Merge tag 'for-linus-5.10b-rc1c-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull more xen updates from Juergen Gross:

 - a series for the Xen pv block drivers adding module parameters for
   better control of resource usge

 - a cleanup series for the Xen event driver

* tag 'for-linus-5.10b-rc1c-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  Documentation: add xen.fifo_events kernel parameter description
  xen/events: unmask a fifo event channel only if it was masked
  xen/events: only register debug interrupt for 2-level events
  xen/events: make struct irq_info private to events_base.c
  xen: remove no longer used functions
  xen-blkfront: Apply changed parameter name to the document
  xen-blkfront: add a parameter for disabling of persistent grants
  xen-blkback: add a parameter for disabling of persistent grants

Documentation/ABI/testing/sysfs-driver-xen-blkback

@@ -35,3 +35,12 @@ Description:
                 controls the duration in milliseconds that blkback will not
                 cache any page not backed by a grant mapping.
                 The default is 10ms.
+
+What:           /sys/module/xen_blkback/parameters/feature_persistent
+Date:           September 2020
+KernelVersion:  5.10
+Contact:        SeongJae Park <sjpark@amazon.de>
+Description:
+                Whether to enable the persistent grants feature or not.  Note
+                that this option only takes effect on newly created backends.
+                The default is Y (enable).

Documentation/ABI/testing/sysfs-driver-xen-blkfront

-What:           /sys/module/xen_blkfront/parameters/max
+What:           /sys/module/xen_blkfront/parameters/max_indirect_segments
 Date:           June 2013
 KernelVersion:  3.11
 Contact:        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
@@ -8,3 +8,12 @@ Description:
                 is 32 - higher value means more potential throughput but more
                 memory usage. The backend picks the minimum of the frontend
                 and its default backend value.
+
+What:           /sys/module/xen_blkfront/parameters/feature_persistent
+Date:           September 2020
+KernelVersion:  5.10
+Contact:        SeongJae Park <sjpark@amazon.de>
+Description:
+                Whether to enable the persistent grants feature or not.  Note
+                that this option only takes effect on newly created frontends.
+                The default is Y (enable).

Documentation/admin-guide/kernel-parameters.txt

@@ -5978,6 +5978,13 @@
 			After which time (jiffies) the event handling loop
 			should start to delay EOI handling. Default is 2.
 
+	xen.fifo_events=	[XEN]
+			Boolean parameter to disable using fifo event handling
+			even if available. Normally fifo event handling is
+			preferred over the 2-level event handling, as it is
+			fairer and the number of possible event channels is
+			much higher. Default is on (use fifo events).
+
 	nopv=		[X86,XEN,KVM,HYPER_V,VMWARE]
 			Disables the PV optimizations forcing the guest to run
 			as generic guest with no PV drivers. Currently support

arch/x86/xen/smp.c

@@ -88,14 +88,17 @@ int xen_smp_intr_init(unsigned int cpu)
 	per_cpu(xen_callfunc_irq, cpu).irq = rc;
 	per_cpu(xen_callfunc_irq, cpu).name = callfunc_name;
 
-	debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
-	rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
-				     IRQF_PERCPU | IRQF_NOBALANCING,
-				     debug_name, NULL);
-	if (rc < 0)
-		goto fail;
-	per_cpu(xen_debug_irq, cpu).irq = rc;
-	per_cpu(xen_debug_irq, cpu).name = debug_name;
+	if (!xen_fifo_events) {
+		debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
+		rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu,
+					     xen_debug_interrupt,
+					     IRQF_PERCPU | IRQF_NOBALANCING,
+					     debug_name, NULL);
+		if (rc < 0)
+			goto fail;
+		per_cpu(xen_debug_irq, cpu).irq = rc;
+		per_cpu(xen_debug_irq, cpu).name = debug_name;
+	}
 
 	callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
 	rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,

arch/x86/xen/xen-ops.h

@@ -29,6 +29,8 @@ extern struct start_info *xen_start_info;
 extern struct shared_info xen_dummy_shared_info;
 extern struct shared_info *HYPERVISOR_shared_info;
 
+extern bool xen_fifo_events;
+
 void xen_setup_mfn_list_list(void);
 void xen_build_mfn_list_list(void);
 void xen_setup_machphys_mapping(void);

drivers/block/xen-blkback/xenbus.c

@@ -473,6 +473,12 @@ static void xen_vbd_free(struct xen_vbd *vbd)
 	vbd->bdev = NULL;
 }
 
