https://bugzilla.kernel.org/show_bug.cgi?id=216045 --- Comment #1 from Eric Li (ercli@xxxxxxxxxxx) --- Explanation of guest behavior 1. BIOS boots XMHF 2. XMHF starts GRUB as a nested guest 3. GRUB by default boots Debian (5 seconds timeout) 4. Debian executes 0xffffffff81062179 (can set a hardware breakpoint using GDB). At this instruction is a WRMSR to 0x80b (IA32_X2APIC_EOI) 5. The WRMSR instruction above will VMEXIT to hypervisor mode (XMHF). The VMEXIT entry point is 0x10206411 (xmhf_parteventhub_arch_x86vmx_entry) 6. At 0x10206434, the hypervisor calls 0x10207eb9 xmhf_parteventhub_arch_x86vmx_intercept_handler() 7. At 0x10208390, the hypervisor calls 0x10206d9f _vmx_handle_intercept_wrmsr() 8. At 0x102070c6, the hypervisor performs WRMSR to 0x80b. The intention is to forward EOI from the guest (Debian) to KVM. Before WRMSR, "info lapic" in QEMU gives ... ISR 48 IRR 48 9. After WRMSR, RIP lands at 0x102070c8. "info lapic" in QEMU gives ... ISR 48 IRR 48 However, I am expecting it to give ... ISR (none) IRR 48 10. After a lot of instructions, the nested Debian guest halts. "info lapic" is ... ISR 236 IRR 48 236 253 -- You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.
