Tag
trap-and-emulate
- Aug 7, 2026 Anatomy of a VM Exit: State Save, Exit Qualification, and Where the Cycles Go What the processor writes to the VMCS on every exit, which exit reasons dominate a running guest, and why the host-side handler usually costs more than the transition itself. virtualization
- Jul 23, 2026 Ring Compression: Deprivileging a Guest Kernel Without Losing Its Own Protection How a hypervisor moves a guest kernel down the x86 privilege ladder, why the choice between ring 1 and ring 3 changes what the guest can enforce against its own processes, and which instructions leak the difference. virtualization
- Feb 11, 2026 Trap-and-Emulate: The Popek-Goldberg Conditions and Sensitive Instructions Why a guest kernel running without real privilege can still appear to control the machine, which instructions break that illusion, and how the 1974 virtualization theorem decides where traps must land. virtualization
- Dec 22, 2025 Paravirtualization and the Hypercall ABI: Trading Transparency for Fewer Traps How a modified guest replaces trapping instructions with explicit calls into the hypervisor, what a hypercall looks like at the instruction level, and why the ABI has to be versioned and discoverable. virtualization
- Dec 15, 2023 Shadow Page Tables: Keeping Two Guest Mappings Consistent With One Hardware Walk Why a hypervisor must build its own page tables from the guest's, which guest writes force a rebuild, and how the reverse-map and write-protection machinery bounds the cost of keeping them honest. virtualization