On 25/03/2024 11:39 pm, Kirill A. Shutemov wrote:
AMD SEV and Intel TDX guests allocate shared buffers for performing I/O. This is done by allocating pages normally from the buddy allocator and then converting them to shared using set_memory_decrypted(). On kexec, the second kernel is unaware of which memory has been converted in this manner. It only sees E820_TYPE_RAM. Accessing shared memory as private is fatal. Therefore, the memory state must be reset to its original state before starting the new kernel with kexec. The process of converting shared memory back to private occurs in two steps: - enc_kexec_stop_conversion() stops new conversions. - enc_kexec_unshare_mem() unshares all existing shared memory, reverting it back to private. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reviewed-by: Nikolay Borisov <nik.borisov@xxxxxxxx>x ---
Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx> _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
