X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fvmm_shadow_paging.c;h=d11f85f7721a43bf29c2c85b635dadd0d1b7f8d4;hb=a71d13e84ccd2ea959299c7f01513e6f9e593b7d;hp=c9546e4d30bfece0df576771d146f085bba7e568;hpb=a109eb919a162bd7de58d62020801bc2e633be50;p=palacios.releases.git diff --git a/palacios/src/palacios/vmm_shadow_paging.c b/palacios/src/palacios/vmm_shadow_paging.c index c9546e4..d11f85f 100644 --- a/palacios/src/palacios/vmm_shadow_paging.c +++ b/palacios/src/palacios/vmm_shadow_paging.c @@ -1,209 +1,1036 @@ +/* + * 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 + * Copyright (c) 2008, The V3VEE Project + * All rights reserved. + * + * Author: Jack Lange + * + * This is free software. You are permitted to use, + * redistribute, and modify it as specified in the file "V3VEE_LICENSE". + */ + + #include + #include #include +#include +#include + +#ifndef DEBUG_SHADOW_PAGING +#undef PrintDebug +#define PrintDebug(fmt, args...) +#endif + + +/*** + *** There be dragons + ***/ + + + + + +DEFINE_HASHTABLE_INSERT(add_cr3_to_cache, addr_t, struct hashtable *); +DEFINE_HASHTABLE_SEARCH(find_cr3_in_cache, addr_t, struct hashtable *); +DEFINE_HASHTABLE_REMOVE(del_cr3_from_cache, addr_t, struct hashtable *, 0); -extern struct vmm_os_hooks * os_hooks; +DEFINE_HASHTABLE_INSERT(add_pte_map, addr_t, addr_t); +DEFINE_HASHTABLE_SEARCH(find_pte_map, addr_t, addr_t); +DEFINE_HASHTABLE_REMOVE(del_pte_map, addr_t, addr_t, 0); + + + +static uint_t pte_hash_fn(addr_t key) { + return hash_long(key, 32); +} + +static int pte_equals(addr_t key1, addr_t key2) { + return (key1 == key2); +} + +static uint_t cr3_hash_fn(addr_t key) { + return hash_long(key, 32); +} + +static int cr3_equals(addr_t key1, addr_t key2) { + return (key1 == key2); +} -int init_shadow_page_state(struct shadow_page_state * state) { - state->guest_mode = PDE32; - state->shadow_mode = PDE32; + + +static int activate_shadow_pt_32(struct guest_info * info); +static int activate_shadow_pt_32pae(struct guest_info * info); +static int activate_shadow_pt_64(struct guest_info * info); + + +static int handle_shadow_pagefault_32(struct guest_info * info, addr_t fault_addr, pf_error_t error_code); +static int handle_shadow_pagefault_32pae(struct guest_info * info, addr_t fault_addr, pf_error_t error_code); +static int handle_shadow_pagefault_64(struct guest_info * info, addr_t fault_addr, pf_error_t error_code); + +int v3_init_shadow_page_state(struct guest_info * info) { + struct shadow_page_state * state = &(info->shdw_pg_state); - state->guest_cr3.r_reg = 0; - state->shadow_cr3.r_reg = 0; + state->guest_cr3 = 0; + state->guest_cr0 = 0; + + state->cr3_cache = create_hashtable(0, &cr3_hash_fn, &cr3_equals); + + state->cached_cr3 = 0; + state->cached_ptes = NULL; + + return 0; +} + + + + +/* + For now we'll do something a little more lightweight +int cache_page_tables32(struct guest_info * info, addr_t pde) { + struct shadow_page_state * state = &(info->shdw_pg_state); + addr_t pde_host_addr; + pde32_t * tmp_pde; + struct hashtable * pte_cache = NULL; + int i = 0; + + + pte_cache = (struct hashtable *)find_cr3_in_cache(state->cr3_cache, pde); + if (pte_cache != NULL) { + PrintError("CR3 already present in cache\n"); + state->current_ptes = pte_cache; + return 1; + } else { + PrintError("Creating new CR3 cache entry\n"); + pte_cache = create_hashtable(0, &pte_hash_fn, &pte_equals); + state->current_ptes = pte_cache; + add_cr3_to_cache(state->cr3_cache, pde, pte_cache); + } + + if (guest_pa_to_host_va(info, pde, &pde_host_addr) == -1) { + PrintError("Could not lookup host address of guest PDE\n"); + return -1; + } + + tmp_pde = (pde32_t *)pde_host_addr; + + add_pte_map(pte_cache, pde, pde_host_addr); + + + for (i = 0; i < MAX_PDE32_ENTRIES; i++) { + if ((tmp_pde[i].present) && (tmp_pde[i].large_page == 0)) { + addr_t pte_host_addr; + + if (guest_pa_to_host_va(info, (addr_t)(PDE32_T_ADDR(tmp_pde[i])), &pte_host_addr) == -1) { + PrintError("Could not lookup host address of guest PDE\n"); + return -1; + } + + add_pte_map(pte_cache, (addr_t)(PDE32_T_ADDR(tmp_pde[i])), pte_host_addr); + } + } + return 