* Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
* All rights reserved.
*
- * Author: Jack Lange <jarusl@cs.northwestern.edu>
+ * Authors: Jack Lange <jarusl@cs.northwestern.edu>
+ * Peter Dinda <pdinda@northwestern.edu> (full hook/string ops)
*
* This is free software. You are permitted to use,
* redistribute, and modify it as specified in the file "V3VEE_LICENSE".
/*
- 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
*/
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;
if (src_emulation_length<dst_emulation_length) {
emulation_length=src_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 if (src_emulation_length>dst_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
// 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;
}
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");
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");
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;
}
// 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);
}
}
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);
}
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");
