On 6/20/25 06:53, Kirill A. Shutemov wrote: > /* > * This needs to follow the FPU initializtion, since EFI depends on it. > + * > + * It also needs to precede the CR pinning setup, because the CR4.LASS > + * bit has to be cleared temporarily in order to execute the > + * set_virtual_address_map() EFI call, which resides in lower addresses > + * and would trip LASS if enabled. > + * > + * Wrapping efi_enter_virtual_mode() into lass_stac()/clac() is not > + * enough because AC flag gates data accesses, but not instruction > + * fetch. Clearing the CR4 bit is required. > */ > if (efi_enabled(EFI_RUNTIME_SERVICES)) > efi_enter_virtual_mode(); > > + setup_cr_pinning(); This is a _bit_ too much of a comment for me in this context. This would be enough: /* EFI twiddles CR4.LASS. Do it before CR pinning: */ if (efi_enabled(EFI_RUNTIME_SERVICES)) efi_enter_virtual_mode(); setup_cr_pinning(); I also dislike comments where code will do. Could efi_enter_virtual_mode() actually check for CR4.LASS? Or check cr4_pinned_bits() or 'cr_pinning.key'? Also, the "lass_stac()/clac() is not enough" comment seems more like changelog material to me than something for a comment.
