+/*
+ * This file is part of the Palacios Virtual Machine Monitor developed
+ * by the V3VEE Project with funding from the United States National
+ * Science Foundation and the Department of Energy.
+ *
+ * The V3VEE Project is a joint project between Northwestern University
+ * and the University of New Mexico. You can find out more at
+ * http://www.v3vee.org
+ *
+ * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu>
+ * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
+ * All rights reserved.
+ *
+ * Author: Jack Lange <jarusl@cs.northwestern.edu>
+ *
+ * This is free software. You are permitted to use,
+ * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
+ */
+
+
#include <palacios/vmm_shadow_paging.h>
#include <palacios/vmm.h>
#include <palacios/vm_guest_mem.h>
#include <palacios/vmm_decoder.h>
+#include <palacios/vmm_ctrl_regs.h>
+#include <palacios/vmm_hashtable.h>
+#include <palacios/vmm_direct_paging.h>
-int init_shadow_page_state(struct shadow_page_state * state) {
- state->guest_mode = PDE32;
- state->shadow_mode = PDE32;
-
- state->guest_cr3 = 0;
- state->shadow_cr3 = 0;
- return 0;
-}
-int handle_shadow_pagefault(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
-
- if (info->mem_mode == PHYSICAL_MEM) {
- // If paging is not turned on we need to handle the special cases
- return handle_special_page_fault(info, fault_addr, error_code);
- } else if (info->mem_mode == VIRTUAL_MEM) {
-
- switch (info->cpu_mode) {
- case PROTECTED:
- return handle_shadow_pagefault32(info, fault_addr, error_code);
- break;
- case PROTECTED_PAE:
- case LONG:
- // currently not handled
- return -1;
- break;
- default:
- return -1;
- }
- } else {
- PrintDebug("Invalid Memory mode\n");
- return -1;
- }
-}
+#ifdef CONFIG_SHADOW_PAGING_TELEMETRY
+#include <palacios/vmm_telemetry.h>
+#endif
-int handle_shadow_pagefault32(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) {
- pde32_t * guest_pd = NULL;
- pde32_t * shadow_pd = (pde32_t *)CR3_TO_PDE32(info->shdw_pg_state.shadow_cr3);
- addr_t guest_cr3 = CR3_TO_PDE32(info->shdw_pg_state.guest_cr3);
- pt_access_status_t guest_pde_access;
- pt_access_status_t shadow_pde_access;
- pde32_t * guest_pde = NULL;
- pde32_t * shadow_pde = (pde32_t *)&(shadow_pd[PDE32_INDEX(fault_addr)]);
+#ifdef CONFIG_SYMBIOTIC_SWAP
+#include <palacios/vmm_sym_swap.h>
+#endif
- if (guest_pa_to_host_va(info, guest_cr3, (addr_t*)&guest_pd) == -1) {
- PrintDebug("Invalid Guest PDE Address: 0x%x\n", guest_cr3);
- return -1;
- }
+#ifndef CONFIG_DEBUG_SHADOW_PAGING
+#undef PrintDebug
+#define PrintDebug(fmt, args...)
