From: Dave Hansen In clone_pgd_range() copy the init user PGDs which cover the kernel half of the address space, so a process has all the required kernel mappings visible. [ tglx: Split out from the big kaiser dump and folded Andys simplification ] Signed-off-by: Dave Hansen Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Brian Gerst Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com --- arch/x86/include/asm/pgtable.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -1119,7 +1119,14 @@ static inline void pmdp_set_wrprotect(st */ static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count) { - memcpy(dst, src, count * sizeof(pgd_t)); + memcpy(dst, src, count * sizeof(pgd_t)); +#ifdef CONFIG_PAGE_TABLE_ISOLATION + if (!static_cpu_has(X86_FEATURE_PTI)) + return; + /* Clone the user space pgd as well */ + memcpy(kernel_to_user_pgdp(dst), kernel_to_user_pgdp(src), + count * sizeof(pgd_t)); +#endif } #define PTE_SHIFT ilog2(PTRS_PER_PTE)