[PATCH v5 0/5] KVM: irqfd consumer based on IRQ bypass manager

[PATCH v5 0/5] KVM: irqfd consumer based on IRQ bypass manager

[Eric Auger]

This series transforms irqfd into an IRQ bypass consumer and
introduce the infrastructure shared by Intel posted-interrupts
and ARM forwarded IRQ series.

The bypass manager gets compiled for x86 and arm/arm64 when
KVM is used. A new kvm_irqfd.h header is created to externalize
some irqfd declarations going to be used by architecture specific
code. A new CONFIG_HAVE_KVM_IRQ_BYPASS option is introduced
to enable architecture specific IRQ manager hooks.

the series depends on the IRQ bypass manager:
- [PATCH v4] virt: IRQ bypass manager (https://lkml.org/lkml/2015/8/6/526)

can be found at:
https://git.linaro.org/people/eric.auger/linux.git/shortlog/refs/heads/v4.2-rc6-irq-forward-v3

Best Regards

Eric

History:

v4 -> v5:
- remove kvm_arch static inline stubs
- add pr_info on registration failure

v3 -> v4:
- fix compilation for arm/arm64
- rearrange signoffs/history on some patch files

v2 -> v3 (Feng Wu):
- rebase on IRQ bypass manager [PATCH v2] virt: IRQ bypass manager:
  https://lkml.org/lkml/2015/7/16/810
- Correct some minor errors and typo
- Add something needed for posted-interrupts

v1 -> v2:
- isolate the bypass manager and irqfd consumer in this series
- take into account Paolo's comments and use container_of strategy and
  remove additional fields introduced in v1.
- create kvm_irqfd.h
- add unregistration in irqfd_shutdown

v1: originally part of [RFC 00/17] ARM IRQ forward control based on IRQ
    bypass manager (https://lkml.org/lkml/2015/7/2/268)

Eric Auger (4):
  KVM: arm/arm64: select IRQ_BYPASS_MANAGER
  KVM: create kvm_irqfd.h
  KVM: introduce kvm_arch functions for IRQ bypass
  KVM: eventfd: add irq bypass consumer management

Feng Wu (1):
  KVM: x86: select IRQ_BYPASS_MANAGER

 arch/arm/kvm/Kconfig      |   2 +
 arch/arm/kvm/Makefile     |   1 +
 arch/arm64/kvm/Kconfig    |   2 +
 arch/arm64/kvm/Makefile   |   1 +
 arch/x86/kvm/Kconfig      |   2 +
 arch/x86/kvm/Makefile     |   3 ++
 include/linux/kvm_host.h  |  10 +++++
 include/linux/kvm_irqfd.h |  71 ++++++++++++++++++++++++++++++
 virt/kvm/Kconfig          |   3 ++
 virt/kvm/eventfd.c        | 110 ++++++++++++++++------------------------------
 10 files changed, 133 insertions(+), 72 deletions(-)
 create mode 100644 include/linux/kvm_irqfd.h

-- 
1.9.1

[PATCH v5 1/5] KVM: x86: select IRQ_BYPASS_MANAGER

[Eric Auger]

From: Feng Wu <feng.wu@intel.com>

Select IRQ_BYPASS_MANAGER for x86 when CONFIG_KVM is set

Signed-off-by: Feng Wu <feng.wu@intel.com>
---
 arch/x86/kvm/Kconfig  | 2 ++
 arch/x86/kvm/Makefile | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
index d8a1d56..c951d44 100644
--- a/arch/x86/kvm/Kconfig
+++ b/arch/x86/kvm/Kconfig
@@ -3,6 +3,7 @@
 #
 
 source "virt/kvm/Kconfig"
+source "virt/lib/Kconfig"
 
 menuconfig VIRTUALIZATION
 	bool "Virtualization"
@@ -28,6 +29,7 @@ config KVM
 	select ANON_INODES
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQFD
+	select IRQ_BYPASS_MANAGER
 	select HAVE_KVM_IRQ_ROUTING
 	select HAVE_KVM_EVENTFD
 	select KVM_APIC_ARCHITECTURE
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 67d215c..05cc2d7 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -6,6 +6,9 @@ CFLAGS_svm.o := -I.
 CFLAGS_vmx.o := -I.
 
 KVM := ../../../virt/kvm
+LIB := ../../../virt/lib
+
+obj-$(CONFIG_IRQ_BYPASS_MANAGER)	+= $(LIB)/
 
 kvm-y			+= $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \
 				$(KVM)/eventfd.o $(KVM)/irqchip.o $(KVM)/vfio.o
-- 
1.9.1

[PATCH v5 2/5] KVM: arm/arm64: select IRQ_BYPASS_MANAGER

[Eric Auger]

Select IRQ_BYPASS_MANAGER when CONFIG_KVM is set
Also add compilation of virt/lib.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Feng Wu <feng.wu@intel.com>

---

v3 -> v4:
- add compilation of virt/lib in arm/arm64 KVM

v2 -> v3:
- [Feng Wu] Correct a typo in 'arch/arm64/kvm/Kconfig'

v1 -> v2:
- also set IRQ_BYPASS_MANAGER for arm64
---
 arch/arm/kvm/Kconfig    | 2 ++
 arch/arm/kvm/Makefile   | 1 +
 arch/arm64/kvm/Kconfig  | 2 ++
 arch/arm64/kvm/Makefile | 1 +
 4 files changed, 6 insertions(+)

diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
index bfb915d..3c565b9 100644
--- a/arch/arm/kvm/Kconfig
+++ b/arch/arm/kvm/Kconfig
@@ -3,6 +3,7 @@
 #
 
 source "virt/kvm/Kconfig"
+source "virt/lib/Kconfig"
 
 menuconfig VIRTUALIZATION
 	bool "Virtualization"
@@ -31,6 +32,7 @@ config KVM
 	select KVM_VFIO
 	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_IRQFD
+	select IRQ_BYPASS_MANAGER
 	depends on ARM_VIRT_EXT && ARM_LPAE && ARM_ARCH_TIMER
 	---help---
 	  Support hosting virtualized guest machines.
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index c5eef02c..a6a41dd 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -24,3 +24,4 @@ obj-y += $(KVM)/arm/vgic.o
 obj-y += $(KVM)/arm/vgic-v2.o
 obj-y += $(KVM)/arm/vgic-v2-emul.o
 obj-y += $(KVM)/arm/arch_timer.o
+obj-y += ../../../virt/lib/
diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
index bfffe8f..2509539 100644
--- a/arch/arm64/kvm/Kconfig
+++ b/arch/arm64/kvm/Kconfig
@@ -3,6 +3,7 @@
 #
 
 source "virt/kvm/Kconfig"
+source "virt/lib/Kconfig"
 
 menuconfig VIRTUALIZATION
 	bool "Virtualization"
@@ -31,6 +32,7 @@ config KVM
 	select KVM_VFIO
 	select HAVE_KVM_EVENTFD
 	select HAVE_KVM_IRQFD
+	select IRQ_BYPASS_MANAGER
 	---help---
 	  Support hosting virtualized guest machines.
 
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index f90f4aa..55eec69 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -27,3 +27,4 @@ kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic-v3.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/vgic-v3-emul.o
 kvm-$(CONFIG_KVM_ARM_HOST) += vgic-v3-switch.o
 kvm-$(CONFIG_KVM_ARM_HOST) += $(KVM)/arm/arch_timer.o
+kvm-$(CONFIG_KVM_ARM_HOST) += ../../../virt/lib/
-- 
1.9.1

[PATCH v5 3/5] KVM: create kvm_irqfd.h

[Eric Auger]

Move _irqfd_resampler and _irqfd struct declarations in a new
public header: kvm_irqfd.h. They are respectively renamed into
kvm_kernel_irqfd_resampler and kvm_kernel_irqfd. Those datatypes
will be used by architecture specific code, in the context of
IRQ bypass manager integration.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
 include/linux/kvm_irqfd.h | 69 ++++++++++++++++++++++++++++++++++
 virt/kvm/eventfd.c        | 95 ++++++++++++-----------------------------------
 2 files changed, 92 insertions(+), 72 deletions(-)
 create mode 100644 include/linux/kvm_irqfd.h

diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h
new file mode 100644
index 0000000..f926b39
--- /dev/null
+++ b/include/linux/kvm_irqfd.h
@@ -0,0 +1,69 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ * irqfd: Allows an fd to be used to inject an interrupt to the guest
+ * Credit goes to Avi Kivity for the original idea.
+ */
+
+#ifndef __LINUX_KVM_IRQFD_H
+#define __LINUX_KVM_IRQFD_H
+
+#include <linux/kvm_host.h>
+#include <linux/poll.h>
+
+/*
+ * Resampling irqfds are a special variety of irqfds used to emulate
+ * level triggered interrupts.  The interrupt is asserted on eventfd
+ * trigger.  On acknowledgment through the irq ack notifier, the
+ * interrupt is de-asserted and userspace is notified through the
+ * resamplefd.  All resamplers on the same gsi are de-asserted
+ * together, so we don't need to track the state of each individual
+ * user.  We can also therefore share the same irq source ID.
+ */
+struct kvm_kernel_irqfd_resampler {
+	struct kvm *kvm;
+	/*
+	 * List of resampling struct _irqfd objects sharing this gsi.
+	 * RCU list modified under kvm->irqfds.resampler_lock
+	 */
+	struct list_head list;
+	struct kvm_irq_ack_notifier notifier;
+	/*
+	 * Entry in list of kvm->irqfd.resampler_list.  Use for sharing
+	 * resamplers among irqfds on the same gsi.
+	 * Accessed and modified under kvm->irqfds.resampler_lock
+	 */
+	struct list_head link;
+};
+
+struct kvm_kernel_irqfd {
+	/* Used for MSI fast-path */
+	struct kvm *kvm;
+	wait_queue_t wait;
+	/* Update side is protected by irqfds.lock */
+	struct kvm_kernel_irq_routing_entry irq_entry;
+	seqcount_t irq_entry_sc;
+	/* Used for level IRQ fast-path */
+	int gsi;
+	struct work_struct inject;
+	/* The resampler used by this irqfd (resampler-only) */
+	struct kvm_kernel_irqfd_resampler *resampler;
+	/* Eventfd notified on resample (resampler-only) */
+	struct eventfd_ctx *resamplefd;
+	/* Entry in list of irqfds for a resampler (resampler-only) */
+	struct list_head resampler_link;
+	/* Used for setup/shutdown */
+	struct eventfd_ctx *eventfd;
+	struct list_head list;
+	poll_table pt;
+	struct work_struct shutdown;
+};
+
+#endif /* __LINUX_KVM_IRQFD_H */
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 9ff4193..647ffb8 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -23,6 +23,7 @@
 
 #include <linux/kvm_host.h>
 #include <linux/kvm.h>
+#include <linux/kvm_irqfd.h>
 #include <linux/workqueue.h>
 #include <linux/syscalls.h>
 #include <linux/wait.h>
@@ -39,68 +40,14 @@
 #include <kvm/iodev.h>
 
 #ifdef CONFIG_HAVE_KVM_IRQFD
-/*
- * --------------------------------------------------------------------
- * irqfd: Allows an fd to be used to inject an interrupt to the guest
- *
- * Credit goes to Avi Kivity for the original idea.
- * --------------------------------------------------------------------
- */
-
-/*
- * Resampling irqfds are a special variety of irqfds used to emulate
- * level triggered interrupts.  The interrupt is asserted on eventfd
- * trigger.  On acknowledgement through the irq ack notifier, the
- * interrupt is de-asserted and userspace is notified through the
- * resamplefd.  All resamplers on the same gsi are de-asserted
- * together, so we don't need to track the state of each individual
- * user.  We can also therefore share the same irq source ID.
- */
-struct _irqfd_resampler {
-	struct kvm *kvm;
-	/*
-	 * List of resampling struct _irqfd objects sharing this gsi.
-	 * RCU list modified under kvm->irqfds.resampler_lock
-	 */
-	struct list_head list;
-	struct kvm_irq_ack_notifier notifier;
-	/*
-	 * Entry in list of kvm->irqfd.resampler_list.  Use for sharing
-	 * resamplers among irqfds on the same gsi.
-	 * Accessed and modified under kvm->irqfds.resampler_lock
-	 */
-	struct list_head link;
-};
-
-struct _irqfd {
-	/* Used for MSI fast-path */
-	struct kvm *kvm;
-	wait_queue_t wait;
-	/* Update side is protected by irqfds.lock */
-	struct kvm_kernel_irq_routing_entry irq_entry;
-	seqcount_t irq_entry_sc;
-	/* Used for level IRQ fast-path */
-	int gsi;
-	struct work_struct inject;
-	/* The resampler used by this irqfd (resampler-only) */
-	struct _irqfd_resampler *resampler;
-	/* Eventfd notified on resample (resampler-only) */
-	struct eventfd_ctx *resamplefd;
-	/* Entry in list of irqfds for a resampler (resampler-only) */
-	struct list_head resampler_link;
-	/* Used for setup/shutdown */
-	struct eventfd_ctx *eventfd;
-	struct list_head list;
-	poll_table pt;
-	struct work_struct shutdown;
-};
 
 static struct workqueue_struct *irqfd_cleanup_wq;
 
 static void
 irqfd_inject(struct work_struct *work)
 {
-	struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
+	struct kvm_kernel_irqfd *irqfd =
+		container_of(work, struct kvm_kernel_irqfd, inject);
 	struct kvm *kvm = irqfd->kvm;
 
 	if (!irqfd->resampler) {
@@ -121,12 +68,13 @@ irqfd_inject(struct work_struct *work)
 static void
 irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
 {
-	struct _irqfd_resampler *resampler;
+	struct kvm_kernel_irqfd_resampler *resampler;
 	struct kvm *kvm;
-	struct _irqfd *irqfd;
+	struct kvm_kernel_irqfd *irqfd;
 	int idx;
 
-	resampler = container_of(kian, struct _irqfd_resampler, notifier);
+	resampler = container_of(kian,
+			struct kvm_kernel_irqfd_resampler, notifier);
 	kvm = resampler->kvm;
 
 	kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
@@ -141,9 +89,9 @@ irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
 }
 
 static void
-irqfd_resampler_shutdown(struct _irqfd *irqfd)
+irqfd_resampler_shutdown(struct kvm_kernel_irqfd *irqfd)
 {
-	struct _irqfd_resampler *resampler = irqfd->resampler;
+	struct kvm_kernel_irqfd_resampler *resampler = irqfd->resampler;
 	struct kvm *kvm = resampler->kvm;
 
 	mutex_lock(&kvm->irqfds.resampler_lock);
@@ -168,7 +116,8 @@ irqfd_resampler_shutdown(struct _irqfd *irqfd)
 static void
 irqfd_shutdown(struct work_struct *work)
 {
-	struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);
+	struct kvm_kernel_irqfd *irqfd =
+		container_of(work, struct kvm_kernel_irqfd, shutdown);
 	u64 cnt;
 
 	/*
@@ -198,7 +147,7 @@ irqfd_shutdown(struct work_struct *work)
 
 /* assumes kvm->irqfds.lock is held */
 static bool
-irqfd_is_active(struct _irqfd *irqfd)
+irqfd_is_active(struct kvm_kernel_irqfd *irqfd)
 {
 	return list_empty(&irqfd->list) ? false : true;
 }
@@ -209,7 +158,7 @@ irqfd_is_active(struct _irqfd *irqfd)
  * assumes kvm->irqfds.lock is held
  */
 static void
-irqfd_deactivate(struct _irqfd *irqfd)
+irqfd_deactivate(struct kvm_kernel_irqfd *irqfd)
 {
 	BUG_ON(!irqfd_is_active(irqfd));
 
@@ -224,7 +173,8 @@ irqfd_deactivate(struct _irqfd *irqfd)
 static int
 irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
 {
-	struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait);
+	struct kvm_kernel_irqfd *irqfd =
+		container_of(wait, struct kvm_kernel_irqfd, wait);
 	unsigned long flags = (unsigned long)key;
 	struct kvm_kernel_irq_routing_entry irq;
 	struct kvm *kvm = irqfd->kvm;
@@ -274,12 +224,13 @@ static void
 irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
 			poll_table *pt)
 {
-	struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt);
+	struct kvm_kernel_irqfd *irqfd =
+		container_of(pt, struct kvm_kernel_irqfd, pt);
 	add_wait_queue(wqh, &irqfd->wait);
 }
 
 /* Must be called under irqfds.lock */
-static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd)
+static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd)
 {
 	struct kvm_kernel_irq_routing_entry *e;
 	struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS];
@@ -304,7 +255,7 @@ static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd)
 static int
 kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 {
-	struct _irqfd *irqfd, *tmp;
+	struct kvm_kernel_irqfd *irqfd, *tmp;
 	struct fd f;
 	struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
 	int ret;
@@ -340,7 +291,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 	irqfd->eventfd = eventfd;
 
 	if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) {
-		struct _irqfd_resampler *resampler;
+		struct kvm_kernel_irqfd_resampler *resampler;
 
 		resamplefd = eventfd_ctx_fdget(args->resamplefd);
 		if (IS_ERR(resamplefd)) {
@@ -525,7 +476,7 @@ kvm_eventfd_init(struct kvm *kvm)
 static int
 kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
 {
-	struct _irqfd *irqfd, *tmp;
+	struct kvm_kernel_irqfd *irqfd, *tmp;
 	struct eventfd_ctx *eventfd;
 
 	eventfd = eventfd_ctx_fdget(args->fd);
@@ -581,7 +532,7 @@ kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
 void
 kvm_irqfd_release(struct kvm *kvm)
 {
-	struct _irqfd *irqfd, *tmp;
+	struct kvm_kernel_irqfd *irqfd, *tmp;
 
 	spin_lock_irq(&kvm->irqfds.lock);
 
@@ -604,7 +555,7 @@ kvm_irqfd_release(struct kvm *kvm)
  */
 void kvm_irq_routing_update(struct kvm *kvm)
 {
-	struct _irqfd *irqfd;
+	struct kvm_kernel_irqfd *irqfd;
 
 	spin_lock_irq(&kvm->irqfds.lock);
 
-- 
1.9.1

[PATCH v5 4/5] KVM: introduce kvm_arch functions for IRQ bypass

[Eric Auger]

This patch introduces
- kvm_arch_irq_bypass_add_producer
- kvm_arch_irq_bypass_del_producer
- kvm_arch_irq_bypass_stop
- kvm_arch_irq_bypass_start

They make possible to specialize the KVM IRQ bypass consumer in
case CONFIG_KVM_HAVE_IRQ_BYPASS is set.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Feng Wu <feng.wu@intel.com>

---
v4 -> v5:
- remove static inline stub functions

v2 -> v3 (Feng Wu):
- use 'kvm_arch_irq_bypass_start' instead of 'kvm_arch_irq_bypass_resume'
- Remove 'kvm_arch_irq_bypass_update', which is not needed to be
  a irqbypass callback per Alex's comments.
- Make kvm_arch_irq_bypass_add_producer return 'int'

v1 -> v2:
- use CONFIG_KVM_HAVE_IRQ_BYPASS instead CONFIG_IRQ_BYPASS_MANAGER
- rename all functions according to Paolo's proposal
- add kvm_arch_irq_bypass_update according to Feng's need
---
 include/linux/kvm_host.h | 10 ++++++++++
 virt/kvm/Kconfig         |  3 +++
 2 files changed, 13 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 05e99b8..5ac8d21 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -24,6 +24,7 @@
 #include <linux/err.h>
 #include <linux/irqflags.h>
 #include <linux/context_tracking.h>
+#include <linux/irqbypass.h>
 #include <asm/signal.h>
 
 #include <linux/kvm.h>
@@ -1151,5 +1152,14 @@ static inline void kvm_vcpu_set_dy_eligible(struct kvm_vcpu *vcpu, bool val)
 {
 }
 #endif /* CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT */
+
+#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
+int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *,
+			   struct irq_bypass_producer *);
+void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *,
+			   struct irq_bypass_producer *);
+void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *);
+void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *);
+#endif /* CONFIG_HAVE_KVM_IRQ_BYPASS */
 #endif
 
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
index e2c876d..9f8014d 100644
--- a/virt/kvm/Kconfig
+++ b/virt/kvm/Kconfig
@@ -47,3 +47,6 @@ config KVM_GENERIC_DIRTYLOG_READ_PROTECT
 config KVM_COMPAT
        def_bool y
        depends on COMPAT && !S390
+
+config HAVE_KVM_IRQ_BYPASS
+       bool
-- 
1.9.1

[PATCH v5 5/5] KVM: eventfd: add irq bypass consumer management

[Eric Auger]

This patch adds the registration/unregistration of an
irq_bypass_consumer on irqfd assignment/deassignment.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Feng Wu <feng.wu@intel.com>

