Currently, MSI messages can only be injected to in-kernel irqchips by
defining a corresponding IRQ route for each message. This is not only
unhandy if the MSI messages are generated "on the fly" by user space,
IRQ routes are a limited resource that user space has to manage
carefully.
By providing a direct injection path, we can both avoid using up limited
resources and simplify the necessary steps for user land. This path is
provide in a way that allows for use with other interrupt sources as
well. Besides MSIs also external interrupt lines can be manipulated
through this interface, obsoleting KVM_IRQ_LINE_STATUS.
Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
This picks up Avi's first suggestion as I still think it is the better
option to provide a direct MSI injection channel.
Documentation/virtual/kvm/api.txt | 46 +++++++++++++++++++++++++++++++++++++
include/linux/kvm.h | 26 +++++++++++++++++++++
include/linux/kvm_host.h | 2 +
virt/kvm/irq_comm.c | 29 +++++++++++++++++++++++
virt/kvm/kvm_main.c | 20 ++++++++++++++++
5 files changed, 123 insertions(+), 0 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 81ff39f..c70be58 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1482,6 +1482,52 @@ See KVM_ASSIGN_DEV_IRQ for the data structure. The target device is specified
by assigned_dev_id. In the flags field, only KVM_DEV_ASSIGN_MASK_INTX is
evaluated.
+4.61 KVM_GENERAL_IRQ
+
+Capability: KVM_CAP_GENERAL_IRQ
+Architectures: x86
+Type: vm ioctl
+Parameters: struct kvm_general_irq (in/out)
+Returns: 0 on success, <0 on error
+
+Inject an interrupt event to the guest. Only valid if in-kernel irqchip is
+enabled.
+
+struct kvm_general_irq {
+ __u32 type;
+ __u32 op;
+ __s32 status;
+ __u32 pad;
+ union {
+ __u32 line;
+ struct {
+ __u32 address_lo;
+ __u32 address_hi;
+ __u32 data;
+ } msi;
+ __u8 pad[32];
+ } u;
+};
+
+Support IRQ types are:
+
+#define KVM_IRQTYPE_EXTERNAL_LINE 0
+#define KVM_IRQTYPE_MSI 1
+
+Available operations are:
+
+#define KVM_IRQOP_LOWER 0
+#define KVM_IRQOP_RAISE 1
+#define KVM_IRQOP_TRIGGER 2
+
+The level of an external interrupt line can either be raised or lowered, a
+MSI can only be triggered.
+
+If 0 is returned from the IOCTL, the status field was updated as well to
+reflect the injection result. It will be >0 on interrupt delivery, 0 if the
+interrupt was coalesced with an already pending one, and <0 if the guest
+blocked the delivery or some delivery error occurred.
+
4.62 KVM_CREATE_SPAPR_TCE
Capability: KVM_CAP_SPAPR_TCE
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 7a9dd4b..cb3afaf 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -590,6 +590,7 @@ struct kvm_ppc_pvinfo {
#define KVM_CAP_SYNC_REGS 74
#define KVM_CAP_PCI_2_3 75
#define KVM_CAP_KVMCLOCK_CTRL 76
+#define KVM_CAP_GENERAL_IRQ 77
#ifdef KVM_CAP_IRQ_ROUTING
@@ -715,6 +716,29 @@ struct kvm_one_reg {
__u64 addr;
};
+#define KVM_IRQTYPE_EXTERNAL_LINE 0
+#define KVM_IRQTYPE_MSI 1
+
+#define KVM_IRQOP_LOWER 0
+#define KVM_IRQOP_RAISE 1
+#define KVM_IRQOP_TRIGGER 2
+
+struct kvm_general_irq {
+ __u32 type;
+ __u32 op;
+ __s32 status;
+ __u32 pad;
+ union {
+ __u32 line;
+ struct {
+ __u32 address_lo;
+ __u32 address_hi;
+ __u32 data;
+ } msi;
+ __u8 pad[32];
+ } u;
+};
+
/*
* ioctls for VM fds
*/
@@ -789,6 +813,8 @@ struct kvm_s390_ucas_mapping {
/* Available with KVM_CAP_PCI_2_3 */
#define KVM_ASSIGN_SET_INTX_MASK _IOW(KVMIO, 0xa4, \
struct kvm_assigned_pci_dev)
+/* Available with KVM_CAP_GENERAL_IRQ */
+#define KVM_GENERAL_IRQ _IOWR(KVMIO, 0xa5, struct kvm_general_irq)
/*
* ioctls for vcpu fds
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 49c2f2f..31d3b44 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -773,6 +773,8 @@ int kvm_set_irq_routing(struct kvm *kvm,
unsigned flags);
void kvm_free_irq_routing(struct kvm *kvm);
+int kvm_general_irq(struct kvm *kvm, struct kvm_general_irq *irq);
+
#else
static inline void kvm_free_irq_routing(struct kvm *kvm) {}
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 9f614b4..e487d3f 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -138,6 +138,35 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
return kvm_irq_delivery_to_apic(kvm, NULL, &irq);
}
+int kvm_general_irq(struct kvm *kvm, struct kvm_general_irq *irq)
+{
+ struct kvm_kernel_irq_routing_entry route;
+
+ if (!irqchip_in_kernel(kvm))
+ return -EINVAL;
+
+ switch (irq->type) {
+ case KVM_IRQTYPE_EXTERNAL_LINE:
+ if (irq->op > KVM_IRQOP_RAISE)
+ return -EINVAL;
+ irq->status = kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
+ irq->u.line, irq->op);
+ break;
+ case KVM_IRQTYPE_MSI:
+ if (irq->op != KVM_IRQOP_TRIGGER)
+ return -EINVAL;
+ route.msi.address_lo = irq->u.msi.address_lo;
+ route.msi.address_hi = irq->u.msi.address_hi;
+ route.msi.data = irq->u.msi.data;
+ irq->status = kvm_set_msi(&route, kvm,
+ KVM_USERSPACE_IRQ_SOURCE_ID, 1);
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
+}
+
/*
* Return value:
* < 0 Interrupt was ignored (masked or not delivered for other reasons)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 6bd34a6..95dffec 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2059,6 +2059,23 @@ static long kvm_vm_ioctl(struct file *filp,
mutex_unlock(&kvm->lock);
break;
#endif
+#ifdef CONFIG_HAVE_KVM_IRQCHIP
+ case KVM_GENERAL_IRQ: {
+ struct kvm_general_irq irq;
+
+ r = -EFAULT;
+ if (copy_from_user(&irq, argp, sizeof(irq)))
+ goto out;
+ r = kvm_general_irq(kvm, &irq);
+ if (r < 0)
+ goto out;
+ if (copy_to_user(argp +
+ offsetof(struct kvm_general_irq, status),
+ &irq.status, sizeof(irq.status)))
+ r = -EFAULT;
+ break;
+ }
+#endif
default:
r = kvm_arch_vm_ioctl(filp, ioctl, arg);
if (r == -ENOTTY)
@@ -2187,6 +2204,9 @@ static long kvm_dev_ioctl_check_extension_generic(long arg)
case KVM_CAP_SET_BOOT_CPU_ID:
#endif
case KVM_CAP_INTERNAL_ERROR_DATA:
+#ifdef CONFIG_HAVE_KVM_IRQCHIP
+ case KVM_CAP_GENERAL_IRQ:
+#endif
return 1;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
case KVM_CAP_IRQ_ROUTING:
--
1.7.3.4
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