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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/tracing.txt | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/docs/tracing.txt b/docs/tracing.txt index f2f553bd4c..3182ee82ad 100644 --- a/docs/tracing.txt +++ b/docs/tracing.txt @@ -344,3 +344,44 @@ This will immediately call: and will generate the TCG code to call: void trace_foo(uint8_t a1, uint32_t a2); + +=== "vcpu" === + +Identifies events that trace vCPU-specific information. It implicitly adds a +"CPUState*" argument, and extends the tracing print format to show the vCPU +information. If used together with the "tcg" property, it adds a second +"TCGv_env" argument that must point to the per-target global TCG register that +points to the vCPU when guest code is executed (usually the "cpu_env" variable). + +The following example events: + + foo(uint32_t a) "a=%x" + vcpu bar(uint32_t a) "a=%x" + tcg vcpu baz(uint32_t a) "a=%x", "a=%x" + +Can be used as: + + #include "trace-tcg.h" + + CPUArchState *env; + TCGv_ptr cpu_env; + + void some_disassembly_func(...) + { + /* trace emitted at this point */ + trace_foo(0xd1); + /* trace emitted at this point */ + trace_bar(ENV_GET_CPU(env), 0xd2); + /* trace emitted at this point (env) and when guest code is executed (cpu_env) */ + trace_baz_tcg(ENV_GET_CPU(env), cpu_env, 0xd3); + } + +If the translating vCPU has address 0xc1 and code is later executed by vCPU +0xc2, this would be an example output: + + // at guest code translation + foo a=0xd1 + bar cpu=0xc1 a=0xd2 + baz_trans cpu=0xc1 a=0xd3 + // at guest code execution + baz_exec cpu=0xc2 a=0xd3 |