From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vk0-f71.google.com (mail-vk0-f71.google.com [209.85.213.71]) by kanga.kvack.org (Postfix) with ESMTP id 6D7F9440843 for ; Sat, 8 Jul 2017 08:57:29 -0400 (EDT) Received: by mail-vk0-f71.google.com with SMTP id r125so21431948vkf.6 for ; Sat, 08 Jul 2017 05:57:29 -0700 (PDT) Received: from mail-vk0-x243.google.com (mail-vk0-x243.google.com. [2607:f8b0:400c:c05::243]) by mx.google.com with ESMTPS id a2si13892vkc.9.2017.07.08.05.57.28 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 08 Jul 2017 05:57:28 -0700 (PDT) Received: by mail-vk0-x243.google.com with SMTP id y70so3736888vky.3 for ; Sat, 08 Jul 2017 05:57:28 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20170707133925.29711.39301.stgit@tlendack-t1.amdoffice.net> References: <20170707133804.29711.1616.stgit@tlendack-t1.amdoffice.net> <20170707133925.29711.39301.stgit@tlendack-t1.amdoffice.net> From: Brian Gerst Date: Sat, 8 Jul 2017 08:57:27 -0400 Message-ID: Subject: Re: [PATCH v9 07/38] x86/mm: Remove phys_to_virt() usage in ioremap() Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Tom Lendacky Cc: linux-arch , linux-efi@vger.kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, the arch/x86 maintainers , kexec@lists.infradead.org, Linux Kernel Mailing List , kasan-dev@googlegroups.com, xen-devel@lists.xen.org, Linux-MM , iommu@lists.linux-foundation.org, Brijesh Singh , Toshimitsu Kani , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , 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 , Thomas Gleixner , Paolo Bonzini On Fri, Jul 7, 2017 at 9:39 AM, 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, the default is to add pagetable > mappings with the encryption bit set unless specifically overridden. The > resulting pagetable mapping from phys_to_virt() will result in a mapping > that has the encryption bit set. With SME, the use of ioremap() is > intended to generate pagetable mappings that do not have the encryption > bit set through the use of the PAGE_KERNEL_IO protection value. > > Rather than special case the SME scenario, remove the ISA range check and > usage of phys_to_virt() and have ISA range mappings continue through the > remaining ioremap() path. > > Signed-off-by: Tom Lendacky > --- > arch/x86/mm/ioremap.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c > index 4c1b5fd..bfc3e2d 100644 > --- a/arch/x86/mm/ioremap.c > +++ b/arch/x86/mm/ioremap.c > @@ -13,6 +13,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -106,12 +107,6 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr, > } > > /* > - * Don't remap the low PCI/ISA area, it's always mapped.. > - */ > - if (is_ISA_range(phys_addr, last_addr)) > - return (__force void __iomem *)phys_to_virt(phys_addr); > - > - /* > * Don't allow anybody to remap normal RAM that we're using.. > */ > pfn = phys_addr >> PAGE_SHIFT; > Removing this also affects 32-bit, which is more likely to access legacy devices in this range. Put in a check for SME instead (provided you follow my recommendations to not set the SME feature bit on 32-bit even when the processor supports it). -- Brian Gerst -- 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