KVM: Improve emulation failure reporting

Report failed opcodes from all locations.

Signed-off-by: Avi Kivity <avi@qumranet.com>

4 files changed, 11 insertions, 10 deletions

diff --git a/drivers/kvm/kvm.h b/drivers/kvm/kvm.h
index d93ab48424c6..ad0813843adc 100644
--- a/drivers/kvm/kvm.h
+++ b/drivers/kvm/kvm.h
@@ -558,6 +558,7 @@ enum emulation_result {
 
 int emulate_instruction(struct kvm_vcpu *vcpu, struct kvm_run *run,
                         unsigned long cr2, u16 error_code);
+void kvm_report_emulation_failure(struct kvm_vcpu *cvpu, const char *context);
 void realmode_lgdt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);
 void realmode_lidt(struct kvm_vcpu *vcpu, u16 size, unsigned long address);
 void realmode_lmsw(struct kvm_vcpu *vcpu, unsigned long msw,
diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index e17b433152cb..3b046507ebc6 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -1240,25 +1240,25 @@ int emulator_set_dr(struct x86_emulate_ctxt *ctxt, int dr, unsigned long value)
         return X86EMUL_CONTINUE;
 }
 
-static void report_emulation_failure(struct x86_emulate_ctxt *ctxt)
+void kvm_report_emulation_failure(struct kvm_vcpu *vcpu, const char *context)
 {
         static int reported;
         u8 opcodes[4];
-        unsigned long rip = ctxt->vcpu->rip;
+        unsigned long rip = vcpu->rip;
         unsigned long rip_linear;
 
-        rip_linear = rip + get_segment_base(ctxt->vcpu, VCPU_SREG_CS);
+        rip_linear = rip + get_segment_base(vcpu, VCPU_SREG_CS);
 
         if (reported)
                 return;
 
-        emulator_read_std(rip_linear, (void *)opcodes, 4, ctxt->vcpu);
+        emulator_read_std(rip_linear, (void *)opcodes, 4, vcpu);
 
-        printk(KERN_ERR "emulation failed but !mmio_needed?"
-               " rip %lx %02x %02x %02x %02x\n",
-               rip, opcodes[0], opcodes[1], opcodes[2], opcodes[3]);
+        printk(KERN_ERR "emulation failed (%s) rip %lx %02x %02x %02x %02x\n",
+               context, rip, opcodes[0], opcodes[1], opcodes[2], opcodes[3]);
         reported = 1;
 }
+EXPORT_SYMBOL_GPL(kvm_report_emulation_failure);
 
 struct x86_emulate_ops emulate_ops = {
         .read_std            = emulator_read_std,
@@ -1323,7 +1323,7 @@ int emulate_instruction(struct kvm_vcpu *vcpu,
                 if (kvm_mmu_unprotect_page_virt(vcpu, cr2))
                         return EMULATE_DONE;
                 if (!vcpu->mmio_needed) {
-                        report_emulation_failure(&emulate_ctxt);
+                        kvm_report_emulation_failure(vcpu, "mmio");
                         return EMULATE_FAIL;
                 }
                 return EMULATE_DO_MMIO;
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 95681ea16382..729f1cd93606 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -960,7 +960,7 @@ static int pf_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
                 ++svm->vcpu.stat.mmio_exits;
                 return 0;
         case EMULATE_FAIL:
-                vcpu_printf(&svm->vcpu, "%s: emulate fail\n", __FUNCTION__);
+                kvm_report_emulation_failure(&svm->vcpu, "pagetable");
                 break;
         default:
                 BUG();
diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c
index c44c9ac79ca5..4f115a8e45ef 100644
--- a/drivers/kvm/vmx.c
+++ b/drivers/kvm/vmx.c
@@ -1798,7 +1798,7 @@ static int handle_exception(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                         ++vcpu->stat.mmio_exits;
                         return 0;
                  case EMULATE_FAIL:
-                        vcpu_printf(vcpu, "%s: emulate fail\n", __FUNCTION__);
+                        kvm_report_emulation_failure(vcpu, "pagetable");
                         break;
                 default:
                         BUG();