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.
So looking at the code the only thing which would prevent refactoring to
exit logic to directly call exit_boot_func etc and setup_e820 before
calling efi_exit_boot_services is if the memory map changes. The current
code ensures that we really have the latest memory map version and so
setup_e820 is called with the latest version.
Ard, how likely it is that the memory map can indeed change between the
calls to getmemorymap and exitbootservice?
