palacios/src/geekos/svm.c

   1 #include <geekos/svm.h>
   2 #include <geekos/vmm.h>
   3
   4 #include <geekos/vmcb.h>
   5
   6 extern struct vmm_os_hooks * os_hooks;
   7
   8 extern uint_t cpuid_ecx(uint_t op);
   9 extern uint_t cpuid_edx(uint_t op);
  10 extern void Get_MSR(uint_t MSR, uint_t * high_byte, uint_t * low_byte);
  11 extern void Set_MSR(uint_t MSR, uint_t high_byte, uint_t low_byte);
  12 extern uint_t launch_svm(vmcb_t * vmcb_addr);
  13
  14
  15 /* Checks machine SVM capability */
  16 /* Implemented from: AMD Arch Manual 3, sect 15.4 */
  17 int is_svm_capable() {
  18   uint_t ret =  cpuid_ecx(CPUID_FEATURE_IDS);
  19   uint_t vm_cr_low = 0, vm_cr_high = 0;
  20
  21
  22   if ((ret & CPUID_FEATURE_IDS_ecx_svm_avail) == 0) {
  23     PrintDebug("SVM Not Available\n");
  24     return 0;
  25   }
  26
  27   Get_MSR(SVM_VM_CR_MSR, &vm_cr_high, &vm_cr_low);
  28
  29   if ((vm_cr_low & SVM_VM_CR_MSR_svmdis) == 0) {
  30     return 1;
  31   }
  32
  33   ret = cpuid_edx(CPUID_SVM_REV_AND_FEATURE_IDS);
  34
  35   if ((ret & CPUID_SVM_REV_AND_FEATURE_IDS_edx_svml) == 0) {
  36     PrintDebug("SVM BIOS Disabled, not unlockable\n");
  37   } else {
  38     PrintDebug("SVM is locked with a key\n");
  39   }
  40
  41   return 0;
  42 }
  43
  44
  45
  46 void Init_SVM(struct vmm_ctrl_ops * vmm_ops) {
  47   reg_ex_t msr;
  48   void * host_state;
  49
  50
  51   // setup
  52   Get_MSR(EFER_MSR, &(msr.e_reg.high), &(msr.e_reg.low));
  53   msr.e_reg.low |= EFER_MSR_svm_enable;
  54   Set_MSR(EFER_MSR, 0, msr.e_reg.low);
  55
  56   PrintDebug("SVM Enabled\n");
  57
  58
  59   // Setup the host state save area
  60   host_state = os_hooks->Allocate_Pages(1);
  61
  62   msr.e_reg.high = 0;
  63   msr.e_reg.low = (uint_t)host_state;
  64
  65
  66   PrintDebug("Host State being saved at %x\n", (uint_t)host_state);
  67   Set_MSR(SVM_VM_HSAVE_PA_MSR, msr.e_reg.high, msr.e_reg.low);
  68
  69
  70
  71   // Setup the SVM specific vmm operations
  72   vmm_ops->init_guest = &init_svm_guest;
  73   vmm_ops->start_guest = &start_svm_guest;
  74
  75
  76   return;
  77 }
  78
  79
  80 int init_svm_guest(struct guest_info *info) {
  81   PrintDebug("Allocating VMCB\n");
  82   info->vmm_data = (void*)Allocate_VMCB();
  83
  84   PrintDebug("Initializing VMCB (addr=%x)\n", info->vmm_data);
  85   Init_VMCB((vmcb_t*)(info->vmm_data), *info);
  86
  87   return 0;
  88 }
  89
  90
  91 // can we start a kernel thread here...
  92 int start_svm_guest(struct guest_info *info) {
  93   vmcb_ctrl_t * guest_ctrl = 0;
  94
  95   ulong_t exit_code = 0;
  96
  97   PrintDebug("Launching SVM VM (vmcb=%x)\n", info->vmm_data);
  98
  99   launch_svm((vmcb_t*)(info->vmm_data));
 100
 101   guest_ctrl = GET_VMCB_CTRL_AREA((vmcb_t*)(info->vmm_data));
 102
 103
 104   PrintDebug("SVM Returned: (Exit Code=%x) (VMCB=%x)\n",&(guest_ctrl->exit_code), info->vmm_data);
 105
 106
 107   exit_code = guest_ctrl->exit_code;
 108
 109   PrintDebug("SVM Returned: Exit Code: %x\n",exit_code);
 110
 111   return 0;
 112 }
 113
 114
 115
 116 vmcb_t * Allocate_VMCB() {
 117   vmcb_t * vmcb_page = (vmcb_t*)os_hooks->Allocate_Pages(1);
 118
 119
 120   memset(vmcb_page, 0, 4096);
 121
 122   return vmcb_page;
 123 }
 124
 125
 126
 127 void Init_VMCB(vmcb_t *vmcb, guest_info_t vm_info) {
 128   vmcb_ctrl_t * ctrl_area = GET_VMCB_CTRL_AREA(vmcb);
 129   vmcb_saved_state_t * guest_state = GET_VMCB_SAVE_STATE_AREA(vmcb);
 130   uint_t i = 0;
 131
 132
 133   guest_state->rsp = vm_info.rsp;
 134   guest_state->rip = vm_info.rip;
 135
 136
 137   /* I pretty much just gutted this from TVMM */
 138   /* Note: That means its probably wrong */
 139
 140   // set the segment registers to mirror ours
 141   guest_state->cs.selector = 0;
 142   guest_state->cs.attrib.fields.type = 0xa; // Code segment+read
 143   guest_state->cs.attrib.fields.S = 1;
 144   guest_state->cs.attrib.fields.P = 1;
 145   guest_state->cs.attrib.fields.db = 1;
 146   guest_state->cs.limit = 0xffffffff;
 147   guest_state->cs.base = 0;
 148
 149   struct vmcb_selector *segregs [] = {&(guest_state->ss), &(guest_state->ds), &(guest_state->es), &(guest_state->fs), &(guest_state->gs), NULL};
 150   for ( i = 0; segregs[i] != NULL; i++) {
 151     struct vmcb_selector * seg = segregs[i];
 152
 153     seg->selector = 0;
 154     seg->attrib.fields.type = 0x2; // Data Segment+read/write
 155     seg->attrib.fields.S = 1;
 156     seg->attrib.fields.P = 1;
 157     seg->attrib.fields.db = 1;
 158     seg->limit = 0xffffffff;
 159     seg->base = 0;
 160   }
 161
 162
 163   guest_state->efer |= EFER_MSR_svm_enable;
 164   guest_state->cr0 = 0x00000001;    // PE
 165   guest_state->rflags = 0x00000002; // The reserved bit is always 1
 166   ctrl_area->svm_instrs.instrs.VMRUN = 1;
 167   ctrl_area->guest_ASID = 1;
 168
 169
 170
 171   /* ** */
 172
 173 }