On Mon, Jul 09, 2018 at 02:20:55PM -0400, Konrad Rzeszutek Wilk wrote:
> On Tue, Jun 26, 2018 at 05:22:40PM +0300, Kirill A. Shutemov wrote:
> > The new helper mktme_disable() allows to disable MKTME even if it's
> > enumerated successfully. MKTME initialization may fail and this
> > functionality allows system to boot regardless of the failure.
> >
> > MKTME needs per-KeyID direct mapping. It requires a lot more virtual
> > address space which may be a problem in 4-level paging mode. If the
> > system has more physical memory than we can handle with MKTME.
>
> .. then what should happen?
We fail MKTME initialization and boot the system. See next sentence.
> > The feature allows to fail MKTME, but boot the system successfully.
> >
> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> > ---
> > arch/x86/include/asm/mktme.h | 2 ++
> > arch/x86/kernel/cpu/intel.c | 5 +----
> > arch/x86/mm/mktme.c | 9 +++++++++
> > 3 files changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/mktme.h b/arch/x86/include/asm/mktme.h
> > index 44409b8bbaca..ebbee6a0c495 100644
> > --- a/arch/x86/include/asm/mktme.h
> > +++ b/arch/x86/include/asm/mktme.h
> > @@ -6,6 +6,8 @@
> >
> > struct vm_area_struct;
> >
> > +void mktme_disable(void);
> > +
> > #ifdef CONFIG_X86_INTEL_MKTME
> > extern phys_addr_t mktme_keyid_mask;
> > extern int mktme_nr_keyids;
> > diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> > index efc9e9fc47d4..75e3b2602b4a 100644
> > --- a/arch/x86/kernel/cpu/intel.c
> > +++ b/arch/x86/kernel/cpu/intel.c
> > @@ -591,10 +591,7 @@ static void detect_tme(struct cpuinfo_x86 *c)
> > * Maybe needed if there's inconsistent configuation
> > * between CPUs.
> > */
> > - physical_mask = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
> > - mktme_keyid_mask = 0;
> > - mktme_keyid_shift = 0;
> > - mktme_nr_keyids = 0;
> > + mktme_disable();
> > }
> > #endif
> >
> > diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c
> > index 1194496633ce..bb6210dbcf0e 100644
> > --- a/arch/x86/mm/mktme.c
> > +++ b/arch/x86/mm/mktme.c
> > @@ -13,6 +13,15 @@ static inline bool mktme_enabled(void)
> > return static_branch_unlikely(&mktme_enabled_key);
> > }
> >
> > +void mktme_disable(void)
> > +{
> > + physical_mask = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
> > + mktme_keyid_mask = 0;
> > + mktme_keyid_shift = 0;
> > + mktme_nr_keyids = 0;
> > + static_branch_disable(&mktme_enabled_key);
> > +}
> > +
> > int page_keyid(const struct page *page)
> > {
> > if (!mktme_enabled())
> > --
> > 2.18.0
> >
>
--
Kirill A. Shutemov