0; } +*/ + + +int v3_cache_page_tables(struct guest_info * info, addr_t cr3) { + switch(v3_get_cpu_mode(info)) { + case PROTECTED: + return v3_cache_page_tables32(info, CR3_TO_PDE32_PA(cr3)); + default: + return -1; + } +} + +int v3_cache_page_tables32(struct guest_info * info, addr_t pde) { + struct shadow_page_state * state = &(info->shdw_pg_state); + addr_t pde_host_addr; + pde32_t * tmp_pde; + struct hashtable * pte_cache = NULL; + int i = 0; + + if (pde == state->cached_cr3) { + return 1; + } + + if (state->cached_ptes != NULL) { + hashtable_destroy(state->cached_ptes, 0, 0); + state->cached_ptes = NULL; + } + + state->cached_cr3 = pde; + + pte_cache = create_hashtable(0, &pte_hash_fn, &pte_equals); + state->cached_ptes = pte_cache; + + if (guest_pa_to_host_va(info, pde, &pde_host_addr) == -1) { + PrintError("Could not lookup host address of guest PDE\n"); + return -1; + } + + tmp_pde = (pde32_t *)pde_host_addr; + + add_pte_map(pte_cache, pde, pde_host_addr); + + + for (i = 0; i < MAX_PDE32_ENTRIES; i++) { + if ((tmp_pde[i].present) && (tmp_pde[i].large_page == 0)) { + addr_t pte_host_addr; + + if (guest_pa_to_host_va(info, (addr_t)(BASE_TO_PAGE_ADDR(tmp_pde[i].pt_base_addr)), &pte_host_addr) == -1) { + PrintError("Could not lookup host address of guest PDE\n"); + return -1; + } + + add_pte_map(pte_cache, (addr_t)(BASE_TO_PAGE_ADDR(tmp_pde[i].pt_base_addr)), pte_host_addr); + } + } + + return 0; + +} + + + +int v3_replace_shdw_page32(struct guest_info * info, addr_t location, pte32_t * new_page, pte32_t * old_page) { + pde32_t * shadow_pd = (pde32_t *)CR3_TO_PDE32_VA(info->ctrl_regs.cr3); + pde32_t * shadow_pde = (pde32_t *)&(shadow_pd[PDE32_INDEX(location)]); + + if (shadow_pde->large_page == 0) { + pte32_t * shadow_pt = (pte32_t *)(addr_t)BASE_TO_PAGE_ADDR(shadow_pde->pt_base_addr); + pte32_t * shadow_pte = (pte32_t *)&(shadow_pt[PTE32_INDEX(location)]); + + //if (shadow_pte->present == 1) { + *(uint_t *)old_page = *(uint_t *)shadow_pte; + //} + + *(uint_t *)shadow_pte = *(uint_t *)new_page; + + } else { + // currently unhandled + return -1; + } + return 0; +} -int wholesale_update_shadow_page_state(struct guest_info * guest_info) { - unsigned i, j; - pde32_t * guest_pde; - pde32_t * shadow_pde; - struct shadow_page_state * state = &(guest_info->shdw_pg_state); - // For now, we'll only work with PDE32 - if (state->guest_mode != PDE32) { + +// We assume that shdw_pg_state.guest_cr3 is pointing to the page tables we want to activate +// We also assume that the CPU mode has not changed during this page table transition +static int activate_shadow_pt_32(struct guest_info * info) { + struct cr3_32 * shadow_cr3 = (struct cr3_32 *)&(info->ctrl_regs.cr3); + struct cr3_32 * guest_cr3 = (struct cr3_32 *)&(info->shdw_pg_state.guest_cr3); + int cached = 0; + + // Check if shadow page tables are in the cache + cached = v3_cache_page_tables32(info, CR3_TO_PDE32_PA(*(addr_t *)guest_cr3)); + + if (cached == -1) { + PrintError("CR3 Cache failed\n"); + return -1; + } else if (cached == 0) { + addr_t shadow_pt; + + PrintDebug("New CR3 is different - flushing shadow page table %p\n", shadow_cr3 ); + delete_page_tables_32(CR3_TO_PDE32_VA(*(uint_t*)shadow_cr3)); + + shadow_pt = v3_create_new_shadow_pt(); + + shadow_cr3->pdt_base_addr = (addr_t)V3_PAddr((void *)(addr_t)PAGE_BASE_ADDR(shadow_pt)); + PrintDebug( "Created new shadow page table %p\n", (void *)(addr_t)shadow_cr3->pdt_base_addr ); + } else { + PrintDebug("Reusing cached shadow Page table\n"); + } + + shadow_cr3->pwt = guest_cr3->pwt; + shadow_cr3->pcd = guest_cr3->pcd; + + return 0; +} + +static int activate_shadow_pt_32pae(struct guest_info * info) { + PrintError("Activating 32 bit PAE page tables not implemented\n"); + return -1; +} + +static int activate_shadow_pt_64(struct guest_info * info) { + PrintError("Activating 64 bit page tables not implemented\n"); + return -1; +} + + +// 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 * info) { + switch (info->cpu_mode) { + + case PROTECTED: + return activate_shadow_pt_32(info); + case PROTECTED_PAE: + return activate_shadow_pt_32pae(info); + case LONG: + case LONG_32_COMPAT: + case LONG_16_COMPAT: + return activate_shadow_pt_64(info); + default: + PrintError("Invalid CPU mode: %d\n", info->cpu_mode); return -1; } - shadow_pde = (pde32_t *)(CR3_TO_PDE32(state->shadow_cr3.e_reg.low)); + return 0; +} + + +int v3_activate_passthrough_pt(struct guest_info * info) { + // For now... But we need to change this.... + // As soon as shadow paging becomes active the passthrough tables are hosed + // So this will cause chaos if it is called at that time - if (host_pa_to_host_va(CR3_TO_PDE32(state->guest_cr3.e_reg.low), (addr_t*)&guest_pde) != 0) { + info->ctrl_regs.cr3 = *(addr_t*)&(info->direct_map_pt); + //PrintError("Activate Passthrough Page tables not implemented\n"); + return 0; +} + + + +int v3_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 + +#ifdef DEBUG_SHADOW_PAGING + PrintPageTree(info->cpu_mode, fault_addr, info->ctrl_regs.cr3); +#endif + + return handle_special_page_fault(info, fault_addr, fault_addr, error_code); + } else if (info->mem_mode == VIRTUAL_MEM) { + + switch (info->cpu_mode) { + case PROTECTED: + return handle_shadow_pagefault_32(info, fault_addr, error_code); + break; + case PROTECTED_PAE: + return handle_shadow_pagefault_32pae(info, fault_addr, error_code); + case LONG: + return handle_shadow_pagefault_64(info, fault_addr, error_code); + break; + default: + PrintError("Unhandled CPU Mode\n"); + return -1; + } + } else { + PrintError("Invalid Memory mode\n"); return -1; } +} + +addr_t v3_create_new_shadow_pt() { + void * host_pde = 0; + + host_pde = V3_VAddr(V3_AllocPages(1)); + memset(host_pde, 0, PAGE_SIZE); - // Delete the current page table - delete_page_tables_pde32(shadow_pde); + return (addr_t)host_pde; +} - shadow_pde = os_hooks->allocate_pages(1); - state->shadow_cr3.e_reg.low = (addr_t)shadow_pde; +static void inject_guest_pf(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) { + info->ctrl_regs.cr2 = fault_addr; + v3_raise_exception_with_error(info, PF_EXCEPTION, *(uint_t *)&error_code); +} - state->shadow_mode = PDE32; - for (i = 0; i < MAX_PDE32_ENTRIES; i++) { - shadow_pde[i] = guest_pde[i]; +static int 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 - // The shadow can be identical to the guest if it's not present - if (!shadow_pde[i].present) { - continue; + whew... + */ + if (guest_access != PT_ACCESS_OK) { + // Guest Access Error + + if ((shadow_access != PT_ACCESS_NOT_PRESENT) && + (guest_access != PT_ACCESS_NOT_PRESENT)) { + // aka (guest permission error) + return 1; } - if (shadow_pde[i].large_pages) { - // large page - just map it through shadow map to generate its physical location - addr_t guest_addr = PAGE_ADDR(shadow_pde[i].pt_base_addr); - addr_t host_addr; - shadow_region_t * ent; + if ((shadow_access == PT_ACCESS_NOT_PRESENT) && + (guest_access == PT_ACCESS_NOT_PRESENT)) { + // Page tables completely blank, handle guest first + return 1; + } + + // Otherwise we'll handle the guest fault later...? + } + + return 0; +} + + + + +/* + * * + * * + * * 64 bit Page table fault handlers + * * + * * + */ + +static int handle_shadow_pagefault_64(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) { + PrintError("64 bit shadow paging not implemented\n"); + return -1; +} + + +/* + * * + * * + * * 32 bit PAE Page table fault handlers + * * + * * + */ + +static int handle_shadow_pagefault_32pae(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) { + PrintError("32 bit PAE shadow paging not implemented\n"); + return -1; +} + + + + + + + +/* + * * + * * + * * 32 bit Page table fault handlers + * * + * * + */ +static int handle_large_pagefault_32(struct guest_info * info, + addr_t fault_addr, pf_error_t error_code, + pte32_t * shadow_pt, pde32_4MB_t * large_guest_pde); + +static 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); + + +static int handle_shadow_pagefault_32(struct guest_info * info, addr_t fault_addr, pf_error_t error_code) { + pde32_t * guest_pd = NULL; + pde32_t * shadow_pd = CR3_TO_PDE32_VA(info->ctrl_regs.cr3); + addr_t guest_cr3 = CR3_TO_PDE32_PA(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)]); + + PrintDebug("Shadow page fault handler: %p\n", (void*) fault_addr ); + + if (guest_pa_to_host_va(info, guest_cr3, (addr_t*)&guest_pd) == -1) { + PrintError("Invalid Guest PDE Address: 0x%p\n", (void *)guest_cr3); + return -1; + } + + guest_pde = (pde32_t *)&(guest_pd[PDE32_INDEX(fault_addr)]); + + + // Check the guest page permissions + guest_pde_access = v3_can_access_pde32(guest_pd, fault_addr, error_code); + + // Check the shadow page permissions + shadow_pde_access = v3_can_access_pde32(shadow_pd, fault_addr, error_code); + + /* Was the page fault caused by the Guest's page tables? */ + if (is_guest_pf(guest_pde_access, shadow_pde_access) == 1) { + PrintDebug("Injecting PDE pf to guest: (guest access error=%d) (pf error code=%d)\n", + *(uint_t *)&guest_pde_access, *(uint_t *)&error_code); + inject_guest_pf(info, fault_addr, error_code); + return 0; + } + + + if (shadow_pde_access == PT_ACCESS_NOT_PRESENT) + { + pte32_t * shadow_pt = (pte32_t *)v3_create_new_shadow_pt(); - ent = get_shadow_region_by_addr(&(guest_info->mem_map), guest_addr); + shadow_pde->present = 1; + shadow_pde->user_page = guest_pde->user_page; + // shadow_pde->large_page = guest_pde->large_page; + shadow_pde->large_page = 0; - if (!ent) { - // FIXME Panic here - guest is trying to map to physical memory - // it does not own in any way! - return -1; - } - // FIXME Bounds check here to see if it's trying to trick us + // VMM Specific options + shadow_pde->write_through = 0; + shadow_pde->cache_disable = 0; + shadow_pde->global_page = 0; + // - switch (ent->host_type) { - case HOST_REGION_PHYSICAL_MEMORY: - // points into currently allocated physical memory, so we just - // set up the shadow to point to the mapped location - if (guest_pa_to_host_pa(guest_info, guest_addr, &host_addr)) { - // Panic here + guest_pde->accessed = 1; + + shadow_pde->pt_base_addr = PAGE_BASE_ADDR((addr_t)V3_PAddr(shadow_pt)); + + if (guest_pde->large_page == 0) { + shadow_pde->writable = guest_pde->writable; + } else { + // ?? What if guest pde is dirty a this point? + ((pde32_4MB_t *)guest_pde)->dirty = 0; + shadow_pde->writable = 0; + } + } + else if (shadow_pde_access == PT_ACCESS_OK) + { + // + // PTE fault + // + pte32_t * shadow_pt = (pte32_t *)V3_VAddr( (void*)(addr_t) BASE_TO_PAGE_ADDR(shadow_pde->pt_base_addr) ); + + if (guest_pde->large_page == 0) { + pte32_t * guest_pt = NULL; + if (guest_pa_to_host_va(info, BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr), (addr_t*)&guest_pt) == -1) { + // Machine check the guest + PrintDebug("Invalid Guest PTE Address: 0x%p\n", (void *)BASE_TO_PAGE_ADDR(guest_pde->pt_base_addr)); + v3_raise_exception(info, MC_EXCEPTION); + return 0; + } + + if (handle_shadow_pte32_fault(info, fault_addr, error_code, shadow_pt, guest_pt) == -1) { + PrintError("Error handling Page fault caused by PTE\n"); return -1; } + } else if (guest_pde->large_page == 1) { + if (handle_large_pagefault_32(info, fault_addr, error_code, shadow_pt, (pde32_4MB_t *)guest_pde) == -1) { + PrintError("Error handling large pagefault\n"); + return -1; + } + } + } + else if ((shadow_pde_access == PT_ACCESS_WRITE_ERROR) && + (guest_pde->large_page == 1) && + (((pde32_4MB_t *)guest_pde)->dirty == 0)) + { + // + // Page Directory Entry marked read-only + // Its a large page and we need to update the dirty bit in the guest + // - shadow_pde[i].pt_base_addr = PAGE_ALIGNED_ADDR(host_addr); - // FIXME set vmm_info bits here - break; - case HOST_REGION_UNALLOCATED: - // points to physical memory that is *allowed* but that we - // have not yet allocated. We mark as not present and set a - // bit to remind us to allocate it later - shadow_pde[i].present = 0; - // FIXME Set vminfo bits here so that we know that we will be - // allocating it later - break; - case HOST_REGION_NOTHING: - // points to physical memory that is NOT ALLOWED. - // We will mark it as not present and set a bit to