X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fvmm_emulator.c;h=f37135600ebc8d8f2c97b2cd72a6beb3813afa40;hb=0f2e5f3934c769e0e76f290b80b0647dcfc3ade2;hp=1a0e8687a3d6a8bab06e0eadd199d27eb7845b45;hpb=433cc616000bbede723288f391e01a7750f230f6;p=palacios.git diff --git a/palacios/src/palacios/vmm_emulator.c b/palacios/src/palacios/vmm_emulator.c index 1a0e868..f371356 100644 --- a/palacios/src/palacios/vmm_emulator.c +++ b/palacios/src/palacios/vmm_emulator.c @@ -11,7 +11,8 @@ * Copyright (c) 2008, The V3VEE Project * All rights reserved. * - * Author: Jack Lange + * Authors: Jack Lange + * Peter Dinda (full hook/string ops) * * This is free software. You are permitted to use, * redistribute, and modify it as specified in the file "V3VEE_LICENSE". @@ -150,8 +151,11 @@ static int emulate_string_write_op(struct guest_info * info, struct x86_instr * /* - This function is intended to handle pure read hooks, pure write hook, and full hooks, - with and without backing memory for writes + This function is intended to handle pure read hooks, pure write hooks, and full hooks, + with and without backing memory for reads and writes + + A MAXIMUM OF ONE PAGE IS TRANSFERED BUT REGISTERS ARE UPDATED SO THAT + THE INSTRUCTION CAN BE RESTARTED read_fn == NULL orig_src_addr == NULL => data at read_gpa is read @@ -168,29 +172,38 @@ static int emulate_string_write_op(struct guest_info * info, struct x86_instr * */ static int emulate_string_op(struct guest_info * info, struct x86_instr * dec_instr, - addr_t read_gva, addr_t read_gpa, addr_t orig_src_addr, - addr_t write_gva, addr_t write_gpa, addr_t orig_dst_addr, + addr_t read_gva, addr_t read_gpa, addr_t read_hva, + addr_t write_gva, addr_t write_gpa, addr_t write_hva, int (*read_fn)(struct guest_info * core, addr_t guest_addr, void * src, uint_t length, void * priv_data), - int (*write_fn)(struct guest_info * core, addr_t guest_addr, void * dst, uint_t length, void * priv_data), - void * priv_data) + void * read_priv_data, + int (*write_fn)(struct guest_info * core, addr_t guest_addr, void * dst, uint_t length, void * priv_data), + void * write_priv_data) { uint_t src_emulation_length = 0; uint_t dst_emulation_length = 0; uint_t emulation_length = 0; uint_t emulation_iter_cnt = 0; addr_t tmp_rcx = 0; - addr_t src_addr, dst_addr; + addr_t src_hva, dst_hva; + + PrintDebug("emulate_string_op: read_gva=0x%p, read_gpa=0x%p, read_hva=0x%p, write_gva=0x%p, write_gpa=0x%p, write_hva=0x%p, read_fn=0x%p, read_priv_data=0x%p, write_fn=0x%p, write_priv_data=0x%p, len=0x%p\n", + (void*)read_gva,(void*)read_gpa,(void*)read_hva, (void*)write_gva,(void*)write_gpa,(void*)write_hva, + (void*)read_fn, (void*)read_priv_data, (void*)write_fn, (void*)write_priv_data, (void*)(dec_instr->str_op_length)); + + // v3_print_instr(dec_instr); // Sanity check the decoded instruction if (info->shdw_pg_mode == SHADOW_PAGING) { - if (!read_fn && (dec_instr->src_operand.operand != read_gva)) { + // If we're reading, we better have a sane gva + if ((read_hva || read_fn) && (dec_instr->src_operand.operand != read_gva)) { PrintError("Inconsistency between Pagefault and Instruction Decode XED_ADDR=%p, PF_ADDR=%p (Read)\n", (void *)dec_instr->src_operand.operand, (void *)read_gva); return -1; } - if (!write_fn && (dec_instr->dst_operand.operand != write_gva)) { + // if we're writing, we better have a sane gva + if ((write_hva || write_fn) && (dec_instr->dst_operand.operand != write_gva)) { PrintError("Inconsistency between Pagefault and Instruction Decode XED_ADDR=%p, PF_ADDR=%p (Write)\n", (void *)dec_instr->dst_operand.operand, (void *)write_gva); return -1; @@ -230,9 +243,11 @@ static int emulate_string_op(struct guest_info * info, struct x86_instr * dec_in if (src_emulation_lengthdst_emulation_length) { emulation_length=dst_emulation_length; + // Note that this error is what is to be expected