kvm/test/lib/x86/fwcfg.c

   1 #include "fwcfg.h"
   2 #include "smp.h"
   3
   4 static struct spinlock lock;
   5
   6 uint64_t fwcfg_get_u(uint16_t index, int bytes)
   7 {
   8     uint64_t r = 0;
   9     uint8_t b;
  10     int i;
  11
  12     spin_lock(&lock);
  13     asm volatile ("out %0, %1" : : "a"(index), "d"((uint16_t)BIOS_CFG_IOPORT));
  14     for (i = 0; i < bytes; ++i) {
  15         asm volatile ("in %1, %0" : "=a"(b) : "d"((uint16_t)(BIOS_CFG_IOPORT + 1)));
  16         r |= (uint64_t)b << (i * 8);
  17     }
  18     spin_unlock(&lock);
  19     return r;
  20 }
  21
  22 uint8_t fwcfg_get_u8(unsigned index)
  23 {
  24     return fwcfg_get_u(index, 1);
  25 }
  26
  27 uint16_t fwcfg_get_u16(unsigned index)
  28 {
  29     return fwcfg_get_u(index, 2);
  30 }
  31
  32 uint32_t fwcfg_get_u32(unsigned index)
  33 {
  34     return fwcfg_get_u(index, 4);
  35 }
  36
  37 uint64_t fwcfg_get_u64(unsigned index)
  38 {
  39     return fwcfg_get_u(index, 8);
  40 }
  41
  42 unsigned fwcfg_get_nb_cpus(void)
  43 {
  44     return fwcfg_get_u16(FW_CFG_NB_CPUS);
  45 }