Re: [PATCH] Add irqdevice interface + userint implementation

Gregory Haskins
2007-04-09T20:27:54Z

Here is the next pass of the patch with changes based on feedback.

I still have not converted over to kerneldoc format as I cannot find an example anywhere yet, and the documentation under Documentation/kernel-doc-nano-HOWTO was a little vague. Pointers appreciated.

-Greg

---
KVM: Add irqdevice object

The current code is geared towards using a user-mode (A)PIC. This patch adds
an "irqdevice" abstraction, and implements a "userint" model to handle the
duties of the original code. Later, we can develop other irqdevice models
to handle objects like LAPIC, IOAPIC, i8259, etc, as appropriate

Signed-off-by: Gregory Haskins <ghaskins-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org>
---

drivers/kvm/Makefile | 2
drivers/kvm/irqdevice.h | 202 +++++++++++++++++++++++++++++++++++++++++++++
drivers/kvm/kvm.h | 9 +-
drivers/kvm/kvm_main.c | 57 +++++++++----
drivers/kvm/svm.c | 33 ++++---
drivers/kvm/userint.c | 210 +++++++++++++++++++++++++++++++++++++++++++++++
drivers/kvm/vmx.c | 29 +++---
7 files changed, 489 insertions(+), 53 deletions(-)

diff --git a/drivers/kvm/Makefile b/drivers/kvm/Makefile
index c0a789f..540afbc 100644
--- a/drivers/kvm/Makefile
+++ b/drivers/kvm/Makefile
@@ -2,7 +2,7 @@
# Makefile for Kernel-based Virtual Machine module
#

