Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754950AbcKQRj5 (ORCPT ); Thu, 17 Nov 2016 12:39:57 -0500 Received: from mail.skyhub.de ([78.46.96.112]:52187 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753478AbcKQRjv (ORCPT ); Thu, 17 Nov 2016 12:39:51 -0500 Date: Thu, 17 Nov 2016 18:39:45 +0100 From: Borislav Petkov To: Tom Lendacky Cc: linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Rik van Riel , Radim =?utf-8?B?S3LEjW3DocWZ?= , Arnd Bergmann , Jonathan Corbet , Matt Fleming , Joerg Roedel , Konrad Rzeszutek Wilk , Paolo Bonzini , Larry Woodman , Ingo Molnar , Andy Lutomirski , "H. Peter Anvin" , Andrey Ryabinin , Alexander Potapenko , Thomas Gleixner , Dmitry Vyukov Subject: Re: [RFC PATCH v3 11/20] x86: Add support for changing memory encryption attribute Message-ID: <20161117173945.gnar3arpyeeh5xm2@pd.tnic> References: <20161110003426.3280.2999.stgit@tlendack-t1.amdoffice.net> <20161110003655.3280.57333.stgit@tlendack-t1.amdoffice.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20161110003655.3280.57333.stgit@tlendack-t1.amdoffice.net> User-Agent: NeoMutt/20161014 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5092 Lines: 184 On Wed, Nov 09, 2016 at 06:36:55PM -0600, Tom Lendacky wrote: > This patch adds support to be change the memory encryption attribute for > one or more memory pages. "Add support for changing ..." > Signed-off-by: Tom Lendacky > --- > arch/x86/include/asm/cacheflush.h | 3 + > arch/x86/include/asm/mem_encrypt.h | 13 ++++++ > arch/x86/mm/mem_encrypt.c | 43 +++++++++++++++++++++ > arch/x86/mm/pageattr.c | 73 ++++++++++++++++++++++++++++++++++++ > 4 files changed, 132 insertions(+) ... > diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c > index 411210d..41cfdf9 100644 > --- a/arch/x86/mm/mem_encrypt.c > +++ b/arch/x86/mm/mem_encrypt.c > @@ -18,6 +18,7 @@ > #include > #include > #include > +#include > > extern pmdval_t early_pmd_flags; > int __init __early_make_pgtable(unsigned long, pmdval_t); > @@ -33,6 +34,48 @@ EXPORT_SYMBOL_GPL(sme_me_mask); > /* Buffer used for early in-place encryption by BSP, no locking needed */ > static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE); > > +int sme_set_mem_enc(void *vaddr, unsigned long size) > +{ > + unsigned long addr, numpages; > + > + if (!sme_me_mask) > + return 0; So those interfaces look duplicated to me: you have exported sme_set_mem_enc/sme_set_mem_unenc which take @size and then you have set_memory_enc/set_memory_dec which take numpages. And then you're testing sme_me_mask in both. What I'd prefer to have is only *two* set_memory_enc/set_memory_dec which take size in bytes and one workhorse __set_memory_enc_dec() which does it all. The user shouldn't have to care about numpages or size or whatever. Ok? > + > + addr = (unsigned long)vaddr & PAGE_MASK; > + numpages = PAGE_ALIGN(size) >> PAGE_SHIFT; > + > + /* > + * The set_memory_xxx functions take an integer for numpages, make > + * sure it doesn't exceed that. > + */ > + if (numpages > INT_MAX) > + return -EINVAL; > + > + return set_memory_enc(addr, numpages); > +} > +EXPORT_SYMBOL_GPL(sme_set_mem_enc); > + > +int sme_set_mem_unenc(void *vaddr, unsigned long size) > +{ > + unsigned long addr, numpages; > + > + if (!sme_me_mask) > + return 0; > + > + addr = (unsigned long)vaddr & PAGE_MASK; > + numpages = PAGE_ALIGN(size) >> PAGE_SHIFT; > + > + /* > + * The set_memory_xxx functions take an integer for numpages, make > + * sure it doesn't exceed that. > + */ > + if (numpages > INT_MAX) > + return -EINVAL; > + > + return set_memory_dec(addr, numpages); > +} > +EXPORT_SYMBOL_GPL(sme_set_mem_unenc); > + > /* > * This routine does not change the underlying encryption setting of the > * page(s) that map this memory. It assumes that eventually the memory is > diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c > index b8e6bb5..babf3a6 100644 > --- a/arch/x86/mm/pageattr.c > +++ b/arch/x86/mm/pageattr.c > @@ -1729,6 +1729,79 @@ int set_memory_4k(unsigned long addr, int numpages) > __pgprot(0), 1, 0, NULL); > } > > +static int __set_memory_enc_dec(struct cpa_data *cpa) > +{ > + unsigned long addr; > + int numpages; > + int ret; > + > + /* People should not be passing in unaligned addresses */ > + if (WARN_ONCE(*cpa->vaddr & ~PAGE_MASK, > + "misaligned address: %#lx\n", *cpa->vaddr)) > + *cpa->vaddr &= PAGE_MASK; > + > + addr = *cpa->vaddr; > + numpages = cpa->numpages; > + > + /* Must avoid aliasing mappings in the highmem code */ > + kmap_flush_unused(); > + vm_unmap_aliases(); > + > + ret = __change_page_attr_set_clr(cpa, 1); > + > + /* Check whether we really changed something */ > + if (!(cpa->flags & CPA_FLUSHTLB)) > + goto out; That label is used only once - just "return ret;" here. > + /* > + * On success we use CLFLUSH, when the CPU supports it to > + * avoid the WBINVD. > + */ > + if (!ret && static_cpu_has(X86_FEATURE_CLFLUSH)) > + cpa_flush_range(addr, numpages, 1); > + else > + cpa_flush_all(1); > + > +out: > + return ret; > +} > + > +int set_memory_enc(unsigned long addr, int numpages) > +{ > + struct cpa_data cpa; > + > + if (!sme_me_mask) > + return 0; > + > + memset(&cpa, 0, sizeof(cpa)); > + cpa.vaddr = &addr; > + cpa.numpages = numpages; > + cpa.mask_set = __pgprot(_PAGE_ENC); > + cpa.mask_clr = __pgprot(0); > + cpa.pgd = init_mm.pgd; You could move that... > + > + return __set_memory_enc_dec(&cpa); > +} > +EXPORT_SYMBOL(set_memory_enc); > + > +int set_memory_dec(unsigned long addr, int numpages) > +{ > + struct cpa_data cpa; > + > + if (!sme_me_mask) > + return 0; > + > + memset(&cpa, 0, sizeof(cpa)); > + cpa.vaddr = &addr; > + cpa.numpages = numpages; > + cpa.mask_set = __pgprot(0); > + cpa.mask_clr = __pgprot(_PAGE_ENC); > + cpa.pgd = init_mm.pgd; ... and that into __set_memory_enc_dec() too and pass in a "bool dec" or "bool enc" or so which presets mask_set and mask_clr properly. See above. I think two functions exported to other in-kernel users are more than enough. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.