+/* Enable the persistent grants feature. */
+static bool feature_persistent = true;
+module_param(feature_persistent, bool, 0644);
+MODULE_PARM_DESC(feature_persistent,
+		"Enables the persistent grants feature");
+
 static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 			  unsigned major, unsigned minor, int readonly,
 			  int cdrom)
@@ -518,6 +524,8 @@ static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
 	if (q && blk_queue_secure_erase(q))
 		vbd->discard_secure = true;
 
+	vbd->feature_gnt_persistent = feature_persistent;
+
 	pr_debug("Successful creation of handle=%04x (dom=%u)\n",
 		handle, blkif->domid);
 	return 0;
@@ -905,7 +913,8 @@ static void connect(struct backend_info *be)
 
 	xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
 
-	err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1);
+	err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u",
+			be->blkif->vbd.feature_gnt_persistent);
 	if (err) {
 		xenbus_dev_fatal(dev, err, "writing %s/feature-persistent",
 				 dev->nodename);
@@ -1066,7 +1075,6 @@ static int connect_ring(struct backend_info *be)
 {
 	struct xenbus_device *dev = be->dev;
 	struct xen_blkif *blkif = be->blkif;
-	unsigned int pers_grants;
 	char protocol[64] = "";
 	int err, i;
 	char *xspath;
@@ -1092,9 +1100,11 @@ static int connect_ring(struct backend_info *be)
 		xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
 		return -ENOSYS;
 	}
-	pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent",
-					   0);
-	blkif->vbd.feature_gnt_persistent = pers_grants;
+	if (blkif->vbd.feature_gnt_persistent)
+		blkif->vbd.feature_gnt_persistent =
+			xenbus_read_unsigned(dev->otherend,
+					"feature-persistent", 0);
+
 	blkif->vbd.overflow_max_grants = 0;
 
 	/*
@@ -1117,7 +1127,7 @@ static int connect_ring(struct backend_info *be)
 
 	pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename,
 		 blkif->nr_rings, blkif->blk_protocol, protocol,
-		 pers_grants ? "persistent grants" : "");
+		 blkif->vbd.feature_gnt_persistent ? "persistent grants" : "");
 
 	ring_page_order = xenbus_read_unsigned(dev->otherend,
 					       "ring-page-order", 0);

drivers/block/xen-blkfront.c

@@ -1866,8 +1866,8 @@ static int talk_to_blkback(struct xenbus_device *dev,
 		message = "writing protocol";
 		goto abort_transaction;
 	}
-	err = xenbus_printf(xbt, dev->nodename,
-			    "feature-persistent", "%u", 1);
+	err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u",
+			info->feature_persistent);
 	if (err)
 		dev_warn(&dev->dev,
 			 "writing persistent grants feature to xenbus");
@@ -1941,6 +1941,13 @@ static int negotiate_mq(struct blkfront_info *info)
 	}
 	return 0;
 }
+
+/* Enable the persistent grants feature. */
+static bool feature_persistent = true;
+module_param(feature_persistent, bool, 0644);
+MODULE_PARM_DESC(feature_persistent,
+		"Enables the persistent grants feature");
+
 /**
  * Entry point to this code when a new device is created.  Allocate the basic
  * structures and the ring buffer for communication with the backend, and
@@ -2007,6 +2014,8 @@ static int blkfront_probe(struct xenbus_device *dev,
 	info->vdevice = vdevice;
 	info->connected = BLKIF_STATE_DISCONNECTED;
 
+	info->feature_persistent = feature_persistent;
+
 	/* Front end dir is a number, which is used as the id. */
 	info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
 	dev_set_drvdata(&dev->dev, info);
@@ -2316,9 +2325,10 @@ static void blkfront_gather_backend_features(struct blkfront_info *info)
 	if (xenbus_read_unsigned(info->xbdev->otherend, "feature-discard", 0))
 		blkfront_setup_discard(info);
 
-	info->feature_persistent =
-		!!xenbus_read_unsigned(info->xbdev->otherend,
-				       "feature-persistent", 0);
+	if (info->feature_persistent)
+		info->feature_persistent =
+			!!xenbus_read_unsigned(info->xbdev->otherend,
+					       "feature-persistent", 0);
 
 	indirect_segments = xenbus_read_unsigned(info->xbdev->otherend,
 					"feature-max-indirect-segments", 0);

drivers/xen/events/events_2l.c

@@ -47,10 +47,11 @@ static unsigned evtchn_2l_max_channels(void)
 	return EVTCHN_2L_NR_CHANNELS;
 }
 
