1 #include <palacios/vmm_shadow_paging.h>
4 #include <palacios/vmm.h>
5 #include <palacios/vm_guest_mem.h>
10 int init_shadow_page_state(struct shadow_page_state * state) {
11 state->guest_mode = PDE32;
12 state->shadow_mode = PDE32;
15 state->shadow_cr3 = 0;
20 int handle_shadow_pagefault(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
21 if (info->cpu_mode == PROTECTED_PG) {
22 return handle_shadow_pagefault32(info, fault_addr, error_code);
29 int handle_shadow_pagefault32(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
30 pde32_t * guest_pde = NULL;
31 pde32_t * shadow_pde = (pde32_t *)CR3_TO_PDE32(info->shdw_pg_state.shadow_cr3);
32 addr_t guest_cr3 = CR3_TO_PDE32(info->shdw_pg_state.guest_cr3);
33 pt_access_status_t guest_pde_access;
34 pt_access_status_t shadow_pde_access;
35 pde32_t * guest_pde_entry = NULL;
36 pde32_t * shadow_pde_entry = (pde32_t *)&(shadow_pde[PDE32_INDEX(fault_addr)]);
38 if (guest_pa_to_host_va(info, guest_cr3, (addr_t*)&guest_pde) == -1) {
39 PrintDebug("Invalid Guest PDE Address: 0x%x\n", guest_cr3);
44 guest_pde_entry = (pde32_t *)&(guest_pde[PDE32_INDEX(fault_addr)]);
46 // Check the guest page permissions
47 guest_pde_access = can_access_pde32(guest_pde, fault_addr, error_code);
49 if (guest_pde_access != PT_ACCESS_OK) {
50 // inject page fault to the guest (Guest PDE fault)
52 info->ctrl_regs.cr2 = fault_addr;
53 raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code);
58 shadow_pde_access = can_access_pde32(shadow_pde, fault_addr, error_code);
61 if (shadow_pde_access == PT_ENTRY_NOT_PRESENT) {
62 pte32_t * shadow_pte = NULL;
64 V3_AllocPages(shadow_pte, 1);
65 memset(shadow_pte, 0, PAGE_SIZE);
67 shadow_pde_entry->pt_base_addr = PD32_BASE_ADDR(shadow_pte);
70 shadow_pde_entry->present = 1;
71 shadow_pde_entry->user_page = guest_pde_entry->user_page;
73 // VMM Specific options
74 shadow_pde_entry->write_through = 0;
75 shadow_pde_entry->cache_disable = 0;
76 shadow_pde_entry->global_page = 0;
79 guest_pde_entry->accessed = 1;
81 if (guest_pde_entry->large_page == 0) {
82 shadow_pde_entry->writable = guest_pde_entry->writable;
85 * Check the Intel manual because we are ignoring Large Page issues here
89 } else if (shadow_pde_access == PT_WRITE_ERROR) {
92 // Page Directory Entry marked read-only
95 PrintDebug("Shadow Paging Write Error\n");
97 } else if (shadow_pde_access == PT_USER_ERROR) {
100 // Page Directory Entry marked non-user
103 PrintDebug("Shadow Paging User access error\n");
105 } else if (shadow_pde_access == PT_ACCESS_OK) {
106 pte32_t * shadow_pte = (pte32_t *)PDE32_T_ADDR((*shadow_pde_entry));
107 pte32_t * guest_pte = NULL;
109 // Page Table Entry fault
111 if (guest_pa_to_host_va(info, PDE32_T_ADDR((*guest_pde_entry)), (addr_t*)&guest_pte) == -1) {
112 PrintDebug("Invalid Guest PTE Address: 0x%x\n", PDE32_T_ADDR((*guest_pde_entry)));
113 // Machine check the guest
115 raise_exception(info, MC_EXCEPTION);
121 if (handle_shadow_pte32_fault(info, fault_addr, error_code, shadow_pte, guest_pte) == -1) {
122 PrintDebug("Error handling Page fault caused by PTE\n");
127 // Unknown error raise page fault in guest
128 info->ctrl_regs.cr2 = fault_addr;
129 raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code);
131 // For debugging we will return an error here for the time being,
132 // this probably shouldn't ever happen
133 PrintDebug("Unknown Error occurred\n");
134 PrintDebug("Manual Says to inject page fault into guest\n");
138 PrintDebugPageTables(shadow_pde);
146 * We assume the the guest pte pointer has already been translated to a host virtual address
148 int handle_shadow_pte32_fault(struct guest_info * info,
150 pf_error_t error_code,
151 pte32_t * shadow_pte,
152 pte32_t * guest_pte) {
154 pt_access_status_t guest_pte_access;
155 pt_access_status_t shadow_pte_access;
156 pte32_t * guest_pte_entry = (pte32_t *)&(guest_pte[PTE32_INDEX(fault_addr)]);;
157 pte32_t * shadow_pte_entry = (pte32_t *)&(shadow_pte[PTE32_INDEX(fault_addr)]);
160 // Check the guest page permissions
161 guest_pte_access = can_access_pte32(guest_pte, fault_addr, error_code);
164 if (guest_pte_access != PT_ACCESS_OK) {
165 // Inject page fault into the guest
167 info->ctrl_regs.cr2 = fault_addr;
168 raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code);
174 shadow_pte_access = can_access_pte32(shadow_pte, fault_addr, error_code);
176 if (shadow_pte_access == PT_ACCESS_OK) {
177 // Inconsistent state...
