[PATCH net v2 1/2] virtio_net: Do not set rss_indir if RSS is not supported

[PATCH net v2 1/2] virtio_net: Do not set rss_indir if RSS is not supported

[Breno Leitao]

Do not set virtnet_info->rss_indir_table_size if RSS is not available
for the device.

Currently, rss_indir_table_size is set if either has_rss or
has_rss_hash_report is available, but, it should only be set if has_rss
is set.

On the virtnet_set_rxfh(), return an invalid command if the request has
indirection table set, but virtnet does not support RSS.

Suggested-by: Heng Qi <hengqi@linux.alibaba.com>
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/virtio_net.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c22d1118a133..c640fdf28fc5 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3813,6 +3813,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
 	    rxfh->hfunc != ETH_RSS_HASH_TOP)
 		return -EOPNOTSUPP;
 
+	if (rxfh->indir && !vi->has_rss)
+		return -EINVAL;
+
 	if (rxfh->indir) {
 		for (i = 0; i < vi->rss_indir_table_size; ++i)
 			vi->ctrl->rss.indirection_table[i] = rxfh->indir[i];
@@ -4729,13 +4732,15 @@ static int virtnet_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))
 		vi->has_rss_hash_report = true;
 
-	if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS))
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) {
 		vi->has_rss = true;
 
-	if (vi->has_rss || vi->has_rss_hash_report) {
 		vi->rss_indir_table_size =
 			virtio_cread16(vdev, offsetof(struct virtio_net_config,
 				rss_max_indirection_table_length));
+	}
+
+	if (vi->has_rss || vi->has_rss_hash_report) {
 		vi->rss_key_size =
 			virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
 
-- 
2.43.0

[PATCH net v2 2/2] virtio_net: Do not send RSS key if it is not supported

[Breno Leitao]

There is a bug when setting the RSS options in virtio_net that can break
the whole machine, getting the kernel into an infinite loop.

Running the following command in any QEMU virtual machine with virtionet
will reproduce this problem:

    # ethtool -X eth0  hfunc toeplitz

This is how the problem happens:

1) ethtool_set_rxfh() calls virtnet_set_rxfh()

2) virtnet_set_rxfh() calls virtnet_commit_rss_command()

3) virtnet_commit_rss_command() populates 4 entries for the rss
scatter-gather

4) Since the command above does not have a key, then the last
scatter-gatter entry will be zeroed, since rss_key_size == 0.
sg_buf_size = vi->rss_key_size;

5) This buffer is passed to qemu, but qemu is not happy with a buffer
with zero length, and do the following in virtqueue_map_desc() (QEMU
function):

  if (!sz) {
      virtio_error(vdev, "virtio: zero sized buffers are not allowed");

6) virtio_error() (also QEMU function) set the device as broken

    vdev->broken = true;

7) Qemu bails out, and do not repond this crazy kernel.

8) The kernel is waiting for the response to come back (function
virtnet_send_command())

9) The kernel is waiting doing the following :

      while (!virtqueue_get_buf(vi->cvq, &tmp) &&
	     !virtqueue_is_broken(vi->cvq))
	      cpu_relax();

10) None of the following functions above is true, thus, the kernel
loops here forever. Keeping in mind that virtqueue_is_broken() does
not look at the qemu `vdev->broken`, so, it never realizes that the
vitio is broken at QEMU side.

Fix it by not sending RSS commands if the feature is not available in
the device.

Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.")
Cc: stable@vger.kernel.org
Cc: qemu-devel@nongnu.org
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/virtio_net.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c640fdf28fc5..e6b0eaf08ac2 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3809,6 +3809,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
 	struct virtnet_info *vi = netdev_priv(dev);
 	int i;
 
+	if (!vi->has_rss && !vi->has_rss_hash_report)
+		return -EOPNOTSUPP;
+
 	if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
 	    rxfh->hfunc != ETH_RSS_HASH_TOP)
 		return -EOPNOTSUPP;
-- 
2.43.0

Re: [PATCH net v2 1/2] virtio_net: Do not set rss_indir if RSS is not supported

[Xuan Zhuo]

On Tue, 26 Mar 2024 08:19:08 -0700, Breno Leitao <leitao@debian.org> wrote:
> Do not set virtnet_info->rss_indir_table_size if RSS is not available
> for the device.
>
> Currently, rss_indir_table_size is set if either has_rss or
> has_rss_hash_report is available, but, it should only be set if has_rss
> is set.
>
> On the virtnet_set_rxfh(), return an invalid command if the request has
> indirection table set, but virtnet does not support RSS.
>
> Suggested-by: Heng Qi <hengqi@linux.alibaba.com>
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
>  drivers/net/virtio_net.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index c22d1118a133..c640fdf28fc5 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3813,6 +3813,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
>  	    rxfh->hfunc != ETH_RSS_HASH_TOP)
>  		return -EOPNOTSUPP;
>
> +	if (rxfh->indir && !vi->has_rss)
> +		return -EINVAL;
> +
>  	if (rxfh->indir) {

Put !vi->has_rss here?

