From caad057bb6ce86a9cb71520af395fd0bd04a659f Mon Sep 17 00:00:00 2001 From: Eduardo Habkost Date: Wed, 29 Oct 2014 11:26:08 -0200 Subject: smbios: Encode UUID according to SMBIOS specification Differently from older versions, SMBIOS version 2.6 is explicit about the encoding of UUID fields: > Although RFC 4122 recommends network byte order for all fields, the PC > industry (including the ACPI, UEFI, and Microsoft specifications) has > consistently used little-endian byte encoding for the first three fields: > time_low, time_mid, time_hi_and_version. The same encoding, also known as > wire format, should also be used for the SMBIOS representation of the UUID. > > The UUID {00112233-4455-6677-8899-AABBCCDDEEFF} would thus be represented > as 33 22 11 00 55 44 77 66 88 99 AA BB CC DD EE FF. The dmidecode tool implements this and decodes the above "wire format" when SMBIOS version >= 2.6. We moved from SMBIOS version 2.4 to 2.8 when we started building the SMBIOS entry point inside QEMU, on commit c97294ec1b9e36887e119589d456557d72ab37b5. Change smbios_build_type_1_table() to encode the UUID as specified. To make sure we won't change the guest-visible UUID when upgrading to a newer QEMU version, keep the old behavior on pc-*-2.1 and older. Signed-off-by: Eduardo Habkost Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/pc_piix.c | 4 +++- hw/i386/pc_q35.c | 4 +++- hw/i386/smbios.c | 27 ++++++++++++++++++++++++--- 3 files changed, 30 insertions(+), 5 deletions(-) (limited to 'hw/i386') diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c index ce8745d..200ea4f 100644 --- a/hw/i386/pc_piix.c +++ b/hw/i386/pc_piix.c @@ -63,6 +63,7 @@ static bool has_acpi_build = true; static int legacy_acpi_table_size; static bool smbios_defaults = true; static bool smbios_legacy_mode; +static bool smbios_uuid_encoded = true; /* Make sure that guest addresses aligned at 1Gbyte boundaries get mapped to * host addresses aligned at 1Gbyte boundaries. This way we can use 1GByte * pages in the host. @@ -172,7 +173,7 @@ static void pc_init1(MachineState *machine, MachineClass *mc = MACHINE_GET_CLASS(machine); /* These values are guest ABI, do not change */ smbios_set_defaults("QEMU", "Standard PC (i440FX + PIIX, 1996)", - mc->name, smbios_legacy_mode); + mc->name, smbios_legacy_mode, smbios_uuid_encoded); } /* allocate ram and load rom/bios */ @@ -304,6 +305,7 @@ static void pc_init_pci(MachineState *machine) static void pc_compat_2_1(MachineState *machine) { + smbios_uuid_encoded = false; } static void pc_compat_2_0(MachineState *machine) diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index aef4628..f69e4a1 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -52,6 +52,7 @@ static bool has_acpi_build = true; static bool smbios_defaults = true; static bool smbios_legacy_mode; +static bool smbios_uuid_encoded = true; /* Make sure that guest addresses aligned at 1Gbyte boundaries get mapped to * host addresses aligned at 1Gbyte boundaries. This way we can use 1GByte * pages in the host. @@ -163,7 +164,7 @@ static void pc_q35_init(MachineState *machine) MachineClass *mc = MACHINE_GET_CLASS(machine); /* These values are guest ABI, do not change */ smbios_set_defaults("QEMU", "Standard PC (Q35 + ICH9, 2009)", - mc->name, smbios_legacy_mode); + mc->name, smbios_legacy_mode, smbios_uuid_encoded); } /* allocate ram and load rom/bios */ @@ -283,6 +284,7 @@ static void pc_q35_init(MachineState *machine) static void pc_compat_2_1(MachineState *machine) { + smbios_uuid_encoded = false; } static void pc_compat_2_0(MachineState *machine) diff --git a/hw/i386/smbios.c b/hw/i386/smbios.c index 0ae5960..8a7ad48 100644 --- a/hw/i386/smbios.c +++ b/hw/i386/smbios.c @@ -48,6 +48,7 @@ struct smbios_table { static uint8_t *smbios_entries; static size_t smbios_entries_len; static bool smbios_legacy = true; +static bool smbios_uuid_encoded = true; /* end: legacy structures & constants for <= 2.0 machines */ @@ -391,6 +392,11 @@ static void smbios_build_type_1_fields(void) smbios_maybe_add_str(1, offsetof(struct smbios_type_1, family_str), type1.family); if (qemu_uuid_set) { + /* We don't encode the UUID in the "wire format" here because this + * function is for legacy mode and needs to keep the guest ABI, and + * because we don't know what's the SMBIOS version advertised by the + * BIOS. + */ smbios_add_field(1, offsetof(struct smbios_type_1, uuid), qemu_uuid, 16); } @@ -523,6 +529,19 @@ static void smbios_build_type_0_table(void) SMBIOS_BUILD_TABLE_POST; } +/* Encode UUID from the big endian encoding described on RFC4122 to the wire + * format specified by SMBIOS version 2.6. + */ +static void smbios_encode_uuid(struct smbios_uuid *uuid, const uint8_t *buf) +{ + memcpy(uuid, buf, 16); + if (smbios_uuid_encoded) { + uuid->time_low = bswap32(uuid->time_low); + uuid->time_mid = bswap16(uuid->time_mid); + uuid->time_hi_and_version = bswap16(uuid->time_hi_and_version); + } +} + static void smbios_build_type_1_table(void) { SMBIOS_BUILD_TABLE_PRE(1, 0x100, true); /* required */ @@ -532,9 +551,9 @@ static void smbios_build_type_1_table(void) SMBIOS_TABLE_SET_STR(1, version_str, type1.version); SMBIOS_TABLE_SET_STR(1, serial_number_str, type1.serial); if (qemu_uuid_set) { - memcpy(t->uuid, qemu_uuid, 16); + smbios_encode_uuid(&t->uuid, qemu_uuid); } else { - memset(t->uuid, 0, 16); + memset(&t->uuid, 0, 16); } t->wake_up_type = 0x06; /* power switch */ SMBIOS_TABLE_SET_STR(1, sku_number_str, type1.sku); @@ -746,10 +765,12 @@ void smbios_set_cpuid(uint32_t version, uint32_t features) } void smbios_set_defaults(const char *manufacturer, const char *product, - const char *version, bool legacy_mode) + const char *version, bool legacy_mode, + bool uuid_encoded) { smbios_have_defaults = true; smbios_legacy = legacy_mode; + smbios_uuid_encoded = uuid_encoded; /* drop unwanted version of command-line file blob(s) */ if (smbios_legacy) { -- cgit v1.1