if you're coping to a different offset on a page PrintError("Warning: emulate_string_op has src length %u but dst length %u\n", src_emulation_length, dst_emulation_length); } else { // equal @@ -243,60 +258,74 @@ static int emulate_string_op(struct guest_info * info, struct x86_instr * dec_in // Fetch the data if (read_fn) { - src_addr = (addr_t) V3_Malloc(emulation_length); // hideous - should reuse memory - if (!src_addr) { + // This is a full hook - full hooks never have backing memory + // This should use the scratch page allocated for the hook, but + // we do not know where that is at this point + src_hva = (addr_t) V3_Malloc(emulation_length); // hideous - should reuse memory + if (!src_hva) { PrintError("Unable to allocate space for read operation in emulate_string_read_op\n"); return -1; } - if (read_fn(info, read_gpa, (void *)src_addr, emulation_length, priv_data) != emulation_length) { + if (read_fn(info, read_gpa, (void *)src_hva, emulation_length, read_priv_data) != emulation_length) { PrintError("Did not fully read hooked data in emulate_string_op\n"); return -1; } } else { - if (orig_src_addr) { - src_addr=orig_src_addr; + // This is ordinary memory + if (read_hva) { + // The caller told us where to read from + src_hva=read_hva; } else { + // We need to figure out where to read from if (info->mem_mode == PHYSICAL_MEM) { - if (v3_gpa_to_hva(info, dec_instr->src_operand.operand, &src_addr) == -1) { + if (v3_gpa_to_hva(info, dec_instr->src_operand.operand, &src_hva) == -1) { PrintError("Could not translate write Source (Physical) to host VA\n"); return -1; } } else { - if (v3_gva_to_hva(info, dec_instr->src_operand.operand, &src_addr) == -1) { + if (v3_gva_to_hva(info, dec_instr->src_operand.operand, &src_hva) == -1) { PrintError("Could not translate write Source (Virtual) to host VA\n"); return -1; - } + } } } } - // Now src_addr points to the fetched data in HVA + // Now src_hva points to the fetched data or to the in-VM data // Allocate space for the write, in case we need to copy out later if (write_fn) { - if (orig_dst_addr) { - dst_addr=orig_dst_addr; + // This is a full hook or a write hook + if (write_hva) { + // This is a write hook with backing memory + // The caller already told us where that memory is + dst_hva = write_hva; } else { - dst_addr = (addr_t) V3_Malloc(emulation_length); // yuck - if (!dst_addr) { + // This is a full hook without backing memory + // Again, should use the scratch memory + dst_hva = (addr_t) V3_Malloc(emulation_length); // yuck + if (!dst_hva) { PrintError("Unable to allocate space for write operation in emulate_string_op\n"); if (read_fn) { - V3_Free((void*)src_addr); + V3_Free((void*)src_hva); } return -1; } } } else { - if (orig_dst_addr) { - dst_addr=orig_dst_addr; + // This is ordinary memory + if (write_hva) { + // The caller told us where to write + dst_hva=write_hva; } else { + // We need to figure out where to write if (info->mem_mode == PHYSICAL_MEM) { - if (v3_gpa_to_hva(info, dec_instr->dst_operand.operand, &dst_addr) == -1) { + if (v3_gpa_to_hva(info, dec_instr->dst_operand.operand, &dst_hva) == -1) { PrintError("Could not translate write Dest (Physical) to host VA\n"); return -1; } } else { - if (v3_gva_to_hva(info, dec_instr->dst_operand.operand, &dst_addr) == -1) { + if (v3_gva_to_hva(info, dec_instr->dst_operand.operand, &dst_hva) == -1) { PrintError("Could not translate write Dest (Virtual) to host VA\n"); return -1; } @@ -311,19 +340,24 @@ static int emulate_string_op(struct guest_info * info, struct x86_instr * dec_in tmp_rcx = emulation_iter_cnt; + // Do the actual emulation + // The instruction implementation operates from data at src_hva to data at dest_hva + // Furthemore, it must operate for emulation_length steps + // And update tmp_rcx + // And the real rcx if we do have a rep prefix switch (dec_instr->op_type) { case