Merge branch 'slot' of git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci into v7.3/vfio/s390x-pci-error-recovery

PCI dependencies from shared branch supporting vfio-pci error recovery
on s390x.

Signed-off-by: Alex Williamson <alex@shazbot.org>

drivers/pci/hotplug/pnv_php.c

@@ -808,7 +808,7 @@ static struct pnv_php_slot *pnv_php_alloc_slot(struct device_node *dn)
 	if (dn->child && PCI_DN(dn->child))
 		php_slot->slot_no = PCI_SLOT(PCI_DN(dn->child)->devfn);
 	else
-		php_slot->slot_no = -1;   /* Placeholder slot */
+		php_slot->slot_no = PCI_SLOT_PLACEHOLDER;   /* Placeholder slot */
 
 	kref_init(&php_slot->kref);
 	php_slot->state	                = PNV_PHP_STATE_INITIALIZED;

drivers/pci/hotplug/rpaphp_slot.c

@@ -84,7 +84,7 @@ int rpaphp_register_slot(struct slot *slot)
 	struct hotplug_slot *php_slot = &slot->hotplug_slot;
 	u32 my_index;
 	int retval;
-	int slotno = -1;
+	int slotno = PCI_SLOT_PLACEHOLDER;
 
 	dbg("%s registering slot:path[%pOF] index[%x], name[%s] pdomain[%x] type[%d]\n",
 		__func__, slot->dn, slot->index, slot->name,

drivers/pci/msi/msi.c

@@ -870,6 +870,7 @@ void __pci_restore_msix_state(struct pci_dev *dev)
 {
 	struct msi_desc *entry;
 	bool write_msg;
+	u16 cmd;
 
 	if (!dev->msix_enabled)
 		return;
@@ -879,6 +880,14 @@ void __pci_restore_msix_state(struct pci_dev *dev)
 	pci_msix_clear_and_set_ctrl(dev, 0,
 				PCI_MSIX_FLAGS_ENABLE | PCI_MSIX_FLAGS_MASKALL);
 
+	/*
+	 * The restored device state may not have Memory Space enabled.
+	 * Since the MSI-X Table and PBA are in Memory Space, enable it
+	 * while restoring them.
+	 */
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	pci_write_config_word(dev, PCI_COMMAND, cmd | PCI_COMMAND_MEMORY);
+
 	write_msg = arch_restore_msi_irqs(dev);
 
 	scoped_guard (msi_descs_lock, &dev->dev) {
@@ -889,6 +898,7 @@ void __pci_restore_msix_state(struct pci_dev *dev)
 		}
 	}
 
+	pci_write_config_word(dev, PCI_COMMAND, cmd);
 	pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
 }
 

drivers/pci/pci.c

@@ -713,6 +713,28 @@ u16 pci_find_dvsec_capability(struct pci_dev *dev, u16 vendor, u16 dvsec)
 }
 EXPORT_SYMBOL_GPL(pci_find_dvsec_capability);
 
+static bool pci_dev_config_accessible(struct pci_dev *dev, char *msg)
+{
+	u32 val;
+
+	/*
+	 * If a device's config space is inaccessible, reads typically
+	 * return ~0.  Since Device and Vendor ID are always ~0 for VFs,
+	 * check the Command and Status registers instead.
+	 *
+	 * N.B. This is racy because the device may become inaccessible
+	 * before the next access.
+	 */
+	pci_read_config_dword(dev, PCI_COMMAND, &val);
+	if (PCI_POSSIBLE_ERROR(val)) {
+		pci_warn(dev, "Device config space inaccessible; unable to %s\n",
+				msg);
+		return false;
+	}
+
+	return true;
+}
+
 /**
  * pci_find_parent_resource - return resource region of parent bus of given
  *			      region
@@ -4363,6 +4385,9 @@ int pcie_flr(struct pci_dev *dev)
 {
 	int ret;
 
