From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f69.google.com (mail-it0-f69.google.com [209.85.214.69]) by kanga.kvack.org (Postfix) with ESMTP id DD53A6B031F for ; Mon, 9 Jul 2018 14:21:04 -0400 (EDT) Received: by mail-it0-f69.google.com with SMTP id k13-v6so14653227ite.5 for ; Mon, 09 Jul 2018 11:21:04 -0700 (PDT) Received: from aserp2120.oracle.com (aserp2120.oracle.com. [141.146.126.78]) by mx.google.com with ESMTPS id w65-v6si6056383iod.280.2018.07.09.11.21.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 09 Jul 2018 11:21:04 -0700 (PDT) Date: Mon, 9 Jul 2018 14:20:55 -0400 From: Konrad Rzeszutek Wilk Subject: Re: [PATCHv4 13/18] x86/mm: Allow to disable MKTME after enumeration Message-ID: <20180709182055.GI6873@char.US.ORACLE.com> References: <20180626142245.82850-1-kirill.shutemov@linux.intel.com> <20180626142245.82850-14-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180626142245.82850-14-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: 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 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? > 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 >