-static void evtchn_2l_bind_to_cpu(struct irq_info *info, unsigned cpu)
+static void evtchn_2l_bind_to_cpu(evtchn_port_t evtchn, unsigned int cpu,
+				  unsigned int old_cpu)
 {
-	clear_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, info->cpu)));
-	set_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, cpu)));
+	clear_bit(evtchn, BM(per_cpu(cpu_evtchn_mask, old_cpu)));
+	set_bit(evtchn, BM(per_cpu(cpu_evtchn_mask, cpu)));
 }
 
 static void evtchn_2l_clear_pending(evtchn_port_t port)

drivers/xen/events/events_base.c

@@ -70,6 +70,57 @@
 #undef MODULE_PARAM_PREFIX
 #define MODULE_PARAM_PREFIX "xen."
 
+/* Interrupt types. */
+enum xen_irq_type {
+	IRQT_UNBOUND = 0,
+	IRQT_PIRQ,
+	IRQT_VIRQ,
+	IRQT_IPI,
+	IRQT_EVTCHN
+};
+
+/*
+ * Packed IRQ information:
+ * type - enum xen_irq_type
+ * event channel - irq->event channel mapping
+ * cpu - cpu this event channel is bound to
+ * index - type-specific information:
+ *    PIRQ - vector, with MSB being "needs EIO", or physical IRQ of the HVM
+ *           guest, or GSI (real passthrough IRQ) of the device.
+ *    VIRQ - virq number
+ *    IPI - IPI vector
+ *    EVTCHN -
+ */
+struct irq_info {
+	struct list_head list;
+	struct list_head eoi_list;
+	short refcnt;
+	short spurious_cnt;
+	enum xen_irq_type type; /* type */
+	unsigned irq;
+	evtchn_port_t evtchn;   /* event channel */
+	unsigned short cpu;     /* cpu bound */
+	unsigned short eoi_cpu; /* EOI must happen on this cpu-1 */
+	unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */
+	u64 eoi_time;           /* Time in jiffies when to EOI. */
+
+	union {
+		unsigned short virq;
+		enum ipi_vector ipi;
+		struct {
+			unsigned short pirq;
+			unsigned short gsi;
+			unsigned char vector;
+			unsigned char flags;
+			uint16_t domid;
+		} pirq;
+	} u;
+};
+
+#define PIRQ_NEEDS_EOI	(1 << 0)
+#define PIRQ_SHAREABLE	(1 << 1)
+#define PIRQ_MSI_GROUP	(1 << 2)
+
 static uint __read_mostly event_loop_timeout = 2;
 module_param(event_loop_timeout, uint, 0644);
 
@@ -110,7 +161,7 @@ static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};
 /* IRQ <-> IPI mapping */
 static DEFINE_PER_CPU(int [XEN_NR_IPIS], ipi_to_irq) = {[0 ... XEN_NR_IPIS-1] = -1};
 
-int **evtchn_to_irq;
+static int **evtchn_to_irq;
 #ifdef CONFIG_X86
 static unsigned long *pirq_eoi_map;
 #endif
@@ -190,7 +241,7 @@ int get_evtchn_to_irq(evtchn_port_t evtchn)
 }
 
 /* Get info for IRQ */
-struct irq_info *info_for_irq(unsigned irq)
+static struct irq_info *info_for_irq(unsigned irq)
 {
 	if (irq < nr_legacy_irqs())
 		return legacy_info_ptrs[irq];
@@ -228,7 +279,7 @@ static int xen_irq_info_common_setup(struct irq_info *info,
 
 	irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
 
-	return xen_evtchn_port_setup(info);
+	return xen_evtchn_port_setup(evtchn);
 }
 
 static int xen_irq_info_evtchn_setup(unsigned irq,
@@ -351,7 +402,7 @@ static enum xen_irq_type type_from_irq(unsigned irq)
 	return info_for_irq(irq)->type;
 }
 
