Trace Format¶

• Table of contents
• Trace Format
  • Instruction record
  • Memory access record
  • Register write record

QEMU4V is able to generate traces of program execution. Here is the description of the trace format.
The QEMU4V trace contains records of the following kinds: instruction records, memory access records, register write records.

Instruction record¶

Appears in the trace when the corresponding instruction from the target program has been executed.
The record format is as follows:

<time> <scale> <cpu> [IT|IS] (<inst_id>) <addr> <opcode> [A|T|X] <mode>_<security> : <disasm>

The record fields are described in the following table:

Field	Description	Value
<time>	Timestamp	Decimal integer value
<scale>	Timestamp unit	String (the clk value means, that the timestamp field shows not physical time but the inex of executed instruction)
<cpu>	Identifier for the processor at which the instruction is executed	Decimal integer value
[IT|IS]	Instruction execution flag	IT when "Instruction Taken", IS when "Instruction Skipped"
<inst_id>	Index of the executed instruction	Decimal integer value
<addr>	Virtual memory address for the instruction	Hexadecimal value
<opcode>	16\32\64-bit code for the instruction	Hexadecimal value
[A|T|X]	Instruction set identifier	TODO
<mode>	Execution mode	String (one of the following: svc, irq, fiq, usr, mon, sys, abt, und)
<security>	Flag for the processor security mode	s when "secure", ns when "non-secure"
<disasm>	Disassembly representation for the instruction	String

Example:

1 clk 0 IT (1) 00000004 3c080001 A svc : lui t0,0x1

Memory access record¶

Appears in the trace when reading from or writing to memory starts.

The record format is as follows:

<time> <scale> M<rw><sz><attrib> <addr> <data>

The record fields are described in the following table:

Field	Description	Value
<time>	Timestamp	Decimal integer value
<scale>	Timestamp unit	String (the clk value means, that the timestamp field shows not physical time but the inex of executed instruction)
<rw>	Type of access	R for reading, W for writing
<sz>	Size of received\transmitted data in bytes	Decimal integer value
<attrib>	Access attribute (optional)	X for privileged, T for non-privileged (translated)
<addr>	Virtual memory address to which an access is made	Hexadecimal value
<data>	The data to be written (has been read)	Hexadecimal value of the corresponding size

Example:

10 clk MR8 00103fc4 0010400000000000

Register write record¶

Appears in the trace when writing to register happens.

The record format is as follows:

<time> <scale> R <register> <value>

The record fields are described in the following table:

Field	Description	Value
<time>	Timestamp	Decimal integer value
<scale>	Timestamp unit	String (the clk value means, that the timestamp field shows not physical time but the inex of executed instruction)
<register>	Name of register	lowercase string
<value>	The value to be written in the register	Hexadecimal value

Example:

14 clk R r8 00000000