From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84984C282DA for ; Wed, 17 Apr 2019 12:36:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4240220835 for ; Wed, 17 Apr 2019 12:36:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732097AbfDQMgS (ORCPT ); Wed, 17 Apr 2019 08:36:18 -0400 Received: from foss.arm.com ([217.140.101.70]:44130 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726708AbfDQMgR (ORCPT ); Wed, 17 Apr 2019 08:36:17 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CBD00374; Wed, 17 Apr 2019 05:36:16 -0700 (PDT) Received: from [10.162.0.144] (a075553-lin.blr.arm.com [10.162.0.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4DBD83F59C; Wed, 17 Apr 2019 05:36:14 -0700 (PDT) Subject: Re: [kvmtool PATCH v9 5/5] KVM: arm/arm64: Add a vcpu feature for pointer authentication To: Dave Martin Cc: linux-arm-kernel@lists.infradead.org, Marc Zyngier , Catalin Marinas , Will Deacon , Kristina Martsenko , kvmarm@lists.cs.columbia.edu, Ramana Radhakrishnan , linux-kernel@vger.kernel.org References: <1555039236-10608-1-git-send-email-amit.kachhap@arm.com> <1555039236-10608-6-git-send-email-amit.kachhap@arm.com> <20190416163221.GY3567@e103592.cambridge.arm.com> From: Amit Daniel Kachhap Message-ID: <364bccb9-a818-3cad-1885-724781b99c9e@arm.com> Date: Wed, 17 Apr 2019 18:06:11 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190416163221.GY3567@e103592.cambridge.arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 4/16/19 10:02 PM, Dave Martin wrote: > On Fri, Apr 12, 2019 at 08:50:36AM +0530, Amit Daniel Kachhap wrote: >> This patch adds a runtime capabality for KVM tool to enable Arm64 8.3 >> Pointer Authentication in guest kernel. Two vcpu features >> KVM_ARM_VCPU_PTRAUTH_[ADDRESS/GENERIC] are supplied together to enable >> Pointer Authentication in KVM guest after checking the capability. >> >> Command line options --enable-ptrauth and --disable-ptrauth are added >> to use this feature. However, if those options are not provided then >> also this feature is enabled if host supports this capability. >> >> The macros defined in the headers are not in sync and should be replaced >> from the upstream. >> >> Signed-off-by: Amit Daniel Kachhap >> --- >> Changes since v8: >> * Added option --enable-ptrauth and --disable-ptrauth to use ptrauth. Also >> enable ptrauth if no option provided and Host supports ptrauth. [Dave Martin] >> * The macro definition are not linear as the kvmtool is not synchronised with the >> kernel changes present in kvmarm/next tree. >> >> arm/aarch32/include/kvm/kvm-cpu-arch.h | 1 + >> arm/aarch64/include/asm/kvm.h | 2 ++ >> arm/aarch64/include/kvm/kvm-config-arch.h | 6 +++++- >> arm/aarch64/include/kvm/kvm-cpu-arch.h | 2 ++ >> arm/include/arm-common/kvm-config-arch.h | 2 ++ >> arm/kvm-cpu.c | 11 +++++++++++ >> include/linux/kvm.h | 2 ++ >> 7 files changed, 25 insertions(+), 1 deletion(-) >> >> diff --git a/arm/aarch32/include/kvm/kvm-cpu-arch.h b/arm/aarch32/include/kvm/kvm-cpu-arch.h >> index d28ea67..520ea76 100644 >> --- a/arm/aarch32/include/kvm/kvm-cpu-arch.h >> +++ b/arm/aarch32/include/kvm/kvm-cpu-arch.h >> @@ -13,4 +13,5 @@ >> #define ARM_CPU_ID 0, 0, 0 >> #define ARM_CPU_ID_MPIDR 5 >> >> +#define ARM_VCPU_PTRAUTH_FEATURE 0 >> #endif /* KVM__KVM_CPU_ARCH_H */ >> diff --git a/arm/aarch64/include/asm/kvm.h b/arm/aarch64/include/asm/kvm.h >> index 97c3478..a2546e6 100644 >> --- a/arm/aarch64/include/asm/kvm.h >> +++ b/arm/aarch64/include/asm/kvm.h >> @@ -102,6 +102,8 @@ struct kvm_regs { >> #define KVM_ARM_VCPU_EL1_32BIT 1 /* CPU running a 32bit VM */ >> #define KVM_ARM_VCPU_PSCI_0_2 2 /* CPU uses PSCI v0.2 */ >> #define KVM_ARM_VCPU_PMU_V3 3 /* Support guest PMUv3 */ >> +#define KVM_ARM_VCPU_PTRAUTH_ADDRESS 5 /* CPU