Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue

Tony Nguyen says:

====================
ice: managing MSI-X in driver

Michal Swiatkowski says:

It is another try to allow user to manage amount of MSI-X used for each
feature in ice. First was via devlink resources API, it wasn't accepted
in upstream. Also static MSI-X allocation using devlink resources isn't
really user friendly.

This try is using more dynamic way. "Dynamic" across whole kernel when
platform supports it and "dynamic" across the driver when not.

To achieve that reuse global devlink parameter pf_msix_max and
pf_msix_min. It fits how ice hardware counts MSI-X. In case of ice amount
of MSI-X reported on PCI is a whole MSI-X for the card (with MSI-X for
VFs also). Having pf_msix_max allow user to statically set how many
MSI-X he wants on PF and how many should be reserved for VFs.

pf_msix_min is used to set minimum number of MSI-X with which ice driver
should probe correctly.

Meaning of this field in case of dynamic vs static allocation:
- on system with dynamic MSI-X allocation support
 * alloc pf_msix_min as static, rest will be allocated dynamically
- on system without dynamic MSI-X allocation support
 * try alloc pf_msix_max as static, minimum acceptable result is
 pf_msix_min

As Jesse and Piotr suggested pf_msix_max and pf_msix_min can (an
probably should) be stored in NVM. This patchset isn't implementing
that.

Dynamic (kernel or driver) way means that splitting MSI-X across the
RDMA and eth in case there is a MSI-X shortage isn't correct. Can work
when dynamic is only on driver site, but can't when dynamic is on kernel
site.

Let's remove this code and move to MSI-X allocation feature by feature.
If there is no more MSI-X for a feature, a feature is working with less
MSI-X or it is turned off.

There is a regression here. With MSI-X splitting user can run RDMA and
eth even on system with not enough MSI-X. Now only eth will work. RDMA
can be turned on by changing number of PF queues (lowering) and reprobe
RDMA driver.

Example:
72 CPU number, eth, RDMA and flow director (1 MSI-X), 1 MSI-X for OICR
on PF, and 1 more for RDMA. Card is using 1 + 72 + 1 + 72 + 1 = 147.

We set pf_msix_min = 2, pf_msix_max = 128

OICR: 1
eth: 72
flow director: 1
RDMA: 128 - 74 = 54

We can change number of queues on pf to 36 and do devlink reinit

OICR: 1
eth: 36
RDMA: 73
flow director: 1

We can also (implemented in "ice: enable_rdma devlink param") turned
RDMA off.

OICR: 1
eth: 72
RDMA: 0 (turned off)
flow director: 1

After this changes we have a static base vector for SRIOV (SIOV probably
in the feature). Last patch from this series is simplifying managing VF
MSI-X code based on static vector.

Now changing queues using ethtool is also changing MSI-X. If there is
enough MSI-X it is always one to one. When there is not enough there
will be more queues than MSI-X.

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue:
  ice: init flow director before RDMA
  ice: simplify VF MSI-X managing
  ice: enable_rdma devlink param
  ice: treat dyn_allowed only as suggestion
  ice, irdma: move interrupts code to irdma
  ice: get rid of num_lan_msix field
  ice: remove splitting MSI-X between features
  ice: devlink PF MSI-X max and min parameter
  ice: count combined queues using Rx/Tx count
====================

Link: https://patch.msgid.link/20250205185512.895887-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 86 insertions, 189 deletions

diff --git a/drivers/net/ethernet/intel/ice/ice_irq.c b/drivers/net/ethernet/intel/ice/ice_irq.c
index ad82ff7d1995..cbae3d81f0f1 100644
--- a/drivers/net/ethernet/intel/ice/ice_irq.c
+++ b/drivers/net/ethernet/intel/ice/ice_irq.c
@@ -20,6 +20,19 @@ ice_init_irq_tracker(struct ice_pf *pf, unsigned int max_vectors,
 	xa_init_flags(&pf->irq_tracker.entries, XA_FLAGS_ALLOC);
 }
 
+static int
+ice_init_virt_irq_tracker(struct ice_pf *pf, u32 base, u32 num_entries)
+{
+	pf->virt_irq_tracker.bm = bitmap_zalloc(num_entries, GFP_KERNEL);
+	if (!pf->virt_irq_tracker.bm)
+		return -ENOMEM;
+
+	pf->virt_irq_tracker.num_entries = num_entries;
+	pf->virt_irq_tracker.base = base;
+
+	return 0;
+}
+
 /**
  * ice_deinit_irq_tracker - free xarray tracker
  * @pf: board private structure
@@ -29,6 +42,11 @@ static void ice_deinit_irq_tracker(struct ice_pf *pf)
 	xa_destroy(&pf->irq_tracker.entries);
 }
 
+static void ice_deinit_virt_irq_tracker(struct ice_pf *pf)
+{
+	bitmap_free(pf->virt_irq_tracker.bm);
+}
+
 /**
  * ice_free_irq_res - free a block of resources
  * @pf: board private structure
@@ -45,7 +63,7 @@ static void ice_free_irq_res(struct ice_pf *pf, u16 index)
 /**
  * ice_get_irq_res - get an interrupt resource
  * @pf: board private structure
- * @dyn_only: force entry to be dynamically allocated
+ * @dyn_allowed: allow entry to be dynamically allocated
  *
  * Allocate new irq entry in the free slot of the tracker. Since xarray
  * is used, always allocate new entry at the lowest possible index. Set
@@ -53,11 +71,12 @@ static void ice_free_irq_res(struct ice_pf *pf, u16 index)
  *
  * Returns allocated irq entry or NULL on failure.
  */
-static struct ice_irq_entry *ice_get_irq_res(struct ice_pf *pf, bool dyn_only)
+static struct ice_irq_entry *ice_get_irq_res(struct ice_pf *pf,
+					     bool dyn_allowed)
 {
-	struct xa_limit limit = { .max = pf->irq_tracker.num_entries,
+	struct xa_limit limit = { .max = pf->irq_tracker.num_entries - 1,
 				  .min = 0 };
-	unsigned int num_static = pf->irq_tracker.num_static;
+	unsigned int num_static = pf->irq_tracker.num_static - 1;
 	struct ice_irq_entry *entry;
 	unsigned int index;
 	int ret;
@@ -66,9 +85,9 @@ static struct ice_irq_entry *ice_get_irq_res(struct ice_pf *pf, bool dyn_only)
 	if (!entry)
 		return NULL;
 
-	/* skip preallocated entries if the caller says so */
-	if (dyn_only)
-		limit.min = num_static;
+	/* only already allocated if the caller says so */
+	if (!dyn_allowed)
+		limit.max = num_static;
 
 	ret = xa_alloc(&pf->irq_tracker.entries, &index, entry, limit,
 		       GFP_KERNEL);
@@ -78,161 +97,18 @@ static struct ice_irq_entry *ice_get_irq_res(struct ice_pf *pf, bool dyn_only)
 		entry = NULL;
 	} else {
 		entry->index = index;
-		entry->dynamic = index >= num_static;
+		entry->dynamic = index > num_static;
 	}
 
 	return entry;
 }
 
-/**
- * ice_reduce_msix_usage - Reduce usage of MSI-X vectors
- * @pf: board private structure
- * @v_remain: number of remaining MSI-X vectors to be distributed
- *
- * Reduce the usage of MSI-X vectors when entire request cannot be fulfilled.
- * pf->num_lan_msix and pf->num_rdma_msix values are set based on number of
- * remaining vectors.
- */
-static void ice_reduce_msix_usage(struct ice_pf *pf, int v_remain)
+#define ICE_RDMA_AEQ_MSIX 1
+static int ice_get_default_msix_amount(struct ice_pf *pf)
 {
-	int v_rdma;
-
-	if (!ice_is_rdma_ena(pf)) {
-		pf->num_lan_msix = v_remain;
-		return;
-	}
-
-	/* RDMA needs at least 1 interrupt in addition to AEQ MSIX */
-	v_rdma = ICE_RDMA_NUM_AEQ_MSIX + 1;
-
-	if (v_remain < ICE_MIN_LAN_TXRX_MSIX + ICE_MIN_RDMA_MSIX) {
-		dev_warn(ice_pf_to_dev(pf), "Not enough MSI-X vectors to support RDMA.\n");
-		clear_bit(ICE_FLAG_RDMA_ENA, pf->flags);
-
-		pf->num_rdma_msix = 0;
-		pf->num_lan_msix = ICE_MIN_LAN_TXRX_MSIX;
-	} else if ((v_remain < ICE_MIN_LAN_TXRX_MSIX + v_rdma) ||
-		   (v_remain - v_rdma < v_rdma)) {
-		/* Support minimum RDMA and give remaining vectors to LAN MSIX
-		 */
-		pf->num_rdma_msix = ICE_MIN_RDMA_MSIX;
-		pf->num_lan_msix = v_remain - ICE_MIN_RDMA_MSIX;
-	} else {
-		/* Split remaining MSIX with RDMA after accounting for AEQ MSIX
-		 */
-		pf->num_rdma_msix = (v_remain - ICE_RDMA_NUM_AEQ_MSIX) / 2 +
-				    ICE_RDMA_NUM_AEQ_MSIX;
-		pf->num_lan_msix = v_remain - pf->num_rdma_msix;
-	}
-}
-
-/**
- * ice_ena_msix_range - Request a range of MSIX vectors from the OS
- * @pf: board private structure
- *
- * Compute the number of MSIX vectors wanted and request from the OS. Adjust
- * device usage if there are not enough vectors. Return the number of vectors
- * reserved or negative on failure.
- */
-static int ice_ena_msix_range(struct ice_pf *pf)
-{
-	int num_cpus, hw_num_msix, v_other, v_wanted, v_actual;
-	struct device *dev = ice_pf_to_dev(pf);
-	int err;
-
-	hw_num_msix = pf->hw.func_caps.common_cap.num_msix_vectors;
-	num_cpus = num_online_cpus();
-
-	/* LAN miscellaneous handler */
-	v_other = ICE_MIN_LAN_OICR_MSIX;
-
-	/* Flow Director */
-	if (test_bit(ICE_FLAG_FD_ENA, pf->flags))
-		v_other += ICE_FDIR_MSIX;
-
-	/* switchdev */
-	v_other += ICE_ESWITCH_MSIX;
-
-	v_wanted = v_other;
-
-	/* LAN traffic */
-	pf->num_lan_msix = num_cpus;
-	v_wanted += pf->num_lan_msix;
-
-	/* RDMA auxiliary driver */
-	if (ice_is_rdma_ena(pf)) {
-		pf->num_rdma_msix = num_cpus + ICE_RDMA_NUM_AEQ_MSIX;
-		v_wanted += pf->num_rdma_msix;
-	}
-
-	if (v_wanted > hw_num_msix) {
-		int v_remain;
-
-		dev_warn(dev, "not enough device MSI-X vectors. wanted = %d, available = %d\n",
-			 v_wanted, hw_num_msix);
-
-		if (hw_num_msix < ICE_MIN_MSIX) {
-			err = -ERANGE;
-			goto exit_err;
-		}
-
-		v_remain = hw_num_msix - v_other;
-		if (v_remain < ICE_MIN_LAN_TXRX_MSIX) {
-			v_other = ICE_MIN_MSIX - ICE_MIN_LAN_TXRX_MSIX;
-			v_remain = ICE_MIN_LAN_TXRX_MSIX;
-		}
-
-		ice_reduce_msix_usage(pf, v_remain);
-		v_wanted = pf->num_lan_msix + pf->num_rdma_msix + v_other;
-
-		dev_notice(dev, "Reducing request to %d MSI-X vectors for LAN traffic.\n",
-			   pf->num_lan_msix);
-		if (ice_is_rdma_ena(pf))
-			dev_notice(dev, "Reducing request to %d MSI-X vectors for RDMA.\n",
-				   pf->num_rdma_msix);
-	}
-
-	/* actually reserve the vectors */
-	v_actual = pci_alloc_irq_vectors(pf->pdev, ICE_MIN_MSIX, v_wanted,
-					 PCI_IRQ_MSIX);
-	if (v_actual < 0) {
-		dev_err(dev, "unable to reserve MSI-X vectors\n");
-		err = v_actual;
-		goto exit_err;
-	}
-
-	if (v_actual < v_wanted) {
-		dev_warn(dev, "not enough OS MSI-X vectors. requested = %d, obtained = %d\n",
-			 v_wanted, v_actual);
-
-		if (v_actual < ICE_MIN_MSIX) {
-			/* error if we can't get minimum vectors */
-			pci_free_irq_vectors(pf->pdev);
-			err = -ERANGE;
-			goto exit_err;
-		} else {
-			int v_remain = v_actual - v_other;
-
-			if (v_remain < ICE_MIN_LAN_TXRX_MSIX)
-				v_remain = ICE_MIN_LAN_TXRX_MSIX;
-
-			ice_reduce_msix_usage(pf, v_remain);
-
-			dev_notice(dev, "Enabled %d MSI-X vectors for LAN traffic.\n",
-				   pf->num_lan_msix);
-
-			if (ice_is_rdma_ena(pf))
-				dev_notice(dev, "Enabled %d MSI-X vectors for RDMA.\n",
-					   pf->num_rdma_msix);
-		}
-	}
-
-	return v_actual;
-
-exit_err:
-	pf->num_rdma_msix = 0;
-	pf->num_lan_msix = 0;
-	return err;
+	return ICE_MIN_LAN_OICR_MSIX + num_online_cpus() +
+	       (test_bit(ICE_FLAG_FD_ENA, pf->flags) ? ICE_FDIR_MSIX : 0) +
+	       (ice_is_rdma_ena(pf) ? num_online_cpus() + ICE_RDMA_AEQ_MSIX : 0);
 }
 
