xen: various flaws (#1501391)
    multiple MSI mapping issues on x86 [XSA-237]
    DMOP map/unmap missing argument checks [XSA-238]
    hypervisor stack leak in x86 I/O intercept code [XSA-239]
    Unlimited recursion in linear pagetable de-typing [XSA-240]
    Stale TLB entry due to page type release race [XSA-241]
    page type reference leak on x86 [XSA-242]
    x86: Incorrect handling of self-linear shadow mappings with translated
            guests [XSA-243]
    x86: Incorrect handling of IST settings during CPU hotplug [XSA-244]