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[2001:8b0:10b:1231::1]) by mx.google.com with ESMTPS id d17si7519678wrp.60.2019.06.17.00.46.55 for (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 17 Jun 2019 00:46:55 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of peterz@infradead.org designates 2001:8b0:10b:1231::1 as permitted sender) client-ip=2001:8b0:10b:1231::1; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=merlin.20170209 header.b="rCvYNa7/"; spf=pass (google.com: best guess record for domain of peterz@infradead.org designates 2001:8b0:10b:1231::1 as permitted sender) smtp.mailfrom=peterz@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=YkzG8FgrjsJE2ZjG5g7hfYDZEeo6+OA/Btz/mk5jlNA=; b=rCvYNa7/NvaIcpx/eS9RsD3zq AfDoAj5ne5PjHAPsNNRhWmX6hypo262EDdiDCPlHuxGce32uhXRLpzjvBzbikSRZJcmLtrNTtSVgW rzcyk4RJqcl8vpfFlcjxtUDMDrotaRgaducgqtG9EcCMf9RifWeZ1/mUP1sMgYNYS63w2MB3TKhdV WTha/hzgsuI74FPHTYlGXhMyYe7cAuTCkFuHtLtoZd2os6d3RGl5hn6JWfW+XwzYRRaOiCB6h5xJ3 17Zg4IQ1oDzAYtM1bSfmTqu6hvkkpvEX7pt8C43DWflPBRQghgLdhMs8wX6E+Du/mc5qmpWo/q3n6 YdnKS7szw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1hcmLk-0005Pt-OF; Mon, 17 Jun 2019 07:46:44 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 3D54C20961A06; Mon, 17 Jun 2019 09:46:43 +0200 (CEST) Date: Mon, 17 Jun 2019 09:46:43 +0200 From: Peter Zijlstra To: Kai Huang Cc: "Kirill A. Shutemov" , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Andy Lutomirski , David Howells , Kees Cook , Dave Hansen , Jacob Pan , Alison Schofield , linux-mm@kvack.org, kvm@vger.kernel.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH, RFC 49/62] mm, x86: export several MKTME variables Message-ID: <20190617074643.GW3436@hirez.programming.kicks-ass.net> References: <20190508144422.13171-1-kirill.shutemov@linux.intel.com> <20190508144422.13171-50-kirill.shutemov@linux.intel.com> <20190614115647.GI3436@hirez.programming.kicks-ass.net> <1560741269.5187.7.camel@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1560741269.5187.7.camel@linux.intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Archived-At: List-Archive: List-Post: On Mon, Jun 17, 2019 at 03:14:29PM +1200, Kai Huang wrote: > On Fri, 2019-06-14 at 13:56 +0200, Peter Zijlstra wrote: > > On Wed, May 08, 2019 at 05:44:09PM +0300, Kirill A. Shutemov wrote: > > > From: Kai Huang > > > > > > KVM needs those variables to get/set memory encryption mask. > > > > > > Signed-off-by: Kai Huang > > > Signed-off-by: Kirill A. Shutemov > > > --- > > > arch/x86/mm/mktme.c | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/arch/x86/mm/mktme.c b/arch/x86/mm/mktme.c > > > index df70651816a1..12f4266cf7ea 100644 > > > --- a/arch/x86/mm/mktme.c > > > +++ b/arch/x86/mm/mktme.c > > > @@ -7,13 +7,16 @@ > > > > > > /* Mask to extract KeyID from physical address. */ > > > phys_addr_t mktme_keyid_mask; > > > +EXPORT_SYMBOL_GPL(mktme_keyid_mask); > > > /* > > > * Number of KeyIDs available for MKTME. > > > * Excludes KeyID-0 which used by TME. MKTME KeyIDs start from 1. > > > */ > > > int mktme_nr_keyids; > > > +EXPORT_SYMBOL_GPL(mktme_nr_keyids); > > > /* Shift of KeyID within physical address. */ > > > int mktme_keyid_shift; > > > +EXPORT_SYMBOL_GPL(mktme_keyid_shift); > > > > > > DEFINE_STATIC_KEY_FALSE(mktme_enabled_key); > > > EXPORT_SYMBOL_GPL(mktme_enabled_key); > > > > NAK, don't export variables. Who owns the values, who enforces this? > > > > Both KVM and IOMMU driver need page_keyid() and mktme_keyid_shift to set page's keyID to the right > place in the PTE (of KVM EPT and VT-d DMA page table). > > MKTME key type code need to know mktme_nr_keyids in order to alloc/free keyID. > > Maybe better to introduce functions instead of exposing variables directly? > > Or instead of introducing page_keyid(), we use page_encrypt_mask(), which essentially holds > "page_keyid() << mktme_keyid_shift"? Yes, that's much better, because that strictly limits the access to R/O.