[PATCH v3 05/40] KVM: x86: Trace hypercall register *after* truncating values for 32-bit

[Sean Christopherson]

When tracing hypercalls, invoke the tracepoint *after* truncating the
register values for 32-bit guests so as not to record unused garbage (in
the extremely unlikely scenario that the guest left garbage in a register
after transitioning from 64-bit mode to 32-bit mode).

Fixes: 229456fc34b1 ("KVM: convert custom marker based tracing to event traces")
Reviewed-by: Yosry Ahmed <yosry@xxxxxxxxxx>
Reviewed-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
 arch/x86/kvm/x86.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e6f1dd84f22d..634a6d0197f6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10429,8 +10429,6 @@ int ____kvm_emulate_hypercall(struct kvm_vcpu *vcpu, int cpl,
 
 	++vcpu->stat.hypercalls;
 
-	trace_kvm_hypercall(nr, a0, a1, a2, a3);
-
 	if (!op_64_bit) {
 		nr &= 0xFFFFFFFF;
 		a0 &= 0xFFFFFFFF;
@@ -10439,6 +10437,8 @@ int ____kvm_emulate_hypercall(struct kvm_vcpu *vcpu, int cpl,
 		a3 &= 0xFFFFFFFF;
 	}
 
+	trace_kvm_hypercall(nr, a0, a1, a2, a3);
+
 	if (cpl) {
 		ret = -KVM_EPERM;
 		goto out;
-- 
2.54.0.823.g6e5bcc1fc9-goog