Hi, On Mon, Jul 20, 2020 at 06:09:19PM -0700, Erdem Aktas wrote: > It looks like there is an expectation that the bootloader will start > from the 64bit entry point in header_64.S. With the current patch > series, it will not boot up if the bootloader jumps to the startup_32 > entry, which might break some default distro images. > What are supported bootloaders and configurations? > I am using grub ( 2.02-2ubuntu8.15) and it fails to boot because of > this reason. I am not a grub expert, so I would appreciate any > pointers on this. This is right, the only supported boot path is via the 64bit EFI entry point. The reason is that SEV-ES requires support in the firmware too, and currently only OVMF is supported in that regard. The firmware needs to setup the AP jump-table, for example. Other boot-paths have not been implemented. Booting via startup_32 would require exception handling in the 32bit-part of the boot-strap code, because verify_cpu is called there. Also an AMD specific MSR can't be accessed there because this would #GP on non-AMD/SEV-ES machines and, as I said, there is no way yet to handle them. How did you get into the startup_32 entry-point, do you have an SEV-ES BIOS supporting this? If it is really needed it could be implemented at a later point. Regards, Joerg