-kvm-objs := kvm_main.o mmu.o x86_emulate.o
+kvm-objs := kvm_main.o mmu.o x86_emulate.o userint.o
obj-$(CONFIG_KVM) += kvm.o
kvm-intel-objs = vmx.o
obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
diff --git a/drivers/kvm/irqdevice.h b/drivers/kvm/irqdevice.h
new file mode 100644
index 0000000..e4377d4
--- /dev/null
+++ b/drivers/kvm/irqdevice.h
@@ -0,0 +1,202 @@
+/*
+ * Defines an interface for an abstract interrupt controller. The model
+ * consists of a unit with an arbitrary number of input lines (IRQ0-N), an
+ * output line (INTR), and methods for completing an interrupt-acknowledge
+ * cycle (INTA). A particular implementation of this model will define
+ * various policies, such as irq-to-vector translation, INTA/auto-EOI policy,
+ * etc.
+ *
+ * In addition, the INTR callback mechanism allows the unit to be "wired" to
+ * an interruptible source in a very flexible manner. For instance, an
+ * irqdevice could have its INTR wired to a VCPU (ala LAPIC), or another
+ * interrupt controller (ala cascaded i8259s)
+ *
+ * Copyright (C) 2007 Novell
+ *
+ * Authors:
+ * Gregory Haskins <ghaskins-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ */
+
+#ifndef __IRQDEVICE_H
+#define __IRQDEVICE_H
+
+#define KVM_IRQFLAGS_NMI (1 << 0)
+#define KVM_IRQFLAGS_PEEK (1 << 1)
+
+struct kvm_irqdevice;
+
+struct kvm_irqsink {
+ void (*raise_intr)(struct kvm_irqsink *this,
+ struct kvm_irqdevice *dev);
+
+ void *private;
+};
+
+struct kvm_irqdevice {
+ int (*pending)(struct kvm_irqdevice *this, int flags);
+ int (*read_vector)(struct kvm_irqdevice *this, int flags);
+ int (*set_pin)(struct kvm_irqdevice *this, int pin, int level);
+ int (*summary)(struct kvm_irqdevice *this, void *data);
+ void (*destructor)(struct kvm_irqdevice *this);
+
+ void *private;
+ struct kvm_irqsink sink;
+};
+
+/*
+ * kvm_irqdevice_init()
+ *
+ * Description:
+ * Initialized the kvm_irqdevice for use. Should be called before calling
+ * any derived implementation init functions
+ *
+ * Parameters:
+ * struct kvm_irqdevice *dev: This device
+ *
+ * Returns: (void)
+ */
+static inline void kvm_irqdevice_init(struct kvm_irqdevice *dev)
+{
+ memset(dev, 0, sizeof(*dev));
+}
+
+/*
+ * kvm_irqdevice_pending()
+ *
+ * Description:
+ * Efficiently determines if an interrupt is pending on an irqdevice
+ *
+ * Parameters:
+ * struct kvm_irqdevice *dev: The device
+ * int flags: Modifies the behavior as follows:
+ *
+ * KVM_IRQFLAGS_NMI: Mask everything but NMIs
+ *
+ * Returns: (int)
+ * 0 = no iterrupts pending (per "flags" criteria)
+ * 1 = one or more interrupts are pending
+ */
+static inline int kvm_irqdevice_pending(struct kvm_irqdevice *dev, int flags)
+{
+ return dev->pending(dev, flags);
+}
+
+/*
+ * kvm_irqdevice_read_vector()
+ *
+ * Description:
+ * Read the highest priority pending vector from the device, potentially
+ * invoking auto-EOI depending on device policy
+ *
+ * Parameters:
+ * struct kvm_irqdevice *dev: The device
+ * int flags: Modifies the behavior as follows:
+ *
+ * KVM_IRQFLAGS_NMI: Mask everything but NMIs
+ * KVM_IRQFLAGS_PEEK: Do not auto-acknowledge interrupt
+ *
+ * Returns: (int)
+ * -1 = no interrupts pending (per "flags" criteria)
+ * >=0 = the highest pending vector
+ */
+static inline int kvm_irqdevice_read_vector(struct kvm_irqdevice *dev,
+ int flags)
+{
+ return dev->read_vector(dev, flags);
+}
+
+/*
+ * kvm_irqdevice_set_pin()
+ *
+ * Description:
+ * Allows the caller to assert/deassert an IRQ input pin to the device
+ * according to device policy.
+ *
+ * Parameters:
+ * struct kvm_irqdevice *dev: The device
+ * int pin: The input pin to alter
+ * int level: The value to set (1 = assert, 0 = deassert)
+ *
+ * Returns: (int)
+ * -1 = failure
+ * 0 = success
+ */
+static inline int kvm_irqdevice_set_pin(struct kvm_irqdevice *dev, int pin,
+ int level)
+{
+ return dev->set_pin(dev, pin, level);
+}
+
+/*
+ * kvm_irqdevice_summary()
+ *
+ * Description:
+ * Loads a summary bitmask of all pending vectors (0-255)
+ *
+ * Parameters:
+ * struct kvm_irqdevice *dev: The device
+ * void *data: A pointer to a region capable of holding a 256 bit bitmap
+ *
+ * Returns: (int)
+ * -1 = failure
+ * 0 = success
+ */
+static inline int kvm_irqdevice_summary(struct kvm_irqdevice *dev, void *data)
+{
+ return dev->summary(dev, data);
+}
+
+/*
+ * kvm_irqdevice_register_sink()
+ *
+ * Description:
+ * Registers an kvm_irqsink object as an INTR callback
+ *
+ * Parameters:
+ * struct kvm_irqdevice *dev: The device
+ * struct kvm_irqsink *sink: The sink to register. Data will be copied
+ * so building object from transient storage is
+ * ok.
+ *
+ * Returns: (void)
+ */
+static inline void kvm_irqdevice_register_sink(struct kvm_irqdevice *dev,
+ const struct kvm_irqsink *sink)
+{
+ dev->sink = *sink;
+}
+
+/*
+ * kvm_irqdevice_raise_intr()
+ *
+ * Description:
+ * Invokes a registered INTR callback (if present). This function is
+ * meant to be used privately by a irqdevice implementation.
+ *
+ * Parameters:
+ * struct kvm_irqdevice *dev: The device
+ *
+ * Returns: (void)
+ */
+static inline void kvm_irqdevice_raise_intr(struct kvm_irqdevice *dev)
+{
+ struct kvm_irqsink *sink = &dev->sink;
+ if (sink->raise_intr)
+ sink->raise_intr(sink, dev);
+}
+
+#endif /* __IRQDEVICE_H */
diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index 181099f..58966d9 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -13,6 +13,7 @@
#include <linux/mm.h>

