Merge branch 'tracing/hw-breakpoints' into perf/core

Conflicts:
	arch/x86/kernel/kprobes.c
	kernel/trace/Makefile

Merge reason: hw-breakpoints perf integration is looking
              good in testing and in reviews, plus conflicts
              are mounting up - so merge & resolve.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 10 insertions, 8 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index ae07d261527c..4fc80174191c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -42,6 +42,7 @@
 #define CREATE_TRACE_POINTS
 #include "trace.h"
 
+#include <asm/debugreg.h>
 #include <asm/uaccess.h>
 #include <asm/msr.h>
 #include <asm/desc.h>
@@ -3643,14 +3644,15 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         trace_kvm_entry(vcpu->vcpu_id);
         kvm_x86_ops->run(vcpu, kvm_run);
 
-        if (unlikely(vcpu->arch.switch_db_regs || test_thread_flag(TIF_DEBUG))) {
-                set_debugreg(current->thread.debugreg0, 0);
-                set_debugreg(current->thread.debugreg1, 1);
-                set_debugreg(current->thread.debugreg2, 2);
-                set_debugreg(current->thread.debugreg3, 3);
-                set_debugreg(current->thread.debugreg6, 6);
-                set_debugreg(current->thread.debugreg7, 7);
-        }
+        /*
+         * If the guest has used debug registers, at least dr7
+         * will be disabled while returning to the host.
+         * If we don't have active breakpoints in the host, we don't
+         * care about the messed up debug address registers. But if
+         * we have some of them active, restore the old state.
+         */
+        if (hw_breakpoint_active())
+                hw_breakpoint_restore();
 
         set_bit(KVM_REQ_KICK, &vcpu->requests);
         local_irq_enable();