• Steve Rutherford's avatar
    KVM: x86: Add EOI exit bitmap inference · b053b2ae
    Steve Rutherford authored
    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: default avatarSteve Rutherford <srutherford@google.com>
    Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
    b053b2ae
irq_comm.c 10.3 KB