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>

3 files changed, 100 insertions, 105 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 6adb7ba13a4..2b24a88f2c6 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3899,60 +3899,6 @@ static void svm_set_supported_cpuid(u32 func, struct kvm_cpuid_entry2 *entry)
         }
 }
 
-static const struct trace_print_flags svm_exit_reasons_str[] = {
-        { SVM_EXIT_READ_CR0,                    "read_cr0" },
-        { SVM_EXIT_READ_CR3,                    "read_cr3" },
-        { SVM_EXIT_READ_CR4,                    "read_cr4" },
-        { SVM_EXIT_READ_CR8,                    "read_cr8" },
-        { SVM_EXIT_WRITE_CR0,                   "write_cr0" },
-        { SVM_EXIT_WRITE_CR3,                   "write_cr3" },
-        { SVM_EXIT_WRITE_CR4,                   "write_cr4" },
-        { SVM_EXIT_WRITE_CR8,                   "write_cr8" },
-        { SVM_EXIT_READ_DR0,                    "read_dr0" },
-        { SVM_EXIT_READ_DR1,                    "read_dr1" },
-        { SVM_EXIT_READ_DR2,                    "read_dr2" },
-        { SVM_EXIT_READ_DR3,                    "read_dr3" },
-        { SVM_EXIT_WRITE_DR0,                   "write_dr0" },
-        { SVM_EXIT_WRITE_DR1,                   "write_dr1" },
-        { SVM_EXIT_WRITE_DR2,                   "write_dr2" },
-        { SVM_EXIT_WRITE_DR3,                   "write_dr3" },
-        { SVM_EXIT_WRITE_DR5,                   "write_dr5" },
-        { SVM_EXIT_WRITE_DR7,                   "write_dr7" },
-        { SVM_EXIT_EXCP_BASE + DB_VECTOR,       "DB excp" },
-        { SVM_EXIT_EXCP_BASE + BP_VECTOR,       "BP excp" },
-        { SVM_EXIT_EXCP_BASE + UD_VECTOR,       "UD excp" },
-        { SVM_EXIT_EXCP_BASE + PF_VECTOR,       "PF excp" },
-        { SVM_EXIT_EXCP_BASE + NM_VECTOR,       "NM excp" },
-        { SVM_EXIT_EXCP_BASE + MC_VECTOR,       "MC excp" },
-        { SVM_EXIT_INTR,                        "interrupt" },
-        { SVM_EXIT_NMI,                         "nmi" },
-        { SVM_EXIT_SMI,                         "smi" },
-        { SVM_EXIT_INIT,                        "init" },
-        { SVM_EXIT_VINTR,                       "vintr" },
-        { SVM_EXIT_CPUID,                       "cpuid" },
-        { SVM_EXIT_INVD,                        "invd" },
-        { SVM_EXIT_HLT,                         "hlt" },
-        { SVM_EXIT_INVLPG,                      "invlpg" },
-        { SVM_EXIT_INVLPGA,                     "invlpga" },
-        { SVM_EXIT_IOIO,                        "io" },
-        { SVM_EXIT_MSR,                         "msr" },
-        { SVM_EXIT_TASK_SWITCH,                 "task_switch" },
-        { SVM_EXIT_SHUTDOWN,                    "shutdown" },
-        { SVM_EXIT_VMRUN,                       "vmrun" },
-        { SVM_EXIT_VMMCALL,                     "hypercall" },
-        { SVM_EXIT_VMLOAD,                      "vmload" },
-        { SVM_EXIT_VMSAVE,                      "vmsave" },
-        { SVM_EXIT_STGI,                        "stgi" },
-        { SVM_EXIT_CLGI,                        "clgi" },
-        { SVM_EXIT_SKINIT,                      "skinit" },
-        { SVM_EXIT_WBINVD,                      "wbinvd" },
-        { SVM_EXIT_MONITOR,                     "monitor" },
-        { SVM_EXIT_MWAIT,                       "mwait" },
-        { SVM_EXIT_XSETBV,                      "xsetbv" },
-        { SVM_EXIT_NPF,                         "npf" },
-        { -1, NULL }
-};
-
 static int svm_get_lpage_level(void)
 {
         return PT_PDPE_LEVEL;
@@ -4225,7 +4171,6 @@ static struct kvm_x86_ops svm_x86_ops = {
         .get_mt_mask = svm_get_mt_mask,
 
         .get_exit_info = svm_get_exit_info,
-        .exit_reasons_str = svm_exit_reasons_str,
 
         .get_lpage_level = svm_get_lpage_level,
 
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 4e1716bf88a..911d2641f14 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -2,6 +2,8 @@
 #define _TRACE_KVM_H
 
 #include <linux/tracepoint.h>
+#include <asm/vmx.h>
+#include <asm/svm.h>
 
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM kvm
@@ -181,6 +183,95 @@ TRACE_EVENT(kvm_apic,
 #define KVM_ISA_VMX   1
 #define KVM_ISA_SVM   2
 
