Changes between Initial Version and Version 1 of Ticket #20625, comment 14
- Timestamp:
- Dec 30, 2021 1:57:21 AM (3 years ago)
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Ticket #20625, comment 14
initial v1 1 1 As mentioned, TESTCFG.SYS ends up causing a BIOS call in real mode. When switch to real mode an identity mapped page virtual address 12000h is installed by tweaking the page directory / tables. When returning to protected mode, these page table and page directory changes are undone after enabling paging, but no CR3 flushing is done afterwards and that's causing trouble. 2 2 {{{ 3 VBoxDbg> u 1200:00000147 L 60 4 1200:00000147 6a 01 push byte 00001h 5 1200:00000149 9c pushfw 6 1200:0000014a 60 pushaw 7 1200:0000014b 66 50 push eax 8 1200:0000014d 66 53 push ebx 9 1200:0000014f fa cli 10 1200:00000150 e9 bf fe jmp -00141h (00012h) 3 VBoxDbg> u 1200:00000153 L 60 11 4 1200:00000153 55 push bp 12 5 1200:00000154 8b ec mov bp, sp