V3_OP_MOVS: { if (dec_instr->dst_operand.size == 1) { - movs8((addr_t *)&dst_addr, &src_addr, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); + movs8((addr_t *)&dst_hva, &src_hva, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); } else if (dec_instr->dst_operand.size == 2) { - movs16((addr_t *)&dst_addr, &src_addr, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); + movs16((addr_t *)&dst_hva, &src_hva, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); } else if (dec_instr->dst_operand.size == 4) { - movs32((addr_t *)&dst_addr, &src_addr, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); + movs32((addr_t *)&dst_hva, &src_hva, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); #ifdef __V3_64BIT__ } else if (dec_instr->dst_operand.size == 8) { - movs64((addr_t *)&dst_addr, &src_addr, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); + movs64((addr_t *)&dst_hva, &src_hva, &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); #endif } else { PrintError("Invalid operand length\n"); @@ -346,14 +380,14 @@ static int emulate_string_op(struct guest_info * info, struct x86_instr * dec_in case V3_OP_STOS: { if (dec_instr->dst_operand.size == 1) { - stos8((addr_t *)&dst_addr, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); + stos8((addr_t *)&dst_hva, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); } else if (dec_instr->dst_operand.size == 2) { - stos16((addr_t *)&dst_addr, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); + stos16((addr_t *)&dst_hva, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); } else if (dec_instr->dst_operand.size == 4) { - stos32((addr_t *)&dst_addr, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); + stos32((addr_t *)&dst_hva, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); #ifdef __V3_64BIT__ } else if (dec_instr->dst_operand.size == 8) { - stos64((addr_t *)&dst_addr, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); + stos64((addr_t *)&dst_hva, (addr_t *)&(info->vm_regs.rax), &tmp_rcx, (addr_t *)&(info->ctrl_regs.rflags)); #endif } else { PrintError("Invalid operand length\n"); @@ -377,16 +411,19 @@ static int emulate_string_op(struct guest_info * info, struct x86_instr * dec_in break; } - // At this point, the data has been written over dst_addr, which - // is either our temporary buffer, or it's the requested target in orig_dst_addr + // At this point, the data has been written over dst_hva, which + // is either our temporary buffer, or it's the requested target in write_hva if (write_fn) { - if (write_fn(info, write_gpa, (void *)dst_addr, emulation_length, priv_data) != emulation_length) { + if (write_fn(info, write_gpa, (void *)dst_hva, emulation_length, write_priv_data) != emulation_length) { PrintError("Did not fully write hooked data\n"); return -1; } } + // We only goto the next instruction if we have finished operating on all the data. + // If we haven't we'll restart the same instruction, but with rdi/rsi/rcx updated + // This is also how we handle going over a page boundary if (emulation_length == dec_instr->str_op_length) { info->rip += dec_instr->instr_length; } @@ -394,10 +431,10 @@ static int emulate_string_op(struct guest_info * info, struct x86_instr * dec_in // Delete temporary buffers if (read_fn) { - V3_Free((void*)src_addr); + V3_Free((void*)src_hva); } - if (write_fn && !orig_dst_addr) { - V3_Free((void*)dst_addr); + if (write_fn && !write_hva) { + V3_Free((void*)dst_hva); } @@ -679,11 +716,102 @@ int v3_emulate_read_op(struct guest_info * info, addr_t read_gva, addr_t read_gp } if (dec_instr.is_str_op) { + // We got here due to a read fault due to a full memory hook on the + // region being READ. Thus our current write_fn is also for that region + // We need the region that will be WRITTEN, which we need to look up + // That region could be write or full hooked, in which case