[PATCH v2] KVM: nVMX: add tracepoint for vmwrite

[Paolo Bonzini]

Both the field and the value are in registers, so they are not clear from
existing tracepoints.

Cc: Ladi Prosek <lpro...@redhat.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
 arch/x86/kvm/trace.h | 23 +++++++++++++++++++++++
 arch/x86/kvm/vmx.c   |  2 ++
 arch/x86/kvm/x86.c   |  1 +
 3 files changed, 26 insertions(+)

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 0a6cc6754ec5..b3d4dec78ae2 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -723,6 +723,29 @@ TRACE_EVENT(kvm_skinit,
        flags;                                          \
        })
 
+/*
+ * Tracepoint for nested #vmexit because of vmwrite
+ */
+TRACE_EVENT(kvm_vmwrite,
+           TP_PROTO(__u64 vmptr, __u16 field, __u64 value),
+           TP_ARGS(vmptr, field, value),
+
+       TP_STRUCT__entry(
+               __field(        __u64,  vmptr   )
+               __field(        __u16,  field   )
+               __field(        __u64,  value   )
+       ),
+
+       TP_fast_assign(
+               __entry->vmptr          =       vmptr;
+               __entry->field          =       field;
+               __entry->value          =       value;
+       ),
+
+       TP_printk("vmcs: 0x%016llx field: 0x%04x value: 0x%llx",
+                 __entry->vmptr, __entry->field, __entry->value)
+);
+
 TRACE_EVENT(kvm_emulate_insn,
        TP_PROTO(struct kvm_vcpu *vcpu, __u8 failed),
        TP_ARGS(vcpu, failed),
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 5382b82462fc..e7d01d7d350b 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -7474,6 +7474,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
 {
        unsigned long field;
        gva_t gva;
+       struct vcpu_vmx *vmx = to_vmx(vcpu);
        unsigned long exit_qualification = vmcs_readl(EXIT_QUALIFICATION);
        u32 vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO);
        /* The value to write might be 32 or 64 bits, depending on L1's long
@@ -7512,6 +7513,7 @@ static int handle_vmwrite(struct kvm_vcpu *vcpu)
                return 1;
        }
 
+       trace_kvm_vmwrite(vmx->nested.current_vmptr, field, field_value);
        if (vmcs12_write_any(vcpu, field, field_value) < 0) {
                nested_vmx_failValid(vcpu, VMXERR_UNSUPPORTED_VMCS_COMPONENT);
                skip_emulated_instruction(vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 7e30c720d0c5..2be66e90f297 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8495,3 +8495,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_pml_full);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_pi_irte_update);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_avic_unaccelerated_access);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_avic_incomplete_ipi);
+EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_vmwrite);
-- 
2.7.4