From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id 120926B0038 for ; Tue, 28 Feb 2017 17:34:48 -0500 (EST) Received: by mail-pg0-f72.google.com with SMTP id x17so32914252pgi.3 for ; Tue, 28 Feb 2017 14:34:48 -0800 (PST) Received: from NAM03-CO1-obe.outbound.protection.outlook.com (mail-co1nam03on0047.outbound.protection.outlook.com. [104.47.40.47]) by mx.google.com with ESMTPS id q77si2908078pfi.41.2017.02.28.14.34.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 28 Feb 2017 14:34:46 -0800 (PST) Subject: Re: [RFC PATCH v4 11/28] x86: Add support to determine the E820 type of an address References: <20170216154158.19244.66630.stgit@tlendack-t1.amdoffice.net> <20170216154430.19244.95519.stgit@tlendack-t1.amdoffice.net> <20170220200955.32e2wqxgulswnr55@pd.tnic> From: Tom Lendacky Message-ID: Date: Tue, 28 Feb 2017 16:34:39 -0600 MIME-Version: 1.0 In-Reply-To: <20170220200955.32e2wqxgulswnr55@pd.tnic> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Borislav Petkov 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 , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Toshimitsu Kani , Arnd Bergmann , Jonathan Corbet , Matt Fleming , "Michael S. Tsirkin" , Joerg Roedel , Konrad Rzeszutek Wilk , Paolo Bonzini , Brijesh Singh , Ingo Molnar , Alexander Potapenko , Andy Lutomirski , "H. Peter Anvin" , Andrey Ryabinin , Thomas Gleixner , Larry Woodman , Dmitry Vyukov On 2/20/2017 2:09 PM, Borislav Petkov wrote: > On Thu, Feb 16, 2017 at 09:44:30AM -0600, Tom Lendacky wrote: >> This patch adds support to return the E820 type associated with an address > > s/This patch adds/Add/ > >> range. >> >> Signed-off-by: Tom Lendacky >> --- >> arch/x86/include/asm/e820/api.h | 2 ++ >> arch/x86/include/asm/e820/types.h | 2 ++ >> arch/x86/kernel/e820.c | 26 +++++++++++++++++++++++--- >> 3 files changed, 27 insertions(+), 3 deletions(-) >> >> diff --git a/arch/x86/include/asm/e820/api.h b/arch/x86/include/asm/e820/api.h >> index 8e0f8b8..7c1bdc9 100644 >> --- a/arch/x86/include/asm/e820/api.h >> +++ b/arch/x86/include/asm/e820/api.h >> @@ -38,6 +38,8 @@ >> extern void e820__reallocate_tables(void); >> extern void e820__register_nosave_regions(unsigned long limit_pfn); >> >> +extern enum e820_type e820__get_entry_type(u64 start, u64 end); >> + >> /* >> * Returns true iff the specified range [start,end) is completely contained inside >> * the ISA region. >> diff --git a/arch/x86/include/asm/e820/types.h b/arch/x86/include/asm/e820/types.h >> index 4adeed0..bf49591 100644 >> --- a/arch/x86/include/asm/e820/types.h >> +++ b/arch/x86/include/asm/e820/types.h >> @@ -7,6 +7,8 @@ >> * These are the E820 types known to the kernel: >> */ >> enum e820_type { >> + E820_TYPE_INVALID = 0, >> + > > Now this is strange - ACPI spec doesn't explicitly say that range type 0 > is invalid. Am I looking at the wrong place? > > "Table 15-312 Address Range Types12" in ACPI spec 6. > > If 0 is really the invalid entry, then e820_print_type() needs updating > too. And then the invalid-entry-add should be a separate patch. The 0 return (originally) was to indicate that an e820 entry for the range wasn't found. This series just gave it a name. So it's not that the type field held a 0. Since 0 isn't defined in the ACPI spec I don't see an issue with creating it and I can add a comment to the effect that this value is used for the type when an e820 entry isn't found. I could always rename it to E820_TYPE_NOT_FOUND if that would help. Or if we want to guard against ACPI adding a type 0 in the future, I could make the function return an int and then return -EINVAL if an e820 entry isn't found. This might be the better option. Thanks, Tom > >> E820_TYPE_RAM = 1, >> E820_TYPE_RESERVED = 2, >> E820_TYPE_ACPI = 3, > -- 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