• Konrad Rzeszutek Wilk's avatar
    xen: Support 64-bit PV guest receiving NMIs · 6efa20e4
    Konrad Rzeszutek Wilk authored
    This is based on a patch that Zhenzhong Duan had sent - which
    was missing some of the remaining pieces. The kernel has the
    logic to handle Xen-type-exceptions using the paravirt interface
    in the assembler code (see PARAVIRT_ADJUST_EXCEPTION_FRAME -
    pv_irq_ops.adjust_exception_frame and and INTERRUPT_RETURN -
    pv_cpu_ops.iret).
    
    That means the nmi handler (and other exception handlers) use
    the hypervisor iret.
    
    The other changes that would be neccessary for this would
    be to translate the NMI_VECTOR to one of the entries on the
    ipi_vector and make xen_send_IPI_mask_allbutself use different
    events.
    
    Fortunately for us commit 1db01b49
    (xen: Clean up apic ipi interface) implemented this and we piggyback
    on the cleanup such that the apic IPI interface will pass the right
    vector value for NMI.
    
    With this patch we can trigger NMIs within a PV guest (only tested
    x86_64).
    
    For this to work with normal PV guests (not initial domain)
    we need the domain to be able to use the APIC ops - they are
    already implemented to use the Xen event channels. For that
    to be turned on in a PV domU we need to remove the masking
    of X86_FEATURE_APIC.
    
    Incidentally that means kgdb will also now work within
    a PV guest without using the 'nokgdbroundup' workaround.
    
    Note that the 32-bit version is different and this patch
    does not enable that.
    
    CC: Lisa Nguyen <lisa@xenapiadmin.com>
    CC: Ben Guthro <benjamin.guthro@citrix.com>
    CC: Zhenzhong Duan <zhenzhong.duan@oracle.com>
    Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    [v1: Fixed up per David Vrabel comments]
    Reviewed-by: default avatarBen Guthro <benjamin.guthro@citrix.com>
    Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
    6efa20e4
vcpu.h 6.59 KB