SEV-SNP does not support the use of the Qemu flash device as SEV-SNP
guests are started using the Qemu -bios option instead of the Qemu -drive
if=pflash option. Perform runtime detection of SEV-SNP and exit early from
the Qemu flash device initialization, indicating the Qemu flash device is
not present. SEV-SNP guests will use the emulated variable support.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
f0d2bc3ab2