Merge tag 'stable/for-linus-3.14-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull Xen updates from Konrad Rzeszutek Wilk:
 "Two major features that Xen community is excited about:

  The first is event channel scalability by David Vrabel - we switch
  over from an two-level per-cpu bitmap of events (IRQs) - to an FIFO
  queue with priorities.  This lets us be able to handle more events,
  have lower latency, and better scalability.  Good stuff.

  The other is PVH by Mukesh Rathor.  In short, PV is a mode where the
  kernel lets the hypervisor program page-tables, segments, etc.  With
  EPT/NPT capabilities in current processors, the overhead of doing this
  in an HVM (Hardware Virtual Machine) container is much lower than the
  hypervisor doing it for us.

  In short we let a PV guest run without doing page-table, segment,
  syscall, etc updates through the hypervisor - instead it is all done
  within the guest container.  It is a "hybrid" PV - hence the 'PVH'
  name - a PV guest within an HVM container.

  The major benefits are less code to deal with - for example we only
  use one function from the the pv_mmu_ops (which has 39 function
  calls); faster performance for syscall (no context switches into the
  hypervisor); less traps on various operations; etc.

  It is still being baked - the ABI is not yet set in stone.  But it is
  pretty awesome and we are excited about it.

  Lastly, there are some changes to ARM code - you should get a simple
  conflict which has been resolved in #linux-next.

  In short, this pull has awesome features.

  Features:
   - FIFO event channels.  Key advantages: support for over 100,000
     events (2^17), 16 different event priorities, improved fairness in
     event latency through the use of FIFOs.
   - Xen PVH support.  "It’s a fully PV kernel mode, running with
     paravirtualized disk and network, paravirtualized interrupts and
     timers, no emulated devices of any kind (and thus no qemu), no BIOS
     or legacy boot — but instead of requiring PV MMU, it uses the HVM
     hardware extensions to virtualize the pagetables, as well as system
     calls and other privileged operations." (from "The
     Paravirtualization Spectrum, Part 2: From poles to a spectrum")

  Bug-fixes:
   - Fixes in balloon driver (refactor and make it work under ARM)
   - Allow xenfb to be used in HVM guests.
   - Allow xen_platform_pci=0 to work properly.
   - Refactors in event channels"

* tag 'stable/for-linus-3.14-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (52 commits)
  xen/pvh: Set X86_CR0_WP and others in CR0 (v2)
  MAINTAINERS: add git repository for Xen
  xen/pvh: Use 'depend' instead of 'select'.
  xen: delete new instances of __cpuinit usage
  xen/fb: allow xenfb initialization for hvm guests
  xen/evtchn_fifo: fix error return code in evtchn_fifo_setup()
  xen-platform: fix error return code in platform_pci_init()
  xen/pvh: remove duplicated include from enlighten.c
  xen/pvh: Fix compile issues with xen_pvh_domain()
  xen: Use dev_is_pci() to check whether it is pci device
  xen/grant-table: Force to use v1 of grants.
  xen/pvh: Support ParaVirtualized Hardware extensions (v3).
  xen/pvh: Piggyback on PVHVM XenBus.
  xen/pvh: Piggyback on PVHVM for grant driver (v4)
  xen/grant: Implement an grant frame array struct (v3).
  xen/grant-table: Refactor gnttab_init
  xen/grants: Remove gnttab_max_grant_frames dependency on gnttab_init.
  xen/pvh: Piggyback on PVHVM for event channels (v2)
  xen/pvh: Update E820 to work with PVH (v2)
  xen/pvh: Secondary VCPU bringup (non-bootup CPUs)
  ...