uses address pointer authentication */ >> +#define KVM_ARM_VCPU_PTRAUTH_GENERIC 6 /* CPU uses generic pointer authentication */ >> >> struct kvm_vcpu_init { >> __u32 target; >> diff --git a/arm/aarch64/include/kvm/kvm-config-arch.h b/arm/aarch64/include/kvm/kvm-config-arch.h >> index 04be43d..0279b13 100644 >> --- a/arm/aarch64/include/kvm/kvm-config-arch.h >> +++ b/arm/aarch64/include/kvm/kvm-config-arch.h >> @@ -8,7 +8,11 @@ >> "Create PMUv3 device"), \ >> OPT_U64('\0', "kaslr-seed", &(cfg)->kaslr_seed, \ >> "Specify random seed for Kernel Address Space " \ >> - "Layout Randomization (KASLR)"), >> + "Layout Randomization (KASLR)"), \ >> + OPT_BOOLEAN('\0', "enable-ptrauth", &(cfg)->enable_ptrauth, \ >> + "Enables pointer authentication"), \ >> + OPT_BOOLEAN('\0', "disable-ptrauth", &(cfg)->disable_ptrauth, \ >> + "Disables pointer authentication"), >> >> #include "arm-common/kvm-config-arch.h" >> >> diff --git a/arm/aarch64/include/kvm/kvm-cpu-arch.h b/arm/aarch64/include/kvm/kvm-cpu-arch.h >> index a9d8563..fcc2107 100644 >> --- a/arm/aarch64/include/kvm/kvm-cpu-arch.h >> +++ b/arm/aarch64/include/kvm/kvm-cpu-arch.h >> @@ -17,4 +17,6 @@ >> #define ARM_CPU_CTRL 3, 0, 1, 0 >> #define ARM_CPU_CTRL_SCTLR_EL1 0 >> >> +#define ARM_VCPU_PTRAUTH_FEATURE ((1UL << KVM_ARM_VCPU_PTRAUTH_ADDRESS) \ >> + | (1UL << KVM_ARM_VCPU_PTRAUTH_GENERIC)) >> #endif /* KVM__KVM_CPU_ARCH_H */ >> diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h >> index 5734c46..1b4287d 100644 >> --- a/arm/include/arm-common/kvm-config-arch.h >> +++ b/arm/include/arm-common/kvm-config-arch.h >> @@ -10,6 +10,8 @@ struct kvm_config_arch { >> bool aarch32_guest; >> bool has_pmuv3; >> u64 kaslr_seed; >> + bool enable_ptrauth; >> + bool disable_ptrauth; >> enum irqchip_type irqchip; >> u64 fw_addr; >> }; >> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c >> index 7780251..a45a649 100644 >> --- a/arm/kvm-cpu.c >> +++ b/arm/kvm-cpu.c >> @@ -69,6 +69,17 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id) >> } >> >> /* >> + * Always enable Pointer Authentication if requested. If system supports >> + * this extension then also enable it by default provided no disable >> + * request present. >> + */ >> + if ((kvm->cfg.arch.enable_ptrauth) || > > Nit: redundant () ok. > >> + (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) && > > Funny indentation? ok will align it. > >> + kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC) && >> + !kvm->cfg.arch.disable_ptrauth)) >> + vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE; >> + > > Hmm, we have some weird behaviours here: --enable-ptrauth > --disable-ptrauth will result in us trying to enable it, and May be 1 more check can be added here like, if (kvm->cfg.arch.enable_ptrauth && kvm->cfg.arch.disable_ptrauth) { print_err("Only 1 option should be supplied\n"); ret -EINVAL; } > --enable-ptrauth without the required caps will result in an unhelpful > "Unable to initialise vcpu" error message. I'm not sure this is a > whole lot worse than the way other options behave today, though. Since now ptrauth is enabled by default if system supports it even though it is not explicitly requested. so I thought --enable-ptrauth option has to now forcefully enable ptrauth and may cause some error message in failure. Did I interpret something different from your last suggestion[1]? Actually we can skip with --enable-ptrauth and have just 2 option, * By default enable ptrauth if system supports it. * --disable-ptrauth: useful to migrate non-ptrauth guests on ptrauth hosts [1]:https://lkml.org/lkml/2019/4/5/171 Thanks, Amit Daniel > > You could try to be more explicit about what happens in these cases, but > I'm not sure it's worth it given the state of the existing