> > This issue was reported by Al Stone when he saw that reboot via EFI > > hangs the machine. Upon debugging, I found that it's > > efi_reset_system() that's touching memory regions which it shouldn't. > > To reproduce the same behavior, I have hacked OVMF and made > > efi_reset_system() buggy. Along with efi_reset_system(), I have also > > modified get_next_high_mono_count() and set_virtual_address_map(). > > They illegally access both boot time and other efi regions. > > > > Testing the patch set: > > ---------------------- > > 1. Download buggy firmware from here [1]. > > 2. Run a qemu instance with this buggy BIOS and boot mainline kernel. > > Add reboot=efi to the kernel command line arguments and after the > > kernel is up and running, type "reboot". The kernel should hang while > rebooting. > > 3. With the same setup, boot kernel after applying patches and the > > reboot should work fine. Also please notice warning/error messages > > printed by kernel. > > > > Did you test these patches with other buggy runtime services? Yes, I did. I have modified efi runtime service GetNextHighMonotonicCount and made it buggy, when invoked from FWTS test suites the efi page fault handler works as expected (i.e. freezing efi_rts_wq and disabling efi runtime services forever). Regards, Sai
