From: Peter Dinda <pdinda@northwestern.edu>
Date: Mon, 26 May 2014 21:20:01 +0000 (-0500)
Subject: Convert shadow paging to use 32 PAE (Require Long Mode)
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=4454a172129d12e97793c9c353339b85d3335af4

Convert shadow paging to use 32 PAE (Require Long Mode)

This changes shadow paging to use, at minimum, 32PAE
shadow page tables.   This makes it possible to place
a guest using shadow paging anywhere in host physical
memory instead of just the first 4 GB

This change requires Palacios to be initialized and
run in long mode.   At minimum, we need PAE to be
available, and ideally, we want the version of PAE
developed for long mode to the one we use, not
the Intel legacy PAE stuff for 32 bit mode.

These patches need to be used together.
---

diff --git a/palacios/src/palacios/vmm.c b/palacios/src/palacios/vmm.c
index 8c34b68..12766b9 100644
--- a/palacios/src/palacios/vmm.c
+++ b/palacios/src/palacios/vmm.c
@@ -107,6 +107,17 @@ static void deinit_cpu(void * arg) {
 
 }
 
+
+static int in_long_mode()
+{
+  uint32_t high, low;
+
+  v3_get_msr(0xc0000080,&high,&low); // EFER
+  
+  return ((low & 0x500)== 0x500);  // LMA and LME set
+}
+  
+
 void Init_V3(struct v3_os_hooks * hooks, char * cpu_mask, int num_cpus, char *options) {
     int i = 0;
     int minor = 0;
@@ -115,6 +126,16 @@ void Init_V3(struct v3_os_hooks * hooks, char * cpu_mask, int num_cpus, char *op
     V3_Print(VM_NONE, VCORE_NONE, "V3 Print statement to fix a Kitten page fault bug\n");
 
 
+
+#ifndef __V3_64BIT__
+#error Palacios does not support compilation for a 32 bit host OS!!!!
+#else
+    if (!in_long_mode()) { 
+      PrintError(VM_NONE,VCORE_NONE,"Palacios supports execution only in long mode (64 bit).\n");
+      return;
+    }
+#endif
+
     // Set global variables. 
     os_hooks = hooks;
 
@@ -310,34 +331,17 @@ static int start_core(void * p)
 
 int v3_start_vm(struct v3_vm_info * vm, unsigned int cpu_mask) {
 
-    uint32_t i,j;
+    uint32_t i;
     uint8_t * core_mask = (uint8_t *)&cpu_mask; // This is to make future expansion easier
     uint32_t avail_cores = 0;
     int vcore_id = 0;
-    extern uint64_t v3_mem_block_size;
-
 
     if (vm->run_state != VM_STOPPED) {
         PrintError(vm, VCORE_NONE, "VM has already been launched (state=%d)\n", (int)vm->run_state);
         return -1;
     }
 
-    
-    // Do not run if any core is using shadow paging and we are out of 4 GB bounds
-    for (i=0;i<vm->num_cores;i++) { 
-	if (vm->cores[i].shdw_pg_mode == SHADOW_PAGING) {
-	    for (j=0;j<vm->mem_map.num_base_regions;j++) {
-		if ((vm->mem_map.base_regions[i].host_addr + v3_mem_block_size)  >= 0x100000000ULL) {
-		    PrintError(vm, VCORE_NONE, "Base memory region %d exceeds 4 GB boundary with shadow paging enabled on core %d.\n",j, i);
-		    PrintError(vm, VCORE_NONE, "Any use of non-64 bit mode in the guest is likely to fail in this configuration.\n");
-		    PrintError(vm, VCORE_NONE, "If you would like to proceed anyway, remove this check and recompile Palacios.\n");
-		    PrintError(vm, VCORE_NONE, "Alternatively, change this VM to use nested paging.\n");
-		    return -1;
-		}
-	    }
-	}
-    }
-    
+
     /// CHECK IF WE ARE MULTICORE ENABLED....
 
     V3_Print(vm, VCORE_NONE, "V3 --  Starting VM (%u cores)\n", vm->num_cores);
@@ -557,12 +561,10 @@ int v3_move_vm_mem(struct v3_vm_info * vm, void *gpa, int target_cpu) {
     // region uses exclusive addressing [guest_start,guest_end)
     num_pages = (reg->guest_end-reg->guest_start)/PAGE_SIZE;
 
-    // Now we allocate space for the new region with the same constraints as
-    // it originally had
     new_hpa = V3_AllocPagesExtended(num_pages,
 				    PAGE_SIZE_4KB,
 				    new_node,
-				    reg->flags.limit32 ? V3_ALLOC_PAGES_CONSTRAINT_4GB : 0);
+				    0);  // no constraints given new shadow pager impl
 
     if (!new_hpa) { 
 	PrintError(vm, VCORE_NONE, "Cannot allocate memory for new base region...\n");