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?
