Hi Dan, On Thu, 4 Apr 2019 at 21:21, Dan Williams <dan.j.willi...@intel.com> 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 <t...@linutronix.de> > Cc: Ingo Molnar <mi...@redhat.com> > Cc: Borislav Petkov <b...@alien8.de> > Cc: "H. Peter Anvin" <h...@zytor.com> > Cc: Ard Biesheuvel <ard.biesheu...@linaro.org> > Cc: Darren Hart <dvh...@infradead.org> > Cc: Andy Shevchenko <a...@infradead.org> > Signed-off-by: Dan Williams <dan.j.willi...@intel.com> > --- > 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 */ > _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm