From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex =?utf-8?Q?Benn=C3=A9e?= Subject: Re: [PATCH v2 23/28] arm64/sve: KVM: Treat guest SVE use as undefined instruction execution Date: Thu, 14 Sep 2017 14:31:13 +0100 Message-ID: <874ls59zku.fsf@linaro.org> References: <1504198860-12951-1-git-send-email-Dave.Martin@arm.com> <1504198860-12951-24-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Return-path: Received: from mail-wr0-f177.google.com ([209.85.128.177]:43651 "EHLO mail-wr0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751165AbdINNbQ (ORCPT ); Thu, 14 Sep 2017 09:31:16 -0400 Received: by mail-wr0-f177.google.com with SMTP id a43so5957506wrc.0 for ; Thu, 14 Sep 2017 06:31:15 -0700 (PDT) In-reply-to: <1504198860-12951-24-git-send-email-Dave.Martin@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Dave Martin Cc: linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Ard Biesheuvel , Szabolcs Nagy , Richard Sandiford , kvmarm@lists.cs.columbia.edu, libc-alpha@sourceware.org, linux-arch@vger.kernel.org, Christoffer Dall , Marc Zyngier Dave Martin writes: > When trapping forbidden attempts by a guest to use SVE, we want the > guest to see a trap consistent with SVE not being implemented. > > This patch injects an undefined instruction exception into the > guest in response to such an exception. I do wonder if this should be merged with the previous trap enabling patch though? > > Signed-off-by: Dave Martin > --- > arch/arm64/kvm/handle_exit.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index 17d8a16..e3e42d0 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -147,6 +147,13 @@ static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run) > return 1; > } > > +static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) > +{ > + /* Until SVE is supported for guests: */ > + kvm_inject_undefined(vcpu); > + return 1; > +} > + > static exit_handle_fn arm_exit_handlers[] = { > [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec, > [ESR_ELx_EC_WFx] = kvm_handle_wfx, > @@ -160,6 +167,7 @@ static exit_handle_fn arm_exit_handlers[] = { > [ESR_ELx_EC_HVC64] = handle_hvc, > [ESR_ELx_EC_SMC64] = handle_smc, > [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg, > + [ESR_ELx_EC_SVE] = handle_sve, > [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort, > [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort, > [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug, From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f177.google.com ([209.85.128.177]:43651 "EHLO mail-wr0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751165AbdINNbQ (ORCPT ); Thu, 14 Sep 2017 09:31:16 -0400 Received: by mail-wr0-f177.google.com with SMTP id a43so5957506wrc.0 for ; Thu, 14 Sep 2017 06:31:15 -0700 (PDT) References: <1504198860-12951-1-git-send-email-Dave.Martin@arm.com> <1504198860-12951-24-git-send-email-Dave.Martin@arm.com> From: Alex =?utf-8?Q?Benn=C3=A9e?= Subject: Re: [PATCH v2 23/28] arm64/sve: KVM: Treat guest SVE use as undefined instruction execution In-reply-to: <1504198860-12951-24-git-send-email-Dave.Martin@arm.com> Date: Thu, 14 Sep 2017 14:31:13 +0100 Message-ID: <874ls59zku.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Dave Martin Cc: linux-arm-kernel@lists.infradead.org, Catalin Marinas , Will Deacon , Ard Biesheuvel , Szabolcs Nagy , Richard Sandiford , kvmarm@lists.cs.columbia.edu, libc-alpha@sourceware.org, linux-arch@vger.kernel.org, Christoffer Dall , Marc Zyngier Message-ID: <20170914133113.RcO28Gzk1CXCSzdMS-zY3TiXV65D7JPyPbBNSjTCH3A@z> Dave Martin writes: > When trapping forbidden attempts by a guest to use SVE, we want the > guest to see a trap consistent with SVE not being implemented. > > This patch injects an undefined instruction exception into the > guest in response to such an exception. I do wonder if this should be merged with the previous trap enabling patch though? > > Signed-off-by: Dave Martin > --- > arch/arm64/kvm/handle_exit.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/arch/arm64/kvm/handle_exit.c b/arch/arm64/kvm/handle_exit.c > index 17d8a16..e3e42d0 100644 > --- a/arch/arm64/kvm/handle_exit.c > +++ b/arch/arm64/kvm/handle_exit.c > @@ -147,6 +147,13 @@ static int kvm_handle_unknown_ec(struct kvm_vcpu *vcpu, struct kvm_run *run) > return 1; > } > > +static int handle_sve(struct kvm_vcpu *vcpu, struct kvm_run *run) > +{ > + /* Until SVE is supported for guests: */ > + kvm_inject_undefined(vcpu); > + return 1; > +} > + > static exit_handle_fn arm_exit_handlers[] = { > [0 ... ESR_ELx_EC_MAX] = kvm_handle_unknown_ec, > [ESR_ELx_EC_WFx] = kvm_handle_wfx, > @@ -160,6 +167,7 @@ static exit_handle_fn arm_exit_handlers[] = { > [ESR_ELx_EC_HVC64] = handle_hvc, > [ESR_ELx_EC_SMC64] = handle_smc, > [ESR_ELx_EC_SYS64] = kvm_handle_sys_reg, > + [ESR_ELx_EC_SVE] = handle_sve, > [ESR_ELx_EC_IABT_LOW] = kvm_handle_guest_abort, > [ESR_ELx_EC_DABT_LOW] = kvm_handle_guest_abort, > [ESR_ELx_EC_SOFTSTP_LOW]= kvm_handle_guest_debug, -- Alex Bennée