1 files changed, 372 insertions, 0 deletions

diff --git a/drivers/xen/events/events_2l.c b/drivers/xen/events/events_2l.c
new file mode 100644
index 000000000000..d7ff91757307
--- /dev/null
+++ b/drivers/xen/events/events_2l.c
@@ -0,0 +1,372 @@
+/*
+ * Xen event channels (2-level ABI)
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
+#include <linux/linkage.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+
+#include <asm/sync_bitops.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/xen-ops.h>
+#include <xen/events.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/event_channel.h>
+
+#include "events_internal.h"
+
+/*
+ * Note sizeof(xen_ulong_t) can be more than sizeof(unsigned long). Be
+ * careful to only use bitops which allow for this (e.g
+ * test_bit/find_first_bit and friends but not __ffs) and to pass
+ * BITS_PER_EVTCHN_WORD as the bitmask length.
+ */
+#define BITS_PER_EVTCHN_WORD (sizeof(xen_ulong_t)*8)
+/*
+ * Make a bitmask (i.e. unsigned long *) of a xen_ulong_t
+ * array. Primarily to avoid long lines (hence the terse name).
+ */
+#define BM(x) (unsigned long *)(x)
+/* Find the first set bit in a evtchn mask */
+#define EVTCHN_FIRST_BIT(w) find_first_bit(BM(&(w)), BITS_PER_EVTCHN_WORD)
+
+static DEFINE_PER_CPU(xen_ulong_t [EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD],
+		      cpu_evtchn_mask);
+
+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)
+{
+	clear_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, info->cpu)));
+	set_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, cpu)));
+}
+
+static void evtchn_2l_clear_pending(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_clear_bit(port, BM(&s->evtchn_pending[0]));
+}
+
+static void evtchn_2l_set_pending(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_set_bit(port, BM(&s->evtchn_pending[0]));
+}
+
+static bool evtchn_2l_is_pending(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	return sync_test_bit(port, BM(&s->evtchn_pending[0]));
+}
+
+static bool evtchn_2l_test_and_set_mask(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	return sync_test_and_set_bit(port, BM(&s->evtchn_mask[0]));
+}
+
+static void evtchn_2l_mask(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_set_bit(port, BM(&s->evtchn_mask[0]));
+}
+
+static void evtchn_2l_unmask(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	unsigned int cpu = get_cpu();
+	int do_hypercall = 0, evtchn_pending = 0;
+
+	BUG_ON(!irqs_disabled());
+
+	if (unlikely((cpu != cpu_from_evtchn(port))))
+		do_hypercall = 1;
+	else {
+		/*
+		 * Need to clear the mask before checking pending to
+		 * avoid a race with an event becoming pending.
+		 *
+		 * EVTCHNOP_unmask will only trigger an upcall if the
+		 * mask bit was set, so if a hypercall is needed
+		 * remask the event.
+		 */
+		sync_clear_bit(port, BM(&s->evtchn_mask[0]));
+		evtchn_pending = sync_test_bit(port, BM(&s->evtchn_pending[0]));
+
+		if (unlikely(evtchn_pending && xen_hvm_domain())) {
+			sync_set_bit(port, BM(&s->evtchn_mask[0]));
+			do_hypercall = 1;
+		}
+	}
+
+	/* Slow path (hypercall) if this is a non-local port or if this is
+	 * an hvm domain and an event is pending (hvm domains don't have
+	 * their own implementation of irq_enable). */
+	if (do_hypercall) {
+		struct evtchn_unmask unmask = { .port = port };
+		(void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
+	} else {
+		struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
+
+		/*
+		 * The following is basically the equivalent of
+		 * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
+		 * the interrupt edge' if the channel is masked.
+		 */
