On Thu, Oct 12, 2023 at 01:51:13PM +0300, Nikolay Borisov wrote: > > > On 12.10.23 г. 13:14 ч., kirill.shutemov@xxxxxxxxxxxxxxx wrote: > > On Wed, Oct 11, 2023 at 10:25:28PM +0300, Nikolay Borisov wrote: > > > setup_e820() is executed after UEFI's ExitBootService has been called. > > > This causes the firmware to throw an exception because Console IO > > > protocol handler is supposed to work only during boot service > > > environment. As per UEFI 2.9, section 12.1: > > > > > > "This protocol isused to handle input and output of text-based > > > information intended for the system user during the operation of code > > > in the boot services environment." > > > > > > Running a TDX guest with TDVF with unaccepted memory disabled results in > > > the following output: > > > > Oh. My bad. > > > > But there's other codepath that does the same. If setup_e820() fails with > > EFI_BUFFER_TOO_SMALL, efi_stub_entry() would try to print "exit_boot() > > failed\n". > > > > I wouldner if it is feasible to hook up earlyprintk console into > > efi_printk() machinery for after ExitBootService() case? Silent boot > > failure is not the best UX. > > > > > In my testing I was able to transpose setup_e820 and efi exit_boot_service > by calling exit_boot_func before setup_e820 which ensures the various memory > variables are populated. Is there any specific reason why ExitBootServices > is called before setting up the e820 table? AFAIU this is an arbitrary > choice? Because if you allocate memory with EFI service it can alter EFI memory map and we need the last version to convert it to e820. -- Kiryl Shutsemau / Kirill A. Shutemov
