[Qemu-devel] [PATCH 2/2] qemu:bios: Read external SMBIOS entries from the VM

[Alex Williamson]

SMBIOS entries can be read from the VM using the same mechanism
as additional ACPI tables.  External entries will supercede
generated entries.

Signed-off-by: Alex Williamson <address@hidden>
--

diff --git a/bios/rombios32.c b/bios/rombios32.c
index 7be4216..f0e0f8c 100644
--- a/bios/rombios32.c
+++ b/bios/rombios32.c
@@ -471,6 +471,7 @@ void wrmsr_smp(uint32_t index, uint64_t val)
 #define QEMU_CFG_UUID       0x02
 #define QEMU_CFG_ARCH_LOCAL     0x8000
 #define QEMU_CFG_ACPI_TABLES  (QEMU_CFG_ARCH_LOCAL + 0)
+#define QEMU_CFG_SMBIOS_ENTRIES  (QEMU_CFG_ARCH_LOCAL + 1)
 
 int qemu_cfg_port;
 
@@ -519,6 +520,16 @@ static int acpi_load_table(int i, uint32_t addr, uint16_t 
*len)
     qemu_cfg_read((uint8_t*)addr, *len);
     return 0;
 }
+
+static uint16_t smbios_entries(void)
+{
+    uint16_t cnt;
+
+    qemu_cfg_select(QEMU_CFG_SMBIOS_ENTRIES);
+    qemu_cfg_read((uint8_t*)&cnt, sizeof(cnt));
+
+    return cnt;
+}
 #endif
 
 void uuid_probe(void)
@@ -1966,7 +1977,7 @@ smbios_entry_point_init(void *start,
 /* Type 0 -- BIOS Information */
 #define RELEASE_DATE_STR "01/01/2007"
 static void *
-smbios_type_0_init(void *start)
+smbios_init_type_0(void *start)
 {
     struct smbios_type_0 *p = (struct smbios_type_0 *)start;
 
@@ -2002,7 +2013,7 @@ smbios_type_0_init(void *start)
 
 /* Type 1 -- System Information */
 static void *
-smbios_type_1_init(void *start)
+smbios_init_type_1(void *start)
 {
     struct smbios_type_1 *p = (struct smbios_type_1 *)start;
     p->header.type = 1;
@@ -2028,7 +2039,7 @@ smbios_type_1_init(void *start)
 
 /* Type 3 -- System Enclosure */
 static void *
-smbios_type_3_init(void *start)
+smbios_init_type_3(void *start)
 {
     struct smbios_type_3 *p = (struct smbios_type_3 *)start;
 
@@ -2058,7 +2069,7 @@ smbios_type_3_init(void *start)
 
 /* Type 4 -- Processor Information */
 static void *
-smbios_type_4_init(void *start, unsigned int cpu_number)
+smbios_init_type_4(void *start, unsigned int cpu_number)
 {
     struct smbios_type_4 *p = (struct smbios_type_4 *)start;
 
@@ -2098,7 +2109,7 @@ smbios_type_4_init(void *start, unsigned int cpu_number)
 
 /* Type 16 -- Physical Memory Array */
 static void *
-smbios_type_16_init(void *start, uint32_t memsize, int nr_mem_devs)
+smbios_init_type_16(void *start, uint32_t memsize, int nr_mem_devs)
 {
     struct smbios_type_16 *p = (struct smbios_type_16*)start;
 
@@ -2121,7 +2132,7 @@ smbios_type_16_init(void *start, uint32_t memsize, int 
nr_mem_devs)
 
 /* Type 17 -- Memory Device */
 static void *
-smbios_type_17_init(void *start, uint32_t memory_size_mb, int instance)
+smbios_init_type_17(void *start, uint32_t memory_size_mb, int instance)
 {
     struct smbios_type_17 *p = (struct smbios_type_17 *)start;
 
@@ -2151,7 +2162,7 @@ smbios_type_17_init(void *start, uint32_t memory_size_mb, 
int instance)
 
 /* Type 19 -- Memory Array Mapped Address */
 static void *
-smbios_type_19_init(void *start, uint32_t memory_size_mb, int instance)
+smbios_init_type_19(void *start, uint32_t memory_size_mb, int instance)
 {
     struct smbios_type_19 *p = (struct smbios_type_19 *)start;
 
@@ -2172,7 +2183,7 @@ smbios_type_19_init(void *start, uint32_t memory_size_mb, 
int instance)
 
 /* Type 20 -- Memory Device Mapped Address */
 static void *
-smbios_type_20_init(void *start, uint32_t memory_size_mb, int instance)
+smbios_init_type_20(void *start, uint32_t memory_size_mb, int instance)
 {
     struct smbios_type_20 *p = (struct smbios_type_20 *)start;
 
@@ -2196,7 +2207,7 @@ smbios_type_20_init(void *start, uint32_t memory_size_mb, 
int instance)
 
 /* Type 32 -- System Boot Information */
 static void *
-smbios_type_32_init(void *start)
+smbios_init_type_32(void *start)
 {
     struct smbios_type_32 *p = (struct smbios_type_32 *)start;
 
@@ -2214,7 +2225,7 @@ smbios_type_32_init(void *start)
 
 /* Type 127 -- End of Table */
 static void *
-smbios_type_127_init(void *start)
+smbios_init_type_127(void *start)
 {
     struct smbios_type_127 *p = (struct smbios_type_127 *)start;
 
@@ -2228,6 +2239,91 @@ smbios_type_127_init(void *start)
     return start + 2;
 }
 
+static int
+smbios_load_external(int type, char **p, char **q, unsigned *nr_structs,
+                     unsigned *max_struct_size)
+{
+#ifdef BX_QEMU
+    static uint64_t used_bitmap[4] = { 0 };
+    static uint16_t used_cnt = 0;
+    char *start = *p;
+    uint16_t len;
+    int i;
+
+    /* Keep track of the entry types we've already processed */
+    if (used_bitmap[(type >> 6) & 0x3] & (1ULL << (type & 0x3f)))
+        return 1;
+
+    /* Skip end markers, they could lead to bogus tables */
+    if (type == 127)
+        return 0;
+
+    /* Check if there are any tables left to report, also reset read index */
+    i = smbios_entries();
+    if (used_cnt == i)
+        return 0;
+
+    for (; i > 0; *q = *p, i--) {
+        int string_data;
+        qemu_cfg_read((uint8_t*)&len, sizeof(len));
+        if (!len)
+            continue;
+        if (len < sizeof(struct smbios_structure_header)) {
+            while (len--)
+                inb(QEMU_CFG_DATA_PORT); /* Invalid, skip to the next one */
+            continue;
+        }
+
+        qemu_cfg_read((uint8_t*)*p, sizeof(struct smbios_structure_header));
+        if (((struct smbios_structure_header *)*p)->type != type) {
+            len -= sizeof(struct smbios_structure_header);
+            while (len--)
+                inb(QEMU_CFG_DATA_PORT); /* skip to the next one */
+            continue;
+        }
+
+        /* Entries end with a double NULL char, if there's a string at
+         * the end (length is greater than formatted length), the string
+         * terminator provides the first NULL. */
+        string_data = (len > ((struct smbios_structure_header *)*p)->length);
+
+        /* Read the rest and terminate the entry */
+        len -= sizeof(struct smbios_structure_header);
+        *p += sizeof(struct smbios_structure_header);
+        qemu_cfg_read((uint8_t*)*p, len);
+        *p += len;
+        *((uint8_t*)*p) = 0;
+        (*p)++;
+        if (!string_data) {
+            *((uint8_t*)*p) = 0;
+            (*p)++;
+        }
+
+        (*nr_structs)++;
+        used_cnt++;
+        if (*p - *q > *max_struct_size)
+            *max_struct_size = *p - *q;
+
+        /* Mark that we've reported on this type */
+        used_bitmap[(type >> 6) & 0x3] |= (1ULL << (type & 0x3f));
+
+        /* A type 1 entry provides a UUID, but so does the QEMU_CFG_UUID
+         * port.  If the QEMU_CFG_UUID value is not zero, use it, otherwise
+         * use whatever was in the provided table. */
+        if (type == 1) {
+            const static uint8_t null_uuid[16] = { 0 };
+            if (memcmp(bios_uuid, null_uuid, 16)) {
+                struct smbios_type_1 *t = (struct smbios_type_1 *)*q;
+                memcpy(t->uuid, bios_uuid, 16);
+            }
+        }
+    }
+    return (start != *p);
+#else /* !BX_QEMU */
+    return 0;
+#endif
+}
+
 void smbios_init(void)
 {
     unsigned cpu_num, nr_structs = 0, max_struct_size = 0;
@@ -2246,34 +2342,39 @@ void smbios_init(void)
 
        p = (char *)start + sizeof(struct smbios_entry_point);
 
-#define add_struct(fn) do{ \
-    q = (fn); \
-    nr_structs++; \
-    if ((q - p) > max_struct_size) \
-        max_struct_size = q - p; \
-    p = q; \
+#define add_struct(type, args...) do{ \
+    if (!smbios_load_external(type, &p, &q, &nr_structs, &max_struct_size)) { \
+        q = smbios_init_type_##type(args); \
+        nr_structs++; \
+        if ((q - p) > max_struct_size) \
+            max_struct_size = q - p; \
+        p = q; \
+    } \
 }while (0)
 
-    add_struct(smbios_type_0_init(p));
-    add_struct(smbios_type_1_init(p));
-    add_struct(smbios_type_3_init(p));
+    add_struct(0, p);
+    add_struct(1, p);
+    add_struct(3, p);
     for (cpu_num = 1; cpu_num <= smp_cpus; cpu_num++)
-        add_struct(smbios_type_4_init(p, cpu_num));
+        add_struct(4, p, cpu_num);
 
     /* Each 'memory device' covers up to 16GB of address space. */
     nr_mem_devs = (memsize + 0x3fff) >> 14;
-    add_struct(smbios_type_16_init(p, memsize, nr_mem_devs));
+    add_struct(16, p, memsize, nr_mem_devs);
     for ( i = 0; i < nr_mem_devs; i++ )
     {
         uint32_t dev_memsize = ((i == (nr_mem_devs - 1))
                                 ? (((memsize-1) & 0x3fff)+1) : 0x4000);
-        add_struct(smbios_type_17_init(p, dev_memsize, i));
-        add_struct(smbios_type_19_init(p, dev_memsize, i));
-        add_struct(smbios_type_20_init(p, dev_memsize, i));
+        add_struct(17, p, dev_memsize, i);
+        add_struct(19, p, dev_memsize, i);
+        add_struct(20, p, dev_memsize, i);
     }
 
-    add_struct(smbios_type_32_init(p));
-    add_struct(smbios_type_127_init(p));
+    add_struct(32, p);
+    /* Add any remaining provided entries before the end marker */
+    for (i = 0; i < 256; i++)
+        smbios_load_external(i, &p, &q, &nr_structs, &max_struct_size);
+    add_struct(127, p);
 
 #undef add_struct