[PATCH 0/1] trace all instructions whose emulation failed

[Manish Regmi <regmi.manish@xxxxxxxxx>]

Hi,
  The following patch makes sure all code path of failed emulation
runs trace_kvm_emulate_insn_failed().
Please let me know if there is anything missing or wrong.
Thank you.

Signed-off-by: Manish Regmi <regmi.manish@xxxxxxxxx>
--------
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b6e7535..fd1e875 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3784,36 +3784,35 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
 		c = &vcpu->arch.emulate_ctxt.decode;
 		if (emulation_type & EMULTYPE_TRAP_UD) {
 			if (!c->twobyte)
-				return EMULATE_FAIL;
+				goto emulate_failed;
 			switch (c->b) {
 			case 0x01: /* VMMCALL */
 				if (c->modrm_mod != 3 || c->modrm_rm != 1)
-					return EMULATE_FAIL;
+					goto emulate_failed;
 				break;
 			case 0x34: /* sysenter */
 			case 0x35: /* sysexit */
 				if (c->modrm_mod != 0 || c->modrm_rm != 0)
-					return EMULATE_FAIL;
+					goto emulate_failed;
 				break;
 			case 0x05: /* syscall */
 				if (c->modrm_mod != 0 || c->modrm_rm != 0)
-					return EMULATE_FAIL;
+					goto emulate_failed;;
 				break;
 			default:
-				return EMULATE_FAIL;
+				goto emulate_failed;
 			}

 			if (!(c->modrm_reg == 0 || c->modrm_reg == 3))
-				return EMULATE_FAIL;
+				goto emulate_failed;
 		}

 		++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;
+			goto emulate_failed;
 		}
 	}

@@ -3848,9 +3847,8 @@ restart:
 			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;
+			goto emulate_failed;
 		}
 		return EMULATE_DO_MMIO;
 	}
@@ -3868,6 +3866,10 @@ done:
 		goto restart;

 	return EMULATE_DONE;
+
+emulate_failed:
+	trace_kvm_emulate_insn_failed(vcpu);
+	return EMULATE_FAIL;
 }
 EXPORT_SYMBOL_GPL(emulate_instruction);


---------------------------------------------------------------
regards
Manish Regmi

http://manish-cs.blogspot.com
http://ext2read.sf.net
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