[PATCH iwl-net] ixgbevf: add missing negotiate_features op to Hyper-V ops table

[PATCH iwl-net] ixgbevf: add missing negotiate_features op to Hyper-V ops table

[Michal Schmidt]

Commit a7075f501bd3 ("ixgbevf: fix mailbox API compatibility by
negotiating supported features") added the .negotiate_features callback
to ixgbe_mac_operations and populated it in ixgbevf_mac_ops, but forgot
to add it to ixgbevf_hv_mac_ops. This leaves the function pointer NULL
on Hyper-V VMs.

During probe, ixgbevf_negotiate_api() calls ixgbevf_set_features(),
which unconditionally dereferences hw->mac.ops.negotiate_features().
On Hyper-V this results in a NULL pointer dereference:

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  [...]
  Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine [...]
  Workqueue: events work_for_cpu_fn
  RIP: 0010:0x0
  [...]
  Call Trace:
   ixgbevf_negotiate_api+0x66/0x160 [ixgbevf]
   ixgbevf_sw_init+0xe4/0x1f0 [ixgbevf]
   ixgbevf_probe+0x20f/0x4a0 [ixgbevf]
   local_pci_probe+0x50/0xa0
   work_for_cpu_fn+0x1a/0x30
   [...]

Add ixgbevf_hv_negotiate_features_vf() that returns -EOPNOTSUPP and
wire it into ixgbevf_hv_mac_ops. The caller already handles -EOPNOTSUPP
gracefully.

Fixes: a7075f501bd3 ("ixgbevf: fix mailbox API compatibility by negotiating supported features")
Reported-by: Xiaoqiang Xiong <xxiong@redhat.com>
Closes: https://issues.redhat.com/browse/RHEL-155455
Assisted-by: Claude:claude-4.6-opus-high Cursor
Tested-by: Xiaoqiang Xiong <xxiong@redhat.com>
Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
---
 drivers/net/ethernet/intel/ixgbevf/vf.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/intel/ixgbevf/vf.c b/drivers/net/ethernet/intel/ixgbevf/vf.c
index b67b580f7f1c..f6df86d124b9 100644
--- a/drivers/net/ethernet/intel/ixgbevf/vf.c
+++ b/drivers/net/ethernet/intel/ixgbevf/vf.c
@@ -709,6 +709,12 @@ static int ixgbevf_negotiate_features_vf(struct ixgbe_hw *hw, u32 *pf_features)
 	return err;
 }
 
+static int ixgbevf_hv_negotiate_features_vf(struct ixgbe_hw *hw,
+					    u32 *pf_features)
+{
+	return -EOPNOTSUPP;
+}
+
 /**
  *  ixgbevf_set_vfta_vf - Set/Unset VLAN filter table address
  *  @hw: pointer to the HW structure
@@ -1142,6 +1148,7 @@ static const struct ixgbe_mac_operations ixgbevf_hv_mac_ops = {
 	.setup_link		= ixgbevf_setup_mac_link_vf,
 	.check_link		= ixgbevf_hv_check_mac_link_vf,
 	.negotiate_api_version	= ixgbevf_hv_negotiate_api_version_vf,
+	.negotiate_features	= ixgbevf_hv_negotiate_features_vf,
 	.set_rar		= ixgbevf_hv_set_rar_vf,
 	.update_mc_addr_list	= ixgbevf_hv_update_mc_addr_list_vf,
 	.update_xcast_mode	= ixgbevf_hv_update_xcast_mode,
-- 
2.53.0

RE: [PATCH iwl-net] ixgbevf: add missing negotiate_features op to Hyper-V ops table

