KVM: x86: Read guest RIP from within the kvm_nested_vmexit tracepoint

Use kvm_rip_read() to read the guest's RIP for the nested VM-Exit
tracepoint instead of having the caller pass in an argument.  Params
that are passed into a tracepoint are evaluated even if the tracepoint
is disabled, i.e. passing in RIP for VMX incurs a VMREAD and retpoline
to retrieve a value that may never be used, e.g. if the exit is due to a
hardware interrupt.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200923201349.16097-3-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 08adac8..c02c2d4 100644 (file)
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2989,7 +2989,7 @@ static int handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath)
        if (is_guest_mode(vcpu)) {
                int vmexit;
 
-               trace_kvm_nested_vmexit(svm->vmcb->save.rip, exit_code,
+               trace_kvm_nested_vmexit(vcpu, exit_code,
                                        svm->vmcb->control.exit_info_1,
                                        svm->vmcb->control.exit_info_2,
                                        svm->vmcb->control.exit_int_info,

diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 7e8edc7..bb5e44f 100644 (file)
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -578,10 +578,10 @@ TRACE_EVENT(kvm_nested_intercepts,
  * Tracepoint for #VMEXIT while nested
  */
 TRACE_EVENT(kvm_nested_vmexit,
-           TP_PROTO(__u64 rip, __u32 exit_code,
+           TP_PROTO(struct kvm_vcpu *vcpu, __u32 exit_code,
                     __u64 exit_info1, __u64 exit_info2,
                     __u32 exit_int_info, __u32 exit_int_info_err, __u32 isa),
-           TP_ARGS(rip, exit_code, exit_info1, exit_info2,
+           TP_ARGS(vcpu, exit_code, exit_info1, exit_info2,
                    exit_int_info, exit_int_info_err, isa),
 
        TP_STRUCT__entry(
@@ -595,7 +595,7 @@ TRACE_EVENT(kvm_nested_vmexit,
        ),
 
        TP_fast_assign(
-               __entry->rip                    = rip;
+               __entry->rip                    = kvm_rip_read(vcpu);
                __entry->exit_code              = exit_code;
                __entry->exit_info1             = exit_info1;
                __entry->exit_info2             = exit_info2;

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 7911c27..d440d38 100644 (file)
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5937,7 +5937,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
        exit_intr_info = vmx_get_intr_info(vcpu);
        exit_qual = vmx_get_exit_qual(vcpu);
 
-       trace_kvm_nested_vmexit(kvm_rip_read(vcpu), exit_reason, exit_qual,
+       trace_kvm_nested_vmexit(vcpu, exit_reason, exit_qual,
                                vmx->idt_vectoring_info, exit_intr_info,
                                vmcs_read32(VM_EXIT_INTR_ERROR_CODE),
                                KVM_ISA_VMX);