From 325782a173d1858bb67a827905e264cd128241d0 Mon Sep 17 00:00:00 2001 From: Jacob Keller Date: Mon, 8 Aug 2016 17:08:19 -0700 Subject: [PATCH] fm10k: don't re-map queues when a mailbox message suffices When the PF assigns a new MAC address to a VF it uses the base address registers to store the MAC address. This allows a VF which loads after this setup the ability to get the initial address without having to wait for a mailbox message. Unfortunately to do this, the PF must take queue ownership away from the VF, which can cause fault errors when there is already an active VF driver. This queue ownership assignment causes race condition between the PF and the VF such that potentially a VF can cause FUM fault errors due to normal PF/VF driver behavior. It is not safe to simply allow the PF to write the base address registers without taking queue ownership back as the PF must also disable the queues, and this would impact active VF use. The current code is safe because the queue ownership will prevent the VF from actually writing but does trigger the FUM fault. We can do better by simply avoiding the register write process when a mailbox message suffices. If the message can be sent over the mailbox, then we will not perform the queue ownership assignment and we won't update the base address to be the same as the MAC address. We do still have to write the TXQCTL registers in order to update the VID of the queue. This is necessary because the TXQCTL register is read-only from the VF, and thus the VF cannot do this for itself. This register does not need to wait for the Tx queue to be disabled and is safe for the PF to write during normal VF operation, so we move this write to the top of the function above the mailbox message. Without this, the TXQCTL register would be misconfigured and cause the VF to Tx hang. Signed-off-by: Jacob Keller Tested-by: Krishneil Singh Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/fm10k/fm10k_pf.c | 46 +++++++++++++-------- 1 file changed, 29 insertions(+), 17 deletions(-) diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pf.c b/drivers/net/ethernet/intel/fm10k/fm10k_pf.c index 682299dd0ce4..23fb319fd2a0 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k_pf.c +++ b/drivers/net/ethernet/intel/fm10k/fm10k_pf.c @@ -867,10 +867,6 @@ static s32 fm10k_iov_assign_default_mac_vlan_pf(struct fm10k_hw *hw, vf_q_idx = fm10k_vf_queue_index(hw, vf_idx); qmap_idx = qmap_stride * vf_idx; - /* MAP Tx queue back to 0 temporarily, and disable it */ - fm10k_write_reg(hw, FM10K_TQMAP(qmap_idx), 0); - fm10k_write_reg(hw, FM10K_TXDCTL(vf_q_idx), 0); - /* Determine correct default VLAN ID. The FM10K_VLAN_OVERRIDE bit is * used here to indicate to the VF that it will not have privilege to * write VLAN_TABLE. All policy is enforced on the PF but this allows @@ -886,9 +882,35 @@ static s32 fm10k_iov_assign_default_mac_vlan_pf(struct fm10k_hw *hw, fm10k_tlv_attr_put_mac_vlan(msg, FM10K_MAC_VLAN_MSG_DEFAULT_MAC, vf_info->mac, vf_vid); - /* load onto outgoing mailbox, ignore any errors on enqueue */ - if (vf_info->mbx.ops.enqueue_tx) - vf_info->mbx.ops.enqueue_tx(hw, &vf_info->mbx, msg); + /* Configure Queue control register with new VLAN ID. The TXQCTL + * register is RO from the VF, so the PF must do this even in the + * case of notifying the VF of a new VID via the mailbox. + */ + txqctl = ((u32)vf_vid << FM10K_TXQCTL_VID_SHIFT) & + FM10K_TXQCTL_VID_MASK; + txqctl |= (vf_idx << FM10K_TXQCTL_TC_SHIFT) | + FM10K_TXQCTL_VF | vf_idx; + + for (i = 0; i < queues_per_pool; i++) + fm10k_write_reg(hw, FM10K_TXQCTL(vf_q_idx + i), txqctl); + + /* try loading a message onto outgoing mailbox first */ + if (vf_info->mbx.ops.enqueue_tx) { + err = vf_info->mbx.ops.enqueue_tx(hw, &vf_info->mbx, msg); + if (err != FM10K_MBX_ERR_NO_MBX) + return err; + err = 0; + } + + /* If we aren't connected to a mailbox, this is most likely because + * the VF driver is not running. It should thus be safe to re-map + * queues and use the registers to pass the MAC address so that the VF + * driver gets correct information during its initialization. + */ + + /* MAP Tx queue back to 0 temporarily, and disable it */ + fm10k_write_reg(hw, FM10K_TQMAP(qmap_idx), 0); + fm10k_write_reg(hw, FM10K_TXDCTL(vf_q_idx), 0); /* verify ring has disabled before modifying base address registers */ txdctl = fm10k_read_reg(hw, FM10K_TXDCTL(vf_q_idx)); @@ -927,16 +949,6 @@ static s32 fm10k_iov_assign_default_mac_vlan_pf(struct fm10k_hw *hw, FM10K_TDLEN_ITR_SCALE_SHIFT); err_out: - /* configure Queue control register */ - txqctl = ((u32)vf_vid << FM10K_TXQCTL_VID_SHIFT) & - FM10K_TXQCTL_VID_MASK; - txqctl |= (vf_idx << FM10K_TXQCTL_TC_SHIFT) | - FM10K_TXQCTL_VF | vf_idx; - - /* assign VLAN ID */ - for (i = 0; i < queues_per_pool; i++) - fm10k_write_reg(hw, FM10K_TXQCTL(vf_q_idx + i), txqctl); - /* restore the queue back to VF ownership */ fm10k_write_reg(hw, FM10K_TQMAP(qmap_idx), vf_q_idx); return err; -- GitLab