#include "vmx.h"
+#include "irqdevice.h"
#include <linux/kvm.h>
#include <linux/kvm_para.h>

@@ -157,6 +158,8 @@ struct vmcs {

struct kvm_vcpu;

+int kvm_userint_init(struct kvm_irqdevice *dev);
+
/*
* x86 supports 3 paging modes (4-level 64-bit, 3-level 64-bit, and 2-level
* 32-bit). The kvm_mmu structure abstracts the details of the current mmu
@@ -266,6 +269,8 @@ struct kvm_io_device *kvm_io_bus_find_dev(struct kvm_io_bus *bus, gpa_t addr);
void kvm_io_bus_register_dev(struct kvm_io_bus *bus,
struct kvm_io_device *dev);

+#define NR_IRQ_WORDS KVM_IRQ_BITMAP_SIZE(unsigned long)
+
struct kvm_vcpu {
struct kvm *kvm;
union {
@@ -278,9 +283,7 @@ struct kvm_vcpu {
u64 host_tsc;
struct kvm_run *run;
int interrupt_window_open;
- unsigned long irq_summary; /* bit vector: 1 per word in irq_pending */
-#define NR_IRQ_WORDS KVM_IRQ_BITMAP_SIZE(unsigned long)
- unsigned long irq_pending[NR_IRQ_WORDS];
+ struct kvm_irqdevice irq_dev;
unsigned long regs[NR_VCPU_REGS]; /* for rsp: vcpu_load_rsp_rip() */
unsigned long rip; /* needs vcpu_load_rsp_rip() */

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index c3c0059..7e00412 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1989,8 +1989,7 @@ static int kvm_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
sregs->efer = vcpu->shadow_efer;
sregs->apic_base = vcpu->apic_base;

- memcpy(sregs->interrupt_bitmap, vcpu->irq_pending,
- sizeof sregs->interrupt_bitmap);
+ kvm_irqdevice_summary(&vcpu->irq_dev, &sregs->interrupt_bitmap);

vcpu_put(vcpu);

@@ -2044,13 +2043,11 @@ static int kvm_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
if (mmu_reset_needed)
kvm_mmu_reset_context(vcpu);

- memcpy(vcpu->irq_pending, sregs->interrupt_bitmap,
- sizeof vcpu->irq_pending);
- vcpu->irq_summary = 0;
- for (i = 0; i < NR_IRQ_WORDS; ++i)
- if (vcpu->irq_pending[i])
- __set_bit(i, &vcpu->irq_summary);
-
+ /* walk the interrupt-bitmap and inject an IRQ for each bit found */
+ for (i = 0; i < 256; ++i)
+ if (test_bit(i, &sregs->interrupt_bitmap[0]))
+ kvm_irqdevice_set_pin(&vcpu->irq_dev, i, 1);
+
set_segment(vcpu, &sregs->cs, VCPU_SREG_CS);
set_segment(vcpu, &sregs->ds, VCPU_SREG_DS);
set_segment(vcpu, &sregs->es, VCPU_SREG_ES);
@@ -2210,14 +2207,8 @@ static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
{
if (irq->irq < 0 || irq->irq >= 256)
return -EINVAL;
- vcpu_load(vcpu);
-
- set_bit(irq->irq, vcpu->irq_pending);
- set_bit(irq->irq / BITS_PER_LONG, &vcpu->irq_summary);

- vcpu_put(vcpu);
-
- return 0;
+ return kvm_irqdevice_set_pin(&vcpu->irq_dev, irq->irq, 1);
}

static int kvm_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,
@@ -2319,6 +2310,36 @@ out1:
}