178 // Guest Re-Entry will flush page tables and everything should now work
180 } else if (shadow_pte_access == PT_ENTRY_NOT_PRESENT) {
182 addr_t guest_pa = PTE32_T_ADDR((*guest_pte_entry));
184 // Page Table Entry Not Present
186 if (get_shadow_addr_type(info, guest_pa) == HOST_REGION_INVALID) {
187 // Inject a machine check in the guest
189 raise_exception(info, MC_EXCEPTION);
191 PrintDebug("Invalid Guest Address in page table (0x%x)\n", guest_pa);
195 shadow_pa = get_shadow_addr(info, guest_pa);
197 shadow_pte_entry->page_base_addr = PT32_BASE_ADDR(shadow_pa);
199 shadow_pte_entry->present = guest_pte_entry->present;
200 shadow_pte_entry->user_page = guest_pte_entry->user_page;
202 //set according to VMM policy
203 shadow_pte_entry->write_through = 0;
204 shadow_pte_entry->cache_disable = 0;
205 shadow_pte_entry->global_page = 0;
208 guest_pte_entry->accessed = 1;
210 if (guest_pte_entry->dirty == 1) {
211 shadow_pte_entry->writable = guest_pte_entry->writable;
212 } else if ((guest_pte_entry->dirty == 0) && (error_code.write == 1)) {
213 shadow_pte_entry->writable = guest_pte_entry->writable;
214 guest_pte_entry->dirty = 1;
215 } else if ((guest_pte_entry->dirty = 0) && (error_code.write == 0)) {
216 shadow_pte_entry->writable = 0;
219 } else if ((shadow_pte_access == PT_WRITE_ERROR) &&
220 (guest_pte_entry->dirty == 0)) {
221 guest_pte_entry->dirty = 1;
222 shadow_pte_entry->writable = guest_pte_entry->writable;
226 // Inject page fault into the guest
228 info->ctrl_regs.cr2 = fault_addr;
229 raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code);
231 PrintDebug("PTE Page fault fell through... Not sure if this should ever happen\n");
232 PrintDebug("Manual Says to inject page fault into guest\n");
241 addr_t create_new_shadow_pt32(struct guest_info * info) {
244 V3_AllocPages(host_pde, 1);
245 memset(host_pde, 0, PAGE_SIZE);
247 return (addr_t)host_pde;
255 addr_t setup_shadow_pt32(struct guest_info * info, addr_t virt_cr3) {
256 addr_t cr3_guest_addr = CR3_TO_PDE32(virt_cr3);
258 pde32_t * host_pde = NULL;
261 // Setup up guest_pde to point to the PageDir in host addr
262 if (guest_pa_to_host_va(info, cr3_guest_addr, (addr_t*)&guest_pde) == -1) {
266 V3_AllocPages(host_pde, 1);
267 memset(host_pde, 0, PAGE_SIZE);
269 for (i = 0; i < MAX_PDE32_ENTRIES; i++) {
270 if (guest_pde[i].present == 1) {
274 if (guest_pa_to_host_va(info, PDE32_T_ADDR(guest_pde[i]), &pt_host_addr) == -1) {
278 if ((host_pte = setup_shadow_pte32(info, pt_host_addr)) == 0) {
282 host_pde[i].present = 1;
283 host_pde[i].pt_base_addr = PD32_BASE_ADDR(host_pte);
286 // Set Page DIR flags
291 PrintDebugPageTables(host_pde);
293 return (addr_t)host_pde;
298 addr_t setup_shadow_pte32(struct guest_info * info, addr_t pt_host_addr) {
299 pte32_t * guest_pte = (pte32_t *)pt_host_addr;
300 pte32_t * host_pte = NULL;
303 V3_AllocPages(host_pte, 1);
304 memset(host_pte, 0, PAGE_SIZE);
306 for (i = 0; i < MAX_PTE32_ENTRIES; i++) {
307 if (guest_pte[i].present == 1) {
308 addr_t guest_pa = PTE32_T_ADDR(guest_pte[i]);
309 shadow_mem_type_t page_type;
312 page_type = get_shadow_addr_type(info, guest_pa);
314 if (page_type == HOST_REGION_PHYSICAL_MEMORY) {
315 host_pa = get_shadow_addr(info, guest_pa);
319 // Setup various memory types
323 host_pte[i].page_base_addr = PT32_BASE_ADDR(host_pa);
324 host_pte[i].present = 1;
328 return (addr_t)host_pte;