Official FAQs

• Xen Project:  XSA-254   •  FAQ   •  Technical FAQ
• Qubes: QSB #37
• Ubuntu Linux:  What you need to know  •  Mitigation Table
• Microsoft: ADV180002   •  FAQ
• Intel: Facts About the New Security Research Findings

Unofficial FAQs

• OpenXT: Meltdown and Spectre Exposure Analysis: Xen, Linux & Windows
• Linux Kernel:  Addressing Meltdown and Spectre in the Linux Kernel   •  4.15 and beyond   
• x86 Performance:  2018-01-07: PCID is now a critical performance/security feature on x86   •  2018-02-09: KPTI/KAISER Meltdown Initial Performance Regressions
• Barkly: A Clear Guide to Meltdown and Spectre Patches
• hannob: Meltdown/Spectre patch status summary   •  woachk: Spectre patch review
• Robert O'Callahan: Long-Term Consequences Of Spectre And Its Mitigations

Explanations

• Issue disclosure: Spectre and Meltdown papers
• Google Project Zero:  Reading privileged memory with a side channel   •  mitigations
• Barkly: Meltdown and Spectre CPU bugs explained
• Eben Upton: Why Raspberry Pi isn't vulnerable to Spectre or Meltdown
• Wikipedia: Meltdown   •  KPTI