Commit 81eef890 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for-linus-6.5a-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip 

Pull xen fixes from Juergen Gross:

 - A fix for a performance problem in QubesOS, adding a way to drain the
   queue of grants experiencing delayed unmaps faster

 - A patch enabling the use of static event channels from user mode,
   which was omitted when introducing supporting static event channels

 - A fix for a problem where Xen related code didn't check properly for
   running in a Xen environment, resulting in a WARN splat

* tag 'for-linus-6.5a-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: speed up grant-table reclaim
  xen/evtchn: Introduce new IOCTL to bind static evtchn
  xenbus: check xen_domain in xenbus_probe_initcall
parents e62e26d3 c04e9894

Documentation/ABI/testing/sysfs-module

+11 −0
Original line number Diff line number Diff line
@@ -60,3 +60,14 @@ Description: Module taint flags: 
			C   staging driver module

			E   unsigned module

			==  =====================



What:		/sys/module/grant_table/parameters/free_per_iteration

Date:		July 2023

KernelVersion:	6.5 but backported to all supported stable branches

Contact:	Xen developer discussion <xen-devel@lists.xenproject.org>

Description:	Read and write number of grant entries to attempt to free per iteration.



		Note: Future versions of Xen and Linux may provide a better

		interface for controlling the rate of deferred grant reclaim

		or may not need it at all.

Users:		Qubes OS (https://www.qubes-os.org)

drivers/xen/events/events_base.c

+5 −11
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ struct irq_info { 
	unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */

	u64 eoi_time;           /* Time in jiffies when to EOI. */

	raw_spinlock_t lock;

	bool is_static;           /* Is event channel static */



	union {

		unsigned short virq;
@@ -815,15 +816,6 @@ static void xen_free_irq(unsigned irq) 
	irq_free_desc(irq);

}



static void xen_evtchn_close(evtchn_port_t port)

{

	struct evtchn_close close;



	close.port = port;

	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)

		BUG();

}



/* Not called for lateeoi events. */

static void event_handler_exit(struct irq_info *info)

{
@@ -982,6 +974,7 @@ static void __unbind_from_irq(unsigned int irq) 
		unsigned int cpu = cpu_from_irq(irq);

		struct xenbus_device *dev;



		if (!info->is_static)

			xen_evtchn_close(evtchn);



		switch (type_from_irq(irq)) {
@@ -1574,7 +1567,7 @@ int xen_set_irq_priority(unsigned irq, unsigned priority) 
}

EXPORT_SYMBOL_GPL(xen_set_irq_priority);



int evtchn_make_refcounted(evtchn_port_t evtchn)

int evtchn_make_refcounted(evtchn_port_t evtchn, bool is_static)

{

	int irq = get_evtchn_to_irq(evtchn);

	struct irq_info *info;
@@ -1590,6 +1583,7 @@ int evtchn_make_refcounted(evtchn_port_t evtchn) 
	WARN_ON(info->refcnt != -1);



	info->refcnt = 1;

	info->is_static = is_static;



	return 0;

}

drivers/xen/evtchn.c

+26 −9
Original line number Diff line number Diff line
@@ -366,10 +366,10 @@ static int evtchn_resize_ring(struct per_user_data *u) 
	return 0;

}



static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port)

static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port,

			       bool is_static)

{

	struct user_evtchn *evtchn;

	struct evtchn_close close;

	int rc = 0;



	/*
@@ -402,14 +402,14 @@ static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port) 
	if (rc < 0)

		goto err;



	rc = evtchn_make_refcounted(port);

	rc = evtchn_make_refcounted(port, is_static);

	return rc;



err:

	/* bind failed, should close the port now */

	close.port = port;

	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)

		BUG();

	if (!is_static)

		xen_evtchn_close(port);



	del_evtchn(u, evtchn);

	return rc;

}
@@ -456,7 +456,7 @@ static long evtchn_ioctl(struct file *file, 
		if (rc != 0)

			break;



		rc = evtchn_bind_to_user(u, bind_virq.port);

		rc = evtchn_bind_to_user(u, bind_virq.port, false);

		if (rc == 0)

			rc = bind_virq.port;

		break;
@@ -482,7 +482,7 @@ static long evtchn_ioctl(struct file *file, 
		if (rc != 0)

			break;



		rc = evtchn_bind_to_user(u, bind_interdomain.local_port);

		rc = evtchn_bind_to_user(u, bind_interdomain.local_port, false);

		if (rc == 0)

			rc = bind_interdomain.local_port;

		break;
@@ -507,7 +507,7 @@ static long evtchn_ioctl(struct file *file, 
		if (rc != 0)

			break;



		rc = evtchn_bind_to_user(u, alloc_unbound.port);

		rc = evtchn_bind_to_user(u, alloc_unbound.port, false);

		if (rc == 0)

			rc = alloc_unbound.port;

		break;
@@ -536,6 +536,23 @@ static long evtchn_ioctl(struct file *file, 
		break;