+#endif
- guest_pde = (pde32_t *)&(guest_pd[PDE32_INDEX(fault_addr)]);
- // Check the guest page permissions
- guest_pde_access = can_access_pde32(guest_pd, fault_addr, error_code);
+static struct hashtable * master_shdw_pg_table = NULL;
- if (guest_pde_access != PT_ACCESS_OK) {
- // inject page fault to the guest (Guest PDE fault)
+static uint_t shdw_pg_hash_fn(addr_t key) {
+ char * name = (char *)key;
+ return v3_hash_buffer((uint8_t *)name, strlen(name));
+}
- info->ctrl_regs.cr2 = fault_addr;
- raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code);
+static int shdw_pg_eq_fn(addr_t key1, addr_t key2) {
+ char * name1 = (char *)key1;
+ char * name2 = (char *)key2;
- PrintDebug("Injecting PDE pf to guest: (guest access error=%d) (pf error code=%d)\n", guest_pde_access, error_code);
- PrintDebug("Guest CR3=%x\n", guest_cr3);
- PrintPD32(guest_pd);
+ return (strcmp(name1, name2) == 0);
+}
- V3_ASSERT(0);
- return 0;
- }
+int V3_init_shdw_paging() {
+ extern struct v3_shdw_pg_impl * __start__v3_shdw_pg_impls[];
+ extern struct v3_shdw_pg_impl * __stop__v3_shdw_pg_impls[];
+ struct v3_shdw_pg_impl ** tmp_impl = __start__v3_shdw_pg_impls;
+ int i = 0;
- shadow_pde_access = can_access_pde32(shadow_pd, fault_addr, error_code);
+ master_shdw_pg_table = v3_create_htable(0, shdw_pg_hash_fn, shdw_pg_eq_fn);
- if (shadow_pde_access == PT_ENTRY_NOT_PRESENT) {
+ while (tmp_impl != __stop__v3_shdw_pg_impls) {
+ V3_Print("Registering Shadow Paging Impl (%s)\n", (*tmp_impl)->name);
- shadow_pde->present = 1;
- shadow_pde->user_page = guest_pde->user_page;
- shadow_pde->large_page = guest_pde->large_page;
+ if (v3_htable_search(master_shdw_pg_table, (addr_t)((*tmp_impl)->name))) {
+ PrintError("Multiple instances of shadow paging impl (%s)\n", (*tmp_impl)->name);
+ return -1;
+ }
- // VMM Specific options
- shadow_pde->write_through = 0;
- shadow_pde->cache_disable = 0;
- shadow_pde->global_page = 0;
- //
+ if (v3_htable_insert(master_shdw_pg_table,
+ (addr_t)((*tmp_impl)->name),
+ (addr_t)(*tmp_impl)) == 0) {
+ PrintError("Could not register shadow paging impl (%s)\n", (*tmp_impl)->name);
+ return -1;
+ }
- guest_pde->accessed = 1;
-
- if (guest_pde->large_page == 0) {
- pte32_t * shadow_pt = NULL;
-
- V3_AllocPages(shadow_pt, 1);
- memset(shadow_pt, 0, PAGE_SIZE);
-
- shadow_pde->pt_base_addr = PD32_BASE_ADDR(shadow_pt);
-
- shadow_pde->writable = guest_pde->writable;
- } else {
- struct shadow_region * mem_reg;
- pde32_4MB_t * large_guest_pde = (pde32_4MB_t *)guest_pde;
- pde32_4MB_t * large_shadow_pde = (pde32_4MB_t *)shadow_pde;
- host_region_type_t host_page_type;
- addr_t guest_start_addr = PDE32_4MB_T_ADDR(*large_guest_pde);
- // addr_t guest_end_addr = guest_start_addr + PAGE_SIZE_4MB; // start address + 4MB
+ tmp_impl = &(__start__v3_shdw_pg_impls[++i]);
+ }
+ return 0;
+}
- /* JRL: THIS COULD BE A PROBLEM....
- * Currently we only support large pages if the region is mapped contiguosly in shadow memory
- * Lets hope this is the case...
- */
- // Check that the Guest PDE entry points to valid memory
- // else Machine Check the guest
- host_page_type = get_shadow_addr_type(info, guest_start_addr);
- if (host_page_type == HOST_REGION_INVALID) {
+/***
+ *** There be dragons
+ ***/
- raise_exception(info, MC_EXCEPTION);
- PrintDebug("Invalid guest address in large page (0x%x)\n", guest_start_addr);
- return -1;
- } else if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) {
- addr_t host_start_addr = 0;
- addr_t region_end_addr = 0;
-
- // Check for a large enough region in host memory
- mem_reg = get_shadow_region_by_addr(&(info->mem_map), guest_start_addr);
- host_start_addr = mem_reg->host_addr + (guest_start_addr - mem_reg->guest_start);
- region_end_addr = mem_reg->host_addr + (mem_reg->guest_end - mem_reg->guest_start);
-
- // Check if the region is at least an additional 4MB
- if (region_end_addr <= host_start_addr + PAGE_SIZE_4MB) {
- PrintDebug("Large page over non contiguous host memory... Not handled\n");
- return -1;
- }
- //4b.
- large_shadow_pde->page_base_addr = PD32_4MB_BASE_ADDR(host_start_addr);
-
- //4f
- if (large_guest_pde->dirty == 1) { // dirty
- large_shadow_pde->writable = guest_pde->writable;
- } else if (error_code.write == 1) { // not dirty, access is write
- large_shadow_pde->writable = guest_pde->writable;
- large_guest_pde->dirty = 1;
- } else { // not dirty, access is read
- large_shadow_pde->writable = 0;
- }
+#ifdef CONFIG_SHADOW_PAGING_TELEMETRY
+static void telemetry_cb(struct v3_vm_info * vm, void * private_data, char * hdr) {
+ int i = 0;
+ for (i = 0; i < vm->num_cores; i++) {
+ struct guest_info * core = &(vm->cores[i]);
- } else {
- // Handle hooked pages as well as other special pages
- if (handle_special_page_fault(info, fault_addr, error_code) == -1) {
- PrintDebug("Special Page Fault handler returned error for address: %x\n", fault_addr);
- return -1;
- }
- }
+ V3_Print("%s Guest Page faults: %d\n", hdr, core->shdw_pg_state.guest_faults);
}
+}
+#endif
- } else if ((shadow_pde_access == PT_WRITE_ERROR) &&
- (guest_pde->large_page = 1) &&
- (((pde32_4MB_t *)guest_pde)->dirty == 0)) {
- //
- // Page Directory Entry marked read-only
- //
- ((pde32_4MB_t *)guest_pde)->dirty = 1;
- shadow_pde->writable = guest_pde->writable;
- return 0;
-
- } else if (shadow_pde_access == PT_USER_ERROR) {
+int v3_init_shdw_pg_state(struct guest_info * core) {
+ struct v3_shdw_pg_state * state = &(core->shdw_pg_state);
+ struct v3_shdw_pg_impl * impl = core->vm_info->shdw_impl.current_impl;
+
- //
- // Page Directory Entry marked non-user
- //
-
- PrintDebug("Shadow Paging User access error\n");
- return -1;
- } else if (shadow_pde_access == PT_ACCESS_OK) {
- pte32_t * shadow_pt = (pte32_t *)PDE32_T_ADDR((*shadow_pde));
- pte32_t * guest_pt = NULL;
+ state->guest_cr3 = 0;
+ state->guest_cr0 = 0;
+ state->guest_efer.value = 0x0LL;
- // Page Table Entry fault
-
- if (guest_pa_to_host_va(info, PDE32_T_ADDR((*guest_pde)), (addr_t*)&guest_pt) == -1) {
- PrintDebug("Invalid Guest PTE Address: 0x%x\n", PDE32_T_ADDR((*guest_pde)));
- // Machine check the guest
- raise_exception(info, MC_EXCEPTION);
-
- return 0;
+ if (impl->local_init(core) == -1) {
+ PrintError("Error in Shadow paging local initialization (%s)\n", impl->name);
+ return -1;
}
- if (handle_shadow_pte32_fault(info, fault_addr, error_code, shadow_pt, guest_pt) == -1) {
- PrintDebug("Error handling Page fault caused by PTE\n");
