IXGBE_ADVTXD_DTYP_CTXT);
>> +               context_desc->mss_l4len_idx     = 0;
>> +
>> +               i = 1;
>
>
> This setting of i looks odd to me.  If i is the index of the next Tx
> descriptor to be used, why are hard coding it to 1 here?  If this bit of
> code is only run the first time after the ring has been configured, then
> next_to_use was 0, and the data is in tx_buffer_info[0], but now tx_desc[1]
> will be filled in?  Or am I misreading this?
>
> sln

No, you are reading this correctly.

We populate tx_buffer_info[0], populate tx_desc[0] with the context
descriptor, and tx_desc[1] with the data descriptor. This only happens
for the first packet placed in the ring so we can just bump the
tx_desc reference directly to 1 in this case since we will always know
that next_to_use will be 0.

We actually do this kind of thing in the normal transmit path,
although there we reference the first tx_buffer_info structure via the
"first" pointer.

Thanks.

- Alex

[Intel-wired-lan] [next-queue PATCH] ixgbevf: Fix coexistence of malicious driver detection with XDP

[Bowers, AndrewX]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at osuosl.org] On
> Behalf Of Alexander Duyck
> Sent: Tuesday, May 22, 2018 8:44 AM
> To: intel-wired-lan at lists.osuosl.org
> Subject: [Intel-wired-lan] [next-queue PATCH] ixgbevf: Fix coexistence of
> malicious driver detection with XDP
> 
> In the case of the VF driver it is supposed to provide a context descriptor that
> allows us to provide information about the header offsets inside of the
> frame. However in the case of XDP we don't really have any of that
> information since the data is minimally processed. As a result we were seeing
> malicious driver detection (MDD) events being triggered when the PF had
> that functionality enabled.
> 
> To address this I have added a bit of new code that will "prime" the XDP ring
> by providing one context descriptor that assumes the minimal setup of an
> Ethernet frame which is an L2 header length of 14. With just that we can
> provide enough information to make the hardware happy so that we don't
> trigger MDD events.
> 
> Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
> ---
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf.h      |    1 +
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |   36
> +++++++++++++++++----
>  2 files changed, 30 insertions(+), 7 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>