KVM: x86: Consolidate guest enter/exit logic to common helpers

[linux-2.6-microblaze.git] / arch / x86 / kvm / x86.h

diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 8ddd381..521f74e 100644 (file)
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -8,6 +8,51 @@
 #include "kvm_cache_regs.h"
 #include "kvm_emulate.h"
 
+static __always_inline void kvm_guest_enter_irqoff(void)
+{
+       /*
+        * VMENTER enables interrupts (host state), but the kernel state is
+        * interrupts disabled when this is invoked. Also tell RCU about
+        * it. This is the same logic as for exit_to_user_mode().
+        *
+        * This ensures that e.g. latency analysis on the host observes
+        * guest mode as interrupt enabled.
+        *
+        * guest_enter_irqoff() informs context tracking about the
+        * transition to guest mode and if enabled adjusts RCU state
+        * accordingly.
+        */
+       instrumentation_begin();
+       trace_hardirqs_on_prepare();
+       lockdep_hardirqs_on_prepare(CALLER_ADDR0);
+       instrumentation_end();
+
+       guest_enter_irqoff();
+       lockdep_hardirqs_on(CALLER_ADDR0);
+}
+
+static __always_inline void kvm_guest_exit_irqoff(void)
+{
+       /*
+        * VMEXIT disables interrupts (host state), but tracing and lockdep
+        * have them in state 'on' as recorded before entering guest mode.
+        * Same as enter_from_user_mode().
+        *
+        * context_tracking_guest_exit() restores host context and reinstates
+        * RCU if enabled and required.
+        *
+        * This needs to be done immediately after VM-Exit, before any code
+        * that might contain tracepoints or call out to the greater world,
+        * e.g. before x86_spec_ctrl_restore_host().
+        */
+       lockdep_hardirqs_off(CALLER_ADDR0);
+       context_tracking_guest_exit();
+
+       instrumentation_begin();
+       trace_hardirqs_off_finish();
+       instrumentation_end();
+}
+
 #define KVM_NESTED_VMENTER_CONSISTENCY_CHECK(consistency_check)                \
 ({                                                                     \
        bool failed = (consistency_check);                              \