/*
+ * This function will be invoked whenever the vcpu->irq_dev raises its INTR
+ * line
+ */
+static void kvm_vcpu_intr(struct kvm_irqsink *this,
+ struct kvm_irqdevice *dev)
+{
+ /*
+ * Our irq device is requesting to interrupt the vcpu. If it is
+ * currently running, we should inject a host IPI to force a VMEXIT
+ */
+
+ /*
+ * FIXME: Implement this or the CPU wont notice the interrupt until
+ * the next natural VMEXIT. Note that this is how the system
+ * has always worked, so nothing is broken here. This is a future
+ * enhancement
+ */
+}
+
+static void kvm_vcpu_irqsink_init(struct kvm_vcpu *vcpu)
+{
+ struct kvm_irqsink sink = {
+ .raise_intr = kvm_vcpu_intr,
+ .private = vcpu
+ };
+
+ kvm_irqdevice_register_sink(&vcpu->irq_dev, &sink);
+}
+
+/*
* Creates some virtual cpus. Good luck creating more than one.
*/
static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
@@ -2364,6 +2385,10 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, int n)
if (r < 0)
goto out_free_vcpus;

+ kvm_irqdevice_init(&vcpu->irq_dev);
+ kvm_vcpu_irqsink_init(vcpu);
+ kvm_userint_init(&vcpu->irq_dev);
+
kvm_arch_ops->vcpu_load(vcpu);
r = kvm_mmu_setup(vcpu);
if (r >= 0)
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index b7e1410..e59a548 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -108,20 +108,16 @@ static unsigned get_addr_size(struct kvm_vcpu *vcpu)

static inline u8 pop_irq(struct kvm_vcpu *vcpu)
{
- int word_index = __ffs(vcpu->irq_summary);
- int bit_index = __ffs(vcpu->irq_pending[word_index]);
- int irq = word_index * BITS_PER_LONG + bit_index;
-
- clear_bit(bit_index, &vcpu->irq_pending[word_index]);
- if (!vcpu->irq_pending[word_index])
- clear_bit(word_index, &vcpu->irq_summary);
- return irq;
+ return kvm_irqdevice_read_vector(&vcpu->irq_dev, 0);
}

static inline void push_irq(struct kvm_vcpu *vcpu, u8 irq)
{
- set_bit(irq, vcpu->irq_pending);
- set_bit(irq / BITS_PER_LONG, &vcpu->irq_summary);
+ /* FIXME: We probably want to reserve the "set_pin" verb for
+ * actual interrupt requests, not for putting back something
+ * previously pending. Lets revisit this
+ */
+ kvm_irqdevice_set_pin(&vcpu->irq_dev, irq, 1);
}

static inline void clgi(void)
@@ -1092,7 +1088,7 @@ static int halt_interception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
vcpu->svm->next_rip = vcpu->svm->vmcb->save.rip + 1;
skip_emulated_instruction(vcpu);
- if (vcpu->irq_summary)
+ if (kvm_irqdevice_pending(&vcpu->irq_dev, 0))
return 1;

kvm_run->exit_reason = KVM_EXIT_HLT;
@@ -1263,7 +1259,7 @@ static int interrupt_window_interception(struct kvm_vcpu *vcpu,
* possible
*/
if (kvm_run->request_interrupt_window &&
- !vcpu->irq_summary) {
+ !kvm_irqdevice_pending(&vcpu->irq_dev, 0)) {
++kvm_stat.irq_window_exits;
kvm_run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
return 0;
@@ -1399,7 +1395,8 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
(!(control->int_state & SVM_INTERRUPT_SHADOW_MASK) &&
(vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF));