remind - // us that it's bad later and insert a GPF then - shadow_pde[i].present = 0; - break; - case HOST_REGION_MEMORY_MAPPED_DEVICE: - case HOST_REGION_REMOTE: - case HOST_REGION_SWAPPED: - default: - // Panic. Currently unhandled - return -1; - break; + PrintDebug("Large page write error... Setting dirty bit and returning\n"); + ((pde32_4MB_t *)guest_pde)->dirty = 1; + shadow_pde->writable = guest_pde->writable; + return 0; + + } + else if (shadow_pde_access == PT_ACCESS_USER_ERROR) + { + // + // Page Directory Entry marked non-user + // + PrintDebug("Shadow Paging User access error (shadow_pde_access=0x%x, guest_pde_access=0x%x)\n", + shadow_pde_access, guest_pde_access); + inject_guest_pf(info, fault_addr, error_code); + return 0; + } + else + { + // inject page fault in guest + inject_guest_pf(info, fault_addr, error_code); + PrintDebug("Unknown Error occurred (shadow_pde_access=%d)\n", shadow_pde_access); + PrintDebug("Manual Says to inject page fault into guest\n"); +#ifdef DEBUG_SHADOW_PAGING + PrintDebug("Guest PDE: (access=%d)\n\t", guest_pde_access); + PrintPDE32(fault_addr, guest_pde); + PrintDebug("Shadow PDE: (access=%d)\n\t", shadow_pde_access); + PrintPDE32(fault_addr, shadow_pde); +#endif + + return 0; + } + + PrintDebug("Returning end of PDE function (rip=%p)\n", (void *)(addr_t)(info->rip)); + return 0; +} + + + +/* The guest status checks have already been done, + * only special case shadow checks remain + */ +static int handle_large_pagefault_32(struct guest_info * info, + addr_t fault_addr, pf_error_t error_code, + pte32_t * shadow_pt, pde32_4MB_t * large_guest_pde) +{ + pt_access_status_t shadow_pte_access = v3_can_access_pte32(shadow_pt, fault_addr, error_code); + pte32_t * shadow_pte = (pte32_t *)&(shadow_pt[PTE32_INDEX(fault_addr)]); + + if (shadow_pte_access == PT_ACCESS_OK) { + // Inconsistent state... + // Guest Re-Entry will flush tables and everything should now workd + PrintDebug("Inconsistent state... Guest re-entry should flush tlb\n"); + return 0; + } + + + if (shadow_pte_access == PT_ACCESS_NOT_PRESENT) { + // Get the guest physical address of the fault + addr_t guest_fault_pa = BASE_TO_PAGE_ADDR_4MB(large_guest_pde->page_base_addr) + PAGE_OFFSET_4MB(fault_addr); + host_region_type_t host_page_type = get_shadow_addr_type(info, guest_fault_pa); + + + if (host_page_type == HOST_REGION_INVALID) { + // Inject a machine check in the guest + PrintDebug("Invalid Guest Address in page table (0x%p)\n", (void *)guest_fault_pa); + v3_raise_exception(info, MC_EXCEPTION); + return 0; + } + + if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) { + struct shadow_page_state * state = &(info->shdw_pg_state); + addr_t shadow_pa = get_shadow_addr(info, guest_fault_pa); + + shadow_pte->page_base_addr = PAGE_BASE_ADDR(shadow_pa); + + shadow_pte->present = 1; + + /* We are assuming that the PDE entry has precedence + * so the Shadow PDE will mirror the guest PDE settings, + * and we don't have to worry about them here + * Allow everything + */ + shadow_pte->user_page = 1; + + if (find_pte_map(state->cached_ptes, PAGE_ADDR(guest_fault_pa)) != NULL) { + // Check if the entry is a page table... + PrintDebug("Marking page as Guest Page Table (large page)\n"); + shadow_pte->vmm_info = PT32_GUEST_PT; + shadow_pte->writable = 0; + } else { + shadow_pte->writable = 1; } + + + //set according to VMM policy + shadow_pte->write_through = 0; + shadow_pte->cache_disable = 0; + shadow_pte->global_page = 0; + // + } else { - pte32_t * guest_pte; - pte32_t * shadow_pte; - addr_t guest_addr; - addr_t guest_pte_host_addr; - shadow_region_t * ent; + // Handle hooked pages as well as other special pages + if (handle_special_page_fault(info, fault_addr, guest_fault_pa, error_code) == -1) { + PrintError("Special Page Fault handler returned error for address: %p\n", (void *)fault_addr); + return -1; + } + } + } else if ((shadow_pte_access == PT_ACCESS_WRITE_ERROR) && + (shadow_pte->vmm_info == PT32_GUEST_PT)) { + + struct shadow_page_state * state = &(info->shdw_pg_state); + PrintDebug("Write operation on Guest PAge Table Page (large page)\n"); + state->cached_cr3 = 0; + shadow_pte->writable = 1; + + } else { + PrintError("Error in large page fault handler...