	}



	case IOCTL_EVTCHN_BIND_STATIC: {

		struct ioctl_evtchn_bind bind;

		struct user_evtchn *evtchn;



		rc = -EFAULT;

		if (copy_from_user(&bind, uarg, sizeof(bind)))

			break;



		rc = -EISCONN;

		evtchn = find_evtchn(u, bind.port);

		if (evtchn)

			break;



		rc = evtchn_bind_to_user(u, bind.port, true);

		break;

	}



	case IOCTL_EVTCHN_NOTIFY: {

		struct ioctl_evtchn_notify notify;

		struct user_evtchn *evtchn;

drivers/xen/grant-table.c

+29 −11
Original line number Diff line number Diff line
@@ -498,14 +498,21 @@ static LIST_HEAD(deferred_list); 
static void gnttab_handle_deferred(struct timer_list *);

static DEFINE_TIMER(deferred_timer, gnttab_handle_deferred);



static atomic64_t deferred_count;

static atomic64_t leaked_count;

static unsigned int free_per_iteration = 10;

module_param(free_per_iteration, uint, 0600);



static void gnttab_handle_deferred(struct timer_list *unused)

{

	unsigned int nr = 10;

	unsigned int nr = READ_ONCE(free_per_iteration);

	const bool ignore_limit = nr == 0;

	struct deferred_entry *first = NULL;

	unsigned long flags;

	size_t freed = 0;



	spin_lock_irqsave(&gnttab_list_lock, flags);

	while (nr--) {

	while ((ignore_limit || nr--) && !list_empty(&deferred_list)) {

		struct deferred_entry *entry

			= list_first_entry(&deferred_list,

					   struct deferred_entry, list);
@@ -515,10 +522,14 @@ static void gnttab_handle_deferred(struct timer_list *unused) 
		list_del(&entry->list);

		spin_unlock_irqrestore(&gnttab_list_lock, flags);

		if (_gnttab_end_foreign_access_ref(entry->ref)) {

			uint64_t ret = atomic64_dec_return(&deferred_count);



			put_free_entry(entry->ref);

			pr_debug("freeing g.e. %#x (pfn %#lx)\n",

				 entry->ref, page_to_pfn(entry->page));

			pr_debug("freeing g.e. %#x (pfn %#lx), %llu remaining\n",

				 entry->ref, page_to_pfn(entry->page),

				 (unsigned long long)ret);

			put_page(entry->page);

			freed++;

			kfree(entry);

			entry = NULL;

		} else {
@@ -530,21 +541,22 @@ static void gnttab_handle_deferred(struct timer_list *unused) 
		spin_lock_irqsave(&gnttab_list_lock, flags);

		if (entry)

			list_add_tail(&entry->list, &deferred_list);

		else if (list_empty(&deferred_list))

			break;

	}

	if (!list_empty(&deferred_list) && !timer_pending(&deferred_timer)) {

	if (list_empty(&deferred_list))

		WARN_ON(atomic64_read(&deferred_count));

	else if (!timer_pending(&deferred_timer)) {

		deferred_timer.expires = jiffies + HZ;

		add_timer(&deferred_timer);

	}

	spin_unlock_irqrestore(&gnttab_list_lock, flags);

	pr_debug("Freed %zu references", freed);

}



static void gnttab_add_deferred(grant_ref_t ref, struct page *page)

{

	struct deferred_entry *entry;

	gfp_t gfp = (in_atomic() || irqs_disabled()) ? GFP_ATOMIC : GFP_KERNEL;

	const char *what = KERN_WARNING "leaking";

	uint64_t leaked, deferred;



	entry = kmalloc(sizeof(*entry), gfp);

	if (!page) {
@@ -567,10 +579,16 @@ static void gnttab_add_deferred(grant_ref_t ref, struct page *page) 
			add_timer(&deferred_timer);

		}

		spin_unlock_irqrestore(&gnttab_list_lock, flags);

		what = KERN_DEBUG "deferring";

		deferred = atomic64_inc_return(&deferred_count);

		leaked = atomic64_read(&leaked_count);

		pr_debug("deferring g.e. %#x (pfn %#lx) (total deferred %llu, total leaked %llu)\n",

			 ref, page ? page_to_pfn(page) : -1, deferred, leaked);

	} else {

		deferred = atomic64_read(&deferred_count);

		leaked = atomic64_inc_return(&leaked_count);

		pr_warn("leaking g.e. %#x (pfn %#lx) (total deferred %llu, total leaked %llu)\n",

			ref, page ? page_to_pfn(page) : -1, deferred, leaked);

	}

	printk("%s g.e. %#x (pfn %#lx)\n",

	       what, ref, page ? page_to_pfn(page) : -1);

}



int gnttab_try_end_foreign_access(grant_ref_t ref)

drivers/xen/xenbus/xenbus_probe.c

+3 −0
Original line number Diff line number Diff line
@@ -811,6 +811,9 @@ static int xenbus_probe_thread(void *unused) 


static int __init xenbus_probe_initcall(void)

{

	if (!xen_domain())

		return -ENODEV;



	/*

	 * Probe XenBus here in the XS_PV case, and also XS_HVM unless we

	 * need to wait for the platform PCI device to come up or