- if (vcpu->interrupt_window_open && vcpu->irq_summary)
+ if (vcpu->interrupt_window_open &&
+ kvm_irqdevice_pending(&vcpu->irq_dev, 0))
/*
* If interrupts enabled, and not blocked by sti or mov ss. Good.
*/
@@ -1409,7 +1406,8 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
* Interrupts blocked. Wait for unblock.
*/
if (!vcpu->interrupt_window_open &&
- (vcpu->irq_summary || kvm_run->request_interrupt_window)) {
+ (kvm_irqdevice_pending(&vcpu->irq_dev, 0) ||
+ kvm_run->request_interrupt_window)) {
control->intercept |= 1ULL << INTERCEPT_VINTR;
} else
control->intercept &= ~(1ULL << INTERCEPT_VINTR);
@@ -1418,8 +1416,9 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
static void post_kvm_run_save(struct kvm_vcpu *vcpu,
struct kvm_run *kvm_run)
{
- kvm_run->ready_for_interrupt_injection = (vcpu->interrupt_window_open &&
- vcpu->irq_summary == 0);
+ kvm_run->ready_for_interrupt_injection =
+ (vcpu->interrupt_window_open &&
+ !kvm_irqdevice_pending(&vcpu->irq_dev, 0));
kvm_run->if_flag = (vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF) != 0;
kvm_run->cr8 = vcpu->cr8;
kvm_run->apic_base = vcpu->apic_base;
@@ -1434,7 +1433,7 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu,
static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu,
struct kvm_run *kvm_run)
{
- return (!vcpu->irq_summary &&
+ return (!kvm_irqdevice_pending(&vcpu->irq_dev, 0) &&
kvm_run->request_interrupt_window &&
vcpu->interrupt_window_open &&
(vcpu->svm->vmcb->save.rflags & X86_EFLAGS_IF));
diff --git a/drivers/kvm/userint.c b/drivers/kvm/userint.c
new file mode 100644
index 0000000..42b6fb3
--- /dev/null
+++ b/drivers/kvm/userint.c
@@ -0,0 +1,210 @@
+/*
+ * User Interrupts IRQ device
+ *
+ * This acts as an extention of an interrupt controller that exists elsewhere
+ * (typically in userspace/QEMU). Because this PIC is a pseudo device that
+ * is downstream from a real emulated PIC, the "IRQ-to-vector" mapping has
+ * already occured. Therefore, this PIC has the following unusal properties:
+ *
+ * 1) It has 256 "pins" which are literal vectors (i.e. no translation)
+ * 2) It only supports "auto-EOI" behavior since it is expected that the
+ * upstream emulated PIC will handle the real EOIs (if applicable)
+ * 3) It only listens to "asserts" on the pins (deasserts are dropped)
+ * because its an auto-EOI device anyway.
+ *
+ * Copyright (C) 2007 Novell
+ *
+ * bitarray code based on original vcpu->irq_pending code,
+ * Copyright (C) 2007 Qumranet
+ *
+ * Authors:
+ * Gregory Haskins <ghaskins-Et1tbQHTxzrQT0dZR+AlfA@public.gmane.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ */
+
+#include "kvm.h"
+
+/*
+ *----------------------------------------------------------------------
+ * optimized bitarray object - works like bitarrays in bitops, but uses
+ * a summary field to accelerate lookups. Assumes external locking
+ *---------------------------------------------------------------------
+ */
+
+struct bitarray {
+ unsigned long summary; /* 1 per word in pending */
+ unsigned long pending[NR_IRQ_WORDS];
+};
+
+static inline int bitarray_pending(struct bitarray *this)
+{
+ return this->summary ? 1 : 0;
+}
+
+static inline int bitarray_findhighest(struct bitarray *this)
+{
+ if (!this->summary)
+ return -1;
+ else {
+ int word_index = __fls(this->summary);
+ int bit_index = __fls(this->pending[word_index]);
+
+ return word_index * BITS_PER_LONG + bit_index;