\n"); + PrintError("This case should have been handled at the top level handler\n"); + return -1; + } + + PrintDebug("Returning from large page fault handler\n"); + return 0; +} + + + - // small page - set PDE and follow down to the child table - shadow_pde[i] = guest_pde[i]; +/* + * We assume the the guest pte pointer has already been translated to a host virtual address + */ +static 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)]); + + + // Check the guest page permissions + guest_pte_access = v3_can_access_pte32(guest_pt, fault_addr, error_code); + + // Check the shadow page permissions + shadow_pte_access = v3_can_access_pte32(shadow_pt, fault_addr, error_code); + +#ifdef DEBUG_SHADOW_PAGING + PrintDebug("Guest PTE: (access=%d)\n\t", guest_pte_access); + PrintPTE32(fault_addr, guest_pte); + PrintDebug("Shadow PTE: (access=%d)\n\t", shadow_pte_access); + PrintPTE32(fault_addr, shadow_pte); +#endif + + /* Was the page fault caused by the Guest's page tables? */ + if (is_guest_pf(guest_pte_access, shadow_pte_access) == 1) { + PrintDebug("Access error injecting pf to guest (guest access error=%d) (pf error code=%d)\n", + guest_pte_access, *(uint_t*)&error_code); + inject_guest_pf(info, fault_addr, error_code); + return 0; + } + + + 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; + } - guest_addr = PAGE_ADDR(guest_pde[i].pt_base_addr); - // Allocate a new second level page table for the shadow - shadow_pte = os_hooks->allocate_pages(1); + if (shadow_pte_access == PT_ACCESS_NOT_PRESENT) { - // make our first level page table in the shadow point to it - shadow_pde[i].pt_base_addr = PAGE_ALIGNED_ADDR(shadow_pte); + addr_t guest_pa = BASE_TO_PAGE_ADDR((addr_t)(guest_pte->page_base_addr)) + PAGE_OFFSET(fault_addr); + + // Page Table Entry Not Present + PrintDebug("guest_pa =%p\n", (void *)guest_pa); + + 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 + PrintDebug("Invalid Guest Address in page table (0x%p)\n", (void *)guest_pa); + v3_raise_exception(info, MC_EXCEPTION); + return 0; + } + + // else... + + if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) { + struct shadow_page_state * state = &(info->shdw_pg_state); + addr_t shadow_pa = get_shadow_addr(info, guest_pa); + + shadow_pte->page_base_addr = PAGE_BASE_ADDR(shadow_pa); + + shadow_pte->present = guest_pte->present; + shadow_pte->user_page = guest_pte->user_page; - ent = get_shadow_region_by_addr(&(guest_info->mem_map), guest_addr); + //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 (find_pte_map(state->cached_ptes, PAGE_ADDR(guest_pa)) != NULL) { + // Check if the entry is a page table... + PrintDebug("Marking page as Guest Page Table %d\n", shadow_pte->writable); + shadow_pte->vmm_info = PT32_GUEST_PT; + } - /* JRL: This is bad.... */ - // For now the guest Page Table must always be mapped to host physical memory - /* If we swap out a page table or if it isn't present for some reason, this turns real ugly */ + 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; + + if (shadow_pte->vmm_info == PT32_GUEST_PT) { + // Well that was quick... + struct shadow_page_state * state = &(info->shdw_pg_state); + PrintDebug("Immediate Write operation on Guest PAge Table Page\n"); + state->cached_cr3 = 0; + } - if ((!ent) || (ent->host_type != HOST_REGION_PHYSICAL_MEMORY)) { - // FIXME Panic here - guest is trying to map to physical memory - // it does not own in any way! - return -1; + } else if ((guest_pte->dirty == 0) && (error_code.write == 0)) { // was = + shadow_pte->writable = 0; } - // Address of the relevant second level page table in the guest - if (guest_pa_to_host_pa(guest_info, guest_addr, &guest_pte_host_addr)) { - // Panic here + + + } else { + // Page fault handled by hook functions + if (handle_special_page_fault(info, fault_addr, guest_pa, error_code) == -1) { + PrintError("Special Page fault handler returned error for address: %p\n", (void *)fault_addr); return -1; } + } + } else if ((shadow_pte_access == PT_ACCESS_WRITE_ERROR) && + (guest_pte->dirty == 0)) { - // host_addr now contains the host physical address for the guest's 2nd level page table - // Now we transform it to relevant virtual address - guest_pte = os_hooks->paddr_to_vaddr((void *)guest_pte_host_addr); + PrintDebug("Shadow PTE Write Error\n"); + guest_pte->dirty = 1; + shadow_pte->writable = guest_pte->writable; + + if (shadow_pte->vmm_info == PT32_GUEST_PT) { + struct shadow_page_state * state = &(info->shdw_pg_state); + PrintDebug("Write operation on Guest PAge Table Page\n"); + state->cached_cr3 = 0; + } + + return 0; + + } else { + // Inject page fault into the guest + inject_guest_pf(info, fault_addr, error_code); + PrintError("PTE Page fault fell through... Not sure if this should ever happen\n"); + PrintError("Manual Says to inject page fault into guest\n"); + return -1; + } + + PrintDebug("Returning end of function\n"); + return 0; +} - // Now we walk through the second level guest page table - // and clone it into the shadow - for (j = 0; j < MAX_PTE32_ENTRIES; j++) { - shadow_pte[j] = guest_pte[j]; - addr_t guest_addr = PAGE_ADDR(shadow_pte[j].page_base_addr); - - shadow_region_t * ent; - ent = get_shadow_region_by_addr(&(guest_info->mem_map), guest_addr); + + + +/* Currently Does not work with Segmentation!!! */ +int v3_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 + PrintError("ERROR: INVLPG called in non paged mode\n"); + return -1; + } + + + if (info->cpu_mode != PROTECTED) { + return 0; + } + + uchar_t instr[15]; + int index = 0; + + int ret = read_guest_va_memory(info, get_addr_linear(info, info->rip, &(info->segments.cs)), 15, instr); + if (ret != 15) { + PrintError("Could not read instruction 0x%p (ret=%d)\n", (void *)(addr_t)(info->rip), ret); + return -1; + } + + + /* Can INVLPG work with Segments?? */ + while (is_prefix_byte(instr[index])) { + index++; + } + + + if( (instr[index + 0] != (uchar_t) 0x0f) || + (instr[index + 1] != (uchar_t) 0x01) ) { + PrintError("invalid Instruction Opcode\n"); + PrintTraceMemDump(instr, 15); + return -1; + } + + addr_t first_operand; + addr_t second_operand; + addr_t guest_cr3 = CR3_TO_PDE32_PA(info->shdw_pg_state.guest_cr3); + + pde32_t * guest_pd = NULL; + + if (guest_pa_to_host_va(info, guest_cr3, (addr_t*)&guest_pd) == -1) { + PrintError("Invalid Guest PDE Address: 0x%p\n", (void *)guest_cr3); + return -1; + } + + index += 2; + + v3_operand_type_t addr_type = decode_operands32(&(info->vm_regs), instr + index, &index, &first_operand, &second_operand, REG32); + + if (addr_type != MEM_OPERAND) { + PrintError("Invalid Operand type\n"); + return -1; + } + + pde32_t * shadow_pd = (pde32_t *)CR3_TO_PDE32_VA(info->ctrl_regs.cr3); + pde32_t * shadow_pde = (pde32_t *)&shadow_pd[PDE32_INDEX(first_operand)]; + pde32_t * guest_pde; + + //PrintDebug("PDE Index=%d\n", PDE32_INDEX(first_operand)); + //PrintDebug("FirstOperand = %x\n", first_operand); + + PrintDebug("Invalidating page for %p\n", (void *)first_operand); + + guest_pde = (pde32_t *)&(guest_pd[PDE32_INDEX(first_operand)]); + + if (guest_pde->large_page == 1) { + shadow_pde->present = 0; + PrintDebug("Invalidating Large Page\n"); + } else + if (shadow_pde->present == 1) { + pte32_t * shadow_pt = (pte32_t *)(addr_t)BASE_TO_PAGE_ADDR(shadow_pde->pt_base_addr); + pte32_t * shadow_pte = (pte32_t *) V3_VAddr( (void*) &shadow_pt[PTE32_INDEX(first_operand)] ); - if (!ent) { - // FIXME Panic here - guest is trying to map to physical memory - // it does not own in any way! - return -1; - } +#ifdef DEBUG_SHADOW_PAGING + PrintDebug("Setting not present\n"); + PrintPTE32(first_operand, shadow_pte ); +#endif + + shadow_pte->present = 0; + } + + info->rip += index; + + return 0; +} - switch (ent->host_type) { - case HOST_REGION_PHYSICAL_MEMORY: - { - addr_t host_addr; - - // points into currently allocated physical memory, so we just - // set up the shadow to point to the mapped location - if (guest_pa_to_host_pa(guest_info, guest_addr, &host_addr)) { - // Panic