diff mbox series

virtio-net: Zero max_tx_vq field for VIRTIO_NET_CTRL_MQ_HASH_CONFIG case

Message ID 20230810031557.135557-1-yin31149@gmail.com
State New
Headers
Series virtio-net: Zero max_tx_vq field for VIRTIO_NET_CTRL_MQ_HASH_CONFIG case |

Commit Message

Hawkins Jiawei Aug. 10, 2023, 3:15 a.m. UTC 
  Kernel uses `struct virtio_net_ctrl_rss` to save command-specific-data
for both the VIRTIO_NET_CTRL_MQ_HASH_CONFIG and
VIRTIO_NET_CTRL_MQ_RSS_CONFIG commands.

According to the VirtIO standard, "Field reserved MUST contain zeroes.
It is defined to make the structure to match the layout of
virtio_net_rss_config structure, defined in 5.1.6.5.7.".

Yet for the VIRTIO_NET_CTRL_MQ_HASH_CONFIG command case, the `max_tx_vq`
field in struct virtio_net_ctrl_rss, which corresponds to the
`reserved` field in struct virtio_net_hash_config, is not zeroed,
thereby violating the VirtIO standard.

This patch solves this problem by zeroing this field in
virtnet_init_default_rss().

Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
---

TestStep
========
1. Boot QEMU with one virtio-net-pci net device with `mq` and `hash`
feature on, command line like:
      -netdev tap,vhost=off,...
      -device virtio-net-pci,mq=on,hash=on,...

2. Trigger VIRTIO_NET_CTRL_MQ_HASH_CONFIG command in guest, command
line like:
	ethtool -K eth0 rxhash on

Without this patch, in virtnet_commit_rss_command(), we can see the
`max_tx_vq` field is 1 in gdb like below:

	pwndbg> p vi->ctrl->rss
	$1 = {
	  hash_types = 63,
	  indirection_table_mask = 0,
	  unclassified_queue = 0,
	  indirection_table = {0 <repeats 128 times>},
	  max_tx_vq = 1,
	  hash_key_length = 40 '(',
	  ...
	}

With this patch, in virtnet_commit_rss_command(), we can see the
`max_tx_vq` field is 0 in gdb like below:

	pwndbg> p vi->ctrl->rss
	$1 = {
	  hash_types = 63,
	  indirection_table_mask = 0,
	  unclassified_queue = 0,
	  indirection_table = {0 <repeats 128 times>},
	  max_tx_vq = 0,
	  hash_key_length = 40 '(',
	  ...
	}

 drivers/net/virtio_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jason Wang Aug. 10, 2023, 4:12 a.m. UTC | #1 
On Thu, Aug 10, 2023 at 11:16 AM Hawkins Jiawei <yin31149@gmail.com> wrote:
>
> Kernel uses `struct virtio_net_ctrl_rss` to save command-specific-data
> for both the VIRTIO_NET_CTRL_MQ_HASH_CONFIG and
> VIRTIO_NET_CTRL_MQ_RSS_CONFIG commands.

This is tricky.

>
> According to the VirtIO standard, "Field reserved MUST contain zeroes.
> It is defined to make the structure to match the layout of
> virtio_net_rss_config structure, defined in 5.1.6.5.7.".
>
> Yet for the VIRTIO_NET_CTRL_MQ_HASH_CONFIG command case, the `max_tx_vq`
> field in struct virtio_net_ctrl_rss, which corresponds to the
> `reserved` field in struct virtio_net_hash_config, is not zeroed,
> thereby violating the VirtIO standard.
>
> This patch solves this problem by zeroing this field in
> virtnet_init_default_rss().
>
> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
> ---

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks
Eugenio Perez Martin Aug. 10, 2023, 8:44 a.m. UTC | #2 
On Thu, Aug 10, 2023 at 5:16 AM Hawkins Jiawei <yin31149@gmail.com> wrote:
>
> Kernel uses `struct virtio_net_ctrl_rss` to save command-specific-data
> for both the VIRTIO_NET_CTRL_MQ_HASH_CONFIG and
> VIRTIO_NET_CTRL_MQ_RSS_CONFIG commands.
>
> According to the VirtIO standard, "Field reserved MUST contain zeroes.
> It is defined to make the structure to match the layout of
> virtio_net_rss_config structure, defined in 5.1.6.5.7.".
>
> Yet for the VIRTIO_NET_CTRL_MQ_HASH_CONFIG command case, the `max_tx_vq`
> field in struct virtio_net_ctrl_rss, which corresponds to the
> `reserved` field in struct virtio_net_hash_config, is not zeroed,
> thereby violating the VirtIO standard.
>
> This patch solves this problem by zeroing this field in
> virtnet_init_default_rss().
>
> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>

Acked-by: Eugenio Pérez <eperezma@redhat.com>

> ---
>
> TestStep
> ========
> 1. Boot QEMU with one virtio-net-pci net device with `mq` and `hash`
> feature on, command line like:
>       -netdev tap,vhost=off,...
>       -device virtio-net-pci,mq=on,hash=on,...
>
> 2. Trigger VIRTIO_NET_CTRL_MQ_HASH_CONFIG command in guest, command
> line like:
>         ethtool -K eth0 rxhash on
>
> Without this patch, in virtnet_commit_rss_command(), we can see the
> `max_tx_vq` field is 1 in gdb like below:
>
>         pwndbg> p vi->ctrl->rss
>         $1 = {
>           hash_types = 63,
>           indirection_table_mask = 0,
>           unclassified_queue = 0,
>           indirection_table = {0 <repeats 128 times>},
>           max_tx_vq = 1,
>           hash_key_length = 40 '(',
>           ...
>         }
>
> With this patch, in virtnet_commit_rss_command(), we can see the
> `max_tx_vq` field is 0 in gdb like below:
>
>         pwndbg> p vi->ctrl->rss
>         $1 = {
>           hash_types = 63,
>           indirection_table_mask = 0,
>           unclassified_queue = 0,
>           indirection_table = {0 <repeats 128 times>},
>           max_tx_vq = 0,
>           hash_key_length = 40 '(',
>           ...
>         }
>
>  drivers/net/virtio_net.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 1270c8d23463..8db38634ae82 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2761,7 +2761,7 @@ static void virtnet_init_default_rss(struct virtnet_info *vi)
>                 vi->ctrl->rss.indirection_table[i] = indir_val;
>         }
>
> -       vi->ctrl->rss.max_tx_vq = vi->curr_queue_pairs;
> +       vi->ctrl->rss.max_tx_vq = vi->has_rss ? vi->curr_queue_pairs : 0;
>         vi->ctrl->rss.hash_key_length = vi->rss_key_size;
>
>         netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size);
> --
> 2.34.1
>
Michael S. Tsirkin Aug. 10, 2023, 8:49 a.m. UTC | #3 
On Thu, Aug 10, 2023 at 11:15:57AM +0800, Hawkins Jiawei wrote:
> Kernel uses `struct virtio_net_ctrl_rss` to save command-specific-data
> for both the VIRTIO_NET_CTRL_MQ_HASH_CONFIG and
> VIRTIO_NET_CTRL_MQ_RSS_CONFIG commands.
> 
> According to the VirtIO standard, "Field reserved MUST contain zeroes.
> It is defined to make the structure to match the layout of
> virtio_net_rss_config structure, defined in 5.1.6.5.7.".
> 
> Yet for the VIRTIO_NET_CTRL_MQ_HASH_CONFIG command case, the `max_tx_vq`
> field in struct virtio_net_ctrl_rss, which corresponds to the
> `reserved` field in struct virtio_net_hash_config, is not zeroed,
> thereby violating the VirtIO standard.
> 
> This patch solves this problem by zeroing this field in
> virtnet_init_default_rss().
> 
> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
> ---
> 
> TestStep
> ========
> 1. Boot QEMU with one virtio-net-pci net device with `mq` and `hash`
> feature on, command line like:
>       -netdev tap,vhost=off,...
>       -device virtio-net-pci,mq=on,hash=on,...
> 
> 2. Trigger VIRTIO_NET_CTRL_MQ_HASH_CONFIG command in guest, command
> line like:
> 	ethtool -K eth0 rxhash on
> 
> Without this patch, in virtnet_commit_rss_command(), we can see the
> `max_tx_vq` field is 1 in gdb like below:
> 
> 	pwndbg> p vi->ctrl->rss
> 	$1 = {
> 	  hash_types = 63,
> 	  indirection_table_mask = 0,
> 	  unclassified_queue = 0,
> 	  indirection_table = {0 <repeats 128 times>},
> 	  max_tx_vq = 1,
> 	  hash_key_length = 40 '(',
> 	  ...
> 	}
> 
> With this patch, in virtnet_commit_rss_command(), we can see the
> `max_tx_vq` field is 0 in gdb like below:
> 
> 	pwndbg> p vi->ctrl->rss
> 	$1 = {
> 	  hash_types = 63,
> 	  indirection_table_mask = 0,
> 	  unclassified_queue = 0,
> 	  indirection_table = {0 <repeats 128 times>},
> 	  max_tx_vq = 0,
> 	  hash_key_length = 40 '(',
> 	  ...
> 	}
> 
>  drivers/net/virtio_net.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Fixes tag pls?

> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 1270c8d23463..8db38634ae82 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2761,7 +2761,7 @@ static void virtnet_init_default_rss(struct virtnet_info *vi)
>  		vi->ctrl->rss.indirection_table[i] = indir_val;
>  	}
>  
> -	vi->ctrl->rss.max_tx_vq = vi->curr_queue_pairs;
> +	vi->ctrl->rss.max_tx_vq = vi->has_rss ? vi->curr_queue_pairs : 0;
>  	vi->ctrl->rss.hash_key_length = vi->rss_key_size;
>  
>  	netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size);
> -- 
> 2.34.1
Michael S. Tsirkin Aug. 10, 2023, 8:51 a.m. UTC | #4 
On Thu, Aug 10, 2023 at 11:15:57AM +0800, Hawkins Jiawei wrote:
> Kernel uses `struct virtio_net_ctrl_rss` to save command-specific-data
> for both the VIRTIO_NET_CTRL_MQ_HASH_CONFIG and
> VIRTIO_NET_CTRL_MQ_RSS_CONFIG commands.
> 
> According to the VirtIO standard, "Field reserved MUST contain zeroes.
> It is defined to make the structure to match the layout of
> virtio_net_rss_config structure, defined in 5.1.6.5.7.".
> 
> Yet for the VIRTIO_NET_CTRL_MQ_HASH_CONFIG command case, the `max_tx_vq`
> field in struct virtio_net_ctrl_rss, which corresponds to the
> `reserved` field in struct virtio_net_hash_config, is not zeroed,
> thereby violating the VirtIO standard.
> 
> This patch solves this problem by zeroing this field in
> virtnet_init_default_rss().
> 
> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>



Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.")
Cc: Andrew Melnychenko <andrew@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>

And this is stable material I believe.



> ---
> 
> TestStep
> ========
> 1. Boot QEMU with one virtio-net-pci net device with `mq` and `hash`
> feature on, command line like:
>       -netdev tap,vhost=off,...
>       -device virtio-net-pci,mq=on,hash=on,...
> 
> 2. Trigger VIRTIO_NET_CTRL_MQ_HASH_CONFIG command in guest, command
> line like:
> 	ethtool -K eth0 rxhash on
> 
> Without this patch, in virtnet_commit_rss_command(), we can see the
> `max_tx_vq` field is 1 in gdb like below:
> 
> 	pwndbg> p vi->ctrl->rss
> 	$1 = {
> 	  hash_types = 63,
> 	  indirection_table_mask = 0,
> 	  unclassified_queue = 0,
> 	  indirection_table = {0 <repeats 128 times>},
> 	  max_tx_vq = 1,
> 	  hash_key_length = 40 '(',
> 	  ...
> 	}
> 
> With this patch, in virtnet_commit_rss_command(), we can see the
> `max_tx_vq` field is 0 in gdb like below:
> 
> 	pwndbg> p vi->ctrl->rss
> 	$1 = {
> 	  hash_types = 63,
> 	  indirection_table_mask = 0,
> 	  unclassified_queue = 0,
> 	  indirection_table = {0 <repeats 128 times>},
> 	  max_tx_vq = 0,
> 	  hash_key_length = 40 '(',
> 	  ...
> 	}
> 
>  drivers/net/virtio_net.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 1270c8d23463..8db38634ae82 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -2761,7 +2761,7 @@ static void virtnet_init_default_rss(struct virtnet_info *vi)
>  		vi->ctrl->rss.indirection_table[i] = indir_val;
>  	}
>  
> -	vi->ctrl->rss.max_tx_vq = vi->curr_queue_pairs;
> +	vi->ctrl->rss.max_tx_vq = vi->has_rss ? vi->curr_queue_pairs : 0;
>  	vi->ctrl->rss.hash_key_length = vi->rss_key_size;
>  
>  	netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size);
> -- 
> 2.34.1
Hawkins Jiawei Aug. 10, 2023, 10:41 a.m. UTC | #5 
On 2023/8/10 16:51, Michael S. Tsirkin wrote:
> On Thu, Aug 10, 2023 at 11:15:57AM +0800, Hawkins Jiawei wrote:
>> Kernel uses `struct virtio_net_ctrl_rss` to save command-specific-data
>> for both the VIRTIO_NET_CTRL_MQ_HASH_CONFIG and
>> VIRTIO_NET_CTRL_MQ_RSS_CONFIG commands.
>>
>> According to the VirtIO standard, "Field reserved MUST contain zeroes.
>> It is defined to make the structure to match the layout of
>> virtio_net_rss_config structure, defined in 5.1.6.5.7.".
>>
>> Yet for the VIRTIO_NET_CTRL_MQ_HASH_CONFIG command case, the `max_tx_vq`
>> field in struct virtio_net_ctrl_rss, which corresponds to the
>> `reserved` field in struct virtio_net_hash_config, is not zeroed,
>> thereby violating the VirtIO standard.
>>
>> This patch solves this problem by zeroing this field in
>> virtnet_init_default_rss().
>>
>> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
>
>
>
> Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.")
> Cc: Andrew Melnychenko <andrew@daynix.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
>
> And this is stable material I believe.