+#define VMX_EXIT_REASONS \
+        { EXIT_REASON_EXCEPTION_NMI,            "EXCEPTION_NMI" }, \
+        { EXIT_REASON_EXTERNAL_INTERRUPT,       "EXTERNAL_INTERRUPT" }, \
+        { EXIT_REASON_TRIPLE_FAULT,             "TRIPLE_FAULT" }, \
+        { EXIT_REASON_PENDING_INTERRUPT,        "PENDING_INTERRUPT" }, \
+        { EXIT_REASON_NMI_WINDOW,               "NMI_WINDOW" }, \
+        { EXIT_REASON_TASK_SWITCH,              "TASK_SWITCH" }, \
+        { EXIT_REASON_CPUID,                    "CPUID" }, \
+        { EXIT_REASON_HLT,                      "HLT" }, \
+        { EXIT_REASON_INVLPG,                   "INVLPG" }, \
+        { EXIT_REASON_RDPMC,                    "RDPMC" }, \
+        { EXIT_REASON_RDTSC,                    "RDTSC" }, \
+        { EXIT_REASON_VMCALL,                   "VMCALL" }, \
+        { EXIT_REASON_VMCLEAR,                  "VMCLEAR" }, \
+        { EXIT_REASON_VMLAUNCH,                 "VMLAUNCH" }, \
+        { EXIT_REASON_VMPTRLD,                  "VMPTRLD" }, \
+        { EXIT_REASON_VMPTRST,                  "VMPTRST" }, \
+        { EXIT_REASON_VMREAD,                   "VMREAD" }, \
+        { EXIT_REASON_VMRESUME,                 "VMRESUME" }, \
+        { EXIT_REASON_VMWRITE,                  "VMWRITE" }, \
+        { EXIT_REASON_VMOFF,                    "VMOFF" }, \
+        { EXIT_REASON_VMON,                     "VMON" }, \
+        { EXIT_REASON_CR_ACCESS,                "CR_ACCESS" }, \
+        { EXIT_REASON_DR_ACCESS,                "DR_ACCESS" }, \
+        { EXIT_REASON_IO_INSTRUCTION,           "IO_INSTRUCTION" }, \
+        { EXIT_REASON_MSR_READ,                 "MSR_READ" }, \
+        { EXIT_REASON_MSR_WRITE,                "MSR_WRITE" }, \
+        { EXIT_REASON_MWAIT_INSTRUCTION,        "MWAIT_INSTRUCTION" }, \
+        { EXIT_REASON_MONITOR_INSTRUCTION,      "MONITOR_INSTRUCTION" }, \
+        { EXIT_REASON_PAUSE_INSTRUCTION,        "PAUSE_INSTRUCTION" }, \
+        { EXIT_REASON_MCE_DURING_VMENTRY,       "MCE_DURING_VMENTRY" }, \
+        { EXIT_REASON_TPR_BELOW_THRESHOLD,      "TPR_BELOW_THRESHOLD" },        \
+        { EXIT_REASON_APIC_ACCESS,              "APIC_ACCESS" }, \
+        { EXIT_REASON_EPT_VIOLATION,            "EPT_VIOLATION" }, \
+        { EXIT_REASON_EPT_MISCONFIG,            "EPT_MISCONFIG" }, \
+        { EXIT_REASON_WBINVD,                   "WBINVD" }
+
+#define SVM_EXIT_REASONS \
+        { SVM_EXIT_READ_CR0,                    "read_cr0" }, \
+        { SVM_EXIT_READ_CR3,                    "read_cr3" }, \
+        { SVM_EXIT_READ_CR4,                    "read_cr4" }, \
+        { SVM_EXIT_READ_CR8,                    "read_cr8" }, \
+        { SVM_EXIT_WRITE_CR0,                   "write_cr0" }, \
+        { SVM_EXIT_WRITE_CR3,                   "write_cr3" }, \
+        { SVM_EXIT_WRITE_CR4,                   "write_cr4" }, \
+        { SVM_EXIT_WRITE_CR8,                   "write_cr8" }, \
+        { SVM_EXIT_READ_DR0,                    "read_dr0" }, \
+        { SVM_EXIT_READ_DR1,                    "read_dr1" }, \
+        { SVM_EXIT_READ_DR2,                    "read_dr2" }, \
+        { SVM_EXIT_READ_DR3,                    "read_dr3" }, \
+        { SVM_EXIT_WRITE_DR0,                   "write_dr0" }, \
+        { SVM_EXIT_WRITE_DR1,                   "write_dr1" }, \
+        { SVM_EXIT_WRITE_DR2,                   "write_dr2" }, \
+        { SVM_EXIT_WRITE_DR3,                   "write_dr3" }, \
+        { SVM_EXIT_WRITE_DR5,                   "write_dr5" }, \
+        { SVM_EXIT_WRITE_DR7,                   "write_dr7" }, \
+        { SVM_EXIT_EXCP_BASE + DB_VECTOR,       "DB excp" }, \
+        { SVM_EXIT_EXCP_BASE + BP_VECTOR,       "BP excp" }, \
+        { SVM_EXIT_EXCP_BASE + UD_VECTOR,       "UD excp" }, \
+        { SVM_EXIT_EXCP_BASE + PF_VECTOR,       "PF excp" }, \
+        { SVM_EXIT_EXCP_BASE + NM_VECTOR,       "NM excp" }, \
+        { SVM_EXIT_EXCP_BASE + MC_VECTOR,       "MC excp" }, \
+        { SVM_EXIT_INTR,                        "interrupt" }, \
+        { SVM_EXIT_NMI,                         "nmi" }, \
+        { SVM_EXIT_SMI,                         "smi" }, \
+        { SVM_EXIT_INIT,                        "init" }, \
+        { SVM_EXIT_VINTR,                       "vintr" }, \
+        { SVM_EXIT_CPUID,                       "cpuid" }, \
+        { SVM_EXIT_INVD,                        "invd" }, \
+        { SVM_EXIT_HLT,                         "hlt" }, \
+        { SVM_EXIT_INVLPG,                      "invlpg" }, \
+        { SVM_EXIT_INVLPGA,                     "invlpga" }, \
+        { SVM_EXIT_IOIO,                        "io" }, \
+        { SVM_EXIT_MSR,                         "msr" }, \
+        { SVM_EXIT_TASK_SWITCH,                 "task_switch" }, \
+        { SVM_EXIT_SHUTDOWN,                    "shutdown" }, \
+        { SVM_EXIT_VMRUN,                       "vmrun" }, \
+        { SVM_EXIT_VMMCALL,                     "hypercall" }, \
+        { SVM_EXIT_VMLOAD,                      "vmload" }, \
+        { SVM_EXIT_VMSAVE,                      "vmsave" }, \
+        { SVM_EXIT_STGI,                        "stgi" }, \
+        { SVM_EXIT_CLGI,                        "clgi" }, \
+        { SVM_EXIT_SKINIT,                      "skinit" }, \
+        { SVM_EXIT_WBINVD,                      "wbinvd" }, \
+        { SVM_EXIT_MONITOR,                     "monitor" }, \
+        { SVM_EXIT_MWAIT,                       "mwait" }, \
+        { SVM_EXIT_XSETBV,                      "xsetbv" }, \
+        { SVM_EXIT_NPF,                         "npf" }
+
 /*
  * Tracepoint for kvm guest exit:
  */
@@ -205,8 +296,9 @@ TRACE_EVENT(kvm_exit,
         ),
 
