KVM: Use __print_symbolic() for vmexit tracepoints

The vmexit tracepoints format the exit_reason to make it human-readable.
Since the exit_reason depends on the instruction set (vmx or svm),
formatting is handled with ftrace_print_symbols_seq() by referring to
the appropriate exit reason table.

However, the ftrace_print_symbols_seq() function is not meant to be used
directly in tracepoints since it does not export the formatting table
which userspace tools like trace-cmd and perf use to format traces.

In practice perf dies when formatting vmexit-related events and
trace-cmd falls back to printing the numeric value (with extra
formatting code in the kvm plugin to paper over this limitation).  Other
userspace consumers of vmexit-related tracepoints would be in similar
trouble.

To avoid significant changes to the kvm_exit tracepoint, this patch
moves the vmx and svm exit reason tables into arch/x86/kvm/trace.h and
selects the right table with __print_symbolic() depending on the
instruction set.  Note that __print_symbolic() is designed for exporting
the formatting table to userspace and allows trace-cmd and perf to work.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 0 insertions, 44 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e65a158..e26629f 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6241,49 +6241,6 @@ static u64 vmx_get_mt_mask(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio)
 	return ret;
 }
 
-#define _ER(x) { EXIT_REASON_##x, #x }
-
-static const struct trace_print_flags vmx_exit_reasons_str[] = {
-	_ER(EXCEPTION_NMI),
-	_ER(EXTERNAL_INTERRUPT),
-	_ER(TRIPLE_FAULT),
-	_ER(PENDING_INTERRUPT),
-	_ER(NMI_WINDOW),
-	_ER(TASK_SWITCH),
-	_ER(CPUID),
-	_ER(HLT),
-	_ER(INVLPG),
-	_ER(RDPMC),
-	_ER(RDTSC),
-	_ER(VMCALL),
-	_ER(VMCLEAR),
-	_ER(VMLAUNCH),
-	_ER(VMPTRLD),
-	_ER(VMPTRST),
-	_ER(VMREAD),
-	_ER(VMRESUME),
-	_ER(VMWRITE),
-	_ER(VMOFF),
-	_ER(VMON),
-	_ER(CR_ACCESS),
-	_ER(DR_ACCESS),
-	_ER(IO_INSTRUCTION),
-	_ER(MSR_READ),
-	_ER(MSR_WRITE),
-	_ER(MWAIT_INSTRUCTION),
-	_ER(MONITOR_INSTRUCTION),
-	_ER(PAUSE_INSTRUCTION),
-	_ER(MCE_DURING_VMENTRY),
-	_ER(TPR_BELOW_THRESHOLD),
-	_ER(APIC_ACCESS),
-	_ER(EPT_VIOLATION),
-	_ER(EPT_MISCONFIG),
-	_ER(WBINVD),
-	{ -1, NULL }
-};
-
-#undef _ER
-
 static int vmx_get_lpage_level(void)
 {
 	if (enable_ept && !cpu_has_vmx_ept_1g_page())
@@ -7039,7 +6996,6 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.get_mt_mask = vmx_get_mt_mask,
 
 	.get_exit_info = vmx_get_exit_info,
-	.exit_reasons_str = vmx_exit_reasons_str,
 
 	.get_lpage_level = vmx_get_lpage_level,