From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id C42CF6B000A for ; Tue, 10 Jul 2018 06:49:16 -0400 (EDT) Received: by mail-pl0-f70.google.com with SMTP id az8-v6so11912066plb.15 for ; Tue, 10 Jul 2018 03:49:16 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id d31-v6sor5416381pld.59.2018.07.10.03.49.15 for (Google Transport Security); Tue, 10 Jul 2018 03:49:15 -0700 (PDT) Date: Tue, 10 Jul 2018 13:49:10 +0300 From: "Kirill A. Shutemov" Subject: Re: [PATCHv4 13/18] x86/mm: Allow to disable MKTME after enumeration Message-ID: <20180710104910.3xpiniksptpby4fo@kshutemo-mobl1> References: <20180626142245.82850-1-kirill.shutemov@linux.intel.com> <20180626142245.82850-14-kirill.shutemov@linux.intel.com> <20180709182055.GI6873@char.US.ORACLE.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180709182055.GI6873@char.US.ORACLE.com> Sender: owner-linux-mm@kvack.org List-ID: To: Konrad Rzeszutek Wilk Cc: "Kirill A. Shutemov" , Ingo Molnar , x86@kernel.org, Thomas Gleixner , "H. Peter Anvin" , Tom Lendacky , Dave Hansen , Kai Huang , Jacob Pan , linux-kernel@vger.kernel.org, linux-mm@kvack.org 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 > > --- > > 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