[3.11] main/xen: security fixes for XSA-317, XSA-319, XSA-321, XSA-327 and XSA-328
Fixes CVEs:
- CVE-2020-15566
- CVE-2020-15563
- CVE-2020-15565
- CVE-2020-15564
- CVE-2020-15567
Backport of !10194 (merged) to 3.11-stable.
Fixes CVEs:
Backport of !10194 (merged) to 3.11-stable.