On 09/04/18 01:42, Kirill A. Shutemov wrote: > > Switching between 4- and 5-level paging modes (in either direction) > requires paing disabling. It means the code that does the switching has to > be under 4G otherwise we would lose control. > > We handle the switching correctly in kernel decompression code, but not on > kexec caller side. > > XLF_5LEVEL indicates that kernel decompression code can deal with > switching between paging modes and it's safe to jump there in 5-level > paging mode. > > As an alternative we can change kexec to switch to 4-level paging mode > before starting the new kernel. Not sure how hard it will be. > Have a flag saying entering in 5-level mode is fine. However, you really should support returning to 4-level mode in kexec. It is *much* easier to do on the caller side as you have total control of memory allocation there. -hpa _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