- return -1;
- }
-
- } else {
- // Unknown error raise page fault in guest
- info->ctrl_regs.cr2 = fault_addr;
- raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code);
-
- // For debugging we will return an error here for the time being,
- // this probably shouldn't ever happen
- PrintDebug("Unknown Error occurred\n");
- PrintDebug("Manual Says to inject page fault into guest\n");
- return -1;
- }
-
- //PrintDebugPageTables(shadow_pd);
- PrintDebug("Returning end of PDE function\n");
- return 0;
+#ifdef CONFIG_SHADOW_PAGING_TELEMETRY
+ v3_add_telemetry_cb(core->vm_info, telemetry_cb, NULL);
+#endif
+
+ return 0;
}
-/*
- * We assume the the guest pte pointer has already been translated to a host virtual address
- */
-int handle_shadow_pte32_fault(struct guest_info * info,
- addr_t fault_addr,
- pf_error_t error_code,
- pte32_t * shadow_pt,
- pte32_t * guest_pt) {
-
- pt_access_status_t guest_pte_access;
- pt_access_status_t shadow_pte_access;
- pte32_t * guest_pte = (pte32_t *)&(guest_pt[PTE32_INDEX(fault_addr)]);;
- pte32_t * shadow_pte = (pte32_t *)&(shadow_pt[PTE32_INDEX(fault_addr)]);
-
+int v3_init_shdw_impl(struct v3_vm_info * vm) {
+ struct v3_shdw_impl_state * impl_state = &(vm->shdw_impl);
+ v3_cfg_tree_t * pg_cfg = v3_cfg_subtree(vm->cfg_data->cfg, "paging");
+ char * type_name = v3_cfg_val(pg_cfg, NULL);
+ char * impl_name = v3_cfg_val(pg_cfg, "mode");
+ struct v3_shdw_pg_impl * impl = NULL;
+
+ if (type_name && (strcasecmp(type_name, "shadow") != 0)) {
+ PrintDebug("Shadow paging not specified for VM.\n");
+ return 0;
+ }
+
+ V3_Print("Initialization of Shadow Paging implementation\n");
- // Check the guest page permissions
- guest_pte_access = can_access_pte32(guest_pt, fault_addr, error_code);
+ impl = (struct v3_shdw_pg_impl *)v3_htable_search(master_shdw_pg_table, (addr_t)impl_name);
-
- if (guest_pte_access != PT_ACCESS_OK) {
- // Inject page fault into the guest
-
- info->ctrl_regs.cr2 = fault_addr;
- raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code);
-
- PrintDebug("Access error injecting pf to guest\n");
- return 0;
- }
-
-
- shadow_pte_access = can_access_pte32(shadow_pt, fault_addr, error_code);
+ if (impl == NULL) {
+ PrintError("Could not find shadow paging impl (%s)\n", impl_name);
+ return -1;
+ }
+
+ impl_state->current_impl = impl;
- if (shadow_pte_access == PT_ACCESS_OK) {
- // Inconsistent state...
