KVM: s390: migrate vcpu interrupt state

This patch adds support to migrate vcpu interrupts. Two new vcpu ioctls
are added which get/set the complete status of pending interrupts in one
go. The ioctls are marked as available with the new capability
KVM_CAP_S390_IRQ_STATE.

We can not use a ONEREG, as the number of pending local interrupts is not
constant and depends on the number of CPUs.

To retrieve the interrupt state we add an ioctl KVM_S390_GET_IRQ_STATE.
Its input parameter is a pointer to a struct kvm_s390_irq_state which
has a buffer and length.  For all currently pending interrupts, we copy
a struct kvm_s390_irq into the buffer and pass it to userspace.

To store interrupt state into a buffer provided by userspace, we add an
ioctl KVM_S390_SET_IRQ_STATE. It passes a struct kvm_s390_irq_state into
the kernel and injects all interrupts contained in the buffer.

Signed-off-by: Jens Freimann <jfrei@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index c0632e87a00f..c045c725e521 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -558,6 +558,13 @@ struct kvm_s390_irq {
         } u;
 };
 
+struct kvm_s390_irq_state {
+        __u64 buf;
+        __u32 flags;
+        __u32 len;
+        __u32 reserved[4];
+};
+
 /* for KVM_SET_GUEST_DEBUG */
 
 #define KVM_GUESTDBG_ENABLE             0x00000001
@@ -803,6 +810,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_S390_USER_STSI 109
 #define KVM_CAP_S390_SKEYS 110
 #define KVM_CAP_S390_INJECT_IRQ 113
+#define KVM_CAP_S390_IRQ_STATE 114
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1185,6 +1193,9 @@ struct kvm_s390_ucas_mapping {
 #define KVM_S390_SET_SKEYS      _IOW(KVMIO, 0xb3, struct kvm_s390_skeys)
 /* Available with KVM_CAP_S390_INJECT_IRQ */
 #define KVM_S390_IRQ              _IOW(KVMIO,  0xb4, struct kvm_s390_irq)
+/* Available with KVM_CAP_S390_IRQ_STATE */
+#define KVM_S390_SET_IRQ_STATE    _IOW(KVMIO, 0xb5, struct kvm_s390_irq_state)
+#define KVM_S390_GET_IRQ_STATE    _IOW(KVMIO, 0xb6, struct kvm_s390_irq_state)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU     (1 << 0)
 #define KVM_DEV_ASSIGN_PCI_2_3          (1 << 1)