here - return -1; - } - - shadow_pte[j].page_base_addr = PAGE_ALIGNED_ADDR(host_addr); - // FIXME set vmm_info bits here - break; - } - case HOST_REGION_UNALLOCATED: - // points to physical memory that is *allowed* but that we - // have not yet allocated. We mark as not present and set a - // bit to remind us to allocate it later - shadow_pte[j].present = 0; - // FIXME Set vminfo bits here so that we know that we will be - // allocating it later - break; - case HOST_REGION_NOTHING: - // points to physical memory that is NOT ALLOWED. - // We will mark it as not present and set a bit to remind - // us that it's bad later and insert a GPF then - shadow_pte[j].present = 0; - break; - case HOST_REGION_MEMORY_MAPPED_DEVICE: - case HOST_REGION_REMOTE: - case HOST_REGION_SWAPPED: - default: - // Panic. Currently unhandled - return -1; - break; - } - } + +/* + + +static int create_pd32_nonaligned_4MB_page(struct guest_info * info, pte32_t * pt, addr_t guest_addr, pde32_4MB_t * large_shadow_pde) { + uint_t i = 0; + pte32_t * pte_cursor; + addr_t guest_pa = 0; + + for (i = 0; i < 1024; i++) { + guest_pa = guest_addr + (PAGE_SIZE * i); + host_region_type_t host_page_type = get_shadow_addr_type(info, guest_pa); + + pte_cursor = &(pt[i]); + + if (host_page_type == HOST_REGION_INVALID) { + // Currently we don't support this, but in theory we could + PrintError("Invalid Host Memory Type\n"); + return -1; + } else if (host_page_type == HOST_REGION_PHYSICAL_MEMORY) { + addr_t shadow_pa = get_shadow_addr(info, guest_pa); + + + pte_cursor->page_base_addr = PT32_BASE_ADDR(shadow_pa); + pte_cursor->present = 1; + pte_cursor->writable = large_shadow_pde->writable; + pte_cursor->user_page = large_shadow_pde->user_page; + pte_cursor->write_through = 0; + pte_cursor->cache_disable = 0; + pte_cursor->global_page = 0; + + } else { + PrintError("Unsupported Host Memory Type\n"); + return -1; } } return 0; } + + +static int handle_large_pagefault32(struct guest_info * info, + pde32_t * guest_pde, pde32_t * shadow_pde, + addr_t fault_addr, pf_error_t error_code ) { + 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 + + + // Check that the Guest PDE entry points to valid memory + // else Machine Check the guest + PrintDebug("Large Page: Page Base Addr=%x\n", guest_start_addr); + + host_page_type = get_shadow_addr_type(info, guest_start_addr); + + if (host_page_type == HOST_REGION_INVALID) { + PrintError("Invalid guest address in large page (0x%x)\n", guest_start_addr); + v3_raise_exception(info, MC_EXCEPTION); + 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); + PrintDebug("Host region: host_addr=%x (guest_start=%x, end=%x)\n", + mem_reg->host_addr, mem_reg->guest_start, mem_reg->guest_end); + 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); + + PrintDebug("Host Start Addr=%x; Region End Addr=%x\n", host_start_addr, region_end_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; + } + + + // Check if the region is at least an additional 4MB + + + //4b. + if ((PD32_4MB_PAGE_OFFSET(host_start_addr) == 0) && + (region_end_addr >= host_start_addr + PAGE_SIZE_4MB)) { // if 4MB boundary + large_shadow_pde->page_base_addr = PD32_4MB_BASE_ADDR(host_start_addr); + } else { // else generate 4k pages + pte32_t * shadow_pt = NULL; + PrintDebug("Handling non aligned large page\n"); + + shadow_pde->large_page = 0; + shadow_pt = create_new_shadow_pt32(); + if (create_pd32_nonaligned_4MB_page(info, shadow_pt, guest_start_addr, large_shadow_pde) == -1) { + PrintError("Non Aligned Large Page Error\n"); + V3_Free(shadow_pt); + return -1; + } + + +#ifdef DEBUG_SHADOW_PAGING + PrintDebug("non-aligned Shadow PT\n"); + PrintPT32(PT32_PAGE_ADDR(fault_addr), shadow_pt); +#endif + shadow_pde->pt_base_addr = PD32_BASE_ADDR(shadow_pt); + } + + } else { + // Handle hooked pages as well as other special pages + if (handle_special_page_fault(info, fault_addr, guest_start_addr, error_code) == -1) { + PrintError("Special Page Fault handler returned error for address: %x\n", fault_addr); + return -1; + } + } + + return 0; +} +*/