code. > > [...] > > Cheers > ---Dave > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DF66C282DC for ; Wed, 17 Apr 2019 12:36:23 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 8675820835 for ; Wed, 17 Apr 2019 12:36:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8675820835 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id DA4AE4A4FB; Wed, 17 Apr 2019 08:36:21 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Q+3fLlJePIZ4; Wed, 17 Apr 2019 08:36:20 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 71F6B4A4FE; Wed, 17 Apr 2019 08:36:20 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 59D7B4A4FB for ; Wed, 17 Apr 2019 08:36:19 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 1PpDLJGkLU1J for ; Wed, 17 Apr 2019 08:36:17 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 84D194A4BB for ; Wed, 17 Apr 2019 08:36:17 -0400 (EDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CBD00374; Wed, 17 Apr 2019 05:36:16 -0700 (PDT) Received: from [10.162.0.144] (a075553-lin.blr.arm.com [10.162.0.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4DBD83F59C; Wed, 17 Apr 2019 05:36:14 -0700 (PDT) Subject: Re: [kvmtool PATCH v9 5/5] KVM: arm/arm64: Add a vcpu feature for pointer authentication To: Dave Martin References: <1555039236-10608-1-git-send-email-amit.kachhap@arm.com> <1555039236-10608-6-git-send-email-amit.kachhap@arm.com> <20190416163221.GY3567@e103592.cambridge.arm.com> From: Amit Daniel Kachhap Message-ID: <364bccb9-a818-3cad-1885-724781b99c9e@arm.com> Date: Wed, 17 Apr 2019 18:06:11 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190416163221.GY3567@e103592.cambridge.arm.com> Content-Language: en-US Cc: Marc Zyngier , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Kristina Martsenko , Ramana Radhakrishnan , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="UTF-8"; format="flowed" Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu Message-ID: <20190417123611.oLyCelx-NLIQaLQy0WsvNKDQBAFxnb5YP6yuRiPLgUA@z> Hi, On 4/16/19 10:02 PM, Dave Martin wrote: > On Fri, Apr 12, 2019 at 08:50:36AM +0530, Amit Daniel Kachhap wrote: >> This patch adds a runtime capabality for KVM tool to enable Arm64 8.3 >> Pointer Authentication in guest kernel. Two vcpu features >> KVM_ARM_VCPU_PTRAUTH_[ADDRESS/GENERIC] are supplied together to enable >> Pointer Authentication in KVM guest after checking the capability. >> >> Command line options --enable-ptrauth and --disable-ptrauth are added >> to use this feature. However, if those options are not provided then >> also this feature is enabled if host supports this capability. >> >> The macros defined in the headers are not in sync and should be replaced >> from the upstream. >> >> Signed-off-by: Amit Daniel Kachhap >> --- >> Changes since v8: >> * Added option --enable-ptrauth and --disable-ptrauth to use ptrauth. Also >> enable ptrauth if no option provided and Host supports ptrauth. [Dave Martin] >> * The macro definition are not linear as the kvmtool is not synchronised with the >> kernel changes present in kvmarm/next tree. >> >> arm/aarch32/include/kvm/kvm-cpu-arch.h | 1 + >> arm/aarch64/include/asm/kvm.h | 2 ++ >> arm/aarch64/include/kvm/kvm-config-arch.h | 6 +++++- >> arm/aarch64/include/kvm/kvm-cpu-arch.h | 2 ++ >> arm/include/arm-common/kvm-config-arch.h | 2 ++ >> arm/kvm-cpu.c | 11 +++++++++++ >> include/linux/kvm.h | 2 ++ >> 7 files changed, 25 insertions(+), 1 deletion(-) >> >> diff --git a/arm/aarch32/include/kvm/kvm-cpu-arch.h b/arm/aarch32/include/kvm/kvm-cpu-arch.h >> index d28ea67..520ea76 100644 >> --- a/arm/aarch32/include/kvm/kvm-cpu-arch.h >> +++ b/arm/aarch32/include/kvm/kvm-cpu-arch.h >> @@ -13,4 +13,5 @@ >> #define ARM_CPU_ID 0, 0, 0 >> #define ARM_CPU_ID_MPIDR 5 >> >> +#define