On Fri, 3 Dec 2021 at 17:22, Tom Lendacky <thomas.lendacky@xxxxxxx> wrote: > > On 12/3/21 4:30 AM, Ard Biesheuvel wrote: > > On Wed, 1 Dec 2021 at 15:06, Tom Lendacky <thomas.lendacky@xxxxxxx> wrote: > >> > >> On 10/27/21 12:04 PM, Tom Lendacky wrote: > >>> > >>> > >>> On 10/27/21 11:59 AM, Ard Biesheuvel wrote: > >>>> On Wed, 27 Oct 2021 at 18:56, Borislav Petkov <bp@xxxxxxxxx> wrote: > >>>>> > >>>>> On Wed, Oct 27, 2021 at 05:14:35PM +0200, Ard Biesheuvel wrote: > >>>>>> I could take it, but since it will ultimately go through -tip anyway, > >>>>>> perhaps better if they just take it directly? (This will change after > >>>>>> the next -rc1 though) > >>>>>> > >>>>>> Boris? > >>>>> > >>>>> Yeah, I'm being told this is not urgent enough to rush in now so you > >>>>> could queue it into your fixes branch for 5.16 once -rc1 is out and send > >>>>> it to Linus then. The stable tag is just so it gets backported to the > >>>>> respective trees. > >>>>> > >>>>> But if you prefer I should take it, then I can queue it after -rc1. > >>>>> It'll boil down to the same thing though. > >>>>> > >>>> > >>>> No, in that case, I can take it myself. > >>>> > >>>> Tom, does that work for you? > >>> > >>> Yup, that works for me. Thanks guys! > >> > >> I don't see this in any tree yet, so just a gentle reminder in case it > >> dropped off the radar. > >> > > > > Apologies for the delay, I've pushed this out to -next now. > > > > Before I send it to Linus, can you please confirm (for my peace of > > mind) how this only affects systems that have memory encryption > > available and enabled in the first place? > > Certainly. > > An early_memremap() call uses the FIXMAP_PAGE_NORMAL protection value for > performing the mapping. Prior to performing the actual mapping though, a > call to early_memremap_pgprot_adjust() is made to possibly alter the > protection value, but only if memory encryption is active. > > Changing the call to early_memremap_prot() and providing > pgprot_encrypted(FIXMAP_PAGE_NORMAL) as the protection value results in an > equivalent call to early_memremap() when memory encryption is not active. > This is because the pgprot_encrypted() is, in effect, a NOP when memory > encryption is not active. > > So when memory encryption is not available or active, the result of an > early_memremap_prot() call with a protection value of > pgprot_encrypted(FIXMAP_PAGE_NORMAL) is equivalent to an early_memremap() > call. > > Let me know if that answers your question. > It does, thanks.