         TP_printk("reason %s rip 0x%lx info %llx %llx",
-                 ftrace_print_symbols_seq(p, __entry->exit_reason,
-                                          kvm_x86_ops->exit_reasons_str),
+                 (__entry->isa == KVM_ISA_VMX) ?
+                 __print_symbolic(__entry->exit_reason, VMX_EXIT_REASONS) :
+                 __print_symbolic(__entry->exit_reason, SVM_EXIT_REASONS),
                  __entry->guest_rip, __entry->info1, __entry->info2)
 );
 
@@ -512,8 +604,9 @@ TRACE_EVENT(kvm_nested_vmexit,
         TP_printk("rip: 0x%016llx reason: %s ext_inf1: 0x%016llx "
                   "ext_inf2: 0x%016llx ext_int: 0x%08x ext_int_err: 0x%08x",
                   __entry->rip,
-                  ftrace_print_symbols_seq(p, __entry->exit_code,
-                                           kvm_x86_ops->exit_reasons_str),
+                 (__entry->isa == KVM_ISA_VMX) ?
+                 __print_symbolic(__entry->exit_code, VMX_EXIT_REASONS) :
+                 __print_symbolic(__entry->exit_code, SVM_EXIT_REASONS),
                   __entry->exit_info1, __entry->exit_info2,
                   __entry->exit_int_info, __entry->exit_int_info_err)
 );
@@ -548,8 +641,9 @@ TRACE_EVENT(kvm_nested_vmexit_inject,
 
         TP_printk("reason: %s ext_inf1: 0x%016llx "
                   "ext_inf2: 0x%016llx ext_int: 0x%08x ext_int_err: 0x%08x",
-                  ftrace_print_symbols_seq(p, __entry->exit_code,
-                                           kvm_x86_ops->exit_reasons_str),
+                 (__entry->isa == KVM_ISA_VMX) ?
+                 __print_symbolic(__entry->exit_code, VMX_EXIT_REASONS) :
+                 __print_symbolic(__entry->exit_code, SVM_EXIT_REASONS),
                 __entry->exit_info1, __entry->exit_info2,
                 __entry->exit_int_info, __entry->exit_int_info_err)
 );
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e65a158dee6..e26629fbf1d 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,