KVM: Add instruction-set-specific exit qualifications to kvm_exit trace

The exit reason alone is insufficient to understand exactly why an exit
occured; add ISA-specific trace parameters for additional information.

Because fetching these parameters is expensive on vmx, and because these
parameters are fetched even if tracing is disabled, we fetch the
parameters via a callback instead of as traditional trace arguments.

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 2495910..ab05ff6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3690,6 +3690,12 @@
 static const int kvm_vmx_max_exit_handlers =
 	ARRAY_SIZE(kvm_vmx_exit_handlers);
 
+static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2)
+{
+	*info1 = vmcs_readl(EXIT_QUALIFICATION);
+	*info2 = vmcs_read32(VM_EXIT_INTR_INFO);
+}
+
 /*
  * The guest has exited.  See if we can fix it or if we need userspace
  * assistance.
@@ -4334,7 +4340,9 @@
 	.get_tdp_level = get_ept_level,
 	.get_mt_mask = vmx_get_mt_mask,
 
+	.get_exit_info = vmx_get_exit_info,
 	.exit_reasons_str = vmx_exit_reasons_str,
+
 	.get_lpage_level = vmx_get_lpage_level,
 
 	.cpuid_update = vmx_cpuid_update,