From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Thu, 1 Sep 2016 13:56:16 +0200 Subject: [PATCH 1/5] arm/arm64: KVM: Don't BUG_ON if IT bits are set in ARM mode In-Reply-To: <1471610295-1456-2-git-send-email-marc.zyngier@arm.com> References: <1471610295-1456-1-git-send-email-marc.zyngier@arm.com> <1471610295-1456-2-git-send-email-marc.zyngier@arm.com> Message-ID: <20160901115616.GD10162@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Aug 19, 2016 at 01:38:11PM +0100, Marc Zyngier wrote: > 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 not sure how this relates to the series, but looks fine otherwise: Reviewed-by: Christoffer Dall > --- > 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 >