+		if (evtchn_pending &&
+		    !sync_test_and_set_bit(port / BITS_PER_EVTCHN_WORD,
+					   BM(&vcpu_info->evtchn_pending_sel)))
+			vcpu_info->evtchn_upcall_pending = 1;
+	}
+
+	put_cpu();
+}
+
+static DEFINE_PER_CPU(unsigned int, current_word_idx);
+static DEFINE_PER_CPU(unsigned int, current_bit_idx);
+
+/*
+ * Mask out the i least significant bits of w
+ */
+#define MASK_LSBS(w, i) (w & ((~((xen_ulong_t)0UL)) << i))
+
+static inline xen_ulong_t active_evtchns(unsigned int cpu,
+					 struct shared_info *sh,
+					 unsigned int idx)
+{
+	return sh->evtchn_pending[idx] &
+		per_cpu(cpu_evtchn_mask, cpu)[idx] &
+		~sh->evtchn_mask[idx];
+}
+
+/*
+ * Search the CPU's pending events bitmasks.  For each one found, map
+ * the event number to an irq, and feed it into do_IRQ() for handling.
+ *
+ * Xen uses a two-level bitmap to speed searching.  The first level is
+ * a bitset of words which contain pending event bits.  The second
+ * level is a bitset of pending events themselves.
+ */
+static void evtchn_2l_handle_events(unsigned cpu)
+{
+	int irq;
+	xen_ulong_t pending_words;
+	xen_ulong_t pending_bits;
+	int start_word_idx, start_bit_idx;
+	int word_idx, bit_idx;
+	int i;
+	struct irq_desc *desc;
+	struct shared_info *s = HYPERVISOR_shared_info;
+	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
+
+	/* Timer interrupt has highest priority. */
+	irq = irq_from_virq(cpu, VIRQ_TIMER);
+	if (irq != -1) {
+		unsigned int evtchn = evtchn_from_irq(irq);
+		word_idx = evtchn / BITS_PER_LONG;
+		bit_idx = evtchn % BITS_PER_LONG;
+		if (active_evtchns(cpu, s, word_idx) & (1ULL << bit_idx)) {
+			desc = irq_to_desc(irq);
+			if (desc)
+				generic_handle_irq_desc(irq, desc);
+		}
+	}
+
+	/*
+	 * Master flag must be cleared /before/ clearing
+	 * selector flag. xchg_xen_ulong must contain an
+	 * appropriate barrier.
+	 */
+	pending_words = xchg_xen_ulong(&vcpu_info->evtchn_pending_sel, 0);
+
+	start_word_idx = __this_cpu_read(current_word_idx);
+	start_bit_idx = __this_cpu_read(current_bit_idx);
+
+	word_idx = start_word_idx;
+
+	for (i = 0; pending_words != 0; i++) {
+		xen_ulong_t words;
+
+		words = MASK_LSBS(pending_words, word_idx);
+
+		/*
+		 * If we masked out all events, wrap to beginning.
+		 */
+		if (words == 0) {
+			word_idx = 0;
+			bit_idx = 0;
+			continue;
+		}
+		word_idx = EVTCHN_FIRST_BIT(words);
+
+		pending_bits = active_evtchns(cpu, s, word_idx);
+		bit_idx = 0; /* usually scan entire word from start */
+		/*
+		 * We scan the starting word in two parts.
+		 *
+		 * 1st time: start in the middle, scanning the
+		 * upper bits.
+		 *
+		 * 2nd time: scan the whole word (not just the
+		 * parts skipped in the first pass) -- if an
+		 * event in the previously scanned bits is
+		 * pending again it would just be scanned on
+		 * the next loop anyway.
+		 */
+		if (word_idx == start_word_idx) {
+			if (i == 0)
+				bit_idx = start_bit_idx;
+		}
+
+		do {
+			xen_ulong_t bits;
+			int port;
+
+			bits = MASK_LSBS(pending_bits, bit_idx);
+
+			/* If we masked out all events, move on. */
+			if (bits == 0)
+				break;
+
+			bit_idx = EVTCHN_FIRST_BIT(bits);
+
+			/* Process port. */
+			port = (word_idx * BITS_PER_EVTCHN_WORD) + bit_idx;
+			irq = get_evtchn_to_irq(port);
+
+			if (irq != -1) {
+				desc = irq_to_desc(irq);
+				if (desc)
+					generic_handle_irq_desc(irq, desc);
+			}
+
+			bit_idx = (bit_idx + 1) % BITS_PER_EVTCHN_WORD;
+
+			/* Next caller starts at last processed + 1 */
+			__this_cpu_write(current_word_idx,
+					 bit_idx ? word_idx :
+					 (word_idx+1) % BITS_PER_EVTCHN_WORD);
+			__this_cpu_write(current_bit_idx, bit_idx);
+		} while (bit_idx != 0);
