KVM: x86: Add EOI exit bitmap inference

In order to support a userspace IOAPIC interacting with an in kernel
APIC, the EOI exit bitmaps need to be configurable.

If the IOAPIC is in userspace (i.e. the irqchip has been split), the
EOI exit bitmaps will be set whenever the GSI Routes are configured.
In particular, for the low MSI routes are reservable for userspace
IOAPICs. For these MSI routes, the EOI Exit bit corresponding to the
destination vector of the route will be set for the destination VCPU.

The intention is for the userspace IOAPICs to use the reservable MSI
routes to inject interrupts into the guest.

This is a slight abuse of the notion of an MSI Route, given that MSIs
classically bypass the IOAPIC. It might be worthwhile to add an
additional route type to improve clarity.

Compile tested for Intel x86.

Signed-off-by: Steve Rutherford <srutherford@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 10 deletions

diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index d7ea8e20dae4..716a1c4db528 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -31,16 +31,6 @@
 #include <trace/events/kvm.h>
 #include "irq.h"
 
-struct kvm_irq_routing_table {
-        int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS];
-        u32 nr_rt_entries;
-        /*
-         * Array indexed by gsi. Each entry contains list of irq chips
-         * the gsi is connected to.
-         */
-        struct hlist_head map[0];
-};
-
 int kvm_irq_map_gsi(struct kvm *kvm,
                     struct kvm_kernel_irq_routing_entry *entries, int gsi)
 {
@@ -231,6 +221,8 @@ int kvm_set_irq_routing(struct kvm *kvm,
         kvm_irq_routing_update(kvm);
         mutex_unlock(&kvm->irq_lock);
 
+        kvm_arch_irq_routing_update(kvm);
+
         synchronize_srcu_expedited(&kvm->irq_srcu);
 
         new = old;