+ }
+}
+
+static inline void bitarray_set(struct bitarray *this, int nr)
+{
+ __set_bit(nr, &this->pending);
+ __set_bit(nr / BITS_PER_LONG, &this->summary);
+}
+
+static inline void bitarray_clear(struct bitarray *this, int nr)
+{
+ int word = nr / BITS_PER_LONG;
+
+ __clear_bit(nr, &this->pending);
+ if (!this->pending[word])
+ __clear_bit(word, &this->summary);
+}
+
+static inline int bitarray_test(struct bitarray *this, int nr)
+{
+ return test_bit(nr, &this->pending);
+}
+
+/*
+ *----------------------------------------------------------------------
+ * userint interface - provides the actual kvm_irqdevice implementation
+ *---------------------------------------------------------------------
+ */
+
+struct kvm_userint {
+ spinlock_t lock;
+ struct bitarray irq_pending;
+ int nmi_pending;
+};
+
+static int userint_pending(struct kvm_irqdevice *this, int flags)
+{
+ struct kvm_userint *s = (struct kvm_userint*)this->private;
+ int ret;
+
+ spin_lock_irq(&s->lock);
+
+ if (flags & KVM_IRQFLAGS_NMI)
+ ret = s->nmi_pending;
+ else
+ ret = bitarray_pending(&s->irq_pending);
+
+ spin_unlock_irq(&s->lock);
+
+ return ret;
+}
+
+static int userint_read_vector(struct kvm_irqdevice *this, int flags)
+{
+ struct kvm_userint *s = (struct kvm_userint*)this->private;
+ int irq;
+
+ spin_lock_irq(&s->lock);
+
+ /*
+ * NMIs take priority, so if there is an NMI pending, or
+ * if we are filtering out NMIs, only consider them
+ */
+ if (s->nmi_pending || (flags & KVM_IRQFLAGS_NMI))
+ irq = s->nmi_pending ? 2 : -1;
+ else
+ irq = bitarray_findhighest(&s->irq_pending);
+
+ if ((irq > -1) && !(flags & KVM_IRQFLAGS_PEEK)) {
+ /*
+ * If the "peek" flag is not set, automatically clear the
+ * interrupt as the EOI mechanism (if any) will take place
+ * in userspace
+ */
+ bitarray_clear(&s->irq_pending, irq);
+ if (irq == 2)
+ s->nmi_pending = 0;
+ }
+
+ spin_unlock_irq(&s->lock);
+
+ return irq;
+}
+
+static int userint_set_pin(struct kvm_irqdevice* this, int irq, int level)
+{
+ struct kvm_userint *s = (struct kvm_userint*)this->private;
+
+ if (!level)
+ return 0; /* We dont care about deasserts */
+
+ spin_lock_irq(&s->lock);
+
+ /*
+ * Update the local state
+ */
+ bitarray_set(&s->irq_pending, irq);
+ if (irq == 2)
+ s->nmi_pending = 1;
+
+ spin_unlock_irq(&s->lock);
+
+ /*
+ * And then alert the higher layer software we have changes
+ */
+ kvm_irqdevice_raise_intr(this);
+
+ return 0;
+}
+
+static int userint_summary(struct kvm_irqdevice* this, void *data)
+{
+ struct kvm_userint *s = (struct kvm_userint*)this->private;
+
+ spin_lock_irq(&s->lock);
+ memcpy(data, s->irq_pending.pending, sizeof s->irq_pending.pending);
+ spin_unlock_irq(&s->lock);
+
+ return 0;
+}
+
+static void userint_destructor(struct kvm_irqdevice *this)
+{
+ kfree(this->private);
+}
+
+int kvm_userint_init(struct kvm_irqdevice *dev)
+{
+ struct kvm_userint *s;
+
+ s = kzalloc(sizeof(*s), GFP_KERNEL);
+
+ spin_lock_init(&s->lock);
+
+ dev->pending = userint_pending;
+ dev->read_vector = userint_read_vector;
+ dev->set_pin = userint_set_pin;
+ dev->summary = userint_summary;
+ dev->destructor = userint_destructor;
+
+ dev->private = s;
+
+ return 0;
+}
+
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index 61a6116..a0fdf02 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1219,13 +1219,8 @@ static void inject_rmode_irq(struct kvm_vcpu *vcpu, int irq)

