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, 2 insertions, 0 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index e42d85ae854..ec171c1d087 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -546,6 +546,7 @@ struct kvm_assigned_dev_kernel {
         unsigned int entries_nr;
         int host_irq;
         bool host_irq_disabled;
+        bool pci_2_3;
         struct msix_entry *host_msix_entries;
         int guest_irq;
         struct msix_entry *guest_msix_entries;
@@ -555,6 +556,7 @@ struct kvm_assigned_dev_kernel {
         struct pci_dev *dev;
         struct kvm *kvm;
         spinlock_t intx_lock;
+        struct mutex intx_mask_lock;
         char irq_name[32];
         struct pci_saved_state *pci_saved_state;
 };