---

v4 -> v5:
- due to removal of static inline stubs, add
  #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
  around consumer registration/unregistration
- add pr_info when registration fails

v2 -> v3 (Feng Wu):
- Use kvm_arch_irq_bypass_start
- Remove kvm_arch_irq_bypass_update
- Add member 'struct irq_bypass_producer *producer' in
  'struct kvm_kernel_irqfd', it is needed by posted interrupt.
- Remove 'irq_bypass_unregister_consumer' in kvm_irqfd_deassign()

v1 -> v2:
- populate of kvm and gsi removed
- unregister the consumer on irqfd_shutdown
---
 include/linux/kvm_irqfd.h |  2 ++
 virt/kvm/eventfd.c        | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h
index f926b39..0c1de05 100644
--- a/include/linux/kvm_irqfd.h
+++ b/include/linux/kvm_irqfd.h
@@ -64,6 +64,8 @@ struct kvm_kernel_irqfd {
 	struct list_head list;
 	poll_table pt;
 	struct work_struct shutdown;
+	struct irq_bypass_consumer consumer;
+	struct irq_bypass_producer *producer;
 };
 
 #endif /* __LINUX_KVM_IRQFD_H */
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 647ffb8..d7a230f 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -35,6 +35,7 @@
 #include <linux/srcu.h>
 #include <linux/slab.h>
 #include <linux/seqlock.h>
+#include <linux/irqbypass.h>
 #include <trace/events/kvm.h>
 
 #include <kvm/iodev.h>
@@ -140,6 +141,9 @@ irqfd_shutdown(struct work_struct *work)
 	/*
 	 * It is now safe to release the object's resources
 	 */
+#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
+	irq_bypass_unregister_consumer(&irqfd->consumer);
+#endif
 	eventfd_ctx_put(irqfd->eventfd);
 	kfree(irqfd);
 }
@@ -379,6 +383,17 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 	 * we might race against the POLLHUP
 	 */
 	fdput(f);
+#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
+	irqfd->consumer.token = (void *)irqfd->eventfd;
+	irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
+	irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
+	irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
+	irqfd->consumer.start = kvm_arch_irq_bypass_start;
+	ret = irq_bypass_register_consumer(&irqfd->consumer);
+	if (ret)
+		pr_info("irq bypass consumer (token %p) registration fails: %d\n",
+				irqfd->consumer.token, ret);
+#endif
 
 	return 0;
 
-- 
1.9.1

[PATCH v5 5/5] KVM: eventfd: add irq bypass consumer management

[Alex Williamson]

On Mon, 2015-08-10 at 15:31 +0200, Eric Auger wrote:
> This patch adds the registration/unregistration of an
> irq_bypass_consumer on irqfd assignment/deassignment.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> Signed-off-by: Feng Wu <feng.wu@intel.com>
> 
> ---
> 
> v4 -> v5:
> - due to removal of static inline stubs, add
>   #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
>   around consumer registration/unregistration
> - add pr_info when registration fails
> 
> v2 -> v3 (Feng Wu):
> - Use kvm_arch_irq_bypass_start
> - Remove kvm_arch_irq_bypass_update
> - Add member 'struct irq_bypass_producer *producer' in
>   'struct kvm_kernel_irqfd', it is needed by posted interrupt.
> - Remove 'irq_bypass_unregister_consumer' in kvm_irqfd_deassign()
> 
> v1 -> v2:
> - populate of kvm and gsi removed
> - unregister the consumer on irqfd_shutdown
> ---
>  include/linux/kvm_irqfd.h |  2 ++
>  virt/kvm/eventfd.c        | 15 +++++++++++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h
> index f926b39..0c1de05 100644
> --- a/include/linux/kvm_irqfd.h
> +++ b/include/linux/kvm_irqfd.h
> @@ -64,6 +64,8 @@ struct kvm_kernel_irqfd {
>  	struct list_head list;
>  	poll_table pt;
>  	struct work_struct shutdown;
> +	struct irq_bypass_consumer consumer;
> +	struct irq_bypass_producer *producer;
>  };
>  
>  #endif /* __LINUX_KVM_IRQFD_H */
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index 647ffb8..d7a230f 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -35,6 +35,7 @@
>  #include <linux/srcu.h>
>  #include <linux/slab.h>
>  #include <linux/seqlock.h>
> +#include <linux/irqbypass.h>
>  #include <trace/events/kvm.h>
>  
>  #include <kvm/iodev.h>
> @@ -140,6 +141,9 @@ irqfd_shutdown(struct work_struct *work)
>  	/*
>  	 * It is now safe to release the object's resources
>  	 */
> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
> +	irq_bypass_unregister_consumer(&irqfd->consumer);
> +#endif
>  	eventfd_ctx_put(irqfd->eventfd);
>  	kfree(irqfd);
>  }
> @@ -379,6 +383,17 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
>  	 * we might race against the POLLHUP
>  	 */
>  	fdput(f);
> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
> +	irqfd->consumer.token = (void *)irqfd->eventfd;
> +	irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
> +	irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
> +	irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
> +	irqfd->consumer.start = kvm_arch_irq_bypass_start;
> +	ret = irq_bypass_register_consumer(&irqfd->consumer);
> +	if (ret)
> +		pr_info("irq bypass consumer (token %p) registration fails: %d\n",
> +				irqfd->consumer.token, ret);
> +#endif

Does this series compile on its own?  Aren't all these arch function
unresolved?

>  
>  	return 0;
>  

[PATCH v5 5/5] KVM: eventfd: add irq bypass consumer management

[Eric Auger]

Hi Alex,
On 08/12/2015 09:05 PM, Alex Williamson wrote:
> On Mon, 2015-08-10 at 15:31 +0200, Eric Auger wrote:
>> This patch adds the registration/unregistration of an
>> irq_bypass_consumer on irqfd assignment/deassignment.
>>
>> Signed-off-by: Eric Auger <eric.auger@linaro.org>
>> Signed-off-by: Feng Wu <feng.wu@intel.com>
>>
>> ---
>>
>> v4 -> v5:
>> - due to removal of static inline stubs, add
>>   #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
>>   around consumer registration/unregistration
>> - add pr_info when registration fails
>>
>> v2 -> v3 (Feng Wu):
>> - Use kvm_arch_irq_bypass_start
>> - Remove kvm_arch_irq_bypass_update
>> - Add member 'struct irq_bypass_producer *producer' in
>>   'struct kvm_kernel_irqfd', it is needed by posted interrupt.
>> - Remove 'irq_bypass_unregister_consumer' in kvm_irqfd_deassign()
>>
>> v1 -> v2:
>> - populate of kvm and gsi removed
>> - unregister the consumer on irqfd_shutdown
>> ---
>>  include/linux/kvm_irqfd.h |  2 ++
>>  virt/kvm/eventfd.c        | 15 +++++++++++++++
>>  2 files changed, 17 insertions(+)
>>
>> diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h
>> index f926b39..0c1de05 100644
>> --- a/include/linux/kvm_irqfd.h
>> +++ b/include/linux/kvm_irqfd.h
>> @@ -64,6 +64,8 @@ struct kvm_kernel_irqfd {
>>  	struct list_head list;
>>  	poll_table pt;
>>  	struct work_struct shutdown;
>> +	struct irq_bypass_consumer consumer;
>> +	struct irq_bypass_producer *producer;
>>  };
>>  
>>  #endif /* __LINUX_KVM_IRQFD_H */
>> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
>> index 647ffb8..d7a230f 100644
>> --- a/virt/kvm/eventfd.c
>> +++ b/virt/kvm/eventfd.c
>> @@ -35,6 +35,7 @@
>>  #include <linux/srcu.h>
>>  #include <linux/slab.h>
>>  #include <linux/seqlock.h>
>> +#include <linux/irqbypass.h>
>>  #include <trace/events/kvm.h>
>>  
>>  #include <kvm/iodev.h>
>> @@ -140,6 +141,9 @@ irqfd_shutdown(struct work_struct *work)
>>  	/*
>>  	 * It is now safe to release the object's resources
>>  	 */
>> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
>> +	irq_bypass_unregister_consumer(&irqfd->consumer);
>> +#endif
>>  	eventfd_ctx_put(irqfd->eventfd);
>>  	kfree(irqfd);
>>  }
>> @@ -379,6 +383,17 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
>>  	 * we might race against the POLLHUP
>>  	 */
>>  	fdput(f);
>> +#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
>> +	irqfd->consumer.token = (void *)irqfd->eventfd;
>> +	irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
>> +	irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
>> +	irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
>> +	irqfd->consumer.start = kvm_arch_irq_bypass_start;
>> +	ret = irq_bypass_register_consumer(&irqfd->consumer);
>> +	if (ret)
>> +		pr_info("irq bypass consumer (token %p) registration fails: %d\n",
>> +				irqfd->consumer.token, ret);
>> +#endif
> 
> Does this series compile on its own?  Aren't all these arch function
> unresolved?
yes it does since by default CONFIG_HAVE_KVM_IRQ_BYPASS is not defined

Best Regards

Eric
> 
>>  
>>  	return 0;
>>  
> 
> 
>