static void kvm_do_inject_irq(struct kvm_vcpu *vcpu)
{
- int word_index = __ffs(vcpu->irq_summary);
- int bit_index = __ffs(vcpu->irq_pending[word_index]);
- int irq = word_index * BITS_PER_LONG + bit_index;
-
- clear_bit(bit_index, &vcpu->irq_pending[word_index]);
- if (!vcpu->irq_pending[word_index])
- clear_bit(word_index, &vcpu->irq_summary);
+ int irq = kvm_irqdevice_read_vector(&vcpu->irq_dev, 0);
+ BUG_ON(irq < 0);

if (vcpu->rmode.active) {
inject_rmode_irq(vcpu, irq);
@@ -1246,7 +1241,7 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,
(vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0);

if (vcpu->interrupt_window_open &&
- vcpu->irq_summary &&
+ kvm_irqdevice_pending(&vcpu->irq_dev, 0) &&
!(vmcs_read32(VM_ENTRY_INTR_INFO_FIELD) & INTR_INFO_VALID_MASK))
/*
* If interrupts enabled, and not blocked by sti or mov ss. Good.
@@ -1255,7 +1250,8 @@ static void do_interrupt_requests(struct kvm_vcpu *vcpu,

cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
if (!vcpu->interrupt_window_open &&
- (vcpu->irq_summary || kvm_run->request_interrupt_window))
+ (kvm_irqdevice_pending(&vcpu->irq_dev, 0) ||
+ kvm_run->request_interrupt_window))
/*
* Interrupts blocked. Wait for unblock.
*/
@@ -1314,8 +1310,8 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)

if (is_external_interrupt(vect_info)) {
int irq = vect_info & VECTORING_INFO_VECTOR_MASK;
- set_bit(irq, vcpu->irq_pending);
- set_bit(irq / BITS_PER_LONG, &vcpu->irq_summary);
+ /* FIXME: Is this right? */
+ kvm_irqdevice_set_pin(&vcpu->irq_dev, irq, 1);
}

if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == 0x200) { /* nmi */
@@ -1619,8 +1615,9 @@ static void post_kvm_run_save(struct kvm_vcpu *vcpu,
kvm_run->if_flag = (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) != 0;
kvm_run->cr8 = vcpu->cr8;
kvm_run->apic_base = vcpu->apic_base;
- kvm_run->ready_for_interrupt_injection = (vcpu->interrupt_window_open &&
- vcpu->irq_summary == 0);
+ kvm_run->ready_for_interrupt_injection =
+ (vcpu->interrupt_window_open &&
+ !kvm_irqdevice_pending(&vcpu->irq_dev, 0));
}

static int handle_interrupt_window(struct kvm_vcpu *vcpu,
@@ -1631,7 +1628,7 @@ static int handle_interrupt_window(struct kvm_vcpu *vcpu,
* possible
*/
if (kvm_run->request_interrupt_window &&
- !vcpu->irq_summary) {
+ !kvm_irqdevice_pending(&vcpu->irq_dev, 0)) {
kvm_run->exit_reason = KVM_EXIT_IRQ_WINDOW_OPEN;
++kvm_stat.irq_window_exits;
return 0;
@@ -1642,7 +1639,7 @@ static int handle_interrupt_window(struct kvm_vcpu *vcpu,
static int handle_halt(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
skip_emulated_instruction(vcpu);
- if (vcpu->irq_summary)
+ if (kvm_irqdevice_pending(&vcpu->irq_dev, 0))
return 1;

kvm_run->exit_reason = KVM_EXIT_HLT;
@@ -1713,7 +1710,7 @@ static int kvm_handle_exit(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu)
static int dm_request_for_irq_injection(struct kvm_vcpu *vcpu,
struct kvm_run *kvm_run)
{
- return (!vcpu->irq_summary &&
+ return (!kvm_irqdevice_pending(&vcpu->irq_dev, 0) &&
kvm_run->request_interrupt_window &&
vcpu->interrupt_window_open &&
(vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF));