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>

4 files changed, 25 insertions, 2 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index f1e8d5b99f5d..3cc80c478003 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -594,6 +594,7 @@ struct kvm_x86_ops {
 
         void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
 
+        void (*get_exit_info)(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2);
         const struct trace_print_flags *exit_reasons_str;
 };
 
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 78a23086e16d..28274cf307ba 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2974,6 +2974,14 @@ void dump_vmcb(struct kvm_vcpu *vcpu)
 
 }
 
+static void svm_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2)
+{
+        struct vmcb_control_area *control = &to_svm(vcpu)->vmcb->control;
+
+        *info1 = control->exit_info_1;
+        *info2 = control->exit_info_2;
+}
+
 static int handle_exit(struct kvm_vcpu *vcpu)
 {
         struct vcpu_svm *svm = to_svm(vcpu);
@@ -3684,7 +3692,9 @@ static struct kvm_x86_ops svm_x86_ops = {
         .get_tdp_level = get_npt_level,
         .get_mt_mask = svm_get_mt_mask,
 
+        .get_exit_info = svm_get_exit_info,
         .exit_reasons_str = svm_exit_reasons_str,
+
         .get_lpage_level = svm_get_lpage_level,
 
         .cpuid_update = svm_cpuid_update,
diff --git a/arch/x86/kvm/trace.h b/arch/x86/kvm/trace.h
index 10610229b248..1357d7cf4ec8 100644
--- a/arch/x86/kvm/trace.h
+++ b/arch/x86/kvm/trace.h
@@ -192,18 +192,22 @@ TRACE_EVENT(kvm_exit,
                 __field(        unsigned int,   exit_reason     )
                 __field(        unsigned long,  guest_rip       )
                 __field(        u32,            isa             )
+                __field(        u64,            info1           )
+                __field(        u64,            info2           )
         ),
 
         TP_fast_assign(
                 __entry->exit_reason    = exit_reason;
                 __entry->guest_rip      = kvm_rip_read(vcpu);
                 __entry->isa            = isa;
+                kvm_x86_ops->get_exit_info(vcpu, &__entry->info1,
+                                           &__entry->info2);
         ),
 
-        TP_printk("reason %s rip 0x%lx",
+        TP_printk("reason %s rip 0x%lx info %llx %llx",
                  ftrace_print_symbols_seq(p, __entry->exit_reason,
                                           kvm_x86_ops->exit_reasons_str),
-                 __entry->guest_rip)
+                 __entry->guest_rip, __entry->info1, __entry->info2)
 );
 
 /*
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 24959105d7fc..ab05ff68bcd7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3690,6 +3690,12 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
 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 @@ static struct kvm_x86_ops vmx_x86_ops = {
         .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,