 /**
@@ -243,6 +119,7 @@ void ice_clear_interrupt_scheme(struct ice_pf *pf)
 {
 	pci_free_irq_vectors(pf->pdev);
 	ice_deinit_irq_tracker(pf);
+	ice_deinit_virt_irq_tracker(pf);
 }
 
 /**
@@ -252,27 +129,38 @@ void ice_clear_interrupt_scheme(struct ice_pf *pf)
 int ice_init_interrupt_scheme(struct ice_pf *pf)
 {
 	int total_vectors = pf->hw.func_caps.common_cap.num_msix_vectors;
-	int vectors, max_vectors;
+	int vectors;
 
-	vectors = ice_ena_msix_range(pf);
+	/* load default PF MSI-X range */
+	if (!pf->msix.min)
+		pf->msix.min = ICE_MIN_MSIX;
 
-	if (vectors < 0)
-		return -ENOMEM;
+	if (!pf->msix.max)
+		pf->msix.max = min(total_vectors,
+				   ice_get_default_msix_amount(pf));
+
+	pf->msix.total = total_vectors;
+	pf->msix.rest = total_vectors - pf->msix.max;
 
 	if (pci_msix_can_alloc_dyn(pf->pdev))
-		max_vectors = total_vectors;
+		vectors = pf->msix.min;
 	else
-		max_vectors = vectors;
+		vectors = pf->msix.max;
+
+	vectors = pci_alloc_irq_vectors(pf->pdev, pf->msix.min, vectors,
+					PCI_IRQ_MSIX);
+	if (vectors < pf->msix.min)
+		return -ENOMEM;
 
-	ice_init_irq_tracker(pf, max_vectors, vectors);
+	ice_init_irq_tracker(pf, pf->msix.max, vectors);
 
-	return 0;
+	return ice_init_virt_irq_tracker(pf, pf->msix.max, pf->msix.rest);
 }
 
