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=-7.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 16D7CC10F06 for ; Sat, 6 Apr 2019 04:21:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB2EC2186A for ; Sat, 6 Apr 2019 04:21:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="jagFMzES" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726427AbfDFEVM (ORCPT ); Sat, 6 Apr 2019 00:21:12 -0400 Received: from mail-it1-f194.google.com ([209.85.166.194]:55953 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725973AbfDFEVM (ORCPT ); Sat, 6 Apr 2019 00:21:12 -0400 Received: by mail-it1-f194.google.com with SMTP id y134so6276952itc.5 for ; Fri, 05 Apr 2019 21:21:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=qz+8OqDkF24TbcUTJDyBgOK2AmCiu/Pftke8BYCkCxo=; b=jagFMzESs6y4nl0fr+uRpN380vD8IlLOw0tjgNbw5X2gsP2KBakWazmHKLwb8JrZ1o cEIaYLWIvi+XNAO7tUeHqnwSBP/F3Bw4WhHMLWqEORp1fNekr2+feU3QwjEQwDXapioH 3GQj5L99v86WPDbryWKTMfgPnwfgUBrjIonPrdlifus5QQhiBKSwLGCUbYlPBobKMbol Zj7EpPQcXzhSmOkZJsZA2hP2W6ox791da8QlJQzq9XkvOo2zDHuu+4fpxy7r1TGP8KfX 6gUbUBHANGNJbxBLkL4gUjzRfQhFNg/abLRNeX56suFtJOmbABJw14xRxVdEU4zM6pYc crNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=qz+8OqDkF24TbcUTJDyBgOK2AmCiu/Pftke8BYCkCxo=; b=l2D2KN67KQVg7uTCBwmjW7qsxCSKOL2CUPTNF9gHBktz+UGKNhlP9Q/B9LcdH8q7TU bOr4KlQ51A9tdnziZU4NsmIQBk63fNmTgHVH6eehyIAnEjS8N7dD2f2EuJLeUgMdD8Lt f+oe5B5Kys43r6M8p0L07YirVqSWq6/HFVgg2o0wzZUfSC27iNVMTpq1XO86YNk7brVX 1zbRFB7MPcg1xKrP8rkTgbZrQo47fnYY9CK/z7XajfIy6OuIMfUDe7KO66FYcbma/P6g 6IYq6zwAEFKRxmLhSKeSFnUmFyxtBjRA0Uo0CpbLSmHJnCUHhor4waJiKyWvewJDKl1b W+Ng== X-Gm-Message-State: APjAAAU6rVsP+n3Nx4gKrbt5O2v5yf6yckizVEJAvqxn1ge/PCTlBQvb sy0UYtparl6lwAn4qUsottllbCTYngAUzn7ZE5hwKA== X-Google-Smtp-Source: APXvYqyVIdmCHaSw6XfTZj9niiHeSauqfPJjg3rvY7asfH7IMjVPsRiQSciJ/M7WTPCpNTKpwiRqfGH59UH+WoderLU= X-Received: by 2002:a24:a70f:: with SMTP id a15mr5372975itf.117.1554524470893; Fri, 05 Apr 2019 21:21:10 -0700 (PDT) MIME-Version: 1.0 References: <155440490809.3190322.15060922240602775809.stgit@dwillia2-desk3.amr.corp.intel.com> <155440491334.3190322.44013027330479237.stgit@dwillia2-desk3.amr.corp.intel.com> In-Reply-To: <155440491334.3190322.44013027330479237.stgit@dwillia2-desk3.amr.corp.intel.com> From: Ard Biesheuvel Date: Sat, 6 Apr 2019 06:21:00 +0200 Message-ID: Subject: Re: [RFC PATCH 1/5] efi: Detect UEFI 2.8 Special Purpose Memory To: Dan Williams Cc: Linux Kernel Mailing List , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Darren Hart , Andy Shevchenko , vishal.l.verma@intel.com, "the arch/x86 maintainers" , Linux-MM , keith.busch@intel.com, linux-nvdimm@lists.01.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dan, On Thu, 4 Apr 2019 at 21:21, Dan Williams wrote: > > UEFI 2.8 defines an EFI_MEMORY_SP attribute bit to augment the > interpretation of the EFI Memory Types as "reserved for a special > purpose". > > The proposed Linux behavior for special purpose memory is that it is > reserved for direct-access (device-dax) by default and not available for > any kernel usage, not even as an OOM fallback. Later, through udev > scripts or another init mechanism, these device-dax claimed ranges can > be reconfigured and hot-added to the available System-RAM with a unique > node identifier. > > A follow-on patch integrates parsing of the ACPI HMAT to identify the > node and sub-range boundaries of EFI_MEMORY_SP designated memory. For > now, arrange for EFI_MEMORY_SP memory to be reserved. > > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Borislav Petkov > Cc: "H. Peter Anvin" > Cc: Ard Biesheuvel > Cc: Darren Hart > Cc: Andy Shevchenko > Signed-off-by: Dan Williams > --- > arch/x86/Kconfig | 18 ++++++++++++++++++ > arch/x86/boot/compressed/eboot.c | 5 ++++- > arch/x86/boot/compressed/kaslr.c | 2 +- > arch/x86/include/asm/e820/types.h | 9 +++++++++ > arch/x86/kernel/e820.c | 9 +++++++-- > arch/x86/platform/efi/efi.c | 10 +++++++++- > include/linux/efi.h | 14 ++++++++++++++ > include/linux/ioport.h | 1 + > 8 files changed, 63 