From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E64DAECE59D for ; Wed, 16 Oct 2019 01:13:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C3F282168B for ; Wed, 16 Oct 2019 01:13:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390552AbfJPBNz (ORCPT ); Tue, 15 Oct 2019 21:13:55 -0400 Received: from mga18.intel.com ([134.134.136.126]:4233 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390538AbfJPBNz (ORCPT ); Tue, 15 Oct 2019 21:13:55 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Oct 2019 18:13:54 -0700 X-IronPort-AV: E=Sophos;i="5.67,301,1566889200"; d="scan'208";a="199903469" Received: from dwillia2-desk3.jf.intel.com (HELO dwillia2-desk3.amr.corp.intel.com) ([10.54.39.16]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 15 Oct 2019 18:13:54 -0700 Subject: [PATCH v7 02/12] efi: Enumerate EFI_MEMORY_SP From: Dan Williams To: mingo@redhat.com Cc: Ard Biesheuvel , Dave Hansen , peterz@infradead.org, vishal.l.verma@intel.com, x86@kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org Date: Tue, 15 Oct 2019 17:59:36 -0700 Message-ID: <157118757690.2063440.10362378797818353669.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <157118756627.2063440.9878062995925617180.stgit@dwillia2-desk3.amr.corp.intel.com> References: <157118756627.2063440.9878062995925617180.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: StGit/0.18-2-gc94f MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org UEFI 2.8 defines an EFI_MEMORY_SP attribute bit to augment the interpretation of the EFI Memory Types as "reserved for a specific purpose". The intent of this bit is to allow the OS to identify precious or scarce memory resources and optionally manage it separately from EfiConventionalMemory. As defined older OSes that do not know about this attribute are permitted to ignore it and the memory will be handled according to the OS default policy for the given memory type. In other words, this "specific purpose" hint is deliberately weaker than EfiReservedMemoryType in that the system continues to operate if the OS takes no action on the attribute. The risk of taking no action is potentially unwanted / unmovable kernel allocations from the designated resource that prevent the full realization of the "specific purpose". For example, consider a system with a high-bandwidth memory pool. Older kernels are permitted to boot and consume that memory as conventional "System-RAM" newer kernels may arrange for that memory to be set aside (soft reserved) by the system administrator for a dedicated high-bandwidth memory aware application to consume. Specifically, this mechanism allows for the elimination of scenarios where platform firmware tries to game OS policy by lying about ACPI SLIT values, i.e. claiming that a precious memory resource has a high distance to trigger the OS to avoid it by default. This reservation hint allows platform-firmware to instead tell the truth about performance characteristics by indicate to OS memory management to put immovable allocations elsewhere. Implement simple detection of the bit for EFI memory table dumps and save the kernel policy for a follow-on change. Reviewed-by: Ard Biesheuvel Reviewed-by: Dave Hansen Signed-off-by: Dan Williams --- drivers/firmware/efi/efi.c | 5 +++-- include/linux/efi.h | 1 + 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 8d3e778e988b..68a4ec24b823 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -839,15 +839,16 @@ char * __init efi_md_typeattr_format(char *buf, size_t size, if (attr & ~(EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_RO | EFI_MEMORY_WP | EFI_MEMORY_RP | EFI_MEMORY_XP | - EFI_MEMORY_NV | + EFI_MEMORY_NV | EFI_MEMORY_SP | EFI_MEMORY_RUNTIME | EFI_MEMORY_MORE_RELIABLE)) snprintf(pos, size, "|attr=0x%016llx]", (unsigned long long)attr); else snprintf(pos, size, - "|%3s|%2s|%2s|%2s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]", + "|%3s|%2s|%2s|%2s|%2s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]", attr & EFI_MEMORY_RUNTIME ? "RUN" : "", attr & EFI_MEMORY_MORE_RELIABLE ? "MR" : "", + attr & EFI_MEMORY_SP ? "SP" : "", attr & EFI_MEMORY_NV ? "NV" : "", attr & EFI_MEMORY_XP ? "XP" : "", attr & EFI_MEMORY_RP ? "RP" : "", diff --git a/include/linux/efi.h b/include/linux/efi.h index bd3837022307..5c1dd0221384 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -112,6 +112,7 @@ typedef struct { #define EFI_MEMORY_MORE_RELIABLE \ ((u64)0x0000000000010000ULL) /* higher reliability */ #define EFI_MEMORY_RO ((u64)0x0000000000020000ULL) /* read-only */ +#define EFI_MEMORY_SP ((u64)0x0000000000040000ULL) /* soft reserved */ #define EFI_MEMORY_RUNTIME ((u64)0x8000000000000000ULL) /* range requires runtime mapping */ #define EFI_MEMORY_DESCRIPTOR_VERSION 1