Hi Michael,

Thank you for the reminder, I will send the v2 patch with all these tags
included.

Thanks!


>
>
>
>> ---
>>
>> TestStep
>> ========
>> 1. Boot QEMU with one virtio-net-pci net device with `mq` and `hash`
>> feature on, command line like:
>>        -netdev tap,vhost=off,...
>>        -device virtio-net-pci,mq=on,hash=on,...
>>
>> 2. Trigger VIRTIO_NET_CTRL_MQ_HASH_CONFIG command in guest, command
>> line like:
>>      ethtool -K eth0 rxhash on
>>
>> Without this patch, in virtnet_commit_rss_command(), we can see the
>> `max_tx_vq` field is 1 in gdb like below:
>>
>>      pwndbg> p vi->ctrl->rss
>>      $1 = {
>>        hash_types = 63,
>>        indirection_table_mask = 0,
>>        unclassified_queue = 0,
>>        indirection_table = {0 <repeats 128 times>},
>>        max_tx_vq = 1,
>>        hash_key_length = 40 '(',
>>        ...
>>      }
>>
>> With this patch, in virtnet_commit_rss_command(), we can see the
>> `max_tx_vq` field is 0 in gdb like below:
>>
>>      pwndbg> p vi->ctrl->rss
>>      $1 = {
>>        hash_types = 63,
>>        indirection_table_mask = 0,
>>        unclassified_queue = 0,
>>        indirection_table = {0 <repeats 128 times>},
>>        max_tx_vq = 0,
>>        hash_key_length = 40 '(',
>>        ...
>>      }
>>
>>   drivers/net/virtio_net.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>> index 1270c8d23463..8db38634ae82 100644
>> --- a/drivers/net/virtio_net.c
>> +++ b/drivers/net/virtio_net.c
>> @@ -2761,7 +2761,7 @@ static void virtnet_init_default_rss(struct virtnet_info *vi)
>>              vi->ctrl->rss.indirection_table[i] = indir_val;
>>      }
>>
>> -    vi->ctrl->rss.max_tx_vq = vi->curr_queue_pairs;
>> +    vi->ctrl->rss.max_tx_vq = vi->has_rss ? vi->curr_queue_pairs : 0;
>>      vi->ctrl->rss.hash_key_length = vi->rss_key_size;
>>
>>      netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size);
>> --
>> 2.34.1
>
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 1270c8d23463..8db38634ae82 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2761,7 +2761,7 @@  static void virtnet_init_default_rss(struct virtnet_info *vi)
 		vi->ctrl->rss.indirection_table[i] = indir_val;
 	}
 
-	vi->ctrl->rss.max_tx_vq = vi->curr_queue_pairs;
+	vi->ctrl->rss.max_tx_vq = vi->has_rss ? vi->curr_queue_pairs : 0;
 	vi->ctrl->rss.hash_key_length = vi->rss_key_size;
 
 	netdev_rss_key_fill(vi->ctrl->rss.key, vi->rss_key_size);