- // Guest Re-Entry will flush page tables and everything should now work
- PrintDebug("Inconsistent state... Guest re-entry should flush tlb\n");
- return 0;
- } else if (shadow_pte_access == PT_ENTRY_NOT_PRESENT) {
- addr_t shadow_pa;
- addr_t guest_pa = PTE32_T_ADDR((*guest_pte));
-
- // Page Table Entry Not Present
-
- host_region_type_t host_page_type = get_shadow_addr_type(info, guest_pa);
-
- if (host_page_type == HOST_REGION_INVALID) {
- // Inject a machine check in the guest
-
- raise_exception(info, MC_EXCEPTION);
-
- PrintDebug("Invalid Guest Address in page table (0x%x)\n", guest_pa);
- return 0;
-
- } else if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) {
-
- shadow_pa = get_shadow_addr(info, guest_pa);
-
- shadow_pte->page_base_addr = PT32_BASE_ADDR(shadow_pa);
-
- shadow_pte->present = guest_pte->present;
- shadow_pte->user_page = guest_pte->user_page;
-
- //set according to VMM policy
- shadow_pte->write_through = 0;
- shadow_pte->cache_disable = 0;
- shadow_pte->global_page = 0;
- //
-
- guest_pte->accessed = 1;
-
- if (guest_pte->dirty == 1) {
- shadow_pte->writable = guest_pte->writable;
- } else if ((guest_pte->dirty == 0) && (error_code.write == 1)) {
- shadow_pte->writable = guest_pte->writable;
- guest_pte->dirty = 1;
- } else if ((guest_pte->dirty = 0) && (error_code.write == 0)) {
- shadow_pte->writable = 0;
- }
- } else {
- // Page fault handled by hook functions
- if (handle_special_page_fault(info, fault_addr, error_code) == -1) {
- PrintDebug("Special Page fault handler returned error for address: %x\n", fault_addr);
+ if (impl->init(vm, pg_cfg) == -1) {
+ PrintError("Could not initialize Shadow paging implemenation (%s)\n", impl->name);
return -1;
- }
}
- } else if ((shadow_pte_access == PT_WRITE_ERROR) &&
- (guest_pte->dirty == 0)) {
- guest_pte->dirty = 1;
- shadow_pte->writable = guest_pte->writable;
+
- PrintDebug("Shadow PTE Write Error\n");
return 0;
- } else {
- // Inject page fault into the guest
-
- info->ctrl_regs.cr2 = fault_addr;
- raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code);
-
- PrintDebug("PTE Page fault fell through... Not sure if this should ever happen\n");
- PrintDebug("Manual Says to inject page fault into guest\n");
- return -1;
- }
-
- PrintDebug("Returning end of function\n");
- return 0;
}
+// Reads the guest CR3 register
+// creates new shadow page tables
+// updates the shadow CR3 register to point to the new pts
+int v3_activate_shadow_pt(struct guest_info * core) {
+ struct v3_shdw_impl_state * state = &(core->vm_info->shdw_impl);
+ struct v3_shdw_pg_impl * impl = state->current_impl;
+ return impl->activate_shdw_pt(core);
+}
-addr_t create_new_shadow_pt32(struct guest_info * info) {
- void * host_pde = 0;
- V3_AllocPages(host_pde, 1);
- memset(host_pde, 0, PAGE_SIZE);
- return (addr_t)host_pde;
+// This must flush any caches
+// and reset the cr3 value to the correct value
+int v3_invalidate_shadow_pts(struct guest_info * core) {
+ struct v3_shdw_impl_state * state = &(core->vm_info->shdw_impl);
+ struct v3_shdw_pg_impl * impl = state->current_impl;
+ return impl->invalidate_shdw_pt(core);
}
-
-/* Currently Does not work with Segmentation!!! */
-int handle_shadow_invlpg(struct guest_info * info) {
- if (info->mem_mode != VIRTUAL_MEM) {
- // Paging must be turned on...
- // should handle with some sort of fault I think
- PrintDebug("ERROR: INVLPG called in non paged mode\n");
- return -1;
- }
+int v3_handle_shadow_pagefault(struct guest_info * core, addr_t fault_addr, pf_error_t error_code) {
+
+ if (v3_get_vm_mem_mode(core) == PHYSICAL_MEM) {
+ // If paging is not turned on we need to handle the special cases
+ return v3_handle_passthrough_pagefault(core, fault_addr, error_code);
+ } else if (v3_get_vm_mem_mode(core) == VIRTUAL_MEM) {
+ struct v3_shdw_impl_state * state = &(core->vm_info->shdw_impl);
+ struct v3_shdw_pg_impl * impl = state->current_impl;
+
+ return impl->handle_pagefault(core, fault_addr, error_code);
+ } else {
+ PrintError("Invalid Memory mode\n");
+ return -1;
+ }
+}
- if (info->cpu_mode == PROTECTED) {
- char instr[15];
- int ret;
- int index = 0;
+int v3_handle_shadow_invlpg(struct guest_info * core) {
+ uchar_t instr[15];
+ struct x86_instr dec_instr;
+ int ret = 0;
+ addr_t vaddr = 0;
- ret = read_guest_va_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr);
- if (ret != 15) {
- PrintDebug("Could not read instruction 0x%x (ret=%d)\n", info->rip, ret);
- return -1;
+ if (v3_get_vm_mem_mode(core) != VIRTUAL_MEM) {
+ // Paging must be turned on...