+	if (!pci_dev_config_accessible(dev, "FLR"))
+		return -ENOTTY;
+
 	if (!pci_wait_for_pending_transaction(dev))
 		pci_err(dev, "timed out waiting for pending transaction; performing function level reset anyway\n");
 
@@ -4897,8 +4922,9 @@ static int pci_reset_hotplug_slot(struct hotplug_slot *hotplug, bool probe)
 
 static int pci_dev_reset_slot_function(struct pci_dev *dev, bool probe)
 {
-	if (dev->multifunction || dev->subordinate || !dev->slot ||
-	    dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET)
+	if (dev->subordinate || !dev->slot ||
+	    dev->dev_flags & PCI_DEV_FLAGS_NO_BUS_RESET ||
+	    (dev->multifunction && !dev->slot->per_func_slot))
 		return -ENOTTY;
 
 	return pci_reset_hotplug_slot(dev->slot->hotplug, probe);
@@ -5058,6 +5084,9 @@ static void pci_dev_save_and_disable(struct pci_dev *dev)
 	 */
 	pci_set_power_state(dev, PCI_D0);
 
+	if (!pci_dev_config_accessible(dev, "save state"))
+		return;
+
 	pci_save_state(dev);
 	/*
 	 * Disable the device by clearing the Command register, except for

drivers/pci/slot.c

@@ -37,7 +37,7 @@ static const struct sysfs_ops pci_slot_sysfs_ops = {
 
 static ssize_t address_read_file(struct pci_slot *slot, char *buf)
 {
-	if (slot->number == 0xff)
+	if (slot->number == PCI_SLOT_PLACEHOLDER)
 		return sysfs_emit(buf, "%04x:%02x\n",
 				  pci_domain_nr(slot->bus),
 				  slot->bus->number);
@@ -72,6 +72,23 @@ static ssize_t cur_speed_read_file(struct pci_slot *slot, char *buf)
 	return bus_speed_read(slot->bus->cur_bus_speed, buf);
 }
 
+static bool pci_dev_matches_slot(struct pci_dev *dev, struct pci_slot *slot)
+{
+	if (slot->per_func_slot)
+		return dev->devfn == slot->number;
+
+	return slot->number == PCI_SLOT_ALL_DEVICES ||
+		PCI_SLOT(dev->devfn) == slot->number;
+}
+
+static bool pci_slot_enabled_per_func(void)
+{
+	if (IS_ENABLED(CONFIG_S390))
+		return true;
+
+	return false;
+}
+
 static void pci_slot_release(struct kobject *kobj)
 {
 	struct pci_dev *dev;
@@ -82,8 +99,7 @@ static void pci_slot_release(struct kobject *kobj)
 
 	down_read(&pci_bus_sem);
 	list_for_each_entry(dev, &slot->bus->devices, bus_list)
-		if (slot->number == PCI_SLOT_ALL_DEVICES ||
-		    PCI_SLOT(dev->devfn) == slot->number)
+		if (pci_dev_matches_slot(dev, slot))
 			dev->slot = NULL;
 	up_read(&pci_bus_sem);
 
@@ -187,8 +203,7 @@ void pci_dev_assign_slot(struct pci_dev *dev)
 
 	mutex_lock(&pci_slot_mutex);
 	list_for_each_entry(slot, &dev->bus->slots, list)
-		if (slot->number == PCI_SLOT_ALL_DEVICES ||
-		    PCI_SLOT(dev->devfn) == slot->number)
+		if (pci_dev_matches_slot(dev, slot))
 			dev->slot = slot;
 	mutex_unlock(&pci_slot_mutex);
 }
@@ -210,7 +225,7 @@ static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
 /**
  * pci_create_slot - create or increment refcount for physical PCI slot
  * @parent: struct pci_bus of parent bridge
- * @slot_nr: PCI_SLOT(pci_dev->devfn), -1 for placeholder, or
+ * @slot_nr: PCI_SLOT(pci_dev->devfn), PCI_SLOT_PLACEHOLDER for placeholder, or
  *	PCI_SLOT_ALL_DEVICES
  * @name: user visible string presented in /sys/bus/pci/slots/<name>
  * @hotplug: set if caller is hotplug driver, NULL otherwise
@@ -236,15 +251,16 @@ static struct pci_slot *get_slot(struct pci_bus *parent, int slot_nr)
  * In most cases, @pci_bus, @slot_nr will be sufficient to uniquely identify
  * a slot. There is one notable exception - pSeries (rpaphp), where the
  * @slot_nr cannot be determined until a device is actually inserted into
- * the slot. In this scenario, the caller may pass -1 for @slot_nr.
+ * the slot. In this scenario, the caller may pass PCI_SLOT_PLACEHOLDER for @slot_nr.
  *
  * The following semantics are imposed when the caller passes @slot_nr ==
- * -1. First, we no longer check for an existing %struct pci_slot, as there
- * may be many slots with @slot_nr of -1.  The other change in semantics is
- * user-visible, which is the 'address' parameter presented in sysfs will
- * consist solely of a dddd:bb tuple, where dddd is the PCI domain of the
- * %struct pci_bus and bb is the bus number. In other words, the devfn of
- * the 'placeholder' slot will not be displayed.
+ * PCI_SLOT_PLACEHOLDER. First, we no longer check for an existing %struct
+ * pci_slot, as there may be many slots with @slot_nr of
+ * PCI_SLOT_PLACEHOLDER. The other change in semantics is user-visible,
+ * which is the 'address' parameter presented in sysfs will consist solely
+ * of a dddd:bb tuple, where dddd is the PCI domain of the %struct pci_bus
+ * and bb is the bus number. In other words, the devfn of the 'placeholder'
+ * slot will not be displayed.
  *
  * Bus-wide slots:
  * For PCIe hotplug, the physical slot encompasses the entire secondary
@@ -267,7 +283,7 @@ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 
 	mutex_lock(&pci_slot_mutex);
 
-	if (slot_nr == -1)
+	if (slot_nr == PCI_SLOT_PLACEHOLDER)
 		goto placeholder;
 
 	/*
@@ -298,6 +314,9 @@ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 	slot->bus = pci_bus_get(parent);
 	slot->number = slot_nr;
 
+	if (pci_slot_enabled_per_func())
+		slot->per_func_slot = 1;
+
 	slot->kobj.kset = pci_slots_kset;
 
 	slot_name = make_slot_name(name);
@@ -318,8 +337,7 @@ struct pci_slot *pci_create_slot(struct pci_bus *parent, int slot_nr,
 
 	down_read(&pci_bus_sem);
 	list_for_each_entry(dev, &parent->devices, bus_list)
-		if (slot_nr == PCI_SLOT_ALL_DEVICES ||
-		    PCI_SLOT(dev->devfn) == slot_nr)
+		if (pci_dev_matches_slot(dev, slot))
 			dev->slot = slot;
 	up_read(&pci_bus_sem);
 

include/linux/pci.h

@@ -79,14 +79,18 @@
  * and, if ARI Forwarding is enabled, functions may appear to be on multiple
  * devices.
  */
-#define PCI_SLOT_ALL_DEVICES	0xfe
+#define PCI_SLOT_ALL_DEVICES	0xfeff
+
+/* Used to identify a slot as a placeholder */
+#define PCI_SLOT_PLACEHOLDER	0xffff
 
 /* pci_slot represents a physical slot */
 struct pci_slot {
 	struct pci_bus		*bus;		/* Bus this slot is on */
 	struct list_head	list;		/* Node in list of slots */
 	struct hotplug_slot	*hotplug;	/* Hotplug info (move here) */
-	unsigned char		number;		/* Device nr, or PCI_SLOT_ALL_DEVICES */
+	u16			number;		/* Device nr, or PCI_SLOT_ALL_DEVICES */
+	unsigned int		per_func_slot:1; /* Allow per function slot */
 	struct kobject		kobj;
 };