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index c1f9b3cf437c..cb9ca27de7a5 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -1961,6 +1961,24 @@ config EFI_MIXED > > If unsure, say N. > > +config EFI_SPECIAL_MEMORY > + bool "EFI Special Purpose Memory Support" > + depends on EFI > + ---help--- > + On systems that have mixed performance classes of memory EFI > + may indicate special purpose memory with an attribute (See > + EFI_MEMORY_SP in UEFI 2.8). A memory range tagged with this > + attribute may have unique performance characteristics compared > + to the system's general purpose "System RAM" pool. On the > + expectation that such memory has application specific usage > + answer Y to arrange for the kernel to reserve it for > + direct-access (device-dax) by default. The memory range can > + later be optionally assigned to the page allocator by system > + administrator policy. Say N to have the kernel treat this > + memory as general purpose by default. > + > + If unsure, say Y. > + EFI_MEMORY_SP is now part of the UEFI spec proper, so it does not make sense to make any understanding of it Kconfigurable. Instead, what I would prefer is to implement support for EFI_MEMORY_SP unconditionally (including the ability to identify it in the debug dump of the memory map etc), in a way that all architectures can use it. Then, I think we should never treat it as ordinary memory and make it the firmware's problem not to use the EFI_MEMORY_SP attribute in cases where it results in undesired behavior in the OS. Also, sInce there is a generic component and a x86 component, can you please split those up? You only cc'ed me on patch #1 this time, but could you please cc me on the entire series for v2? Thanks. > config SECCOMP > def_bool y > prompt "Enable seccomp to safely compute untrusted bytecode" > diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c > index 544ac4fafd11..9b90fae21abe 100644 > --- a/arch/x86/boot/compressed/eboot.c > +++ b/arch/x86/boot/compressed/eboot.c > @@ -560,7 +560,10 @@ setup_e820(struct boot_params *params, struct setup_data *e820ext, u32 e820ext_s > case EFI_BOOT_SERVICES_CODE: > case EFI_BOOT_SERVICES_DATA: > case EFI_CONVENTIONAL_MEMORY: > - e820_type = E820_TYPE_RAM; > + if (is_efi_special(d)) > + e820_type = E820_TYPE_SPECIAL; > + else > + e820_type = E820_TYPE_RAM; > break; > > case EFI_ACPI_MEMORY_NVS: > diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > index 2e53c056ba20..897e46eb9714 100644 > --- a/arch/x86/boot/compressed/kaslr.c > +++ b/arch/x86/boot/compressed/kaslr.c > @@ -757,7 +757,7 @@ process_efi_entries(unsigned long minimum, unsigned long image_size) > * > * Only EFI_CONVENTIONAL_MEMORY is guaranteed to be free. > */ > - if (md->type != EFI_CONVENTIONAL_MEMORY) > + if (md->type != EFI_CONVENTIONAL_MEMORY || is_efi_special(md)) > continue; > > if (efi_mirror_found && > diff --git a/arch/x86/include/asm/e820/types.h b/arch/x86/include/asm/e820/types.h > index c3aa4b5e49e2..0ab8abae2e8b 100644 > --- a/arch/x86/include/asm/e820/types.h > +++ b/arch/x86/include/asm/e820/types.h > @@ -28,6 +28,15 @@ enum e820_type { > */ > E820_TYPE_PRAM = 12, > > + /* > + * Special-purpose / application-specific memory is indicated to > + * the system via the EFI_MEMORY_SP attribute. Define an e820 > + * translation of this memory type for the purpose of > + * reserving this range and marking it with the > + * IORES_DESC_APPLICATION_RESERVED designation. > + */ > + E820_TYPE_SPECIAL = 0xefffffff, > + > /* > * Reserved RAM used by the kernel itself if > * CONFIG_INTEL_TXT=y is enabled, memory of this type > diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c > index 2879e234e193..9f50dd0bbb04 100644 > --- a/arch/x86/kernel/e820.c > +++ b/arch/x86/kernel/e820.c > @@ -176,6 +176,7 @@ static void __init e820_print_type(enum e820_type type) > switch (type) { > case E820_TYPE_RAM: /* Fall through: */ > case E820_TYPE_RESERVED_KERN: pr_cont("usable"); break; > + case E820_TYPE_SPECIAL: /* Fall through: */ > case