From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751873AbeBBMdN (ORCPT ); Fri, 2 Feb 2018 07:33:13 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:54518 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751416AbeBBMdH (ORCPT ); Fri, 2 Feb 2018 07:33:07 -0500 X-Google-Smtp-Source: AH8x224+NP0T/mxsleFedb7mtl1/EWiPpu+n74bhX0PYtughhqs9+BG1JjbwhAes85BMJTJV9BjX2A== Date: Fri, 2 Feb 2018 13:33:03 +0100 From: Christoffer Dall To: Marc Zyngier Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, Catalin Marinas , Will Deacon , Peter Maydell , Lorenzo Pieralisi , Mark Rutland , Robin Murphy , Ard Biesheuvel , Andrew Jones , Hanjun Guo , Jayachandran C , Jon Masters , Russell King - ARM Linux Subject: Re: [PATCH v3 03/18] arm64: KVM: Increment PC after handling an SMC trap Message-ID: <20180202123303.GF21802@cbox> References: <20180201114657.7323-1-marc.zyngier@arm.com> <20180201114657.7323-4-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180201114657.7323-4-marc.zyngier@arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 01, 2018 at 11:46:42AM +0000, Marc Zyngier wrote: > When handling an SMC trap, the "preferred return address" is set > to that of the SMC, and not the next PC (which is a departure from > the behaviour of an SMC that isn't trapped). > > Increment PC in the handler, as the guest is otherwise forever > stuck... > Reviewed-by: Christoffer Dall > Cc: stable@vger.kernel.org > Fixes: acfb3b883f6d ("arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls") > Signed-off-by: Marc Zyngier > --- > arch/arm64/kvm/handle_exit.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index 520b0dad3c62..5493bbefbd0d 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -62,7 +62,16 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) > > static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) > { > + /* > + * "If an SMC instruction executed at Non-secure EL1 is > + * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a > + * Trap exception, not a Secure Monitor Call exception [...]" > + * > + * We need to advance the PC after the trap, as it would > + * otherwise return to the same address... > + */ > vcpu_set_reg(vcpu, 0, ~0UL); > + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); > return 1; > } > > -- > 2.14.2 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: christoffer.dall@linaro.org (Christoffer Dall) Date: Fri, 2 Feb 2018 13:33:03 +0100 Subject: [PATCH v3 03/18] arm64: KVM: Increment PC after handling an SMC trap In-Reply-To: <20180201114657.7323-4-marc.zyngier@arm.com> References: <20180201114657.7323-1-marc.zyngier@arm.com> <20180201114657.7323-4-marc.zyngier@arm.com> Message-ID: <20180202123303.GF21802@cbox> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Feb 01, 2018 at 11:46:42AM +0000, Marc Zyngier wrote: > When handling an SMC trap, the "preferred return address" is set > to that of the SMC, and not the next PC (which is a departure from > the behaviour of an SMC that isn't trapped). > > Increment PC in the handler, as the guest is otherwise forever > stuck... > Reviewed-by: Christoffer Dall > Cc: stable at vger.kernel.org > Fixes: acfb3b883f6d ("arm64: KVM: Fix SMCCC handling of unimplemented SMC/HVC calls") > Signed-off-by: Marc Zyngier > --- > arch/arm64/kvm/handle_exit.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index 520b0dad3c62..5493bbefbd0d 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -62,7 +62,16 @@ static int handle_hvc(struct kvm_vcpu *vcpu, struct kvm_run *run) > > static int handle_smc(struct kvm_vcpu *vcpu, struct kvm_run *run) > { > + /* > + * "If an SMC instruction executed at Non-secure EL1 is > + * trapped to EL2 because HCR_EL2.TSC is 1, the exception is a > + * Trap exception, not a Secure Monitor Call exception [...]" > + * > + * We need to advance the PC after the trap, as it would > + * otherwise return to the same address... > + */ > vcpu_set_reg(vcpu, 0, ~0UL); > + kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu)); > return 1; > } > > -- > 2.14.2 >