[PATCH 4/4] hw-breakpoints: Wrap in the KVM breakpoint active state check

[Frederic Weisbecker]

Wrap in the cpu dr7 check that tells if we have active
breakpoints that need to be restored in the cpu.

This wrapper makes the check more self-explainable and also
reusable for any further other uses.

Reported-by: Jan Kiszka <jan.kiszka@xxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxx>
Cc: "K. Prasad" <prasad@xxxxxxxxxxxxxxxxxx>
---
 arch/x86/include/asm/debugreg.h |    5 +++++
 arch/x86/kvm/x86.c              |    2 +-
 2 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h
index f1b673f..0f6e92a 100644
--- a/arch/x86/include/asm/debugreg.h
+++ b/arch/x86/include/asm/debugreg.h
@@ -89,6 +89,11 @@ static inline void hw_breakpoint_disable(void)
 	set_debugreg(0UL, 3);
 }
 
+static inline int hw_breakpoint_active(void)
+{
+	return __get_cpu_var(dr7) & DR_GLOBAL_ENABLE_MASK;
+}
+
 extern void aout_dump_debugregs(struct user *dump);
 
 #ifdef CONFIG_KVM
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 22dee7a..3817220 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3651,7 +3651,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 	 * care about the messed up debug address registers. But if
 	 * we have some of them active, restore the old state.
 	 */
-	if (__get_cpu_var(dr7) & DR_GLOBAL_ENABLE_MASK)
+	if (hw_breakpoint_active())
 		hw_breakpoint_restore();
 
 	set_bit(KVM_REQ_KICK, &vcpu->requests);
-- 
1.6.2.3

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