5 security fixes
    
    denial of service in find_next_bit() [XSA-307, CVE-2019-19581,
            CVE-2019-19582] (#1780559)
    denial of service in HVM/PVH guest userspace code [XSA-308,
            CVE-2019-19583] (#1782206)
    privilege escalation due to malicious PV guest [XSA-309, CVE-2019-19578]
            (#1782210)
    Further issues with restartable PV type change operations [XSA-310,
            CVE-2019-19580] (#1782207)
    vulnerability in dynamic height handling for AMD IOMMU pagetables
            [XSA-311, CVE-2019-19577] (#1782208)