+ // should handle with some sort of fault I think
+ PrintError("ERROR: INVLPG called in non paged mode\n");
+ return -1;
}
-
- /* Can INVLPG work with Segments?? */
- while (is_prefix_byte(instr[index])) {
- index++;
+ if (v3_get_vm_mem_mode(core) == PHYSICAL_MEM) {
+ ret = v3_read_gpa_memory(core, get_addr_linear(core, core->rip, &(core->segments.cs)), 15, instr);
+ } else {
+ ret = v3_read_gva_memory(core, get_addr_linear(core, core->rip, &(core->segments.cs)), 15, instr);
}
-
-
- if ((instr[index] == (uchar_t)0x0f) &&
- (instr[index + 1] == (uchar_t)0x01)) {
- addr_t first_operand;
- addr_t second_operand;
- operand_type_t addr_type;
-
- index += 2;
-
- addr_type = decode_operands32(&(info->vm_regs), instr + index, &index, &first_operand, &second_operand, REG32);
-
- if (addr_type == MEM_OPERAND) {
- pde32_t * shadow_pd = (pde32_t *)CR3_TO_PDE32(info->shdw_pg_state.shadow_cr3);
- pde32_t * shadow_pde = (pde32_t *)&shadow_pd[PDE32_INDEX(first_operand)];
+ if (ret == -1) {
+ PrintError("Could not read instruction into buffer\n");
+ return -1;
+ }
- //PrintDebug("PDE Index=%d\n", PDE32_INDEX(first_operand));
- //PrintDebug("FirstOperand = %x\n", first_operand);
+ if (v3_decode(core, (addr_t)instr, &dec_instr) == -1) {
+ PrintError("Decoding Error\n");
+ return -1;
+ }
+
+ if ((dec_instr.op_type != V3_OP_INVLPG) ||
+ (dec_instr.num_operands != 1) ||
+ (dec_instr.dst_operand.type != MEM_OPERAND)) {
+ PrintError("Decoder Error: Not a valid INVLPG instruction...\n");
+ return -1;
+ }
- if (shadow_pde->large_page == 1) {
- shadow_pde->present = 0;
- } else {
- if (shadow_pde->present == 1) {
- pte32_t * shadow_pt = (pte32_t *)PDE32_T_ADDR((*shadow_pde));
- pte32_t * shadow_pte = (pte32_t *)&shadow_pt[PTE32_INDEX(first_operand)];
+ vaddr = dec_instr.dst_operand.operand;
- shadow_pte->present = 0;
- }
- }
+ core->rip += dec_instr.instr_length;
- info->rip += index;
+ {
+ struct v3_shdw_impl_state * state = &(core->vm_info->shdw_impl);
+ struct v3_shdw_pg_impl * impl = state->current_impl;
- } else {
- PrintDebug("Invalid Operand type\n");
- return -1;
- }
- } else {
- PrintDebug("invalid Instruction Opcode\n");
- PrintTraceMemDump(instr, 15);
- return -1;
+ return impl->handle_invlpg(core, vaddr);
}
- }
-
- return 0;
}
-/* Deprecated */
-/*
-addr_t setup_shadow_pt32(struct guest_info * info, addr_t virt_cr3) {
- addr_t cr3_guest_addr = CR3_TO_PDE32(virt_cr3);
- pde32_t * guest_pde;
- pde32_t * host_pde = NULL;
- int i;
-
- // Setup up guest_pde to point to the PageDir in host addr
- if (guest_pa_to_host_va(info, cr3_guest_addr, (addr_t*)&guest_pde) == -1) {
- return 0;
- }
-
- V3_AllocPages(host_pde, 1);
- memset(host_pde, 0, PAGE_SIZE);