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Michal Schmidt <mschmidt@redhat.com>
> Sent: Friday, March 13, 2026 9:22 AM
> To: Nguyen, Anthony L <anthony.l.nguyen@intel.com>; Kitszel,
> Przemyslaw <przemyslaw.kitszel@intel.com>; Andrew Lunn
> <andrew+netdev@lunn.ch>; David S. Miller <davem@davemloft.net>; Eric
> Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
> Abeni <pabeni@redhat.com>; Keller, Jacob E <jacob.e.keller@intel.com>;
> Loktionov, Aleksandr <aleksandr.loktionov@intel.com>; Jagielski,
> Jedrzej <jedrzej.jagielski@intel.com>
> Cc: Xiaoqiang Xiong <xxiong@redhat.com>; intel-wired-
> lan@lists.osuosl.org; netdev@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: [PATCH iwl-net] ixgbevf: add missing negotiate_features op to
> Hyper-V ops table
> 
> Commit a7075f501bd3 ("ixgbevf: fix mailbox API compatibility by
> negotiating supported features") added the .negotiate_features
> callback to ixgbe_mac_operations and populated it in ixgbevf_mac_ops,
> but forgot to add it to ixgbevf_hv_mac_ops. This leaves the function
> pointer NULL on Hyper-V VMs.
> 
> During probe, ixgbevf_negotiate_api() calls ixgbevf_set_features(),
> which unconditionally dereferences hw->mac.ops.negotiate_features().
> On Hyper-V this results in a NULL pointer dereference:
> 
>   BUG: kernel NULL pointer dereference, address: 0000000000000000
>   [...]
>   Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine
> [...]
>   Workqueue: events work_for_cpu_fn
>   RIP: 0010:0x0
>   [...]
>   Call Trace:
>    ixgbevf_negotiate_api+0x66/0x160 [ixgbevf]
>    ixgbevf_sw_init+0xe4/0x1f0 [ixgbevf]
>    ixgbevf_probe+0x20f/0x4a0 [ixgbevf]
>    local_pci_probe+0x50/0xa0
>    work_for_cpu_fn+0x1a/0x30
>    [...]
> 
> Add ixgbevf_hv_negotiate_features_vf() that returns -EOPNOTSUPP and
> wire it into ixgbevf_hv_mac_ops. The caller already handles -
> EOPNOTSUPP gracefully.
> 
> Fixes: a7075f501bd3 ("ixgbevf: fix mailbox API compatibility by
> negotiating supported features")
> Reported-by: Xiaoqiang Xiong <xxiong@redhat.com>
> Closes: https://issues.redhat.com/browse/RHEL-155455
> Assisted-by: Claude:claude-4.6-opus-high Cursor
> Tested-by: Xiaoqiang Xiong <xxiong@redhat.com>
> Signed-off-by: Michal Schmidt <mschmidt@redhat.com>
> ---
>  drivers/net/ethernet/intel/ixgbevf/vf.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ixgbevf/vf.c
> b/drivers/net/ethernet/intel/ixgbevf/vf.c
> index b67b580f7f1c..f6df86d124b9 100644
> --- a/drivers/net/ethernet/intel/ixgbevf/vf.c
> +++ b/drivers/net/ethernet/intel/ixgbevf/vf.c
> @@ -709,6 +709,12 @@ static int ixgbevf_negotiate_features_vf(struct
> ixgbe_hw *hw, u32 *pf_features)
>  	return err;
>  }
> 
> +static int ixgbevf_hv_negotiate_features_vf(struct ixgbe_hw *hw,
> +					    u32 *pf_features)
> +{
> +	return -EOPNOTSUPP;
> +}
> +
>  /**
>   *  ixgbevf_set_vfta_vf - Set/Unset VLAN filter table address
>   *  @hw: pointer to the HW structure
> @@ -1142,6 +1148,7 @@ static const struct ixgbe_mac_operations
> ixgbevf_hv_mac_ops = {
>  	.setup_link		= ixgbevf_setup_mac_link_vf,
>  	.check_link		= ixgbevf_hv_check_mac_link_vf,
>  	.negotiate_api_version	=
> ixgbevf_hv_negotiate_api_version_vf,
> +	.negotiate_features	= ixgbevf_hv_negotiate_features_vf,
>  	.set_rar		= ixgbevf_hv_set_rar_vf,
>  	.update_mc_addr_list	= ixgbevf_hv_update_mc_addr_list_vf,
>  	.update_xcast_mode	= ixgbevf_hv_update_xcast_mode,
> --
> 2.53.0

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>