Merge branch '200GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/net-queue

Tony Nguyen says:

====================
idpf: trigger SW interrupt when exiting wb_on_itr mode

Joshua Hay says:

This patch series introduces SW triggered interrupt support for idpf,
then uses said interrupt to fix a race condition between completion
writebacks and re-enabling interrupts.

* '200GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/net-queue:
  idpf: trigger SW interrupt when exiting wb_on_itr mode
  idpf: add support for SW triggered interrupts
====================

Link: https://patch.msgid.link/20241217225715.4005644-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

4 files changed, 32 insertions, 11 deletions

diff --git a/drivers/net/ethernet/intel/idpf/idpf_dev.c b/drivers/net/ethernet/intel/idpf/idpf_dev.c
index 6c913a703df6..41e4bd49402a 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_dev.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_dev.c
@@ -101,6 +101,9 @@ static int idpf_intr_reg_init(struct idpf_vport *vport)
 		intr->dyn_ctl_itridx_s = PF_GLINT_DYN_CTL_ITR_INDX_S;
 		intr->dyn_ctl_intrvl_s = PF_GLINT_DYN_CTL_INTERVAL_S;
 		intr->dyn_ctl_wb_on_itr_m = PF_GLINT_DYN_CTL_WB_ON_ITR_M;
+		intr->dyn_ctl_swint_trig_m = PF_GLINT_DYN_CTL_SWINT_TRIG_M;
+		intr->dyn_ctl_sw_itridx_ena_m =
+			PF_GLINT_DYN_CTL_SW_ITR_INDX_ENA_M;
 
 		spacing = IDPF_ITR_IDX_SPACING(reg_vals[vec_id].itrn_index_spacing,
 					       IDPF_PF_ITR_IDX_SPACING);
diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.c b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
index 34f4118c7bc0..2fa9c36e33c9 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c
@@ -3604,21 +3604,31 @@ static void idpf_vport_intr_dis_irq_all(struct idpf_vport *vport)
 /**
  * idpf_vport_intr_buildreg_itr - Enable default interrupt generation settings
  * @q_vector: pointer to q_vector
- * @type: itr index
- * @itr: itr value
  */
-static u32 idpf_vport_intr_buildreg_itr(struct idpf_q_vector *q_vector,
-					const int type, u16 itr)
+static u32 idpf_vport_intr_buildreg_itr(struct idpf_q_vector *q_vector)
 {
-	u32 itr_val;
+	u32 itr_val = q_vector->intr_reg.dyn_ctl_intena_m;
+	int type = IDPF_NO_ITR_UPDATE_IDX;
+	u16 itr = 0;
+
+	if (q_vector->wb_on_itr) {
+		/*
+		 * Trigger a software interrupt when exiting wb_on_itr, to make
+		 * sure we catch any pending write backs that might have been
+		 * missed due to interrupt state transition.
+		 */
+		itr_val |= q_vector->intr_reg.dyn_ctl_swint_trig_m |
+			   q_vector->intr_reg.dyn_ctl_sw_itridx_ena_m;
+		type = IDPF_SW_ITR_UPDATE_IDX;
+		itr = IDPF_ITR_20K;
+	}
 
 	itr &= IDPF_ITR_MASK;
 	/* Don't clear PBA because that can cause lost interrupts that
 	 * came in while we were cleaning/polling
 	 */
-	itr_val = q_vector->intr_reg.dyn_ctl_intena_m |
-		  (type << q_vector->intr_reg.dyn_ctl_itridx_s) |
-		  (itr << (q_vector->intr_reg.dyn_ctl_intrvl_s - 1));
+	itr_val |= (type << q_vector->intr_reg.dyn_ctl_itridx_s) |
+		   (itr << (q_vector->intr_reg.dyn_ctl_intrvl_s - 1));
 
 	return itr_val;
 }
@@ -3716,9 +3726,8 @@ void idpf_vport_intr_update_itr_ena_irq(struct idpf_q_vector *q_vector)
 	/* net_dim() updates ITR out-of-band using a work item */
 	idpf_net_dim(q_vector);
 
+	intval = idpf_vport_intr_buildreg_itr(q_vector);
 	q_vector->wb_on_itr = false;
-	intval = idpf_vport_intr_buildreg_itr(q_vector,
-					      IDPF_NO_ITR_UPDATE_IDX, 0);
 
 	writel(intval, q_vector->intr_reg.dyn_ctl);
 }
diff --git a/drivers/net/ethernet/intel/idpf/idpf_txrx.h b/drivers/net/ethernet/intel/idpf/idpf_txrx.h
index 9c1fe84108ed..0f71a6f5557b 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.h
+++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.h
@@ -354,6 +354,8 @@ struct idpf_vec_regs {
  * @dyn_ctl_itridx_m: Mask for ITR index
  * @dyn_ctl_intrvl_s: Register bit offset for ITR interval
  * @dyn_ctl_wb_on_itr_m: Mask for WB on ITR feature
+ * @dyn_ctl_sw_itridx_ena_m: Mask for SW ITR index
+ * @dyn_ctl_swint_trig_m: Mask for dyn_ctl SW triggered interrupt enable
  * @rx_itr: RX ITR register
  * @tx_itr: TX ITR register
  * @icr_ena: Interrupt cause register offset
@@ -367,6 +369,8 @@ struct idpf_intr_reg {
 	u32 dyn_ctl_itridx_m;
 	u32 dyn_ctl_intrvl_s;
 	u32 dyn_ctl_wb_on_itr_m;
+	u32 dyn_ctl_sw_itridx_ena_m;
+	u32 dyn_ctl_swint_trig_m;
 	void __iomem *rx_itr;
 	void __iomem *tx_itr;
 	void __iomem *icr_ena;
@@ -437,7 +441,7 @@ struct idpf_q_vector {
 	cpumask_var_t affinity_mask;
 	__cacheline_group_end_aligned(cold);
 };
-libeth_cacheline_set_assert(struct idpf_q_vector, 112,
+libeth_cacheline_set_assert(struct idpf_q_vector, 120,
 			    24 + sizeof(struct napi_struct) +
 			    2 * sizeof(struct dim),
 			    8 + sizeof(cpumask_var_t));
@@ -471,6 +475,8 @@ struct idpf_tx_queue_stats {
 #define IDPF_ITR_IS_DYNAMIC(itr_mode) (itr_mode)
 #define IDPF_ITR_TX_DEF		IDPF_ITR_20K
 #define IDPF_ITR_RX_DEF		IDPF_ITR_20K
+/* Index used for 'SW ITR' update in DYN_CTL register */
+#define IDPF_SW_ITR_UPDATE_IDX	2
 /* Index used for 'No ITR' update in DYN_CTL register */
 #define IDPF_NO_ITR_UPDATE_IDX	3
 #define IDPF_ITR_IDX_SPACING(spacing, dflt)	(spacing ? spacing : dflt)
diff --git a/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c b/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
index aad62e270ae4..aba828abcb17 100644
--- a/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
+++ b/drivers/net/ethernet/intel/idpf/idpf_vf_dev.c
@@ -101,6 +101,9 @@ static int idpf_vf_intr_reg_init(struct idpf_vport *vport)
 		intr->dyn_ctl_itridx_s = VF_INT_DYN_CTLN_ITR_INDX_S;
 		intr->dyn_ctl_intrvl_s = VF_INT_DYN_CTLN_INTERVAL_S;
 		intr->dyn_ctl_wb_on_itr_m = VF_INT_DYN_CTLN_WB_ON_ITR_M;
+		intr->dyn_ctl_swint_trig_m = VF_INT_DYN_CTLN_SWINT_TRIG_M;
+		intr->dyn_ctl_sw_itridx_ena_m =
+			VF_INT_DYN_CTLN_SW_ITR_INDX_ENA_M;
 
 		spacing = IDPF_ITR_IDX_SPACING(reg_vals[vec_id].itrn_index_spacing,
 					       IDPF_VF_ITR_IDX_SPACING);