Thanks.


>  		for (i = 0; i < vi->rss_indir_table_size; ++i)
>  			vi->ctrl->rss.indirection_table[i] = rxfh->indir[i];
> @@ -4729,13 +4732,15 @@ static int virtnet_probe(struct virtio_device *vdev)
>  	if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))
>  		vi->has_rss_hash_report = true;
>
> -	if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS))
> +	if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) {
>  		vi->has_rss = true;
>
> -	if (vi->has_rss || vi->has_rss_hash_report) {
>  		vi->rss_indir_table_size =
>  			virtio_cread16(vdev, offsetof(struct virtio_net_config,
>  				rss_max_indirection_table_length));
> +	}
> +
> +	if (vi->has_rss || vi->has_rss_hash_report) {
>  		vi->rss_key_size =
>  			virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
>
> --
> 2.43.0
>

Re: [PATCH net v2 2/2] virtio_net: Do not send RSS key if it is not supported

[Heng Qi]

在 2024/3/26 下午11:19, Breno Leitao 写道:
> There is a bug when setting the RSS options in virtio_net that can break
> the whole machine, getting the kernel into an infinite loop.
>
> Running the following command in any QEMU virtual machine with virtionet
> will reproduce this problem:
>
>      # ethtool -X eth0  hfunc toeplitz
>
> This is how the problem happens:
>
> 1) ethtool_set_rxfh() calls virtnet_set_rxfh()
>
> 2) virtnet_set_rxfh() calls virtnet_commit_rss_command()
>
> 3) virtnet_commit_rss_command() populates 4 entries for the rss
> scatter-gather
>
> 4) Since the command above does not have a key, then the last
> scatter-gatter entry will be zeroed, since rss_key_size == 0.
> sg_buf_size = vi->rss_key_size;
>
> 5) This buffer is passed to qemu, but qemu is not happy with a buffer
> with zero length, and do the following in virtqueue_map_desc() (QEMU
> function):
>
>    if (!sz) {
>        virtio_error(vdev, "virtio: zero sized buffers are not allowed");
>
> 6) virtio_error() (also QEMU function) set the device as broken
>
>      vdev->broken = true;
>
> 7) Qemu bails out, and do not repond this crazy kernel.
>
> 8) The kernel is waiting for the response to come back (function
> virtnet_send_command())
>
> 9) The kernel is waiting doing the following :
>
>        while (!virtqueue_get_buf(vi->cvq, &tmp) &&
> 	     !virtqueue_is_broken(vi->cvq))
> 	      cpu_relax();
>
> 10) None of the following functions above is true, thus, the kernel
> loops here forever. Keeping in mind that virtqueue_is_broken() does
> not look at the qemu `vdev->broken`, so, it never realizes that the
> vitio is broken at QEMU side.
>
> Fix it by not sending RSS commands if the feature is not available in
> the device.
>
> Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.")
> Cc: stable@vger.kernel.org
> Cc: qemu-devel@nongnu.org
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
>   drivers/net/virtio_net.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index c640fdf28fc5..e6b0eaf08ac2 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3809,6 +3809,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
>   	struct virtnet_info *vi = netdev_priv(dev);
>   	int i;
>   
> +	if (!vi->has_rss && !vi->has_rss_hash_report)
> +		return -EOPNOTSUPP;
> +

Why not make the second patch as the first, this seems to work better.
Or squash them into one patch.

Apart from these and Xuan's comments.

