Palacios Public Git Repository

To checkout Palacios execute

  git clone http://v3vee.org/palacios/palacios.web/palacios.git
This will give you the master branch. You probably want the devel branch or one of the release branches. To switch to the devel branch, simply execute
  cd palacios
  git checkout --track -b devel origin/devel
The other branches are similar.


HVM capability enhancments
[palacios.git] / palacios / src / palacios / vmm_hvm.c
index edff2fd..3e506d7 100644 (file)
@@ -56,7 +56,7 @@
   <mem ... >RAM</mem>   (MB)  Note these are  
   <cores count="CORES" ...>   backward compatible
 
-  <hvm enable="y">
+  <hvm enable="y" >
     <ros cores="ROS_CORES" mem="ROS_MEM" /> (MB)
     <hrt file_id="hrtelf" /hrt>
   </hvm>
 #endif
 
 
-// if set, we will map the first 1 GB of memory using a 3 level
-// hierarchy, for compatibility with Nautilus out of the box.
-// Otherwise we will map the first 512 GB using a 2 level
-// hieratchy
-#define HVM_MAP_1G_2M 1
-
 int v3_init_hvm()
 {
     PrintDebug(VM_NONE,VCORE_NONE, "hvm: init\n");
@@ -87,19 +81,245 @@ int v3_deinit_hvm()
     return 0;
 }
 
+// ignore requests from when we are in the wrong state
+#define ENFORCE_STATE_MACHINE 1
+
+// invoke the HRT using a page fault instead of
+// the SWINTR mechanism
+#define USE_UPCALL_MAGIC_PF  1
+#define UPCALL_MAGIC_ADDRESS 0x0000800df00df00dULL
+#define UPCALL_MAGIC_ERROR   0xf00df00d
 
+/*
+  64 bit only hypercall:
+
+  rax = hypercall number
+  rbx = 0x646464...
+  then args are:  rcx, rdx, rsi, rdi r8, r9, r10, r11
+  rcx = 1st arg
+*/
 static int hvm_hcall_handler(struct guest_info * core , hcall_id_t hcall_id, void * priv_data)
 {
     uint64_t c;
+    uint64_t bitness = core->vm_regs.rbx;
+    uint64_t a1 = core->vm_regs.rcx;
+    uint64_t a2 = core->vm_regs.rdx;
+    struct v3_vm_hvm *h = &core->vm_info->hvm_state;
+
+
+    if (bitness!=0x6464646464646464) { 
+       PrintError(core->vm_info,core,"hvm: unable to handle non-64 bit hypercall\n");
+       core->vm_regs.rax = -1;
+       return 0;
+    }
+
+    switch (a1) {
+       case 0x0:   // null
+           
+           rdtscll(c);
+           
+           V3_Print(core->vm_info,core, "hvm: received hypercall %x  rax=%llx rbx=%llx rcx=%llx at cycle count %llu (%llu cycles since last boot start) num_exits=%llu since initial boot\n",
+                    hcall_id, core->vm_regs.rax, core->vm_regs.rbx, core->vm_regs.rcx, c, core->hvm_state.last_boot_start, core->num_exits);
+           //v3_print_core_telemetry(core);
+           //    v3_print_guest_state(core);
+           core->vm_regs.rax = 0;
+           break;
+           
+       case 0x1: // reset ros
+           PrintDebug(core->vm_info,core, "hvm: reset ROS\n");
+           if (v3_reset_vm_extended(core->vm_info,V3_VM_RESET_ROS,0)) { 
+               PrintError(core->vm_info,core, "hvm: reset of ROS failed\n");
+               core->vm_regs.rax = -1;
+           } else {
+               core->vm_regs.rax = 0;
+           }
+           break;
+
+       case 0x2: // reset hrt
+           PrintDebug(core->vm_info,core, "hvm: reset HRT\n");
+           if (v3_reset_vm_extended(core->vm_info,V3_VM_RESET_HRT,0)) { 
+               PrintError(core->vm_info,core, "hvm: reset of HRT failed\n");
+               core->vm_regs.rax = -1;
+           } else {
+               core->vm_regs.rax = 0;
+           }
+           break;
+
+       case 0x3: // reset both
+           PrintDebug(core->vm_info,core, "hvm: reset ROS+HRT\n");
+           if (v3_reset_vm_extended(core->vm_info,V3_VM_RESET_ALL,0)) { 
+               PrintError(core->vm_info,core, "hvm: reset of HRT failed\n");
+               core->vm_regs.rax = -1;
+           } else {
+               core->vm_regs.rax = 0;
+           }
+           break;
+           
+       case 0xf: // get HRT state
+           core->vm_regs.rax = h->trans_state;
+           //PrintDebug(core->vm_info,core,"hvm: get HRT transaction state 0x%llx\n",core->vm_regs.rax);
+           break;
 
-    rdtscll(c);
+       case 0x20: // invoke function (ROS->HRT)
+       case 0x21: // invoke parallel function (ROS->HRT)
+           if (v3_is_hvm_hrt_core(core)) { 
+               PrintError(core->vm_info,core,"hvm: %s function invocation not supported from HRT core\n", a1==0x20 ? "" : "parallel");
+               core->vm_regs.rax = -1;
+           } else {
+               if (ENFORCE_STATE_MACHINE && h->trans_state!=HRT_IDLE) { 
+                   PrintError(core->vm_info,core, "hvm: cannot invoke %s function %p in state %d\n",a1==0x20 ? "" : "parallel", (void*)a2,h->trans_state);
+                   core->vm_regs.rax = -1;
+               } else {
+                   uint64_t *page = (uint64_t *) h->comm_page_hva;
+                   uint64_t first, last, cur;
+
+                   PrintDebug(core->vm_info,core, "hvm: %s invoke function %p\n",a1==0x20 ? "" : "parallel",(void*)a2);
+                   page[0] = a1;
+                   page[1] = a2;
+
+                   if (a1==0x20) { 
+                       first=last=h->first_hrt_core;
+                   } else {
+                       first=h->first_hrt_core;
+                       last=core->vm_info->num_cores-1;
+                   }
+
+                   core->vm_regs.rax = 0;
+
+                   h->trans_count = last-first+1;
+
+                   for (cur=first;cur<=last;cur++) { 
+
+#if USE_UPCALL_MAGIC_PF
+                       PrintDebug(core->vm_info,core,"hvm: injecting magic #PF into core %llu\n",cur);
+                       core->vm_info->cores[cur].ctrl_regs.cr2 = UPCALL_MAGIC_ADDRESS;
+                       if (v3_raise_exception_with_error(&core->vm_info->cores[cur],
+                                                         PF_EXCEPTION, 
+                                                         UPCALL_MAGIC_ERROR)) { 
+                           PrintError(core->vm_info,core, "hvm: cannot inject HRT #PF to core %llu\n",cur);
+                           core->vm_regs.rax = -1;
+                           break;
+                       }
+#else
+                       PrintDebug(core->vm_info,core,"hvm: injecting SW intr 0x%u into core %llu\n",h->hrt_int_vector,cur);
+                       if (v3_raise_swintr(&core->vm_info->cores[cur],h->hrt_int_vector)) { 
+                           PrintError(core->vm_info,core, "hvm: cannot inject HRT interrupt to core %llu\n",cur);
+                           core->vm_regs.rax = -1;
+                           break;
+                       }
+#endif
+                       // Force core to exit now
+                       v3_interrupt_cpu(core->vm_info,core->vm_info->cores[cur].pcpu_id,0);
+                         
+                   }
+                   if (core->vm_regs.rax==0) { 
+                       if (a1==0x20) { 
+                           h->trans_state = HRT_CALL;
+                       } else {
+                           h->trans_state = HRT_PARCALL;
+                       }
+                   }  else {
+                       PrintError(core->vm_info,core,"hvm: in inconsistent state due to HRT call failure\n");
+                       h->trans_state = HRT_IDLE;
+                       h->trans_count = 0;
+                   }
+               }
+           }
+           break;
 
 
-    V3_Print(core->vm_info,core, "hvm: received hypercall %x  rax=%llx rbx=%llx rcx=%llx at cycle count %llu (%llu cycles since last boot start) num_exits=%llu since initial boot\n",
-            hcall_id, core->vm_regs.rax, core->vm_regs.rbx, core->vm_regs.rcx, c, c-core->hvm_state.last_boot_start, core->num_exits);
-    v3_print_core_telemetry(core);
-    //    v3_print_guest_state(core);
+       case 0x2f: // function exec done
+           if (v3_is_hvm_ros_core(core)) { 
+               PrintError(core->vm_info,core, "hvm: request for exec done from ROS core\n");
+               core->vm_regs.rax=-1;
+           } else {
+               if (ENFORCE_STATE_MACHINE && h->trans_state!=HRT_CALL && h->trans_state!=HRT_PARCALL) {
+                   PrintError(core->vm_info,core,"hvm: function completion when not in HRT_CALL or HRT_PARCALL state\n");
+                   core->vm_regs.rax=-1;
+               } else {
+                   uint64_t one=1;
+                   PrintDebug(core->vm_info,core, "hvm: function complete\n");
+                   if (__sync_fetch_and_sub(&h->trans_count,one)==1) {
+                       // last one, switch state
+                       h->trans_state=HRT_IDLE;
+                       PrintDebug(core->vm_info,core, "hvm: function complete - back to idle\n");
+                   }
+                   core->vm_regs.rax=0;
+               }
+           }
+                   
+           break;
 
+       case 0x30: // merge address space
+       case 0x31: // unmerge address space
+           if (v3_is_hvm_hrt_core(core)) { 
+               PrintError(core->vm_info,core,"hvm: request to %smerge address space from HRT core\n", a1==0x30 ? "" : "un");
+               core->vm_regs.rax=-1;
+           } else {
+               if (ENFORCE_STATE_MACHINE && h->trans_state!=HRT_IDLE) { 
+                   PrintError(core->vm_info,core,"hvm: request to %smerge address space in non-idle state\n",a1==0x30 ? "" : "un");
+                   core->vm_regs.rax=-1;
+               } else {
+                   uint64_t *page = (uint64_t *) h->comm_page_hva;
+
+                   PrintDebug(core->vm_info,core,"hvm: %smerge address space request with %p\n",a1==0x30 ? "" : "un",(void*)core->ctrl_regs.cr3);
+                   // should sanity check to make sure guest is in 64 bit without anything strange
+
+                   page[0] = a1;
+                   page[1] = core->ctrl_regs.cr3;  // this is a do-not-care for an unmerge
+
+                   core->vm_regs.rax = 0;
+#if USE_UPCALL_MAGIC_PF
+                   PrintDebug(core->vm_info,core,"hvm: injecting magic #PF into core %u\n",h->first_hrt_core);
+                   core->vm_info->cores[h->first_hrt_core].ctrl_regs.cr2 = UPCALL_MAGIC_ADDRESS;
+                   if (v3_raise_exception_with_error(&core->vm_info->cores[h->first_hrt_core],
+                                                     PF_EXCEPTION,  
+                                                     UPCALL_MAGIC_ERROR)) { 
+                     PrintError(core->vm_info,core, "hvm: cannot inject HRT #PF to core %u\n",h->first_hrt_core);
+                     core->vm_regs.rax = -1;
+                     break;
+                   }
+#else
+                   PrintDebug(core->vm_info,core,"hvm: injecting SW intr 0x%u into core %u\n",h->hrt_int_vector,h->first_hrt_core);
+                   if (v3_raise_swintr(&core->vm_info->cores[h->first_hrt_core],h->hrt_int_vector)) { 
+                       PrintError(core->vm_info,core, "hvm: cannot inject HRT interrupt to core %u\n",h->first_hrt_core);
+                       core->vm_regs.rax = -1;
+                   } 
+#endif         
+                   // Force core to exit now
+                   v3_interrupt_cpu(core->vm_info,core->vm_info->cores[h->first_hrt_core].pcpu_id,0);
+
+                   h->trans_state = HRT_MERGE;
+               }
+               
+           }
+               
+           break;
+           
+
+       case 0x3f: // merge operation done
+           if (v3_is_hvm_ros_core(core)) { 
+               PrintError(core->vm_info,core, "hvm: request for merge done from ROS core\n");
+               core->vm_regs.rax=-1;
+           } else {
+               if (ENFORCE_STATE_MACHINE && h->trans_state!=HRT_MERGE) {
+                   PrintError(core->vm_info,core,"hvm: merge/unmerge done when in non-idle state\n");
+                   core->vm_regs.rax=-1;
+               } else {
+                   PrintDebug(core->vm_info,core, "hvm: merge or unmerge complete - back to idle\n");
+                   h->trans_state=HRT_IDLE;
+                   core->vm_regs.rax=0;
+               }
+           }
+                   
+           break;
+
+       default:
+           PrintError(core->vm_info,core,"hvm: unknown hypercall %llx\n",a1);
+           core->vm_regs.rax=-1;
+           break;
+    }
+               
     return 0;
 }
 
@@ -153,7 +373,7 @@ int v3_init_hvm_vm(struct v3_vm_info *vm, struct v3_xml *config)
     }
 
     vm->hvm_state.first_hrt_gpa = ((uint64_t)atoi(ros_mem))*1024*1024;
-       
+
     if (!(hrt_config=v3_cfg_subtree(hvm_config,"hrt"))) { 
        PrintError(vm,VCORE_NONE,"hvm: HVM configuration without HRT block...\n");
        return -1;
@@ -206,6 +426,15 @@ int v3_deinit_hvm_vm(struct v3_vm_info *vm)
 
     v3_remove_hypercall(vm,HVM_HCALL);
 
+    if (vm->hvm_state.comm_page_hpa) { 
+       struct v3_mem_region *r = v3_get_mem_region(vm,-1,(addr_t)vm->hvm_state.comm_page_hpa);
+       if (!r) { 
+           PrintError(vm,VCORE_NONE,"hvm: odd, VM has comm_page_hpa, but no shadow memory\n");
+       } else {
+           v3_delete_mem_region(vm,r);
+       }
+    }
+
     return 0;
 }
 
@@ -238,11 +467,7 @@ uint64_t v3_get_hvm_ros_memsize(struct v3_vm_info *vm)
 }
 uint64_t v3_get_hvm_hrt_memsize(struct v3_vm_info *vm)
 {
-    if (vm->hvm_state.is_hvm) { 
-       return vm->mem_size - vm->hvm_state.first_hrt_gpa;
-    } else {
-       return 0;
-    }
+    return vm->mem_size;
 }
 
 uint32_t v3_get_hvm_ros_cores(struct v3_vm_info *vm)
@@ -335,15 +560,15 @@ void     v3_hvm_find_apics_seen_by_core(struct guest_info *core, struct v3_vm_in
 #define MAX(x,y) ((x)>(y)?(x):(y))
 #define MIN(x,y) ((x)<(y)?(x):(y))
 
-#ifdef HVM_MAP_1G_2M
-#define BOOT_STATE_END_ADDR (MIN(vm->mem_size,0x40000000ULL))
-#else
-#define BOOT_STATE_END_ADDR (MIN(vm->mem_size,0x800000000ULL))
-#endif
 
+static uint64_t boot_state_end_addr(struct v3_vm_info *vm) 
+{
+    return PAGE_ADDR(vm->mem_size);
+}
+   
 static void get_null_int_handler_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 {
-    *base = (void*) PAGE_ADDR(BOOT_STATE_END_ADDR - PAGE_SIZE);
+    *base = (void*) PAGE_ADDR(boot_state_end_addr(vm) - PAGE_SIZE);
     *limit = PAGE_SIZE;
 }
 
@@ -395,7 +620,7 @@ static void write_null_int_handler(struct v3_vm_info *vm)
 
 static void get_idt_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 {
-    *base = (void*) PAGE_ADDR(BOOT_STATE_END_ADDR - 2 * PAGE_SIZE);
+    *base = (void*) PAGE_ADDR(boot_state_end_addr(vm) - 2 * PAGE_SIZE);
     *limit = 16*256;
 }
 
@@ -407,7 +632,7 @@ static void get_idt_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 //    3 ist        => (stack) = 0 => current stack
 //    5 reserved   => 0
 //    4 type       => 0xe=>INT, 0xf=>TRAP 
-//    1 reserved   => 0
+//    1 reserved   => 0  (indicates "system" by being zero)
 //    2 dpl        => 0
 //    1 present    => 1
 //   16 offsetmid  => 0
@@ -418,7 +643,7 @@ static void get_idt_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 // 
 // Note little endian
 //
-static uint64_t idt64_trap_gate_entry_mask[2] = {  0x00008f0000080000, 0x0 } ;
+static uint64_t idt64_trap_gate_entry_mask[2] = { 0x00008f0000080000, 0x0 } ;
 static uint64_t idt64_int_gate_entry_mask[2] =  { 0x00008e0000080000, 0x0 };
 
 static void write_idt(struct v3_vm_info *vm)
@@ -435,6 +660,8 @@ static void write_idt(struct v3_vm_info *vm)
 
     get_null_int_handler_loc(vm,&handler,&handler_len);
 
+    handler += vm->hvm_state.gva_offset;
+
     memcpy(trap_gate,idt64_trap_gate_entry_mask,16);
     memcpy(int_gate,idt64_int_gate_entry_mask,16);
 
@@ -473,7 +700,7 @@ static void write_idt(struct v3_vm_info *vm)
 
 static void get_gdt_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 {
-    *base = (void*)PAGE_ADDR(BOOT_STATE_END_ADDR - 3 * PAGE_SIZE);
+    *base = (void*)PAGE_ADDR(boot_state_end_addr(vm) - 3 * PAGE_SIZE);
     *limit = 8*3;
 }
 
@@ -498,219 +725,376 @@ static void write_gdt(struct v3_vm_info *vm)
 
 static void get_tss_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 {
-    *base = (void*)PAGE_ADDR(BOOT_STATE_END_ADDR - 4 * PAGE_SIZE);
+    *base = (void*)PAGE_ADDR(boot_state_end_addr(vm) - 4 * PAGE_SIZE);
     *limit = PAGE_SIZE;
 }
 
-static uint64_t tss_data=0x0;
-
 static void write_tss(struct v3_vm_info *vm)
 {
     void *base;
     uint64_t limit;
-    int i;
 
     get_tss_loc(vm,&base,&limit);
-    for (i=0;i<limit/8;i++) {
-       v3_write_gpa_memory(&vm->cores[0],(addr_t)(base+8*i),8,(uint8_t*) &tss_data);
-    }
+
+    v3_set_gpa_memory(&vm->cores[0],(addr_t)base,limit,0);
 
     PrintDebug(vm,VCORE_NONE,"hvm: wrote TSS at %p\n",base);
 }
 
+
+#define TOP_HALF_START  0xffff800000000000ULL
+#define BOTTOM_HALF_END 0x00007fffffffffffULL
+
+
+#define L4_UNIT PAGE_SIZE
+#define L3_UNIT (512ULL * L4_UNIT)
+#define L2_UNIT (512ULL * L3_UNIT)
+#define L1_UNIT (512ULL * L2_UNIT)
+
+static void compute_pts_4KB(struct v3_vm_info *vm, 
+                           uint64_t *l1, uint64_t *l2, uint64_t *l3, uint64_t *l4)    
+{
+
+    // we map the physical memory up to max_mem_mapped either at 0x0 or at TOP_HALF start
+    // that is, it either fills in the first 256 rows of PML4 or the last 256 rows of PML4
+    // so it is the same number of page tables regardless
+
+    uint64_t max_gva = vm->hvm_state.max_mem_mapped;
+
+    *l1 = 1;  // 1 PML4
+    *l2 = CEIL_DIV(CEIL_DIV(max_gva,512ULL*512ULL*4096ULL),512);
+    *l3 = CEIL_DIV(CEIL_DIV(max_gva,512ULL*4096ULL),512);
+    *l4 = CEIL_DIV(CEIL_DIV(max_gva,4096ULL),512);
+}
+
+
+
 /*
-  PTS MAP FIRST 512 GB identity mapped: 
-  1 second level
-     512 entries
+  PTS MAP using 1 GB pages
+  n second levels pts, highest gva, highest address
   1 top level
-     1 entries
+
 
 OR
   
-  PTS MAP FIRST 1 GB identity mapped:
-  1 third level
-    512 entries
-  1 second level
-    1 entries
-  1 top level
-    1 entries
+  PTS MAP using 2 MB pages
+  n third level pts, highest gva, highest address
+  m second level pts, highest gva, highest address
+  1 top level pt
+
+OR
+
+  PTS MAP using 4 KB pages
+  n 4th level, highest gva, highest address
+  m 3rd level, highest gva, hihgest address
+  l second level, highest gva, highest address
+  1 top level pt
+
+OR
+  PTS MAP using 512 GB pages when this becomes available
+
 */
 
+
 static void get_pt_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 {
-#ifdef HVM_MAP_1G_2M
-    *base = (void*)PAGE_ADDR(BOOT_STATE_END_ADDR-(5+2)*PAGE_SIZE);
-    *limit =  3*PAGE_SIZE;
-#else
-    *base = (void*)PAGE_ADDR(BOOT_STATE_END_ADDR-(5+1)*PAGE_SIZE);
-    *limit =  2*PAGE_SIZE;
-#endif
+    uint64_t l1,l2,l3,l4;
+    uint64_t num_pt;
+
+    compute_pts_4KB(vm,&l1,&l2,&l3,&l4);
+
+    if (vm->hvm_state.hrt_flags & MB_TAG_MB64_HRT_FLAG_MAP_512GB) { 
+       num_pt = l1;
+    } else if (vm->hvm_state.hrt_flags & MB_TAG_MB64_HRT_FLAG_MAP_1GB) { 
+       num_pt = l1 + l2;
+    } else if (vm->hvm_state.hrt_flags & MB_TAG_MB64_HRT_FLAG_MAP_2MB) {
+       num_pt = l1 + l2 + l3;
+    } else if (vm->hvm_state.hrt_flags & MB_TAG_MB64_HRT_FLAG_MAP_4KB) { 
+       num_pt = l1 + l2 + l3 + l4;
+    } else {
+       PrintError(vm,VCORE_NONE,"hvm: Cannot determine PT location flags=0x%llx memsize=0x%llx\n",vm->hvm_state.hrt_flags,(uint64_t)vm->mem_size);
+       return;
+    }
+
+    *base = (void*)PAGE_ADDR(boot_state_end_addr(vm)-(4+num_pt)*PAGE_SIZE);
+    *limit = num_pt*PAGE_SIZE;
 }
 
-#ifndef HVM_MAP_1G_2M
-static void write_pt_2level_512GB(struct v3_vm_info *vm)
+static void write_pts(struct v3_vm_info *vm)
 {
-    void *base;
     uint64_t size;
-    struct pml4e64 pml4e;
-    struct pdpe64 pdpe;
-    uint64_t i;
-
-    get_pt_loc(vm,&base, &size);
-    if (size!=2*PAGE_SIZE) { 
-       PrintError(vm,VCORE_NONE,"Cannot support pt request, defaulting\n");
+    uint64_t num_l1, num_l2, num_l3, num_l4;
+    void *start_l1, *start_l2, *start_l3, *start_l4;
+    uint64_t max_level;
+    void *cur_pt;
+    void *cur_gva;
+    void *cur_gpa;
+    void *min_gpa = 0;
+    void *max_gpa = (void*) vm->hvm_state.max_mem_mapped;
+    void *min_gva = (void*) vm->hvm_state.gva_offset;
+#ifdef V3_CONFIG_DEBUG_HVM
+    void *max_gva = min_gva+vm->hvm_state.max_mem_mapped;
+#endif
+    uint64_t i, pt;
+    uint64_t i_start,i_end;
+    
+    struct pml4e64 *pml4e;
+    struct pdpe64 *pdpe;
+    struct pde64 *pde;
+    struct pte64 *pte;
+
+    if (vm->hvm_state.hrt_flags & MB_TAG_MB64_HRT_FLAG_MAP_512GB) { 
+       PrintError(vm,VCORE_NONE,"hvm: Attempt to build 512 GB pages\n");
+       max_level = 1;
+    } else if (vm->hvm_state.hrt_flags & MB_TAG_MB64_HRT_FLAG_MAP_1GB) { 
+       max_level = 2;
+    } else if (vm->hvm_state.hrt_flags & MB_TAG_MB64_HRT_FLAG_MAP_2MB) {
+       max_level = 3;
+    } else if (vm->hvm_state.hrt_flags & MB_TAG_MB64_HRT_FLAG_MAP_4KB) { 
+       max_level = 4;
+    } else {
+       PrintError(vm,VCORE_NONE,"hvm: Cannot determine PT levels\n");
+       return;
     }
 
-    if (vm->mem_size > 0x800000000ULL) { 
-       PrintError(vm,VCORE_NONE, "VM has more than 512 GB\n");
+    get_pt_loc(vm,&start_l1,&size);
+    compute_pts_4KB(vm,&num_l1,&num_l2,&num_l3,&num_l4);
+
+    start_l2=start_l1+PAGE_SIZE*num_l1;
+    start_l3=start_l2+PAGE_SIZE*num_l2;
+    start_l4=start_l3+PAGE_SIZE*num_l3;
+
+    PrintDebug(vm,VCORE_NONE,"hvm: writing %llu levels of PTs start at address %p\n", max_level,start_l1);
+    PrintDebug(vm,VCORE_NONE,"hvm: min_gva=%p, max_gva=%p, min_gpa=%p, max_gpa=%p\n",min_gva,max_gva,min_gpa,max_gpa);
+    PrintDebug(vm,VCORE_NONE,"hvm: num_l1=%llu, num_l2=%llu, num_l3=%llu, num_l4=%llu\n", num_l1, num_l2, num_l3, num_l4);
+    PrintDebug(vm,VCORE_NONE,"hvm: start_l1=%p, start_l2=%p, start_l3=%p, start_l4=%p\n", start_l1, start_l2, start_l3, start_l4);
+
+    cur_pt=start_l1;
+
+    // build PML4 (only one)
+    if (v3_gpa_to_hva(&vm->cores[0],(addr_t)cur_pt,(addr_t*)&pml4e)) { 
+       PrintError(vm,VCORE_NONE,"hvm: Cannot translate pml4 location\n");
+       return;
     }
 
-    memset(&pdpe,0,sizeof(pdpe));
-    pdpe.present=1;
-    pdpe.writable=1;
-    pdpe.large_page=1;
-    
-    for (i=0;i<512;i++) {
-       pdpe.pd_base_addr = i*0x40000;  // 0x4000 = 256K pages = 1 GB
-       v3_write_gpa_memory(&vm->cores[0],(addr_t)(base+PAGE_SIZE+i*sizeof(pdpe)),sizeof(pdpe),(uint8_t*)&pdpe);
+    memset(pml4e,0,PAGE_SIZE);
+
+    if (min_gva==0x0) { 
+       i_start=0; i_end = num_l2;
+    } else if (min_gva==(void*)TOP_HALF_START) { 
+       i_start=256; i_end=256+num_l2;
+    } else {
+       PrintError(vm,VCORE_NONE,"hvm: unsupported gva offset\n");
+       return;
     }
 
-    memset(&pml4e,0,sizeof(pml4e));
-    pml4e.present=1;
-    pml4e.writable=1;
-    pml4e.pdp_base_addr = PAGE_BASE_ADDR((addr_t)(base+PAGE_SIZE));
+    for (i=i_start, cur_gva=min_gva, cur_gpa=min_gpa;
+        (i<i_end);
+        i++, cur_gva+=L1_UNIT, cur_gpa+=L1_UNIT) {
 
-    v3_write_gpa_memory(&vm->cores[0],(addr_t)base,sizeof(pml4e),(uint8_t*)&pml4e);    
+       pml4e[i].present=1;
+       pml4e[i].writable=1;
+       
+       if (max_level==1) { 
+           PrintError(vm,VCORE_NONE,"hvm: Intel has not yet defined a PML4E large page\n");
+           pml4e[i].pdp_base_addr = PAGE_BASE_ADDR((addr_t)(cur_gpa));
+           //PrintDebug(vm,VCORE_NONE,"hvm: pml4: gva %p to frame 0%llx\n", cur_gva, (uint64_t)pml4e[i].pdp_base_addr);
+       } else {
+           pml4e[i].pdp_base_addr = PAGE_BASE_ADDR((addr_t)(start_l2+(i-i_start)*PAGE_SIZE));
+           //PrintDebug(vm,VCORE_NONE,"hvm: pml4: gva %p to frame 0%llx\n", cur_gva, (uint64_t)pml4e[i].pdp_base_addr);
+       }
+    }
 
-    for (i=1;i<512;i++) {
-       pml4e.present=0;
-       v3_write_gpa_memory(&vm->cores[0],(addr_t)(base+i*sizeof(pml4e)),sizeof(pml4e),(uint8_t*)&pml4e);
+    // 512 GB only
+    if (max_level==1) {
+       return;
     }
 
-    PrintDebug(vm,VCORE_NONE,"hvm: Wrote page tables (1 PML4, 1 PDPE) at %p (512 GB mapped)\n",base);
-}
 
-#else 
 
-static void write_pt_3level_1GB(struct v3_vm_info *vm)
-{
-    void *base;
-    uint64_t size;
-    struct pml4e64 pml4e;
-    struct pdpe64 pdpe;
-    struct pde64 pde;
+    for (cur_pt=start_l2, pt=0, cur_gpa=min_gpa, cur_gva=min_gva;
+        pt<num_l2;
+        cur_pt+=PAGE_SIZE, pt++) { 
 
-    uint64_t i;
+       // build PDPE
+       if (v3_gpa_to_hva(&vm->cores[0],(addr_t)cur_pt,(addr_t*)&pdpe)) { 
+           PrintError(vm,VCORE_NONE,"hvm: Cannot translate pdpe location\n");
+           return;
+       }
+       
+       memset(pdpe,0,PAGE_SIZE);
+       
+       for (i=0; 
+            i<512 && cur_gpa<max_gpa; 
+            i++, cur_gva+=L2_UNIT, cur_gpa+=L2_UNIT) {
 
-    get_pt_loc(vm,&base, &size);
-    if (size!=3*PAGE_SIZE) { 
-       PrintError(vm,VCORE_NONE,"Cannot support pt request, defaulting\n");
+           pdpe[i].present=1;
+           pdpe[i].writable=1;
+       
+           if (max_level==2) { 
+               pdpe[i].large_page=1;
+               pdpe[i].pd_base_addr = PAGE_BASE_ADDR((addr_t)(cur_gpa));
+               //PrintDebug(vm,VCORE_NONE,"hvm: pdpe: gva %p to frame 0%llx\n", cur_gva, (uint64_t)pdpe[i].pd_base_addr);
+           } else {
+               pdpe[i].pd_base_addr = PAGE_BASE_ADDR((addr_t)(start_l3+(pt*512+i)*PAGE_SIZE));
+               //PrintDebug(vm,VCORE_NONE,"hvm: pdpe: gva %p to frame 0%llx\n", cur_gva, (uint64_t)pdpe[i].pd_base_addr);
+           }
+       }
     }
-
-    if (vm->mem_size > 0x40000000ULL) { 
-       PrintError(vm,VCORE_NONE, "VM has more than 1 GB\n");
+       
+    //1 GB only
+    if (max_level==2) { 
+       return;
     }
 
-    memset(&pde,0,sizeof(pde));
-    pde.present=1;
-    pde.writable=1;
-    pde.large_page=1;
-    
-    for (i=0;i<512;i++) {
-       pde.pt_base_addr = i*0x200;  // 0x200 = 512 pages = 2 MB
-       v3_write_gpa_memory(&vm->cores[0],
-                           (addr_t)(base+2*PAGE_SIZE+i*sizeof(pde)),
-                           sizeof(pde),(uint8_t*)&pde);
-    }
+    for (cur_pt=start_l3, pt=0, cur_gpa=min_gpa, cur_gva=min_gva;
+        pt<num_l3;
+        cur_pt+=PAGE_SIZE, pt++) { 
 
-    memset(&pdpe,0,sizeof(pdpe));
-    pdpe.present=1;
-    pdpe.writable=1;
-    pdpe.large_page=0;
+       // build PDE
+       if (v3_gpa_to_hva(&vm->cores[0],(addr_t)cur_pt,(addr_t*)&pde)) { 
+           PrintError(vm,VCORE_NONE,"hvm: Cannot translate pde location\n");
+           return;
+       }
+       
+       memset(pde,0,PAGE_SIZE);
+       
+       for (i=0; 
+            i<512 && cur_gpa<max_gpa; 
+            i++, cur_gva+=L3_UNIT, cur_gpa+=L3_UNIT) {
 
-    pdpe.pd_base_addr = PAGE_BASE_ADDR((addr_t)(base+2*PAGE_SIZE));
+           pde[i].present=1;
+           pde[i].writable=1;
+       
+           if (max_level==3) { 
+               pde[i].large_page=1;
+               pde[i].pt_base_addr = PAGE_BASE_ADDR((addr_t)(cur_gpa));
+               //PrintDebug(vm,VCORE_NONE,"hvm: pde: gva %p to frame 0%llx\n", cur_gva, (uint64_t) pde[i].pt_base_addr);
+           } else {
+               pde[i].pt_base_addr = PAGE_BASE_ADDR((addr_t)(start_l4+(pt*512+i)*PAGE_SIZE));
+               //PrintDebug(vm,VCORE_NONE,"hvm: pde: gva %p to frame 0%llx\n", cur_gva, (uint64_t)pde[i].pt_base_addr);
+           }
+       }
+    }
 
-    v3_write_gpa_memory(&vm->cores[0],(addr_t)base+PAGE_SIZE,sizeof(pdpe),(uint8_t*)&pdpe);    
-    
-    for (i=1;i<512;i++) {
-       pdpe.present = 0; 
-       v3_write_gpa_memory(&vm->cores[0],(addr_t)(base+PAGE_SIZE+i*sizeof(pdpe)),sizeof(pdpe),(uint8_t*)&pdpe);
+    //2 MB only
+    if (max_level==3) { 
+       return;
     }
 
-    memset(&pml4e,0,sizeof(pml4e));
-    pml4e.present=1;
-    pml4e.writable=1;
-    pml4e.pdp_base_addr = PAGE_BASE_ADDR((addr_t)(base+PAGE_SIZE));
 
-    v3_write_gpa_memory(&vm->cores[0],(addr_t)base,sizeof(pml4e),(uint8_t*)&pml4e);    
+    // 4 KB
+    for (cur_pt=start_l4, pt=0, cur_gpa=min_gpa, cur_gva=min_gva;
+        pt<num_l4;
+        cur_pt+=PAGE_SIZE, pt++) { 
 
-    for (i=1;i<512;i++) {
-       pml4e.present=0;
-       v3_write_gpa_memory(&vm->cores[0],(addr_t)(base+i*sizeof(pml4e)),sizeof(pml4e),(uint8_t*)&pml4e);
+       // build PTE
+       if (v3_gpa_to_hva(&vm->cores[0],(addr_t)cur_pt,(addr_t*)&pte)) { 
+           PrintError(vm,VCORE_NONE,"hvm: Cannot translate pte location\n");
+           return;
+       }
+       
+       memset(pte,0,PAGE_SIZE);
+       
+       for (i=0; 
+            i<512 && cur_gpa<max_gpa; 
+            i++, cur_gva+=L4_UNIT, cur_gpa+=L4_UNIT) {
+
+           pte[i].present=1;
+           pte[i].writable=1;
+           pte[i].page_base_addr = PAGE_BASE_ADDR((addr_t)(cur_gpa));
+           //PrintDebug(vm,VCORE_NONE,"hvm: pte: gva %p to frame 0%llx\n", cur_gva, (uint64_t)pte[i].page_base_addr);
+       }
     }
 
-    PrintDebug(vm,VCORE_NONE,"hvm: Wrote page tables (1 PML4, 1 PDPE, 1 PDP) at %p (1 GB mapped)\n",base);
+    return;
 }
 
-#endif
 
-static void write_pt(struct v3_vm_info *vm)
+static void get_mb_info_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 {
-#ifdef HVM_MAP_1G_2M
-    write_pt_3level_1GB(vm);
-#else
-    write_pt_2level_512GB(vm);
-#endif
+    
+    get_pt_loc(vm,base, limit);
+    *base-=PAGE_SIZE;
+    *limit=PAGE_SIZE;
 }
 
-static void get_bp_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
+
+int v3_build_hrt_multiboot_tag(struct guest_info *core, mb_info_hrt_t *hrt)
 {
-#ifdef HVM_MAP_1G_2M
-    *base = (void*) PAGE_ADDR(BOOT_STATE_END_ADDR-(6+2)*PAGE_SIZE);
-#else
-    *base = (void*) PAGE_ADDR(BOOT_STATE_END_ADDR-(6+1)*PAGE_SIZE);
-#endif
-    *limit =  PAGE_SIZE;
+    struct v3_vm_info *vm = core->vm_info;
+
+    hrt->tag.type = MB_INFO_HRT_TAG;
+    hrt->tag.size = sizeof(mb_info_hrt_t);
+
+    hrt->total_num_apics = vm->num_cores;
+    hrt->first_hrt_apic_id = vm->hvm_state.first_hrt_core;
+    hrt->have_hrt_ioapic=0;
+    hrt->first_hrt_ioapic_entry=0;
+
+    hrt->cpu_freq_khz = V3_CPU_KHZ();
+
+    hrt->hrt_flags = vm->hvm_state.hrt_flags;
+    hrt->max_mem_mapped = vm->hvm_state.max_mem_mapped;
+    hrt->first_hrt_gpa = vm->hvm_state.first_hrt_gpa;
+    hrt->gva_offset = vm->hvm_state.gva_offset;
+    hrt->comm_page_gpa = vm->hvm_state.comm_page_gpa;
+    hrt->hrt_int_vector = vm->hvm_state.hrt_int_vector;
+    
+    return 0;
 }
 
-static void write_bp(struct v3_vm_info *vm)
+static void write_mb_info(struct v3_vm_info *vm) 
 {
-    void *base;
-    uint64_t limit;
-    uint64_t data=-1;
-    int i;
+    if (vm->hvm_state.hrt_type!=HRT_MBOOT64) { 
+       PrintError(vm, VCORE_NONE,"hvm: Cannot handle this HRT type\n");
+       return;
+    } else {
+       uint8_t buf[256];
+       uint64_t size;
+       void *base;
+       uint64_t limit;
 
-    get_bp_loc(vm,&base,&limit);
-    
-    for (i=0;i<limit/8;i++) { 
-       v3_write_gpa_memory(&vm->cores[0],(addr_t)(base+i*8),8,(uint8_t*)&data);
-    }
+       get_mb_info_loc(vm,&base,&limit);
+       
+       if ((size=v3_build_multiboot_table(&vm->cores[vm->hvm_state.first_hrt_core],buf,256))==-1) { 
+           PrintError(vm,VCORE_NONE,"hvm: Failed to build MB info\n");
+           return;
+       }
 
-    PrintDebug(vm,VCORE_NONE,"hvm: wrote boundary page at %p\n", base);
-    
+       if (size>limit) { 
+           PrintError(vm,VCORE_NONE,"hvm: MB info is too large\n");
+           return;
+       }
+       
+       v3_write_gpa_memory(&vm->cores[vm->hvm_state.first_hrt_core],
+                           (addr_t)base,
+                           size,
+                           buf);
+
+       PrintDebug(vm,VCORE_NONE, "hvm: wrote MB info at %p\n", base);
+    }
 }
 
-#define MIN_STACK (4096*4)
+#define SCRATCH_STACK_SIZE 4096
 
 
 static void get_hrt_loc(struct v3_vm_info *vm, void **base, uint64_t *limit)
 {
-    void *bp_base;
-    uint64_t bp_limit;
+    void *mb_base;
+    uint64_t mb_limit;
     
-    get_bp_loc(vm,&bp_base,&bp_limit);
+    get_mb_info_loc(vm,&mb_base,&mb_limit);
     
-    // assume at least a minimal stack
-
-    bp_base-=MIN_STACK;
+    mb_base-=SCRATCH_STACK_SIZE*v3_get_hvm_hrt_cores(vm);
 
     *base = (void*)PAGE_ADDR(vm->hvm_state.first_hrt_gpa);
 
-    if (bp_base < *base+PAGE_SIZE) { 
+    if (mb_base < *base+PAGE_SIZE) { 
        PrintError(vm,VCORE_NONE,"hvm: HRT stack colides with HRT\n");
     }
 
-    *limit = bp_base - *base;
+    *limit = mb_base - *base;
 }
 
 
@@ -748,70 +1132,153 @@ static mb_header_t *find_mb_header(uint8_t *data, uint64_t size)
 }
 
 
-// 
-// BROKEN - THIS DOES NOT DO WHAT YOU THINK
-//
-static int setup_elf(struct v3_vm_info *vm, void *base, uint64_t limit)
+static int configure_hrt(struct v3_vm_info *vm, mb_data_t *mb)
 {
-    v3_write_gpa_memory(&vm->cores[0],(addr_t)base,vm->hvm_state.hrt_file->size,vm->hvm_state.hrt_file->data);
+    struct v3_vm_hvm *h = &vm->hvm_state;
+    uint64_t f = mb->mb64_hrt->hrt_flags;
+    uint64_t maxmap = mb->mb64_hrt->max_mem_to_map;
+    uint64_t gvaoff = mb->mb64_hrt->gva_offset;
+    uint64_t gvaentry = mb->mb64_hrt->gva_entry;
+    uint64_t commgpa = mb->mb64_hrt->comm_page_gpa;
+    uint8_t  vec = mb->mb64_hrt->hrt_int_vector;
+    
+
+    PrintDebug(vm,VCORE_NONE,"hvm: HRT request: flags=0x%llx max_map=0x%llx gva_off=%llx gva_entry=%llx comm_page=0x%llx vector=0x%x\n",
+              f, maxmap, gvaoff,gvaentry,commgpa, vec);
+
+    if (maxmap<0x100000000ULL) { 
+       PrintDebug(vm,VCORE_NONE,"hvm: revising request up to 4 GB max map\n");
+       maxmap=0x100000000ULL;
+    }
+
+    if (f & MB_TAG_MB64_HRT_FLAG_MAP_512GB) { 
+       PrintError(vm,VCORE_NONE,"hvm: support for 512 GB pages is not yet available in hardware\n");
+       return -1;
+    } else if (f & MB_TAG_MB64_HRT_FLAG_MAP_1GB) { 
+       f &= ~0x3c;
+       f |= MB_TAG_MB64_HRT_FLAG_MAP_1GB;
+       h->max_mem_mapped = maxmap;
+       PrintDebug(vm,VCORE_NONE,"hvm: 1 GB pages selected\n");
+    } else if (f & MB_TAG_MB64_HRT_FLAG_MAP_2MB) { 
+       f &= ~0x3c;
+       f |= MB_TAG_MB64_HRT_FLAG_MAP_2MB;
+       h->max_mem_mapped = maxmap;
+       PrintDebug(vm,VCORE_NONE,"hvm: 2 MB pages selected\n");
+    } else if (f & MB_TAG_MB64_HRT_FLAG_MAP_4KB) { 
+       f &= ~0x3c;
+       f |= MB_TAG_MB64_HRT_FLAG_MAP_4KB;
+       h->max_mem_mapped = maxmap;
+       PrintDebug(vm,VCORE_NONE,"hvm: 4 KB pages selected\n");
+    } else {
+       PrintError(vm,VCORE_NONE,"hvm: no page table model is requested\n");
+       return -1;
+    }
+
+    if (f & MB_TAG_MB64_HRT_FLAG_RELOC) {
+       PrintError(vm,VCORE_NONE,"hvm: relocatable hrt not currently supported\n");
+       return -1;
+    }
 
-    vm->hvm_state.hrt_entry_addr = (uint64_t) (base+0x40);
+    h->hrt_flags = f;
 
-    PrintDebug(vm,VCORE_NONE,"hvm: wrote HRT ELF %s at %p\n", vm->hvm_state.hrt_file->tag,base);
-    PrintDebug(vm,VCORE_NONE,"hvm: set ELF entry to %p and hoping for the best...\n", (void*) vm->hvm_state.hrt_entry_addr);
+    if (maxmap>h->max_mem_mapped) { 
+       PrintError(vm,VCORE_NONE,"hvm: requested 0x%llx bytes mapped, which is more than currently supported\n",maxmap);
+       return -1;
+    }
+
+    if (gvaoff!=0 && gvaoff!=TOP_HALF_START) { 
+       PrintError(vm,VCORE_NONE,"hvm: currently only GVA offsets of 0 and %llx are supported\n", TOP_HALF_START);
+       return -1;
+    }
+    
+    h->gva_offset = gvaoff;
+
+    h->gva_entry = gvaentry;
+
+    if (mb->addr->load_addr < h->first_hrt_gpa) { 
+       PrintError(vm,VCORE_NONE,"hvm: load start address of HRT is below first HRT GPA\n");
+       return -1;
+    }
     
-    vm->hvm_state.hrt_type = HRT_ELF64;
+    if (mb->addr->bss_end_addr > (vm->mem_size-(1024*1024*64))) {
+       PrintError(vm,VCORE_NONE,"hvm: bss end address of HRT above last allowed GPA\n");
+       return -1;
+    }
+    
+    if (vec<32) { 
+       PrintError(vm,VCORE_NONE,"hvm: cannot support vector %x\n",vec);
+       return -1;
+    }
+    
+    h->hrt_int_vector = vec;
+    
+    
+    if (commgpa < vm->mem_size) { 
+       PrintError(vm,VCORE_NONE,"hvm: cannot map comm page over physical memory\n");
+       return -1;
+    } 
+
+    h->comm_page_gpa = commgpa;
+
+    if (!h->comm_page_hpa) { 
+       if (!(h->comm_page_hpa=V3_AllocPages(1))) { 
+           PrintError(vm,VCORE_NONE,"hvm: unable to allocate space for comm page\n");
+           return -1;
+       }
 
+       h->comm_page_hva = V3_VAddr(h->comm_page_hpa);
+       
+       memset(h->comm_page_hva,0,PAGE_SIZE_4KB);
+       
+       if (v3_add_shadow_mem(vm,-1,h->comm_page_gpa,h->comm_page_gpa+PAGE_SIZE_4KB,(addr_t)h->comm_page_hpa)) { 
+           PrintError(vm,VCORE_NONE,"hvm: unable to map communication page\n");
+           V3_FreePages((void*)(h->comm_page_gpa),1);
+           return -1;
+       }
+       
+       
+       PrintDebug(vm,VCORE_NONE,"hvm: added comm page for first time\n");
+    }
+
+    memset(h->comm_page_hva,0,PAGE_SIZE_4KB);
+    
+    
+    PrintDebug(vm,VCORE_NONE,"hvm: HRT configuration: flags=0x%llx max_mem_mapped=0x%llx gva_offset=0x%llx gva_entry=0x%llx comm_page=0x%llx vector=0x%x\n",
+              h->hrt_flags,h->max_mem_mapped, h->gva_offset,h->gva_entry, h->comm_page_gpa, h->hrt_int_vector);
+    
     return 0;
 
 }
 
-static int setup_mb_kernel(struct v3_vm_info *vm, void *base, uint64_t limit)
+static int setup_mb_kernel_hrt(struct v3_vm_info *vm)
 {
     mb_data_t mb;
-    uint32_t offset;
-
-
-    // FIX USING GENERIC TOOLS
 
     if (v3_parse_multiboot_header(vm->hvm_state.hrt_file,&mb)) { 
        PrintError(vm,VCORE_NONE, "hvm: failed to parse multiboot kernel header\n");
        return -1;
     }
 
-    if (!mb.addr || !mb.entry) { 
-       PrintError(vm,VCORE_NONE, "hvm: kernel is missing address or entry point\n");
+    if (configure_hrt(vm,&mb)) {
+       PrintError(vm,VCORE_NONE, "hvm: cannot configure HRT\n");
        return -1;
     }
-
-    if (((void*)(uint64_t)(mb.addr->header_addr) < base ) ||
-       ((void*)(uint64_t)(mb.addr->load_end_addr) > base+limit) ||
-       ((void*)(uint64_t)(mb.addr->bss_end_addr) > base+limit)) { 
-       PrintError(vm,VCORE_NONE, "hvm: kernel is not within the allowed portion of HVM\n");
+    
+    if (v3_write_multiboot_kernel(vm,&mb,vm->hvm_state.hrt_file,
+                                 (void*)vm->hvm_state.first_hrt_gpa,
+                                 vm->mem_size-vm->hvm_state.first_hrt_gpa)) {
+       PrintError(vm,VCORE_NONE, "hvm: failed to write multiboot kernel into memory\n");
        return -1;
     }
 
-    offset = mb.addr->load_addr - mb.addr->header_addr;
-
-    // Skip the ELF header - assume 1 page... weird.... 
-    v3_write_gpa_memory(&vm->cores[0],
-                       (addr_t)(mb.addr->load_addr),
-                       vm->hvm_state.hrt_file->size-PAGE_SIZE-offset,
-                       vm->hvm_state.hrt_file->data+PAGE_SIZE+offset);
-
-       
-    // vm->hvm_state.hrt_entry_addr = (uint64_t) mb.entry->entry_addr + PAGE_SIZE; //HACK PAD
+    if (vm->hvm_state.gva_entry) { 
+       vm->hvm_state.hrt_entry_addr = vm->hvm_state.gva_entry;
+    } else {
+       vm->hvm_state.hrt_entry_addr = (uint64_t) mb.entry->entry_addr + vm->hvm_state.gva_offset;
+    }
 
-    vm->hvm_state.hrt_entry_addr = (uint64_t) mb.entry->entry_addr;
-    
     vm->hvm_state.hrt_type = HRT_MBOOT64;
 
-    PrintDebug(vm,VCORE_NONE,
-              "hvm: wrote 0x%llx bytes starting at offset 0x%llx to %p; set entry to %p\n",
-              (uint64_t) vm->hvm_state.hrt_file->size-PAGE_SIZE-offset,
-              (uint64_t) PAGE_SIZE+offset,
-              (void*)(addr_t)(mb.addr->load_addr),
-              (void*) vm->hvm_state.hrt_entry_addr);
     return 0;
 
 }
@@ -819,37 +1286,17 @@ static int setup_mb_kernel(struct v3_vm_info *vm, void *base, uint64_t limit)
 
 static int setup_hrt(struct v3_vm_info *vm)
 {
-    void *base;
-    uint64_t limit;
-
-    get_hrt_loc(vm,&base,&limit);
+    if (is_elf(vm->hvm_state.hrt_file->data,vm->hvm_state.hrt_file->size) && 
+       find_mb_header(vm->hvm_state.hrt_file->data,vm->hvm_state.hrt_file->size)) { 
 
-    if (vm->hvm_state.hrt_file->size > limit) { 
-       PrintError(vm,VCORE_NONE,"hvm: Cannot map HRT because it is too big (%llu bytes, but only have %llu space\n", vm->hvm_state.hrt_file->size, (uint64_t)limit);
-       return -1;
-    }
-
-    if (!is_elf(vm->hvm_state.hrt_file->data,vm->hvm_state.hrt_file->size)) { 
-       PrintError(vm,VCORE_NONE,"hvm: supplied HRT is not an ELF but we are going to act like it is!\n");
-       if (setup_elf(vm,base,limit)) {
-           PrintError(vm,VCORE_NONE,"hvm: Fake ELF setup failed\n");
+       PrintDebug(vm,VCORE_NONE,"hvm: appears to be a multiboot kernel\n");
+       if (setup_mb_kernel_hrt(vm)) { 
+           PrintError(vm,VCORE_NONE,"hvm: multiboot kernel setup failed\n");
            return -1;
-       }
-       vm->hvm_state.hrt_type=HRT_BLOB;
+       } 
     } else {
-       if (find_mb_header(vm->hvm_state.hrt_file->data,vm->hvm_state.hrt_file->size)) { 
-           PrintDebug(vm,VCORE_NONE,"hvm: appears to be a multiboot kernel\n");
-           if (setup_mb_kernel(vm,base,limit)) { 
-               PrintError(vm,VCORE_NONE,"hvm: multiboot kernel setup failed\n");
-               return -1;
-           } 
-       } else {
-           PrintDebug(vm,VCORE_NONE,"hvm: supplied HRT is an ELF\n");
-           if (setup_elf(vm,base,limit)) {
-               PrintError(vm,VCORE_NONE,"hvm: Fake ELF setup failed\n");
-               return -1;
-           }
-       }
+       PrintError(vm,VCORE_NONE,"hvm: supplied HRT is not a multiboot kernel\n");
+       return -1;
     }
 
     return 0;
@@ -873,15 +1320,20 @@ static int setup_hrt(struct v3_vm_info *vm)
   GDT (1 page - page aligned)
   TSS (1 page - page asligned)
   PAGETABLES  (identy map of first N GB)
-     ROOT PT first, followed by 2nd level, etc.
-     Currently PML4 followed by 1 PDPE for 512 GB of mapping
-  BOUNDARY PAGE (all 0xff - avoid smashing page tables in case we keep going...)
-  (stack - we will push machine description)
+     ROOT PT first (lowest memory addr), followed by 2nd level PTs in order,
+     followed by 3rd level PTs in order, followed by 4th level
+     PTs in order.  
+  MBINFO_PAGE
+  SCRATCH_STACK_HRT_CORE0 
+  SCRATCH_STACK_HRT_CORE1
+  ..
+  SCRATCH_STACK_HRT_COREN
   ...
   HRT (as many pages as needed, page-aligned, starting at first HRT address)
   ---
   ROS
-      
+
+
 */
 
 
@@ -894,20 +1346,23 @@ int v3_setup_hvm_vm_for_boot(struct v3_vm_info *vm)
 
     PrintDebug(vm,VCORE_NONE,"hvm: setup of HVM memory begins\n");
 
+    if (setup_hrt(vm)) {
+       PrintError(vm,VCORE_NONE,"hvm: failed to setup HRT\n");
+       return -1;
+    } 
+
+    // the locations of all the other items are determined by
+    // the HRT setup, so these must happen after
+
     write_null_int_handler(vm);
     write_idt(vm);
     write_gdt(vm);
     write_tss(vm);
 
-    write_pt(vm);
-
-    write_bp(vm);
-    
-    if (setup_hrt(vm)) {
-       PrintError(vm,VCORE_NONE,"hvm: failed to setup HRT\n");
-       return -1;
-    } 
+    write_pts(vm);
 
+    // this must happen last
+    write_mb_info(vm);
 
     PrintDebug(vm,VCORE_NONE,"hvm: setup of HVM memory done\n");
 
@@ -915,20 +1370,22 @@ int v3_setup_hvm_vm_for_boot(struct v3_vm_info *vm)
 }
 
 /*
-  On entry:
+  On entry for every core:
 
    IDTR points to stub IDT
    GDTR points to stub GDT
    TS   points to stub TSS
    CR3 points to root page table
    CR0 has PE and PG
-   EFER has LME AND LMA
-   RSP is TOS (looks like a call)
-       INFO                     <= RDI
-       0 (fake return address)  <= RSP
-       
-   RIP is entry point to HRT
-   RDI points to machine info on stack
+   EFER has LME AND LMA (and NX for compatibility with Linux)
+   RSP is TOS of core's scratch stack (looks like a call)
+
+   RAX = MB magic cookie
+   RBX = address of multiboot info table
+   RCX = this core id / apic id (0..N-1)
+   RDX = this core id - first HRT core ID (==0 for the first HRT core)
+
+   All addresses are virtual addresses, offset as needed by gva_offset
 
    Other regs are zeroed
 
@@ -939,16 +1396,20 @@ int v3_setup_hvm_hrt_core_for_boot(struct guest_info *core)
 {
     void *base;
     uint64_t limit;
+    uint64_t gva_offset;
 
     rdtscll(core->hvm_state.last_boot_start);
+    
 
     if (!core->hvm_state.is_hrt) { 
        PrintDebug(core->vm_info,core,"hvm: skipping HRT setup for core %u as it is not an HRT core\n", core->vcpu_id);
        return 0;
     }
 
+
     PrintDebug(core->vm_info, core, "hvm: setting up HRT core (%u) for boot\n", core->vcpu_id);
 
+    gva_offset = core->vm_info->hvm_state.gva_offset;
     
     memset(&core->vm_regs,0,sizeof(core->vm_regs));
     memset(&core->ctrl_regs,0,sizeof(core->ctrl_regs));
@@ -964,17 +1425,55 @@ int v3_setup_hvm_hrt_core_for_boot(struct guest_info *core)
     core->mem_mode = VIRTUAL_MEM; 
     core->core_run_state = CORE_RUNNING ;
 
-    // We are going to enter right into the HRT
-    // HRT stack and argument passing
-    get_bp_loc(core->vm_info, &base,&limit);
-    // TODO: push description here
-    core->vm_regs.rsp = (v3_reg_t) base;  // so if we ret, we will blow up
-    core->vm_regs.rbp = (v3_reg_t) base; 
-    // TODO: RDI should really get pointer to description
-    core->vm_regs.rdi = (v3_reg_t) base;
+
+    // magic
+    core->vm_regs.rax = MB2_INFO_MAGIC;
+
+    // multiboot info pointer
+    get_mb_info_loc(core->vm_info, &base,&limit);
+    core->vm_regs.rbx = (uint64_t) base + gva_offset;  
+
+    // core number
+    core->vm_regs.rcx = core->vcpu_id;
+    
+    // HRT core number
+    core->vm_regs.rdx = core->vcpu_id - core->vm_info->hvm_state.first_hrt_core;
+
+    // Now point to scratch stack for this core
+    // it begins at an ofset relative to the MB info page
+    get_mb_info_loc(core->vm_info, &base,&limit);
+    base = base + gva_offset;
+    base -= core->vm_regs.rdx * SCRATCH_STACK_SIZE;
+    core->vm_regs.rsp = (v3_reg_t) base;  
+    core->vm_regs.rbp = (v3_reg_t) base-8; 
+
+    // push onto the stack a bad rbp and bad return address
+    core->vm_regs.rsp-=16;
+    v3_set_gpa_memory(core,
+                     core->vm_regs.rsp-gva_offset,
+                     16,
+                     0xff);
+
+
     // HRT entry point
     get_hrt_loc(core->vm_info, &base,&limit);
-    core->rip = (uint64_t) core->vm_info->hvm_state.hrt_entry_addr ; 
+    if (core->vm_info->hvm_state.gva_entry) { 
+      core->rip = core->vm_info->hvm_state.gva_entry;
+    } else {
+      core->rip = (uint64_t) core->vm_info->hvm_state.hrt_entry_addr + gva_offset; 
+    }
+      
+
+
+    PrintDebug(core->vm_info,core,"hvm: hrt core %u has rip=%p, rsp=%p, rbp=%p, rax=%p, rbx=%p, rcx=%p, rdx=%p\n",
+              (core->vcpu_id - core->vm_info->hvm_state.first_hrt_core),
+              (void*)(core->rip),
+              (void*)(core->vm_regs.rsp),
+              (void*)(core->vm_regs.rbp),
+              (void*)(core->vm_regs.rax),
+              (void*)(core->vm_regs.rbx),
+              (void*)(core->vm_regs.rcx),
+              (void*)(core->vm_regs.rdx));
 
     // Setup CRs for long mode and our stub page table
     // CR0: PG, PE
@@ -984,7 +1483,7 @@ int v3_setup_hvm_hrt_core_for_boot(struct guest_info *core)
     // CR2: don't care (output from #PF)
     // CE3: set to our PML4E, without setting PCD or PWT
     get_pt_loc(core->vm_info, &base,&limit);
-    core->ctrl_regs.cr3 = PAGE_ADDR((addr_t)base);
+    core->ctrl_regs.cr3 = PAGE_ADDR((addr_t)base);  // not offset as this is a GPA
     core->shdw_pg_state.guest_cr3 = core->ctrl_regs.cr3;
 
     // CR4: PGE, PAE, PSE (last byte: 1 0 1 1 0 0 0 0)
@@ -992,8 +1491,8 @@ int v3_setup_hvm_hrt_core_for_boot(struct guest_info *core)
     core->shdw_pg_state.guest_cr4 = core->ctrl_regs.cr4;
     // CR8 as usual
     // RFLAGS zeroed is fine: come in with interrupts off
-    // EFER needs SVME LMA LME (last 16 bits: 0 0 0 1 0 1 0 1 0 0 0 0 0 0 0 0
-    core->ctrl_regs.efer = 0x1500;
+    // EFER needs SVME LMA LME (last 16 bits: 0 0 0 1 1 1 0 1 0 0 0 0 0 0 0 0
+    core->ctrl_regs.efer = 0x1d00;
     core->shdw_pg_state.guest_efer.value = core->ctrl_regs.efer;
 
 
@@ -1013,47 +1512,50 @@ int v3_setup_hvm_hrt_core_for_boot(struct guest_info *core)
     
     // Install our stub IDT
     get_idt_loc(core->vm_info, &base,&limit);
+    base += gva_offset;
     core->segments.idtr.selector = 0;  // entry 0 (NULL) of the GDT
-    core->segments.idtr.base = (addr_t) base;
+    core->segments.idtr.base = (addr_t) base;  // only base+limit are used
     core->segments.idtr.limit = limit-1;
-    core->segments.idtr.type = 0xe;
-    core->segments.idtr.system = 1; 
+    core->segments.idtr.type = 0x0;
+    core->segments.idtr.system = 0; 
     core->segments.idtr.dpl = 0;
-    core->segments.idtr.present = 1;
-    core->segments.idtr.long_mode = 1;
+    core->segments.idtr.present = 0;
+    core->segments.idtr.long_mode = 0;
 
     // Install our stub GDT
     get_gdt_loc(core->vm_info, &base,&limit);
-    core->segments.gdtr.selector = 0;
+    base += gva_offset;
+    core->segments.gdtr.selector = 0;  // entry 0 (NULL) of the GDT
     core->segments.gdtr.base = (addr_t) base;
-    core->segments.gdtr.limit = limit-1;
-    core->segments.gdtr.type = 0x6;
-    core->segments.gdtr.system = 1; 
+    core->segments.gdtr.limit = limit-1;   // only base+limit are used
+    core->segments.gdtr.type = 0x0;
+    core->segments.gdtr.system = 0; 
     core->segments.gdtr.dpl = 0;
-    core->segments.gdtr.present = 1;
-    core->segments.gdtr.long_mode = 1;
+    core->segments.gdtr.present = 0;
+    core->segments.gdtr.long_mode = 0;
     
     // And our TSS
     get_tss_loc(core->vm_info, &base,&limit);
+    base += gva_offset;  
     core->segments.tr.selector = 0;
     core->segments.tr.base = (addr_t) base;
     core->segments.tr.limit = limit-1;
-    core->segments.tr.type = 0x6;
-    core->segments.tr.system = 1; 
+    core->segments.tr.type = 0x9;
+    core->segments.tr.system = 0;   // available 64 bit TSS 
     core->segments.tr.dpl = 0;
     core->segments.tr.present = 1;
-    core->segments.tr.long_mode = 1;
+    core->segments.tr.long_mode = 0; // not used
     
-    base = 0x0;
+    base = 0x0; // these are not offset as we want to make all gvas visible
     limit = -1;
 
     // And CS
     core->segments.cs.selector = 0x8 ; // entry 1 of GDT (RPL=0)
-    core->segments.cs.base = (addr_t) base;
-    core->segments.cs.limit = limit;
-    core->segments.cs.type = 0xe;
-    core->segments.cs.system = 0; 
-    core->segments.cs.dpl = 0;
+    core->segments.cs.base = (addr_t) base;   // not used
+    core->segments.cs.limit = limit;          // not used
+    core->segments.cs.type = 0xe;             // only C is used
+    core->segments.cs.system = 1;             // not a system segment
+    core->segments.cs.dpl = 0;                       
     core->segments.cs.present = 1;
     core->segments.cs.long_mode = 1;
 
@@ -1061,8 +1563,8 @@ int v3_setup_hvm_hrt_core_for_boot(struct guest_info *core)
     core->segments.ds.selector = 0x10; // entry 2 of GDT (RPL=0)
     core->segments.ds.base = (addr_t) base;
     core->segments.ds.limit = limit;
-    core->segments.ds.type = 0x6;
-    core->segments.ds.system = 0; 
+    core->segments.ds.type = 0x6;            // ignored
+    core->segments.ds.system = 1;            // not a system segment
     core->segments.ds.dpl = 0;
     core->segments.ds.present = 1;
     core->segments.ds.long_mode = 1;
@@ -1073,84 +1575,79 @@ int v3_setup_hvm_hrt_core_for_boot(struct guest_info *core)
     memcpy(&core->segments.gs,&core->segments.ds,sizeof(core->segments.ds));
     
 
-    if (core->vm_info->hvm_state.hrt_type==HRT_MBOOT64) { 
-       /*
-         Temporary hackery for multiboot2 "64"
-         We will push the MB structure onto the stack and update RSP
-         and RBX
-       */
-       uint8_t buf[256];
-       uint64_t size;
-       
-       if ((size=v3_build_multiboot_table(core,buf,256))==-1) { 
-           PrintError(core->vm_info,core,"hvm: Failed to write MB info\n");
-           return -1;
-       }
-       core->vm_regs.rsp -= size;
+    // reset paging here for shadow... 
 
-       v3_write_gpa_memory(core,
-                           core->vm_regs.rsp,
-                           size,
-                           buf);
+    if (core->shdw_pg_mode != NESTED_PAGING) { 
+       PrintError(core->vm_info, core, "hvm: shadow paging guest... this will end badly\n");
+       return -1;
+    }
 
-       PrintDebug(core->vm_info,core, "hvm: wrote MB info at %p\n", (void*)core->vm_regs.rsp);
 
-       if (core->vcpu_id == core->vm_info->hvm_state.first_hrt_core) {
-           // We are the BSP for this HRT
-           // this is where rbx needs to point
-           core->vm_regs.rbx = core->vm_regs.rsp;
-           PrintDebug(core->vm_info,core, "hvm: \"BSP\" core\n");
-       } else {
-           // We are an AP for this HRT
-           // so we don't get the multiboot struct
-           core->vm_regs.rbx = 0;
-           PrintDebug(core->vm_info,core, "hvm: \"AP\" core\n");
-       }
+    return 0;
+}
 
+int v3_handle_hvm_reset(struct guest_info *core)
+{
 
+    if (core->core_run_state != CORE_RESETTING) { 
+       return 0;
+    }
 
-       // one more push, something that looks like a return address
-       size=0;
-       core->vm_regs.rsp -= 8;
+    if (!core->vm_info->hvm_state.is_hvm) { 
+       return 0;
+    }
 
-       v3_write_gpa_memory(core,
-                           core->vm_regs.rsp,
-                           8,
-                           (uint8_t*) &size);
-       
-       // Now for our magic - this signals
-       // the kernel that a multiboot loader loaded it
-       // and that rbx points to its offered data
-       core->vm_regs.rax = MB2_INFO_MAGIC;
-    
-       /* 
-          Note that "real" MB starts in protected mode without paging
-          This hack starts in long mode... so these requirements go
-          out the window for a large part
+    if (v3_is_hvm_hrt_core(core)) { 
+       // this is an HRT reset
+       int rc=0;
 
-          Requirements:
+       // wait for all the HRT cores
+       v3_counting_barrier(&core->vm_info->reset_barrier);
 
-          OK EAX has magic 
-          OK EBX points to MB info
-          OK CS = base 0, offset big, code (LONG MODE)
-          OK DS,ES,FS,GS,SS => base 0, offset big, data (LONG MODE)
-          OK A20 gate on
-          XXX CR0 PE on PG off (nope)
-          XXX EFLAGS IF and VM off
-       */
-          
+       if (core->vcpu_id==core->vm_info->hvm_state.first_hrt_core) { 
+           // I am leader
+           core->vm_info->run_state = VM_RESETTING;
+       }
 
+       core->core_run_state = CORE_RESETTING;
 
-    }
+       if (core->vcpu_id==core->vm_info->hvm_state.first_hrt_core) {
+           // we really only need to clear the bss
+           // and recopy the .data, but for now we'll just
+           // do everything
+           rc |= v3_setup_hvm_vm_for_boot(core->vm_info);
 
+           if (rc) { 
+               PrintError(core->vm_info,core,"hvm: failed to setup HVM VM for boot rc=%d\n",rc);
+           }
+       }
 
-    // reset paging here for shadow... 
+       // now everyone is ready to reset
+       rc |= v3_setup_hvm_hrt_core_for_boot(core);
 
-    if (core->shdw_pg_mode != NESTED_PAGING) { 
-       PrintError(core->vm_info, core, "hvm: shadow paging guest... this will end badly\n");
-       return -1;
-    }
+       if (rc) { 
+           PrintError(core->vm_info,core,"hvm: failed to setup HVM core for boot rc=%d\n",rc);
+       }
 
+       core->core_run_state = CORE_RUNNING;
 
-    return 0;
+       if (core->vcpu_id==core->vm_info->hvm_state.first_hrt_core) { 
+           // leader
+           core->vm_info->run_state = VM_RUNNING;
+            core->vm_info->hvm_state.trans_state = HRT_IDLE;
+       }
+
+       v3_counting_barrier(&core->vm_info->reset_barrier);
+
+       if (rc<0) { 
+           PrintError(core->vm_info,core,"hvm: reset failed\n");
+           return rc;
+       } else {
+           return 1;
+       }
+
+    } else { 
+       // ROS core will be handled by normal reset functionality
+       return 0;
+    }
 }