[PATCH 1/5] arm/arm64: KVM: Don't BUG_ON if IT bits are set in ARM mode

[Marc Zyngier]

The ARM ARM asserts that having the IT bits set in ARM mode is
unpredictable. But should a CPU do that (and still be able to
run correctly), we shouldn't kill the system.

So let's drop the BUG_ON that checks for this, as it is not
very helpful.

Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
 arch/arm/kvm/emulate.c   | 4 +---
 arch/arm64/kvm/emulate.c | 4 +---
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kvm/emulate.c b/arch/arm/kvm/emulate.c
index af93e3f..eda9ddd 100644
--- a/arch/arm/kvm/emulate.c
+++ b/arch/arm/kvm/emulate.c
@@ -221,9 +221,7 @@ static void kvm_adjust_itstate(struct kvm_vcpu *vcpu)
 	unsigned long cpsr = *vcpu_cpsr(vcpu);
 	bool is_arm = !(cpsr & PSR_T_BIT);
 
-	BUG_ON(is_arm && (cpsr & PSR_IT_MASK));
-
-	if (!(cpsr & PSR_IT_MASK))
+	if (is_arm || !(cpsr & PSR_IT_MASK))
 		return;
 
 	cond = (cpsr & 0xe000) >> 13;
diff --git a/arch/arm64/kvm/emulate.c b/arch/arm64/kvm/emulate.c
index f87d8fb..df76590 100644
--- a/arch/arm64/kvm/emulate.c
+++ b/arch/arm64/kvm/emulate.c
@@ -120,9 +120,7 @@ static void kvm_adjust_itstate(struct kvm_vcpu *vcpu)
 	unsigned long cpsr = *vcpu_cpsr(vcpu);
 	bool is_arm = !(cpsr & COMPAT_PSR_T_BIT);
 
-	BUG_ON(is_arm && (cpsr & COMPAT_PSR_IT_MASK));
-
-	if (!(cpsr & COMPAT_PSR_IT_MASK))
+	if (is_arm || !(cpsr & COMPAT_PSR_IT_MASK))
 		return;
 
 	cond = (cpsr & 0xe000) >> 13;
-- 
2.1.4