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i40e/i40evf: don't trust VF to reset itself
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When using 'ethtool -L' on a VF to change number of requested queues
from PF, we shouldn't trust the VF to reset itself after making the
request.  Doing it that way opens the door for a potentially malicious
VF to do nasty things to the PF which should never be the case.

This makes it such that after VF makes a successful request, PF will
then reset the VF to institute required changes.  Only if the request
fails will PF send a message back to VF letting it know the request was
unsuccessful.

Testing-hints:
There should be no real functional changes.  This is simply hardening
against a potentially malicious VF.

Signed-off-by: Alan Brady <alan.brady@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
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Alan Brady authored and Jeff Kirsher committed Oct 13, 2017
1 parent 8fdb69d commit 17a9422
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Showing 3 changed files with 12 additions and 8 deletions.
9 changes: 7 additions & 2 deletions drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
Original file line number Diff line number Diff line change
Expand Up @@ -2045,8 +2045,9 @@ static int i40e_vc_disable_queues_msg(struct i40e_vf *vf, u8 *msg, u16 msglen)
* @msglen: msg length
*
* VFs get a default number of queues but can use this message to request a
* different number. Will respond with either the number requested or the
* maximum we can support.
* different number. If the request is successful, PF will reset the VF and
* return 0. If unsuccessful, PF will send message informing VF of number of
* available queues and return result of sending VF a message.
**/
static int i40e_vc_request_queues_msg(struct i40e_vf *vf, u8 *msg, int msglen)
{
Expand Down Expand Up @@ -2077,7 +2078,11 @@ static int i40e_vc_request_queues_msg(struct i40e_vf *vf, u8 *msg, int msglen)
pf->queues_left);
vfres->num_queue_pairs = pf->queues_left + cur_pairs;
} else {
/* successful request */
vf->num_req_queues = req_pairs;
i40e_vc_notify_vf_reset(vf);
i40e_reset_vf(vf, false);
return 0;
}

return i40e_vc_send_msg_to_vf(vf, VIRTCHNL_OP_REQUEST_QUEUES, 0,
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7 changes: 3 additions & 4 deletions drivers/net/ethernet/intel/i40evf/i40evf_virtchnl.c
Original file line number Diff line number Diff line change
Expand Up @@ -407,6 +407,7 @@ int i40evf_request_queues(struct i40evf_adapter *adapter, int num)
vfres.num_queue_pairs = num;

adapter->current_op = VIRTCHNL_OP_REQUEST_QUEUES;
adapter->flags |= I40EVF_FLAG_REINIT_ITR_NEEDED;
return i40evf_send_pf_msg(adapter, VIRTCHNL_OP_REQUEST_QUEUES,
(u8 *)&vfres, sizeof(vfres));
}
Expand Down Expand Up @@ -1098,15 +1099,13 @@ void i40evf_virtchnl_completion(struct i40evf_adapter *adapter,
case VIRTCHNL_OP_REQUEST_QUEUES: {
struct virtchnl_vf_res_request *vfres =
(struct virtchnl_vf_res_request *)msg;
if (vfres->num_queue_pairs == adapter->num_req_queues) {
adapter->flags |= I40EVF_FLAG_REINIT_ITR_NEEDED;
i40evf_schedule_reset(adapter);
} else {
if (vfres->num_queue_pairs != adapter->num_req_queues) {
dev_info(&adapter->pdev->dev,
"Requested %d queues, PF can support %d\n",
adapter->num_req_queues,
vfres->num_queue_pairs);
adapter->num_req_queues = 0;
adapter->flags &= ~I40EVF_FLAG_REINIT_ITR_NEEDED;
}
}
break;
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4 changes: 2 additions & 2 deletions include/linux/avf/virtchnl.h
Original file line number Diff line number Diff line change
Expand Up @@ -333,8 +333,8 @@ struct virtchnl_vsi_queue_config_info {
* additional queues must be negotiated. This is a best effort request as it
* is possible the PF does not have enough queues left to support the request.
* If the PF cannot support the number requested it will respond with the
* maximum number it is able to support; otherwise it will respond with the
* number requested.
* maximum number it is able to support. If the request is successful, PF will
* then reset the VF to institute required changes.
*/

/* VF resource request */
Expand Down

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