[Qemu-devel] [patch 8/9] kvm: bios: resolve memory device roll over reporting issues with >32G guests

[Marcelo Tosatti]

The field within the Memory Device type 17 is only a word with the MSB being
used to report MB/KB.  Thereby, a guest with 32G and greater would report
incorrect memory device information rolling over to 0.

This presents more than one memory device and associated memory structures
if the memory is larger than 16G

Signed-off-by: Bill Rieske <address@hidden>
Signed-off-by: Avi Kivity <address@hidden>

From: Bill Rieske <address@hidden>

Index: bochs/bios/rombios32.c
===================================================================
--- bochs.orig/bios/rombios32.c
+++ bochs/bios/rombios32.c
@@ -381,6 +381,17 @@ int vsnprintf(char *buf, int buflen, con
     return buf - buf0;
 }
 
+int snprintf(char * buf, size_t size, const char *fmt, ...)
+{
+       va_list args;
+       int i;
+
+       va_start(args, fmt);
+       i=vsnprintf(buf,size,fmt,args);
+       va_end(args);
+       return i;
+}
+
 void bios_printf(int flags, const char *fmt, ...)
 {
     va_list ap;
@@ -2039,7 +2050,7 @@ smbios_type_4_init(void *start, unsigned
 
 /* Type 16 -- Physical Memory Array */
 static void *
-smbios_type_16_init(void *start, uint32_t memsize)
+smbios_type_16_init(void *start, uint32_t memsize, int nr_mem_devs)
 {
     struct smbios_type_16 *p = (struct smbios_type_16*)start;
 
@@ -2052,7 +2063,7 @@ smbios_type_16_init(void *start, uint32_
     p->error_correction = 0x01; /* other */
     p->maximum_capacity = memsize * 1024;
     p->memory_error_information_handle = 0xfffe; /* none provided */
-    p->number_of_memory_devices = 1;
+    p->number_of_memory_devices = nr_mem_devs;
 
     start += sizeof(struct smbios_type_16);
     *((uint16_t *)start) = 0;
@@ -2062,20 +2073,19 @@ smbios_type_16_init(void *start, uint32_
 
 /* Type 17 -- Memory Device */
 static void *
-smbios_type_17_init(void *start, uint32_t memory_size_mb)
+smbios_type_17_init(void *start, uint32_t memory_size_mb, int instance)
 {
     struct smbios_type_17 *p = (struct smbios_type_17 *)start;
 
     p->header.type = 17;
     p->header.length = sizeof(struct smbios_type_17);
-    p->header.handle = 0x1100;
+    p->header.handle = 0x1100 + instance;
 
     p->physical_memory_array_handle = 0x1000;
     p->total_width = 64;
     p->data_width = 64;
-    /* truncate memory_size_mb to 16 bits and clear most significant
-       bit [indicates size in MB] */
-    p->size = (uint16_t) memory_size_mb & 0x7fff;
+/* TODO: should assert in case something is wrong   ASSERT((memory_size_mb & 
~0x7fff) == 0); */
+    p->size = memory_size_mb;
     p->form_factor = 0x09; /* DIMM */
     p->device_set = 0;
     p->device_locator_str = 1;
@@ -2084,8 +2094,8 @@ smbios_type_17_init(void *start, uint32_
     p->type_detail = 0;
 
     start += sizeof(struct smbios_type_17);
-    memcpy((char *)start, "DIMM 1", 7);
-    start += 7;
+    snprintf(start, 8, "DIMM %d", instance);
+    start += strlen(start) + 1;
     *((uint8_t *)start) = 0;
 
     return start+1;
@@ -2093,16 +2103,16 @@ smbios_type_17_init(void *start, uint32_
 
 /* Type 19 -- Memory Array Mapped Address */
 static void *
-smbios_type_19_init(void *start, uint32_t memory_size_mb)
+smbios_type_19_init(void *start, uint32_t memory_size_mb, int instance)
 {
     struct smbios_type_19 *p = (struct smbios_type_19 *)start;
 
     p->header.type = 19;
     p->header.length = sizeof(struct smbios_type_19);
-    p->header.handle = 0x1300;
+    p->header.handle = 0x1300 + instance;
 
-    p->starting_address = 0;
-    p->ending_address = (memory_size_mb * 1024) - 1;
+    p->starting_address = instance << 24;
+    p->ending_address = p->starting_address + (memory_size_mb << 10) - 1;
     p->memory_array_handle = 0x1000;
     p->partition_width = 1;
 
@@ -2114,18 +2124,18 @@ smbios_type_19_init(void *start, uint32_
 
 /* Type 20 -- Memory Device Mapped Address */
 static void *
-smbios_type_20_init(void *start, uint32_t memory_size_mb)
+smbios_type_20_init(void *start, uint32_t memory_size_mb, int instance)
 {
     struct smbios_type_20 *p = (struct smbios_type_20 *)start;
 
     p->header.type = 20;
     p->header.length = sizeof(struct smbios_type_20);
-    p->header.handle = 0x1400;
+    p->header.handle = 0x1400 + instance;
 
-    p->starting_address = 0;
-    p->ending_address = (memory_size_mb * 1024) - 1;
-    p->memory_device_handle = 0x1100;
-    p->memory_array_mapped_address_handle = 0x1300;
+    p->starting_address = instance << 24;
+    p->ending_address = p->starting_address + (memory_size_mb << 10) - 1;
+    p->memory_device_handle = 0x1100 + instance;
+    p->memory_array_mapped_address_handle = 0x1300 + instance;
     p->partition_row_position = 1;
     p->interleave_position = 0;
     p->interleaved_data_depth = 0;
@@ -2176,6 +2186,7 @@ void smbios_init(void)
     char *start, *p, *q;
     int memsize = (ram_end == ram_size) ? ram_size / (1024 * 1024) :
                   (ram_end - (1ull << 32) + ram_size) / (1024 * 1024);
+    int i, nr_mem_devs;
 
 #ifdef BX_USE_EBDA_TABLES
     ebda_cur_addr = align(ebda_cur_addr, 16);
@@ -2187,23 +2198,32 @@ void smbios_init(void)
 
        p = (char *)start + sizeof(struct smbios_entry_point);
 
-#define add_struct(fn) { \
+#define add_struct(fn) do{ \
     q = (fn); \
     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));
     for (cpu_num = 1; cpu_num <= smp_cpus; cpu_num++)
         add_struct(smbios_type_4_init(p, cpu_num));
-    add_struct(smbios_type_16_init(p, memsize));
-    add_struct(smbios_type_17_init(p, memsize));
-    add_struct(smbios_type_19_init(p, ram_end / (1024 * 1024)));
-    add_struct(smbios_type_20_init(p, ram_end / (1024 * 1024)));
+
+    /* 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));
+    for ( i = 0; i < nr_mem_devs; i++ )
+    {
+        uint32_t dev_memsize = ((i == (nr_mem_devs - 1))
+                                ? (memsize & 0x3fff) : 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(smbios_type_32_init(p));
     add_struct(smbios_type_127_init(p));