-
- for (i = 0; i < MAX_PDE32_ENTRIES; i++) {
- if (guest_pde[i].present == 1) {
- addr_t pt_host_addr;
- addr_t host_pte;
-
- if (guest_pa_to_host_va(info, PDE32_T_ADDR(guest_pde[i]), &pt_host_addr) == -1) {
- return 0;
- }
- if ((host_pte = setup_shadow_pte32(info, pt_host_addr)) == 0) {
- return 0;
- }
- host_pde[i].present = 1;
- host_pde[i].pt_base_addr = PD32_BASE_ADDR(host_pte);
- //
- // Set Page DIR flags
- //
- }
- }
+int v3_inject_guest_pf(struct guest_info * core, addr_t fault_addr, pf_error_t error_code) {
+ core->ctrl_regs.cr2 = fault_addr;
- PrintDebugPageTables(host_pde);
+#ifdef CONFIG_SHADOW_PAGING_TELEMETRY
+ core->shdw_pg_state.guest_faults++;
+#endif
- return (addr_t)host_pde;
+ return v3_raise_exception_with_error(core, PF_EXCEPTION, *(uint_t *)&error_code);
}
+int v3_is_guest_pf(pt_access_status_t guest_access, pt_access_status_t shadow_access) {
+ /* basically the reasoning is that there can be multiple reasons for a page fault:
+ If there is a permissions failure for a page present in the guest _BUT_
+ the reason for the fault was that the page is not present in the shadow,
+ _THEN_ we have to map the shadow page in and reexecute, this will generate
+ a permissions fault which is _THEN_ valid to send to the guest
+ _UNLESS_ both the guest and shadow have marked the page as not present
-addr_t setup_shadow_pte32(struct guest_info * info, addr_t pt_host_addr) {
- pte32_t * guest_pte = (pte32_t *)pt_host_addr;
- pte32_t * host_pte = NULL;
- int i;
-
- V3_AllocPages(host_pte, 1);
- memset(host_pte, 0, PAGE_SIZE);
+ whew...
+ */
+ if (guest_access != PT_ACCESS_OK) {
+ // Guest Access Error
- for (i = 0; i < MAX_PTE32_ENTRIES; i++) {
- if (guest_pte[i].present == 1) {
- addr_t guest_pa = PTE32_T_ADDR(guest_pte[i]);
- shadow_mem_type_t page_type;
- addr_t host_pa = 0;
+ if ((shadow_access != PT_ACCESS_NOT_PRESENT) &&
+ (guest_access != PT_ACCESS_NOT_PRESENT)) {
+ // aka (guest permission error)
+ return 1;
+ }
- page_type = get_shadow_addr_type(info, guest_pa);
+ /*
+ if ((shadow_access == PT_ACCESS_NOT_PRESENT) &&
+ (guest_access == PT_ACCESS_NOT_PRESENT)) {
+ // Page tables completely blank, handle guest first
+ return 1;
+ }
+ */
- if (page_type == HOST_REGION_PHYSICAL_MEMORY) {
- host_pa = get_shadow_addr(info, guest_pa);
- } else {
+ if (guest_access == PT_ACCESS_NOT_PRESENT) {
+ // Page tables completely blank, handle guest first
+ return 1;
+ }
- //
- // Setup various memory types
- //
- }
-
- host_pte[i].page_base_addr = PT32_BASE_ADDR(host_pa);
- host_pte[i].present = 1;
+ // Otherwise we'll handle the guest fault later...?
}
- }
- return (addr_t)host_pte;
+ return 0;
}
-*/
+
