Log emulated instructions in ftrace, especially if they failed.
Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
---
arch/x86/kvm/trace.h | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 4 ++
2 files changed, 90 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 32c912c..a6544b8 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -603,6 +603,92 @@ TRACE_EVENT(kvm_skinit,
__entry->rip, __entry->slb)
);
+#define __print_insn(insn, ilen) ({ \
+ int i; \
+ const char *ret = p->buffer + p->len; \
+ \
+ for (i = 0; i < ilen; ++i) \
+ trace_seq_printf(p, " %02x", insn[i]); \
+ trace_seq_printf(p, "%c", 0); \
+ ret; \
+ })
+
+#define KVM_EMUL_INSN_F_CR0_PE (1 << 0)
+#define KVM_EMUL_INSN_F_EFL_VM (1 << 1)
+#define KVM_EMUL_INSN_F_CS_D (1 << 2)
+#define KVM_EMUL_INSN_F_CS_L (1 << 3)
+
+#define kvm_trace_symbol_emul_flags \
+ { 0, "real" }, \
+ { KVM_EMUL_INSN_F_CR0_PE \
+ | KVM_EMUL_INSN_F_EFL_VM, "vm16" }, \
+ { KVM_EMUL_INSN_F_CR0_PE, "prot16" }, \
+ { KVM_EMUL_INSN_F_CR0_PE \
+ | KVM_EMUL_INSN_F_CS_D, "prot32" }, \
+ { KVM_EMUL_INSN_F_CR0_PE \
+ | KVM_EMUL_INSN_F_CS_L, "prot64" }
+
+#define kei_decode_mode(mode) ({ \
+ u8 flags = 0xff; \
+ switch (mode) { \
+ case X86EMUL_MODE_REAL: \
+ flags = 0; \
+ break; \
+ case X86EMUL_MODE_VM86: \
+ flags = KVM_EMUL_INSN_F_EFL_VM; \
+ break; \
+ case X86EMUL_MODE_PROT16: \
+ flags = KVM_EMUL_INSN_F_CR0_PE; \
+ break; \
+ case X86EMUL_MODE_PROT32: \
+ flags = KVM_EMUL_INSN_F_CR0_PE \
+ | KVM_EMUL_INSN_F_CS_D; \
+ break; \
+ case X86EMUL_MODE_PROT64: \
+ flags = KVM_EMUL_INSN_F_CR0_PE \
+ | KVM_EMUL_INSN_F_CS_L; \
+ break; \
+ } \
+ flags; \
+ })
+
+TRACE_EVENT(kvm_emulate_insn,
+ TP_PROTO(struct kvm_vcpu *vcpu, __u8 failed),
+ TP_ARGS(vcpu, failed),
+
+ TP_STRUCT__entry(
+ __field( __u64, rip )
+ __field( __u32, csbase )
+ __field( __u8, len )
+ __array( __u8, insn, 15 )
+ __field( __u8, flags )
+ __field( __u8, failed )
+ ),
+
+ TP_fast_assign(
+ __entry->rip = vcpu->arch.emulate_ctxt.decode.fetch.start;
+ __entry->csbase = kvm_x86_ops->get_segment_base(vcpu, VCPU_SREG_CS);
+ __entry->len = vcpu->arch.emulate_ctxt.decode.eip
+ - vcpu->arch.emulate_ctxt.decode.fetch.start;
+ memcpy(__entry->insn,
+ vcpu->arch.emulate_ctxt.decode.fetch.data,
+ 15);
+ __entry->flags = kei_decode_mode(vcpu->arch.emulate_ctxt.mode);
+ __entry->failed = failed;
+ ),
+
+ TP_printk("%x:%llx:%s (%s)%s",
+ __entry->csbase, __entry->rip,
+ __print_insn(__entry->insn, __entry->len),
+ __print_symbolic(__entry->flags,
+ kvm_trace_symbol_emul_flags),
+ __entry->failed ? " failed" : ""
+ )
+ );
+
+#define trace_kvm_emulate_insn_start(vcpu) trace_kvm_emulate_insn(vcpu, 0)
+#define trace_kvm_emulate_insn_failed(vcpu) trace_kvm_emulate_insn(vcpu, 1)
+
#endif /* _TRACE_KVM_H */
#undef TRACE_INCLUDE_PATH
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fd5c3d3..b3adb5e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3716,6 +3716,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
? X86EMUL_MODE_PROT32 : X86EMUL_MODE_PROT16;
r = x86_decode_insn(&vcpu->arch.emulate_ctxt, &emulate_ops);
+ trace_kvm_emulate_insn_start(vcpu);
/* Only allow emulation of specific instructions on #UD
* (namely VMMCALL, sysenter, sysexit, syscall)*/
@@ -3748,6 +3749,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
++vcpu->stat.insn_emulation;
if (r) {
++vcpu->stat.insn_emulation_fail;
+ trace_kvm_emulate_insn_failed(vcpu);
if (kvm_mmu_unprotect_page_virt(vcpu, cr2))
return EMULATE_DONE;
return EMULATE_FAIL;
@@ -3784,6 +3786,8 @@ restart:
if (kvm_mmu_unprotect_page_virt(vcpu, cr2))
goto done;
if (!vcpu->mmio_needed) {
+ ++vcpu->stat.insn_emulation_fail;
+ trace_kvm_emulate_insn_failed(vcpu);
kvm_report_emulation_failure(vcpu, "mmio");
return EMULATE_FAIL;
}
--
1.7.0.4
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