-unsigned cpu_from_irq(unsigned irq)
+static unsigned cpu_from_irq(unsigned irq)
 {
 	return info_for_irq(irq)->cpu;
 }
@@ -391,7 +442,7 @@ static void bind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int cpu)
 #ifdef CONFIG_SMP
 	cpumask_copy(irq_get_affinity_mask(irq), cpumask_of(cpu));
 #endif
-	xen_evtchn_port_bind_to_cpu(info, cpu);
+	xen_evtchn_port_bind_to_cpu(evtchn, cpu, info->cpu);
 
 	info->cpu = cpu;
 }
@@ -745,7 +796,7 @@ static unsigned int __startup_pirq(unsigned int irq)
 	info->evtchn = evtchn;
 	bind_evtchn_to_cpu(evtchn, 0);
 
-	rc = xen_evtchn_port_setup(info);
+	rc = xen_evtchn_port_setup(evtchn);
 	if (rc)
 		goto err;
 
@@ -1145,14 +1196,6 @@ static int bind_interdomain_evtchn_to_irq_chip(unsigned int remote_domain,
 					       chip);
 }
 
-int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
-				   evtchn_port_t remote_port)
-{
-	return bind_interdomain_evtchn_to_irq_chip(remote_domain, remote_port,
-						   &xen_dynamic_chip);
-}
-EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq);
-
 int bind_interdomain_evtchn_to_irq_lateeoi(unsigned int remote_domain,
 					   evtchn_port_t remote_port)
 {
@@ -1320,19 +1363,6 @@ static int bind_interdomain_evtchn_to_irqhandler_chip(
 	return irq;
 }
 
-int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
-					  evtchn_port_t remote_port,
-					  irq_handler_t handler,
-					  unsigned long irqflags,
-					  const char *devname,
-					  void *dev_id)
-{
-	return bind_interdomain_evtchn_to_irqhandler_chip(remote_domain,
-				remote_port, handler, irqflags, devname,
-				dev_id, &xen_dynamic_chip);
-}
-EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irqhandler);
-
 int bind_interdomain_evtchn_to_irqhandler_lateeoi(unsigned int remote_domain,
 						  evtchn_port_t remote_port,
 						  irq_handler_t handler,
@@ -2020,8 +2050,8 @@ void xen_setup_callback_vector(void) {}
 static inline void xen_alloc_callback_vector(void) {}
 #endif
 
-static bool fifo_events = true;
-module_param(fifo_events, bool, 0);
+bool xen_fifo_events = true;
+module_param_named(fifo_events, xen_fifo_events, bool, 0);
 
 static int xen_evtchn_cpu_prepare(unsigned int cpu)
 {
@@ -2050,10 +2080,12 @@ void __init xen_init_IRQ(void)
 	int ret = -EINVAL;
 	evtchn_port_t evtchn;
 
-	if (fifo_events)
+	if (xen_fifo_events)
 		ret = xen_evtchn_fifo_init();
-	if (ret < 0)
+	if (ret < 0) {
 		xen_evtchn_2l_init();
+		xen_fifo_events = false;
+	}
 
 	xen_cpu_init_eoi(smp_processor_id());
 

drivers/xen/events/events_fifo.c

@@ -138,9 +138,8 @@ static void init_array_page(event_word_t *array_page)
 		array_page[i] = 1 << EVTCHN_FIFO_MASKED;
 }
 
-static int evtchn_fifo_setup(struct irq_info *info)
+static int evtchn_fifo_setup(evtchn_port_t port)
 {
-	evtchn_port_t port = info->evtchn;
 	unsigned new_array_pages;
 	int ret;
 
@@ -186,7 +185,8 @@ static int evtchn_fifo_setup(struct irq_info *info)
 	return ret;
 }
 
-static void evtchn_fifo_bind_to_cpu(struct irq_info *info, unsigned cpu)
+static void evtchn_fifo_bind_to_cpu(evtchn_port_t evtchn, unsigned int cpu, 
+				    unsigned int old_cpu)
 {
 	/* no-op */
 }
@@ -237,6 +237,9 @@ static bool clear_masked_cond(volatile event_word_t *word)
 	w = *word;
 
 	do {
+		if (!(w & (1 << EVTCHN_FIFO_MASKED)))
+			return true;
+
 		if (w & (1 << EVTCHN_FIFO_PENDING))
 			return false;
 