E820_TYPE_RESERVED: pr_cont("reserved"); break; > case E820_TYPE_ACPI: pr_cont("ACPI data"); break; > case E820_TYPE_NVS: pr_cont("ACPI NVS"); break; > @@ -1023,6 +1024,7 @@ static const char *__init e820_type_to_string(struct e820_entry *entry) > case E820_TYPE_UNUSABLE: return "Unusable memory"; > case E820_TYPE_PRAM: return "Persistent Memory (legacy)"; > case E820_TYPE_PMEM: return "Persistent Memory"; > + case E820_TYPE_SPECIAL: /* Fall-through: */ > case E820_TYPE_RESERVED: return "Reserved"; > default: return "Unknown E820 type"; > } > @@ -1038,6 +1040,7 @@ static unsigned long __init e820_type_to_iomem_type(struct e820_entry *entry) > case E820_TYPE_UNUSABLE: /* Fall-through: */ > case E820_TYPE_PRAM: /* Fall-through: */ > case E820_TYPE_PMEM: /* Fall-through: */ > + case E820_TYPE_SPECIAL: /* Fall-through: */ > case E820_TYPE_RESERVED: /* Fall-through: */ > default: return IORESOURCE_MEM; > } > @@ -1050,6 +1053,7 @@ static unsigned long __init e820_type_to_iores_desc(struct e820_entry *entry) > case E820_TYPE_NVS: return IORES_DESC_ACPI_NV_STORAGE; > case E820_TYPE_PMEM: return IORES_DESC_PERSISTENT_MEMORY; > case E820_TYPE_PRAM: return IORES_DESC_PERSISTENT_MEMORY_LEGACY; > + case E820_TYPE_SPECIAL: return IORES_DESC_APPLICATION_RESERVED; > case E820_TYPE_RESERVED_KERN: /* Fall-through: */ > case E820_TYPE_RAM: /* Fall-through: */ > case E820_TYPE_UNUSABLE: /* Fall-through: */ > @@ -1065,13 +1069,14 @@ static bool __init do_mark_busy(enum e820_type type, struct resource *res) > return true; > > /* > - * Treat persistent memory like device memory, i.e. reserve it > - * for exclusive use of a driver > + * Treat persistent memory and other special memory ranges like > + * device memory, i.e. reserve it for exclusive use of a driver > */ > switch (type) { > case E820_TYPE_RESERVED: > case E820_TYPE_PRAM: > case E820_TYPE_PMEM: > + case E820_TYPE_SPECIAL: > return false; > case E820_TYPE_RESERVED_KERN: > case E820_TYPE_RAM: > diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c > index e1cb01a22fa8..d227751f331b 100644 > --- a/arch/x86/platform/efi/efi.c > +++ b/arch/x86/platform/efi/efi.c > @@ -139,7 +139,9 @@ static void __init do_add_efi_memmap(void) > case EFI_BOOT_SERVICES_CODE: > case EFI_BOOT_SERVICES_DATA: > case EFI_CONVENTIONAL_MEMORY: > - if (md->attribute & EFI_MEMORY_WB) > + if (is_efi_special(md)) > + e820_type = E820_TYPE_SPECIAL; > + else if (md->attribute & EFI_MEMORY_WB) > e820_type = E820_TYPE_RAM; > else > e820_type = E820_TYPE_RESERVED; > @@ -753,6 +755,12 @@ static bool should_map_region(efi_memory_desc_t *md) > if (IS_ENABLED(CONFIG_X86_32)) > return false; > > + /* > + * Special purpose memory is not mapped by default. > + */ > + if (is_efi_special(md)) > + return false; > + > /* > * Map all of RAM so that we can access arguments in the 1:1 > * mapping when making EFI runtime calls. > diff --git a/include/linux/efi.h b/include/linux/efi.h > index 54357a258b35..cecbc2bda1da 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) /* special purpose */ > #define EFI_MEMORY_RUNTIME ((u64)0x8000000000000000ULL) /* range requires runtime mapping */ > #define EFI_MEMORY_DESCRIPTOR_VERSION 1 > > @@ -128,6 +129,19 @@ typedef struct { > u64 attribute; > } efi_memory_desc_t; > > +#ifdef CONFIG_EFI_SPECIAL_MEMORY > +static inline bool is_efi_special(efi_memory_desc_t *md) > +{ > + return md->type == EFI_CONVENTIONAL_MEMORY > + && (md->attribute & EFI_MEMORY_SP); > +} > +#else > +static inline bool is_efi_special(efi_memory_desc_t *md) > +{ > + return false; > +} > +#endif > + > typedef struct { > efi_guid_t guid; > u32 headersize; > diff --git a/include/linux/ioport.h b/include/linux/ioport.h > index da0ebaec25f0..2d79841ee9b9 100644 > --- a/include/linux/ioport.h > +++ b/include/linux/ioport.h > @@ -133,6 +133,7 @@ enum { > IORES_DESC_PERSISTENT_MEMORY_LEGACY = 5, > IORES_DESC_DEVICE_PRIVATE_MEMORY = 6, > IORES_DESC_DEVICE_PUBLIC_MEMORY = 7, > + IORES_DESC_APPLICATION_RESERVED = 8, > }; > > /* helpers to define resources */ >