 /**
  * ice_alloc_irq - Allocate new interrupt vector
  * @pf: board private structure
- * @dyn_only: force dynamic allocation of the interrupt
+ * @dyn_allowed: allow dynamic allocation of the interrupt
  *
  * Allocate new interrupt vector for a given owner id.
  * return struct msi_map with interrupt details and track
@@ -285,27 +173,22 @@ int ice_init_interrupt_scheme(struct ice_pf *pf)
  * interrupt will be allocated with pci_msix_alloc_irq_at.
  *
  * Some callers may only support dynamically allocated interrupts.
- * This is indicated with dyn_only flag.
+ * This is indicated with dyn_allowed flag.
  *
  * On failure, return map with negative .index. The caller
  * is expected to check returned map index.
  *
  */
-struct msi_map ice_alloc_irq(struct ice_pf *pf, bool dyn_only)
+struct msi_map ice_alloc_irq(struct ice_pf *pf, bool dyn_allowed)
 {
-	int sriov_base_vector = pf->sriov_base_vector;
 	struct msi_map map = { .index = -ENOENT };
 	struct device *dev = ice_pf_to_dev(pf);
 	struct ice_irq_entry *entry;
 
-	entry = ice_get_irq_res(pf, dyn_only);
+	entry = ice_get_irq_res(pf, dyn_allowed);
 	if (!entry)
 		return map;
 
-	/* fail if we're about to violate SRIOV vectors space */
-	if (sriov_base_vector && entry->index >= sriov_base_vector)
-		goto exit_free_res;
-
 	if (pci_msix_can_alloc_dyn(pf->pdev) && entry->dynamic) {
 		map = pci_msix_alloc_irq_at(pf->pdev, entry->index, NULL);
 		if (map.index < 0)
@@ -353,26 +236,40 @@ void ice_free_irq(struct ice_pf *pf, struct msi_map map)
 }
 
 /**
- * ice_get_max_used_msix_vector - Get the max used interrupt vector
- * @pf: board private structure
+ * ice_virt_get_irqs - get irqs for SR-IOV usacase
+ * @pf: pointer to PF structure
+ * @needed: number of irqs to get
  *
- * Return index of maximum used interrupt vectors with respect to the
- * beginning of the MSIX table. Take into account that some interrupts
- * may have been dynamically allocated after MSIX was initially enabled.
+ * This returns the first MSI-X vector index in PF space that is used by this
+ * VF. This index is used when accessing PF relative registers such as
+ * GLINT_VECT2FUNC and GLINT_DYN_CTL.
+ * This will always be the OICR index in the AVF driver so any functionality
+ * using vf->first_vector_idx for queue configuration_id: id of VF which will
+ * use this irqs
  */
-int ice_get_max_used_msix_vector(struct ice_pf *pf)
+int ice_virt_get_irqs(struct ice_pf *pf, u32 needed)
 {
-	unsigned long start, index, max_idx;
-	void *entry;
+	int res = bitmap_find_next_zero_area(pf->virt_irq_tracker.bm,
+					     pf->virt_irq_tracker.num_entries,
+					     0, needed, 0);
 
-	/* Treat all preallocated interrupts as used */
-	start = pf->irq_tracker.num_static;
-	max_idx = start - 1;
+	if (res >= pf->virt_irq_tracker.num_entries)
+		return -ENOENT;
 
-	xa_for_each_start(&pf->irq_tracker.entries, index, entry, start) {
-		if (index > max_idx)
-			max_idx = index;
-	}
+	bitmap_set(pf->virt_irq_tracker.bm, res, needed);
+
+	/* conversion from number in bitmap to global irq index */
+	return res + pf->virt_irq_tracker.base;
+}
 
-	return max_idx;
+/**
+ * ice_virt_free_irqs - free irqs used by the VF
+ * @pf: pointer to PF structure
+ * @index: first index to be free
+ * @irqs: number of irqs to free
+ */
+void ice_virt_free_irqs(struct ice_pf *pf, u32 index, u32 irqs)
+{
+	bitmap_clear(pf->virt_irq_tracker.bm, index - pf->virt_irq_tracker.base,
+		     irqs);
 }