drivers/xen/events/events_internal.h

@@ -7,65 +7,15 @@
 #ifndef __EVENTS_INTERNAL_H__
 #define __EVENTS_INTERNAL_H__
 
-/* Interrupt types. */
-enum xen_irq_type {
-	IRQT_UNBOUND = 0,
-	IRQT_PIRQ,
-	IRQT_VIRQ,
-	IRQT_IPI,
-	IRQT_EVTCHN
-};
-
-/*
- * Packed IRQ information:
- * type - enum xen_irq_type
- * event channel - irq->event channel mapping
- * cpu - cpu this event channel is bound to
- * index - type-specific information:
- *    PIRQ - vector, with MSB being "needs EIO", or physical IRQ of the HVM
- *           guest, or GSI (real passthrough IRQ) of the device.
- *    VIRQ - virq number
- *    IPI - IPI vector
- *    EVTCHN -
- */
-struct irq_info {
-	struct list_head list;
-	struct list_head eoi_list;
-	short refcnt;
-	short spurious_cnt;
-	enum xen_irq_type type;	/* type */
-	unsigned irq;
-	evtchn_port_t evtchn;	/* event channel */
-	unsigned short cpu;	/* cpu bound */
-	unsigned short eoi_cpu;	/* EOI must happen on this cpu */
-	unsigned int irq_epoch;	/* If eoi_cpu valid: irq_epoch of event */
-	u64 eoi_time;		/* Time in jiffies when to EOI. */
-
-	union {
-		unsigned short virq;
-		enum ipi_vector ipi;
-		struct {
-			unsigned short pirq;
-			unsigned short gsi;
-			unsigned char vector;
-			unsigned char flags;
-			uint16_t domid;
-		} pirq;
-	} u;
-};
-
-#define PIRQ_NEEDS_EOI	(1 << 0)
-#define PIRQ_SHAREABLE	(1 << 1)
-#define PIRQ_MSI_GROUP	(1 << 2)
-
 struct evtchn_loop_ctrl;
 
 struct evtchn_ops {
 	unsigned (*max_channels)(void);
 	unsigned (*nr_channels)(void);
 
-	int (*setup)(struct irq_info *info);
-	void (*bind_to_cpu)(struct irq_info *info, unsigned cpu);
+	int (*setup)(evtchn_port_t port);
+	void (*bind_to_cpu)(evtchn_port_t evtchn, unsigned int cpu,
+			    unsigned int old_cpu);
 
 	void (*clear_pending)(evtchn_port_t port);
 	void (*set_pending)(evtchn_port_t port);
@@ -83,12 +33,9 @@ struct evtchn_ops {
 
 extern const struct evtchn_ops *evtchn_ops;
 
-extern int **evtchn_to_irq;
 int get_evtchn_to_irq(evtchn_port_t evtchn);
 void handle_irq_for_port(evtchn_port_t port, struct evtchn_loop_ctrl *ctrl);
 
-struct irq_info *info_for_irq(unsigned irq);
-unsigned cpu_from_irq(unsigned irq);
 unsigned int cpu_from_evtchn(evtchn_port_t evtchn);
 
 static inline unsigned xen_evtchn_max_channels(void)
@@ -100,17 +47,18 @@ static inline unsigned xen_evtchn_max_channels(void)
  * Do any ABI specific setup for a bound event channel before it can
  * be unmasked and used.
  */
-static inline int xen_evtchn_port_setup(struct irq_info *info)
+static inline int xen_evtchn_port_setup(evtchn_port_t evtchn)
 {
 	if (evtchn_ops->setup)
-		return evtchn_ops->setup(info);
+		return evtchn_ops->setup(evtchn);
 	return 0;
 }
 
-static inline void xen_evtchn_port_bind_to_cpu(struct irq_info *info,
-					       unsigned cpu)
+static inline void xen_evtchn_port_bind_to_cpu(evtchn_port_t evtchn,
+					       unsigned int cpu,
+					       unsigned int old_cpu)
 {
-	evtchn_ops->bind_to_cpu(info, cpu);
+	evtchn_ops->bind_to_cpu(evtchn, cpu, old_cpu);
 }
 
 static inline void clear_evtchn(evtchn_port_t port)

include/xen/events.h

@@ -35,16 +35,8 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi,
 			   unsigned long irqflags,
 			   const char *devname,
 			   void *dev_id);
-int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
-				   evtchn_port_t remote_port);
 int bind_interdomain_evtchn_to_irq_lateeoi(unsigned int remote_domain,
 					   evtchn_port_t remote_port);
-int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
-					  evtchn_port_t remote_port,
-					  irq_handler_t handler,
-					  unsigned long irqflags,
-					  const char *devname,
-					  void *dev_id);
 int bind_interdomain_evtchn_to_irqhandler_lateeoi(unsigned int remote_domain,
 						  evtchn_port_t remote_port,
 						  irq_handler_t handler,