From: Haiwei Li <lihai...@tencent.com>

When vmexit occurs caused by accessing dr, there is no tracepoint to track
this action. Add tracepoint for this on x86 kvm.

Signed-off-by: Haiwei Li <lihai...@tencent.com>
---
v1 -> v2:
 * Improve the changelog 

 arch/x86/kvm/svm/svm.c |  2 ++
 arch/x86/kvm/trace.h   | 27 +++++++++++++++++++++++++++
 arch/x86/kvm/vmx/vmx.c | 10 ++++++++--
 arch/x86/kvm/x86.c     |  1 +
 4 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 4f401fc6a05d..52c69551aea4 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2423,12 +2423,14 @@ static int dr_interception(struct vcpu_svm *svm)
                if (!kvm_require_dr(&svm->vcpu, dr - 16))
                        return 1;
                val = kvm_register_read(&svm->vcpu, reg);
+               trace_kvm_dr_write(dr - 16, val);
                kvm_set_dr(&svm->vcpu, dr - 16, val);
        } else {
                if (!kvm_require_dr(&svm->vcpu, dr))
                        return 1;
                kvm_get_dr(&svm->vcpu, dr, &val);
                kvm_register_write(&svm->vcpu, reg, val);
+               trace_kvm_dr_read(dr, val);
        }
 
        return kvm_skip_emulated_instruction(&svm->vcpu);
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index aef960f90f26..b3bf54405862 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -405,6 +405,33 @@ TRACE_EVENT(kvm_cr,
 #define trace_kvm_cr_read(cr, val)             trace_kvm_cr(0, cr, val)
 #define trace_kvm_cr_write(cr, val)            trace_kvm_cr(1, cr, val)
 
+/*
+ * Tracepoint for guest DR access.
+ */
+TRACE_EVENT(kvm_dr,
+       TP_PROTO(unsigned int rw, unsigned int dr, unsigned long val),
+       TP_ARGS(rw, dr, val),
+
+       TP_STRUCT__entry(
+               __field(        unsigned int,   rw              )
+               __field(        unsigned int,   dr              )
+               __field(        unsigned long,  val             )
+       ),
+
+       TP_fast_assign(
+               __entry->rw             = rw;
+               __entry->dr             = dr;
+               __entry->val            = val;
+       ),
+
+       TP_printk("dr_%s %x = 0x%lx",
+                 __entry->rw ? "write" : "read",
+                 __entry->dr, __entry->val)
+);
+
+#define trace_kvm_dr_read(dr, val)             trace_kvm_dr(0, dr, val)
+#define trace_kvm_dr_write(dr, val)            trace_kvm_dr(1, dr, val)
+
 TRACE_EVENT(kvm_pic_set_irq,
            TP_PROTO(__u8 chip, __u8 pin, __u8 elcr, __u8 imr, bool coalesced),
            TP_ARGS(chip, pin, elcr, imr, coalesced),
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 4551a7e80ebc..f78fd297d51e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5091,10 +5091,16 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 
                if (kvm_get_dr(vcpu, dr, &val))
                        return 1;
+               trace_kvm_dr_read(dr, val);
                kvm_register_write(vcpu, reg, val);
-       } else
-               if (kvm_set_dr(vcpu, dr, kvm_register_readl(vcpu, reg)))
+       } else {
+               unsigned long val;
+
+               val = kvm_register_readl(vcpu, reg);
+               trace_kvm_dr_write(dr, val);
+               if (kvm_set_dr(vcpu, dr, val))
                        return 1;
+       }
 
        return kvm_skip_emulated_instruction(vcpu);
 }
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c4015a43cc8a..68cb7b331324 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -11153,6 +11153,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_msr);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_cr);
+EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_dr);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmrun);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmexit);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_nested_vmexit_inject);
-- 
2.18.4

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