we need + // the associated write function for that region. If it's not + // hooked, then we need the relevant hva + // + // This all assumes that emulate_string_op() will handle at most + // a single page. Therefore we can consider only the starting pages + // for the read and write sides. We will restart the instruction on + // the next page, if needed. + addr_t write_gpa=0; + addr_t write_gva=0; + addr_t write_hva=0; + int (*dest_write_fn)(struct guest_info * core, addr_t guest_addr, void * src, uint_t length, void * priv_data)=0; + void *dest_write_priv_data; + struct v3_mem_region *dest_reg; + + if (dec_instr.dst_operand.type != MEM_OPERAND) { + write_gpa=0; + write_gva=0; + write_hva=0; // should calc target here and continue + dest_write_fn=0; + dest_write_priv_data=0; + PrintError("Emulation of string ops with non-memory destinations currently unsupported\n"); + v3_print_instr(&dec_instr); + return -1; + } else { + if (info->mem_mode == PHYSICAL_MEM) { + write_gpa = dec_instr.dst_operand.operand; + write_gva = write_gpa; + } else { + write_gva = dec_instr.dst_operand.operand; + if (v3_gva_to_gpa(info, dec_instr.dst_operand.operand, &write_gpa) == -1) { + // We are going to inject "Not Present" here to try to force + // the guest to build a PTE we can use. + // This needs to be fixed to inject the appropraite page fault + // given access permissions + struct pf_error_code c; + c.present=0; + c.write=0; + c.user=0; + c.rsvd_access=0; + c.ifetch=0; + c.rsvd=0; + v3_inject_guest_pf(info,write_gva,c); + return 0; + } + } + + // First we need to find the region to determine if we will need to write + // back to it and to check access + if (!(dest_reg=v3_get_mem_region(info->vm_info,info->cpu_id,write_gpa))) { + PrintError("Could not look up region for destination of string op\n"); + v3_print_instr(&dec_instr); + return -1; + } + + + if (dest_reg->flags.alloced) { + // We will need to write back to memory in addition to any hook function + if (v3_gpa_to_hva(info, write_gpa, &write_hva) == -1) { + PrintError("Unable to convert gpa to hva in emulation of string op write\n"); + v3_print_instr(&dec_instr); + return -1; + } + } else { + write_hva=0; // no actual writeback - hook function only + } + + // Now that we have the write_gpa, we need to find out whether it's a hooked region + // or just plain memory + + if (v3_find_mem_hook(info->vm_info, info->cpu_id, write_gpa, + 0, 0, // don't want the read function/data even if they exist + &dest_write_fn,&dest_write_priv_data) == -1) { + PrintError("Finding write destination memory hook failed\n"); + v3_print_instr(&dec_instr); + return -1; + } + + // We must have either or both of a write_hva and a dest_write_fn + if (!dest_write_fn && !write_hva) { + PrintError("Destination of string write has neither physical memory nor write hook!\n"); + v3_print_instr(&dec_instr); + return -1; + } + } + + return emulate_string_op(info,&dec_instr, - read_gva,read_gpa,0, - 0, 0, 0, - read_fn,write_fn, - priv_data); + read_gva,read_gpa, 0, // 0=> read hook has no backing memory + write_gva, write_gpa, write_hva, + read_fn, priv_data, // This is from the original call + dest_write_fn, dest_write_priv_data); // This is from our lookup + } else if (dec_instr.op_type == V3_OP_XCHG) { return emulate_xchg_read_op(info, &dec_instr, read_gva, read_gpa, src_addr, read_fn, write_fn, priv_data); } @@ -720,8 +848,8 @@ int v3_emulate_read_op(struct guest_info * info, addr_t read_gva, addr_t read_gp src_op_len = dec_instr.src_operand.size; dst_op_len = dec_instr.dst_operand.size; - PrintDebug("Dst_Addr = %p, SRC Addr = %p\n", - (void *)dst_addr, (void *)src_addr); + PrintDebug("Dst_Addr = %p, SRC Addr = %p\n", + (void *)dst_addr, (void *)src_addr); if (read_fn(info, read_gpa, (void *)src_addr, src_op_len, priv_data) != src_op_len) { PrintError("Did not fully read hooked data\n");