[RESEND PATCH v2 2/3] hvmloader: Update to SMBIOS 2.6

["Teddy Astie" <teddy.astie@xxxxxxxxxx>]

Currently, hvmloader uses SMBIOS 2.4, however, when using OVMF, the
SMBIOS is patched to 2.8, which has clarified the UUID format (as GUID).

In Linux, if the SMBIOS version is >= 2.6, the GUID format is used, else
(undefined as per SMBIOS spec), big endian is used (used by Xen). Therefore,
you have a endian mismatch causing the UUIDs to mismatch in the guest.

$ cat /sys/hypervisor/uuid
e865e63f-3d30-4f0b-83e0-8fdfc1e30eb7
$ cat /sys/devices/virtual/dmi/id/product_uuid
3fe665e8-303d-0b4f-83e0-8fdfc1e30eb7
$ cat /sys/devices/virtual/dmi/id/product_serial
e865e63f-3d30-4f0b-83e0-8fdfc1e30eb7

This patch updates the SMBIOS version from 2.4 to 2.6 and does the appropriate
modifications of the table. This effectively fix this endianness mismatch with
OVMF; while the UUID displayed by Linux is still the same for SeaBIOS.

Fixes: c683914ef913 ("Add code to generate SMBIOS tables to hvmloader.")
(SMBIOS versions before 2.6 has a ill-defined UUID definition)
Signed-off-by: Teddy Astie <teddy.astie@xxxxxxxxxx>
---
v2:
 - rebase onto staging
 - introduce missing SMBIOS 2.5-2.6 fields
 - check for new SMBIOS 2.6 table lengths
 - update UUID conversion comment
 - add Fixes: note
 ---
 tools/firmware/hvmloader/smbios.c       | 50 ++++++++++++++++++++-----
 tools/firmware/hvmloader/smbios_types.h |  9 +++++
 2 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/tools/firmware/hvmloader/smbios.c 
b/tools/firmware/hvmloader/smbios.c
index 76c7090d16..e445475d78 100644
--- a/tools/firmware/hvmloader/smbios.c
+++ b/tools/firmware/hvmloader/smbios.c
@@ -396,7 +396,7 @@ smbios_entry_point_init(void *start,
     memcpy(ep->anchor_string, "_SM_", 4);
     ep->length = 0x1f;
     ep->smbios_major_version = 2;
-    ep->smbios_minor_version = 4;
+    ep->smbios_minor_version = 6;
     ep->max_structure_size = max_structure_size;
     ep->entry_point_revision = 0;
     memcpy(ep->intermediate_anchor_string, "_DMI_", 5);
@@ -505,7 +505,22 @@ smbios_type_1_init(void *start, const char *xen_version,
     p->version_str = 3;
     p->serial_number_str = 4;
 
-    memcpy(p->uuid, uuid, 16);
+    /*
+     * Xen toolstack uses big endian UUIDs, however GUIDs (which requirement
+     * is clarified by SMBIOS >= 2.6) has the first 3 components appearing as
+     * being little endian and the rest as still being big endian.
+     */
+    /* First component */
+    for ( unsigned int i = 0; i < 4; i++ )
+        p->uuid[i] = uuid[4 - i - 1];
+    /* Second component */
+    p->uuid[4] = uuid[5];
+    p->uuid[5] = uuid[4];
+    /* Third component */
+    p->uuid[6] = uuid[7];
+    p->uuid[7] = uuid[6];
+    /* Rest */
+    memcpy(p->uuid + 8, uuid + 8, 8);
 
     p->wake_up_type = 0x06; /* power switch */
     p->sku_str = 0;
@@ -705,8 +720,8 @@ smbios_type_4_init(
     struct smbios_type_4 *p = start;
     uint32_t eax, ebx, ecx, edx;
 
-    /* Specification says Type 4 table has length of 23h for v2.3+. */
-    BUILD_BUG_ON(sizeof(*p) != 35);
+    /* Specification says Type 4 table has length of 2Ah for v2.6. */
+    BUILD_BUG_ON(sizeof(*p) != 42);
 
     memset(p, 0, sizeof(*p));
 