+
+		/* Scan start_l1i twice; all others once. */
+		if ((word_idx != start_word_idx) || (i != 0))
+			pending_words &= ~(1UL << word_idx);
+
+		word_idx = (word_idx + 1) % BITS_PER_EVTCHN_WORD;
+	}
+}
+
+irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
+{
+	struct shared_info *sh = HYPERVISOR_shared_info;
+	int cpu = smp_processor_id();
+	xen_ulong_t *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
+	int i;
+	unsigned long flags;
+	static DEFINE_SPINLOCK(debug_lock);
+	struct vcpu_info *v;
+
+	spin_lock_irqsave(&debug_lock, flags);
+
+	printk("\nvcpu %d\n  ", cpu);
+
+	for_each_online_cpu(i) {
+		int pending;
+		v = per_cpu(xen_vcpu, i);
+		pending = (get_irq_regs() && i == cpu)
+			? xen_irqs_disabled(get_irq_regs())
+			: v->evtchn_upcall_mask;
+		printk("%d: masked=%d pending=%d event_sel %0*"PRI_xen_ulong"\n  ", i,
+		       pending, v->evtchn_upcall_pending,
+		       (int)(sizeof(v->evtchn_pending_sel)*2),
+		       v->evtchn_pending_sel);
+	}
+	v = per_cpu(xen_vcpu, cpu);
+
+	printk("\npending:\n   ");
+	for (i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
+		printk("%0*"PRI_xen_ulong"%s",
+		       (int)sizeof(sh->evtchn_pending[0])*2,
+		       sh->evtchn_pending[i],
+		       i % 8 == 0 ? "\n   " : " ");
+	printk("\nglobal mask:\n   ");
+	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
+		printk("%0*"PRI_xen_ulong"%s",
+		       (int)(sizeof(sh->evtchn_mask[0])*2),
+		       sh->evtchn_mask[i],
+		       i % 8 == 0 ? "\n   " : " ");
+
+	printk("\nglobally unmasked:\n   ");
+	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
+		printk("%0*"PRI_xen_ulong"%s",
+		       (int)(sizeof(sh->evtchn_mask[0])*2),
+		       sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
+		       i % 8 == 0 ? "\n   " : " ");
+
+	printk("\nlocal cpu%d mask:\n   ", cpu);
+	for (i = (EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD)-1; i >= 0; i--)
+		printk("%0*"PRI_xen_ulong"%s", (int)(sizeof(cpu_evtchn[0])*2),
+		       cpu_evtchn[i],
+		       i % 8 == 0 ? "\n   " : " ");
+
+	printk("\nlocally unmasked:\n   ");
+	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) {
+		xen_ulong_t pending = sh->evtchn_pending[i]
+			& ~sh->evtchn_mask[i]
+			& cpu_evtchn[i];
+		printk("%0*"PRI_xen_ulong"%s",
+		       (int)(sizeof(sh->evtchn_mask[0])*2),
+		       pending, i % 8 == 0 ? "\n   " : " ");
+	}
+
+	printk("\npending list:\n");
+	for (i = 0; i < EVTCHN_2L_NR_CHANNELS; i++) {
+		if (sync_test_bit(i, BM(sh->evtchn_pending))) {
+			int word_idx = i / BITS_PER_EVTCHN_WORD;
+			printk("  %d: event %d -> irq %d%s%s%s\n",
+			       cpu_from_evtchn(i), i,
+			       get_evtchn_to_irq(i),
+			       sync_test_bit(word_idx, BM(&v->evtchn_pending_sel))
+			       ? "" : " l2-clear",
+			       !sync_test_bit(i, BM(sh->evtchn_mask))
+			       ? "" : " globally-masked",
+			       sync_test_bit(i, BM(cpu_evtchn))
+			       ? "" : " locally-masked");
+		}
+	}
+
+	spin_unlock_irqrestore(&debug_lock, flags);
+
+	return IRQ_HANDLED;
+}
+
+static const struct evtchn_ops evtchn_ops_2l = {
+	.max_channels      = evtchn_2l_max_channels,
+	.nr_channels       = evtchn_2l_max_channels,
+	.bind_to_cpu       = evtchn_2l_bind_to_cpu,
+	.clear_pending     = evtchn_2l_clear_pending,
+	.set_pending       = evtchn_2l_set_pending,
+	.is_pending        = evtchn_2l_is_pending,
+	.test_and_set_mask = evtchn_2l_test_and_set_mask,
+	.mask              = evtchn_2l_mask,
+	.unmask            = evtchn_2l_unmask,
+	.handle_events     = evtchn_2l_handle_events,
+};
+
+void __init xen_evtchn_2l_init(void)
+{
+	pr_info("Using 2-level ABI\n");
+	evtchn_ops = &evtchn_ops_2l;
+}