[PATCH v8 3/6] kvm: Add IRQ source ID option to KVM_IRQFD

Alex Williamson
2012-08-10T22:37:40Z

This allows specifying an IRQ source ID to be used when injecting an
interrupt. When not specified KVM_USERSPACE_IRQ_SOURCE_ID is used.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

Documentation/virtual/kvm/api.txt | 5 +++++
arch/x86/kvm/x86.c | 1 +
include/linux/kvm.h | 6 +++++-
virt/kvm/eventfd.c | 14 ++++++++++----
4 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 062cfd5..46f4b4d 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1946,6 +1946,11 @@ the guest using the specified gsi pin. The irqfd is removed using
the KVM_IRQFD_FLAG_DEASSIGN flag, specifying both kvm_irqfd.fd
and kvm_irqfd.gsi.

+When KVM_CAP_IRQFD_IRQ_SOURCE_ID is available, KVM_IRQFD supports the
+KVM_IRQFD_FLAG_IRQ_SOURCE_ID which can be used to specify an IRQ
+source ID (see KVM_IRQ_SOURCE_ID) to be used for the guest interrupt.
+This flag has no effect on deassignment.
+
4.76 KVM_PPC_ALLOCATE_HTAB

Capability: KVM_CAP_PPC_ALLOC_HTAB
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 75e743e..946c5bd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2174,6 +2174,7 @@ int kvm_dev_ioctl_check_extension(long ext)
case KVM_CAP_GET_TSC_KHZ:
case KVM_CAP_PCI_2_3:
case KVM_CAP_KVMCLOCK_CTRL:
+ case KVM_CAP_IRQFD_IRQ_SOURCE_ID:
r = 1;
break;
case KVM_CAP_COALESCED_MMIO:
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 67b6b49..deda8a9 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -619,6 +619,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_S390_COW 79
#define KVM_CAP_PPC_ALLOC_HTAB 80
#define KVM_CAP_NR_IRQ_SOURCE_ID 81
+#define KVM_CAP_IRQFD_IRQ_SOURCE_ID 82

#ifdef KVM_CAP_IRQ_ROUTING

@@ -684,12 +685,15 @@ struct kvm_xen_hvm_config {
#endif

#define KVM_IRQFD_FLAG_DEASSIGN (1 << 0)
+/* Available with KVM_CAP_IRQFD_IRQ_SOURCE_ID */
+#define KVM_IRQFD_FLAG_IRQ_SOURCE_ID (1 << 1)

struct kvm_irqfd {
__u32 fd;
__u32 gsi;
__u32 flags;
- __u8 pad[20];
+ __u32 irq_source_id;
+ __u8 pad[16];
};

#define KVM_IRQ_SOURCE_ID_FLAG_DEASSIGN (1 << 0)
diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 7d7e2aa..30150f1 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -51,6 +51,7 @@ struct _irqfd {
struct kvm_kernel_irq_routing_entry __rcu *irq_entry;
/* Used for level IRQ fast-path */
int gsi;
+ int irq_source_id;
struct work_struct inject;
/* Used for setup/shutdown */
struct eventfd_ctx *eventfd;
@@ -67,8 +68,8 @@ irqfd_inject(struct work_struct *work)
struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
struct kvm *kvm = irqfd->kvm;

- kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1);
- kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
+ kvm_set_irq(kvm, irqfd->irq_source_id, irqfd->gsi, 1);
+ kvm_set_irq(kvm, irqfd->irq_source_id, irqfd->gsi, 0);
}

/*
@@ -138,7 +139,7 @@ irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
irq = rcu_dereference(irqfd->irq_entry);
/* An event has been signaled, inject an interrupt */
if (irq)
- kvm_set_msi(irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1);
+ kvm_set_msi(irq, kvm, irqfd->irq_source_id, 1);
else
schedule_work(&irqfd->inject);
rcu_read_unlock();
@@ -213,6 +214,10 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)

irqfd->kvm = kvm;
irqfd->gsi = args->gsi;
+ if (args->flags & KVM_IRQFD_FLAG_IRQ_SOURCE_ID)
+ irqfd->irq_source_id = args->irq_source_id;
+ else
+ irqfd->irq_source_id = KVM_USERSPACE_IRQ_SOURCE_ID;
INIT_LIST_HEAD(&irqfd->list);
INIT_WORK(&irqfd->inject, irqfd_inject);
INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
@@ -340,7 +345,8 @@ kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
int
kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
{
- if (args->flags & ~KVM_IRQFD_FLAG_DEASSIGN)
+ if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN |
+ KVM_IRQFD_FLAG_IRQ_SOURCE_ID))
return -EINVAL;

if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)