For series:

         Reviewed-by: Heng Qi <hengqi@linux.alibaba.com>

Regards,
Heng

>   	if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
>   	    rxfh->hfunc != ETH_RSS_HASH_TOP)
>   		return -EOPNOTSUPP;

Re: [PATCH net v2 2/2] virtio_net: Do not send RSS key if it is not supported

[Breno Leitao]

On Wed, Mar 27, 2024 at 10:27:58AM +0800, Heng Qi wrote:
> 
> 
> 在 2024/3/26 下午11:19, Breno Leitao 写道:
> > There is a bug when setting the RSS options in virtio_net that can break
> > the whole machine, getting the kernel into an infinite loop.
> > 
> > Running the following command in any QEMU virtual machine with virtionet
> > will reproduce this problem:
> > 
> >      # ethtool -X eth0  hfunc toeplitz
> > 
> > This is how the problem happens:
> > 
> > 1) ethtool_set_rxfh() calls virtnet_set_rxfh()
> > 
> > 2) virtnet_set_rxfh() calls virtnet_commit_rss_command()
> > 
> > 3) virtnet_commit_rss_command() populates 4 entries for the rss
> > scatter-gather
> > 
> > 4) Since the command above does not have a key, then the last
> > scatter-gatter entry will be zeroed, since rss_key_size == 0.
> > sg_buf_size = vi->rss_key_size;
> > 
> > 5) This buffer is passed to qemu, but qemu is not happy with a buffer
> > with zero length, and do the following in virtqueue_map_desc() (QEMU
> > function):
> > 
> >    if (!sz) {
> >        virtio_error(vdev, "virtio: zero sized buffers are not allowed");
> > 
> > 6) virtio_error() (also QEMU function) set the device as broken
> > 
> >      vdev->broken = true;
> > 
> > 7) Qemu bails out, and do not repond this crazy kernel.
> > 
> > 8) The kernel is waiting for the response to come back (function
> > virtnet_send_command())
> > 
> > 9) The kernel is waiting doing the following :
> > 
> >        while (!virtqueue_get_buf(vi->cvq, &tmp) &&
> > 	     !virtqueue_is_broken(vi->cvq))
> > 	      cpu_relax();
> > 
> > 10) None of the following functions above is true, thus, the kernel
> > loops here forever. Keeping in mind that virtqueue_is_broken() does
> > not look at the qemu `vdev->broken`, so, it never realizes that the
> > vitio is broken at QEMU side.
> > 
> > Fix it by not sending RSS commands if the feature is not available in
> > the device.
> > 
> > Fixes: c7114b1249fa ("drivers/net/virtio_net: Added basic RSS support.")
> > Cc: stable@vger.kernel.org
> > Cc: qemu-devel@nongnu.org
> > Signed-off-by: Breno Leitao <leitao@debian.org>
> > ---
> >   drivers/net/virtio_net.c | 3 +++
> >   1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index c640fdf28fc5..e6b0eaf08ac2 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -3809,6 +3809,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
> >   	struct virtnet_info *vi = netdev_priv(dev);
> >   	int i;
> > +	if (!vi->has_rss && !vi->has_rss_hash_report)
> > +		return -EOPNOTSUPP;
> > +
> 
> Why not make the second patch as the first, this seems to work better.

Sure, that works for me. Let me update it in v2.

Re: [PATCH net v2 1/2] virtio_net: Do not set rss_indir if RSS is not supported

[Breno Leitao]

Hello Xuan,

On Wed, Mar 27, 2024 at 09:37:43AM +0800, Xuan Zhuo wrote:
> On Tue, 26 Mar 2024 08:19:08 -0700, Breno Leitao <leitao@debian.org> wrote:
> > Do not set virtnet_info->rss_indir_table_size if RSS is not available
> > for the device.
> >
> > Currently, rss_indir_table_size is set if either has_rss or
> > has_rss_hash_report is available, but, it should only be set if has_rss
> > is set.
> >
> > On the virtnet_set_rxfh(), return an invalid command if the request has
> > indirection table set, but virtnet does not support RSS.
> >
> > Suggested-by: Heng Qi <hengqi@linux.alibaba.com>
> > Signed-off-by: Breno Leitao <leitao@debian.org>
> > ---
> >  drivers/net/virtio_net.c | 9 +++++++--
> >  1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index c22d1118a133..c640fdf28fc5 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -3813,6 +3813,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
> >  	    rxfh->hfunc != ETH_RSS_HASH_TOP)
> >  		return -EOPNOTSUPP;
> >
> > +	if (rxfh->indir && !vi->has_rss)
> > +		return -EINVAL;
> > +
> >  	if (rxfh->indir) {
> 
> Put !vi->has_rss here?

I am not sure I understand the suggestion. Where do you suggest we have
!vi->has_rss?

If we got this far, we either have:

a) rxfh->indir set and vi->has_rss is also set
b) rxfh->indir not set. (vi->has_rss could be set or not).

Thanks for the review,
Breno

Re: [PATCH net v2 1/2] virtio_net: Do not set rss_indir if RSS is not supported

[Xuan Zhuo]

On Wed, 27 Mar 2024 06:51:25 -0700, Breno Leitao <leitao@debian.org> wrote:
> Hello Xuan,
>
> On Wed, Mar 27, 2024 at 09:37:43AM +0800, Xuan Zhuo wrote:
> > On Tue, 26 Mar 2024 08:19:08 -0700, Breno Leitao <leitao@debian.org> wrote:
> > > Do not set virtnet_info->rss_indir_table_size if RSS is not available
> > > for the device.
> > >
> > > Currently, rss_indir_table_size is set if either has_rss or
> > > has_rss_hash_report is available, but, it should only be set if has_rss
> > > is set.
> > >
> > > On the virtnet_set_rxfh(), return an invalid command if the request has
> > > indirection table set, but virtnet does not support RSS.
> > >
> > > Suggested-by: Heng Qi <hengqi@linux.alibaba.com>
> > > Signed-off-by: Breno Leitao <leitao@debian.org>
> > > ---
> > >  drivers/net/virtio_net.c | 9 +++++++--
> > >  1 file changed, 7 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > > index c22d1118a133..c640fdf28fc5 100644
> > > --- a/drivers/net/virtio_net.c
> > > +++ b/drivers/net/virtio_net.c
> > > @@ -3813,6 +3813,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
> > >  	    rxfh->hfunc != ETH_RSS_HASH_TOP)
> > >  		return -EOPNOTSUPP;
> > >
> > > +	if (rxfh->indir && !vi->has_rss)
> > > +		return -EINVAL;
> > > +
> > >  	if (rxfh->indir) {
> >
> > Put !vi->has_rss here?
>
> I am not sure I understand the suggestion. Where do you suggest we have
> !vi->has_rss?
>
> If we got this far, we either have:
>
> a) rxfh->indir set and vi->has_rss is also set
> b) rxfh->indir not set. (vi->has_rss could be set or not).


This function does two tasks.
1. update indir table
2. update rss key

#1 only for has_rss
#2 for has_rss or has_rss_hash_report


So I would code:

	bool update = false

	if (rxfh->indir) {
		if (!vi->has_rss)
			return -EINVAL;

		for (i = 0; i < vi->rss_indir_table_size; ++i)
			vi->ctrl->rss.indirection_table[i] = rxfh->indir[i];

		update = true
	}

	if (rxfh->key) {
		if (!vi->has_rss && !vi->has_rss_hash_report)
			return -EINVAL;

		memcpy(vi->ctrl->rss.key, rxfh->key, vi->rss_key_size);
		update = true
	}


	if (update)
		virtnet_commit_rss_command(vi);

Thanks.


>
> Thanks for the review,
> Breno

Re: [PATCH net v2 1/2] virtio_net: Do not set rss_indir if RSS is not supported

[Breno Leitao]

> > On Wed, Mar 27, 2024 at 09:37:43AM +0800, Xuan Zhuo wrote:
> > > On Tue, 26 Mar 2024 08:19:08 -0700, Breno Leitao <leitao@debian.org> wrote:
> > > > Do not set virtnet_info->rss_indir_table_size if RSS is not available
> > > > for the device.
> > > >
> > > > Currently, rss_indir_table_size is set if either has_rss or
> > > > has_rss_hash_report is available, but, it should only be set if has_rss
> > > > is set.
> > > >
> > > > On the virtnet_set_rxfh(), return an invalid command if the request has
> > > > indirection table set, but virtnet does not support RSS.
> > > >
> > > > Suggested-by: Heng Qi <hengqi@linux.alibaba.com>
> > > > Signed-off-by: Breno Leitao <leitao@debian.org>
> > > > ---
> > > >  drivers/net/virtio_net.c | 9 +++++++--
> > > >  1 file changed, 7 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > > > index c22d1118a133..c640fdf28fc5 100644
> > > > --- a/drivers/net/virtio_net.c
> > > > +++ b/drivers/net/virtio_net.c
> > > > @@ -3813,6 +3813,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
> > > >  	    rxfh->hfunc != ETH_RSS_HASH_TOP)
> > > >  		return -EOPNOTSUPP;
> > > >
> > > > +	if (rxfh->indir && !vi->has_rss)
> > > > +		return -EINVAL;
> > > > +
> > > >  	if (rxfh->indir) {
> > >
> > > Put !vi->has_rss here?
> >
> > I am not sure I understand the suggestion. Where do you suggest we have
> > !vi->has_rss?
> >
> > If we got this far, we either have:
> >
> > a) rxfh->indir set and vi->has_rss is also set
> > b) rxfh->indir not set. (vi->has_rss could be set or not).
> 
> 
> This function does two tasks.
> 1. update indir table
> 2. update rss key
> 
> #1 only for has_rss
> #2 for has_rss or has_rss_hash_report
> 
> 
> So I would code:
> 
> 	bool update = false
> 
> 	if (rxfh->indir) {
> 		if (!vi->has_rss)
> 			return -EINVAL;
> 
> 		for (i = 0; i < vi->rss_indir_table_size; ++i)
> 			vi->ctrl->rss.indirection_table[i] = rxfh->indir[i];
> 
> 		update = true
> 	}
> 
> 	if (rxfh->key) {
> 		if (!vi->has_rss && !vi->has_rss_hash_report)
> 			return -EINVAL;
> 
> 		memcpy(vi->ctrl->rss.key, rxfh->key, vi->rss_key_size);
> 		update = true
> 	}
> 
> 
> 	if (update)
> 		virtnet_commit_rss_command(vi);
> 
> Thanks.

This is a bit different from the previous proposal, but, I like this one
approach better. It makes the code easier to read.

How does the full patch looks like?


diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c22d1118a133..180f342f1898 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -3807,20 +3807,35 @@ static int virtnet_set_rxfh(struct net_device *dev,
 			    struct netlink_ext_ack *extack)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
+	bool update = false;
 	int i;
 
+	if (!vi->has_rss && !vi->has_rss_hash_report)
+		return -EOPNOTSUPP;
+
 	if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
 	    rxfh->hfunc != ETH_RSS_HASH_TOP)
 		return -EOPNOTSUPP;
 
 	if (rxfh->indir) {
+		if (!vi->has_rss)
+			return -EINVAL;
+
 		for (i = 0; i < vi->rss_indir_table_size; ++i)
 			vi->ctrl->rss.indirection_table[i] = rxfh->indir[i];
+		update = true;
 	}
-	if (rxfh->key)
+
+	if (rxfh->key) {
+		if (!vi->has_rss && !vi->has_rss_hash_report)
+			return -EINVAL;
+
 		memcpy(vi->ctrl->rss.key, rxfh->key, vi->rss_key_size);
+		update = true;
+	}
 
-	virtnet_commit_rss_command(vi);
+	if (update)
+		virtnet_commit_rss_command(vi);
 
 	return 0;
 }
@@ -4729,13 +4744,15 @@ static int virtnet_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))
 		vi->has_rss_hash_report = true;
 
-	if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS))
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) {
 		vi->has_rss = true;
 
-	if (vi->has_rss || vi->has_rss_hash_report) {
 		vi->rss_indir_table_size =
 			virtio_cread16(vdev, offsetof(struct virtio_net_config,
 				rss_max_indirection_table_length));
+	}
+
+	if (vi->has_rss || vi->has_rss_hash_report) {
 		vi->rss_key_size =
 			virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
 

Re: [PATCH net v2 1/2] virtio_net: Do not set rss_indir if RSS is not supported

[Heng Qi]

在 2024/3/28 下午10:37, Breno Leitao 写道:
>>> On Wed, Mar 27, 2024 at 09:37:43AM +0800, Xuan Zhuo wrote:
>>>> On Tue, 26 Mar 2024 08:19:08 -0700, Breno Leitao <leitao@debian.org> wrote:
>>>>> Do not set virtnet_info->rss_indir_table_size if RSS is not available
>>>>> for the device.
>>>>>
>>>>> Currently, rss_indir_table_size is set if either has_rss or
>>>>> has_rss_hash_report is available, but, it should only be set if has_rss
>>>>> is set.
>>>>>
>>>>> On the virtnet_set_rxfh(), return an invalid command if the request has
>>>>> indirection table set, but virtnet does not support RSS.
>>>>>
>>>>> Suggested-by: Heng Qi <hengqi@linux.alibaba.com>
>>>>> Signed-off-by: Breno Leitao <leitao@debian.org>
>>>>> ---
>>>>>   drivers/net/virtio_net.c | 9 +++++++--
>>>>>   1 file changed, 7 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
>>>>> index c22d1118a133..c640fdf28fc5 100644
>>>>> --- a/drivers/net/virtio_net.c
>>>>> +++ b/drivers/net/virtio_net.c
>>>>> @@ -3813,6 +3813,9 @@ static int virtnet_set_rxfh(struct net_device *dev,
>>>>>   	    rxfh->hfunc != ETH_RSS_HASH_TOP)
>>>>>   		return -EOPNOTSUPP;
>>>>>
>>>>> +	if (rxfh->indir && !vi->has_rss)
>>>>> +		return -EINVAL;
>>>>> +
>>>>>   	if (rxfh->indir) {
>>>> Put !vi->has_rss here?
>>> I am not sure I understand the suggestion. Where do you suggest we have
>>> !vi->has_rss?
>>>
>>> If we got this far, we either have:
>>>
>>> a) rxfh->indir set and vi->has_rss is also set
>>> b) rxfh->indir not set. (vi->has_rss could be set or not).
>>
>> This function does two tasks.
>> 1. update indir table
>> 2. update rss key
>>
>> #1 only for has_rss
>> #2 for has_rss or has_rss_hash_report
>>
>>
>> So I would code:
>>
>> 	bool update = false
>>
>> 	if (rxfh->indir) {
>> 		if (!vi->has_rss)
>> 			return -EINVAL;
>>
>> 		for (i = 0; i < vi->rss_indir_table_size; ++i)
>> 			vi->ctrl->rss.indirection_table[i] = rxfh->indir[i];
>>
>> 		update = true
>> 	}
>>
>> 	if (rxfh->key) {
>> 		if (!vi->has_rss && !vi->has_rss_hash_report)
>> 			return -EINVAL;
>>
>> 		memcpy(vi->ctrl->rss.key, rxfh->key, vi->rss_key_size);
>> 		update = true
>> 	}
>>
>>
>> 	if (update)
>> 		virtnet_commit_rss_command(vi);
>>
>> Thanks.
> This is a bit different from the previous proposal, but, I like this one
> approach better. It makes the code easier to read.
>
> How does the full patch looks like?
>
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index c22d1118a133..180f342f1898 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3807,20 +3807,35 @@ static int virtnet_set_rxfh(struct net_device *dev,
>   			    struct netlink_ext_ack *extack)
>   {
>   	struct virtnet_info *vi = netdev_priv(dev);
> +	bool update = false;
>   	int i;
>   
> +	if (!vi->has_rss && !vi->has_rss_hash_report)
> +		return -EOPNOTSUPP;
> +

I think this two modifications are no longer needed as they have been 
embedded below.

>   	if (rxfh->hfunc != ETH_RSS_HASH_NO_CHANGE &&
>   	    rxfh->hfunc != ETH_RSS_HASH_TOP)
>   		return -EOPNOTSUPP;
>   
>   	if (rxfh->indir) {
> +		if (!vi->has_rss)
> +			return -EINVAL;

-EOPNOTSUPP seems better.

> +
>   		for (i = 0; i < vi->rss_indir_table_size; ++i)
>   			vi->ctrl->rss.indirection_table[i] = rxfh->indir[i];
> +		update = true;
>   	}
> -	if (rxfh->key)
> +
> +	if (rxfh->key) {
> +		if (!vi->has_rss && !vi->has_rss_hash_report)
> +			return -EINVAL;

Same as above. return -EOPNOTSUPP.

Others look good.

Thanks.

> +
>   		memcpy(vi->ctrl->rss.key, rxfh->key, vi->rss_key_size);
> +		update = true;
> +	}
>   
> -	virtnet_commit_rss_command(vi);
> +	if (update)
> +		virtnet_commit_rss_command(vi);
>   
>   	return 0;
>   }
> @@ -4729,13 +4744,15 @@ static int virtnet_probe(struct virtio_device *vdev)
>   	if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))
>   		vi->has_rss_hash_report = true;
>   
> -	if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS))
> +	if (virtio_has_feature(vdev, VIRTIO_NET_F_RSS)) {
>   		vi->has_rss = true;
>   
> -	if (vi->has_rss || vi->has_rss_hash_report) {
>   		vi->rss_indir_table_size =
>   			virtio_cread16(vdev, offsetof(struct virtio_net_config,
>   				rss_max_indirection_table_length));
> +	}
> +
> +	if (vi->has_rss || vi->has_rss_hash_report) {
>   		vi->rss_key_size =
>   			virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
>