@@ -716,7 +731,7 @@ smbios_type_4_init(
 
     p->socket_designation_str = 1;
     p->processor_type = 0x03; /* CPU */
-    p->processor_family = 0x01; /* other */
+    p->processor_family = p->processor_family_2 = 0x01; /* other */
     p->manufacturer_str = 2;
 
     cpuid(1, &eax, &ebx, &ecx, &edx);
@@ -736,6 +751,22 @@ smbios_type_4_init(
     p->l2_cache_handle = 0xffff; /* No cache information structure provided. */
     p->l3_cache_handle = 0xffff; /* No cache information structure provided. */
 
+    /*
+     * We have a smbios type 4 table per vCPU (which is per socket),
+     * which means here that we have 1 socket per vCPU.
+     */
+    p->core_count = p->core_enabled = p->thread_count = 1;
+
+    /*
+     * We set 64-bits, execute protection and enhanced virtualization.
+     * We don't set Multi-Core (bit 3) because this individual processor
+     * (as being a single vCPU) is only having one core.
+     *
+     * SMBIOS specification says that these bits don't state anything
+     * regarding the actual availability of such features.
+     */
+    p->processor_characteristics = 0x64;
+
     start += sizeof(*p);
 
     strncpy(buf, "CPU ", sizeof(buf));
@@ -780,8 +811,8 @@ smbios_type_8_init(void *start)
 static void *
 smbios_type_9_init(void *start)
 {
-    /* Specification says Type 9 table has length of 0Dh for v2.1-2.5. */
-    BUILD_BUG_ON(sizeof(struct smbios_type_9) != 13);
+    /* Specification says Type 9 table has length of 11h for v2.6+. */
+    BUILD_BUG_ON(sizeof(struct smbios_type_9) != 17);
 
     /* Only present when passed in. */
     return smbios_pt_copy(start, 9, SMBIOS_HANDLE_TYPE9,
@@ -870,8 +901,8 @@ smbios_type_17_init(void *start, uint32_t memory_size_mb, 
int instance)
     char buf[16];
     struct smbios_type_17 *p = start;
 
-    /* Specification says Type 17 table has length of 1Bh for v2.3-2.6. */
-    BUILD_BUG_ON(sizeof(*p) != 27);
+    /* Specification says Type 17 table has length of 1Ch for v2.6. */
+    BUILD_BUG_ON(sizeof(*p) != 28);
 
     memset(p, 0, sizeof(*p));
 
@@ -890,6 +921,7 @@ smbios_type_17_init(void *start, uint32_t memory_size_mb, 
int instance)
     p->bank_locator_str = 0;
     p->memory_type = 0x07; /* RAM */
     p->type_detail = 0;
+    p->attributes = 0;
 
     start += sizeof(*p);
     strcpy(start, "DIMM ");
diff --git a/tools/firmware/hvmloader/smbios_types.h 
b/tools/firmware/hvmloader/smbios_types.h
index c04b435d31..860617d86a 100644
--- a/tools/firmware/hvmloader/smbios_types.h
+++ b/tools/firmware/hvmloader/smbios_types.h
@@ -147,6 +147,11 @@ struct smbios_type_4 {
     uint8_t serial_number_str;
     uint8_t asset_tag_str;
     uint8_t part_number_str;
+    uint8_t core_count;
+    uint8_t core_enabled;
+    uint8_t thread_count;
+    uint16_t processor_characteristics;
+    uint16_t processor_family_2;
 } __attribute__ ((packed));
 
 /* SMBIOS type 7 - Cache Information */
@@ -185,6 +190,9 @@ struct smbios_type_9 {
     uint16_t slot_id;
     uint8_t slot_characteristics_1;
     uint8_t slot_characteristics_2;
+    uint16_t sgn_base;
+    uint8_t bus_number_base;
+    uint8_t devfn_base;
 } __attribute__ ((packed));
 
 /* SMBIOS type 11 - OEM Strings */
@@ -227,6 +235,7 @@ struct smbios_type_17 {
     uint8_t serial_number_str;
     uint8_t asset_tag_str;
     uint8_t part_number_str;
+    uint8_t attributes;
 } __attribute__ ((packed));
 
 /* SMBIOS type 19 - Memory Array Mapped Address */
-- 
2.50.1



Teddy Astie | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech