KVM: Allow host IRQ sharing for assigned PCI 2.3 devices

PCI 2.3 allows to generically disable IRQ sources at device level. This
enables us to share legacy IRQs of such devices with other host devices
when passing them to a guest.

The new IRQ sharing feature introduced here is optional, user space has
to request it explicitly. Moreover, user space can inform us about its
view of PCI_COMMAND_INTX_DISABLE so that we can avoid unmasking the
interrupt and signaling it if the guest masked it via the virtualized
PCI config space.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index acbe42939089..6c322a90b92f 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -588,6 +588,7 @@ struct kvm_ppc_pvinfo {
 #define KVM_CAP_TSC_DEADLINE_TIMER 72
 #define KVM_CAP_S390_UCONTROL 73
 #define KVM_CAP_SYNC_REGS 74
+#define KVM_CAP_PCI_2_3 75
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -784,6 +785,9 @@ struct kvm_s390_ucas_mapping {
 /* Available with KVM_CAP_TSC_CONTROL */
 #define KVM_SET_TSC_KHZ           _IO(KVMIO,  0xa2)
 #define KVM_GET_TSC_KHZ           _IO(KVMIO,  0xa3)
+/* Available with KVM_CAP_PCI_2_3 */
+#define KVM_ASSIGN_SET_INTX_MASK  _IOW(KVMIO,  0xa4, \
+                                       struct kvm_assigned_pci_dev)
 
 /*
  * ioctls for vcpu fds
@@ -857,6 +861,8 @@ struct kvm_s390_ucas_mapping {
 #define KVM_SET_ONE_REG           _IOW(KVMIO,  0xac, struct kvm_one_reg)
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU     (1 << 0)
+#define KVM_DEV_ASSIGN_PCI_2_3          (1 << 1)
+#define KVM_DEV_ASSIGN_MASK_INTX        (1 << 2)
 
 struct kvm_assigned_pci_dev {
         __u32 assigned_dev_id;