From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 186D56B03A4 for ; Wed, 21 Jun 2017 03:37:48 -0400 (EDT) Received: by mail-wr0-f197.google.com with SMTP id 4so12375267wrc.15 for ; Wed, 21 Jun 2017 00:37:48 -0700 (PDT) Received: from Galois.linutronix.de (Galois.linutronix.de. [2a01:7a0:2:106d:700::1]) by mx.google.com with ESMTPS id 101si17358467wrb.364.2017.06.21.00.37.46 for (version=TLS1_2 cipher=AES128-SHA bits=128/128); Wed, 21 Jun 2017 00:37:46 -0700 (PDT) Date: Wed, 21 Jun 2017 09:37:39 +0200 (CEST) From: Thomas Gleixner Subject: Re: [PATCH v7 07/36] x86/mm: Don't use phys_to_virt in ioremap() if SME is active In-Reply-To: <20170616185104.18967.7867.stgit@tlendack-t1.amdoffice.net> Message-ID: References: <20170616184947.18967.84890.stgit@tlendack-t1.amdoffice.net> <20170616185104.18967.7867.stgit@tlendack-t1.amdoffice.net> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: 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, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, xen-devel@lists.xen.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Brijesh Singh , Toshimitsu Kani , =?ISO-8859-2?Q?Radim_Kr=E8m=E1=F8?= , Matt Fleming , Alexander Potapenko , "H. Peter Anvin" , Larry Woodman , Jonathan Corbet , Joerg Roedel , "Michael S. Tsirkin" , Ingo Molnar , Andrey Ryabinin , Dave Young , Rik van Riel , Arnd Bergmann , Konrad Rzeszutek Wilk , Borislav Petkov , Andy Lutomirski , Boris Ostrovsky , Dmitry Vyukov , Juergen Gross , Paolo Bonzini On Fri, 16 Jun 2017, Tom Lendacky wrote: > Currently there is a check if the address being mapped is in the ISA > range (is_ISA_range()), and if it is then phys_to_virt() is used to > perform the mapping. When SME is active, however, this will result > in the mapping having the encryption bit set when it is expected that > an ioremap() should not have the encryption bit set. So only use the > phys_to_virt() function if SME is not active > > Reviewed-by: Borislav Petkov > Signed-off-by: Tom Lendacky > --- > arch/x86/mm/ioremap.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c > index 4c1b5fd..a382ba9 100644 > --- a/arch/x86/mm/ioremap.c > +++ b/arch/x86/mm/ioremap.c > @@ -13,6 +13,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -106,9 +107,11 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, > } > > /* > - * Don't remap the low PCI/ISA area, it's always mapped.. > + * Don't remap the low PCI/ISA area, it's always mapped. > + * But if SME is active, skip this so that the encryption bit > + * doesn't get set. > */ > - if (is_ISA_range(phys_addr, last_addr)) > + if (is_ISA_range(phys_addr, last_addr) && !sme_active()) > return (__force void __iomem *)phys_to_virt(phys_addr); More thoughts about that. Making this conditional on !sme_active() is not the best idea. I'd rather remove that whole thing and make it unconditional so the code pathes get always exercised and any subtle wreckage is detected on a broader base and not only on that hard to access and debug SME capable machine owned by Joe User. Thanks, tglx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org