ARM_VCPU_PTRAUTH_FEATURE 0 >> #endif /* KVM__KVM_CPU_ARCH_H */ >> diff --git a/arm/aarch64/include/asm/kvm.h b/arm/aarch64/include/asm/kvm.h >> index 97c3478..a2546e6 100644 >> --- a/arm/aarch64/include/asm/kvm.h >> +++ b/arm/aarch64/include/asm/kvm.h >> @@ -102,6 +102,8 @@ struct kvm_regs { >> #define KVM_ARM_VCPU_EL1_32BIT 1 /* CPU running a 32bit VM */ >> #define KVM_ARM_VCPU_PSCI_0_2 2 /* CPU uses PSCI v0.2 */ >> #define KVM_ARM_VCPU_PMU_V3 3 /* Support guest PMUv3 */ >> +#define KVM_ARM_VCPU_PTRAUTH_ADDRESS 5 /* CPU uses address pointer authentication */ >> +#define KVM_ARM_VCPU_PTRAUTH_GENERIC 6 /* CPU uses generic pointer authentication */ >> >> struct kvm_vcpu_init { >> __u32 target; >> diff --git a/arm/aarch64/include/kvm/kvm-config-arch.h b/arm/aarch64/include/kvm/kvm-config-arch.h >> index 04be43d..0279b13 100644 >> --- a/arm/aarch64/include/kvm/kvm-config-arch.h >> +++ b/arm/aarch64/include/kvm/kvm-config-arch.h >> @@ -8,7 +8,11 @@ >> "Create PMUv3 device"), \ >> OPT_U64('\0', "kaslr-seed", &(cfg)->kaslr_seed, \ >> "Specify random seed for Kernel Address Space " \ >> - "Layout Randomization (KASLR)"), >> + "Layout Randomization (KASLR)"), \ >> + OPT_BOOLEAN('\0', "enable-ptrauth", &(cfg)->enable_ptrauth, \ >> + "Enables pointer authentication"), \ >> + OPT_BOOLEAN('\0', "disable-ptrauth", &(cfg)->disable_ptrauth, \ >> + "Disables pointer authentication"), >> >> #include "arm-common/kvm-config-arch.h" >> >> diff --git a/arm/aarch64/include/kvm/kvm-cpu-arch.h b/arm/aarch64/include/kvm/kvm-cpu-arch.h >> index a9d8563..fcc2107 100644 >> --- a/arm/aarch64/include/kvm/kvm-cpu-arch.h >> +++ b/arm/aarch64/include/kvm/kvm-cpu-arch.h >> @@ -17,4 +17,6 @@ >> #define ARM_CPU_CTRL 3, 0, 1, 0 >> #define ARM_CPU_CTRL_SCTLR_EL1 0 >> >> +#define ARM_VCPU_PTRAUTH_FEATURE ((1UL << KVM_ARM_VCPU_PTRAUTH_ADDRESS) \ >> + | (1UL << KVM_ARM_VCPU_PTRAUTH_GENERIC)) >> #endif /* KVM__KVM_CPU_ARCH_H */ >> diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h >> index 5734c46..1b4287d 100644 >> --- a/arm/include/arm-common/kvm-config-arch.h >> +++ b/arm/include/arm-common/kvm-config-arch.h >> @@ -10,6 +10,8 @@ struct kvm_config_arch { >> bool aarch32_guest; >> bool has_pmuv3; >> u64 kaslr_seed; >> + bool enable_ptrauth; >> + bool disable_ptrauth; >> enum irqchip_type irqchip; >> u64 fw_addr; >> }; >> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c >> index 7780251..a45a649 100644 >> --- a/arm/kvm-cpu.c >> +++ b/arm/kvm-cpu.c >> @@ -69,6 +69,17 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id) >> } >> >> /* >> + * Always enable Pointer Authentication if requested. If system supports >> + * this extension then also enable it by default provided no disable >> + * request present. >> + */ >> + if ((kvm->cfg.arch.enable_ptrauth) || > > Nit: redundant () ok. > >> + (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) && > > Funny indentation? ok will align it. > >> + kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC) && >> + !kvm->cfg.arch.disable_ptrauth)) >> + vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE; >> + > > Hmm, we have some weird behaviours here: --enable-ptrauth > --disable-ptrauth will result in us trying to enable it, and May be 1 more check can be added here like, if (kvm->cfg.arch.enable_ptrauth && kvm->cfg.arch.disable_ptrauth) { print_err("Only 1 option should be supplied\n"); ret -EINVAL; } > --enable-ptrauth without the required caps will result in an unhelpful > "Unable to initialise vcpu" error message. I'm not sure this is a > whole lot worse than the way other options behave today, though. Since now ptrauth is enabled by default if system supports it even though it is not explicitly requested. so I thought --enable-ptrauth option has to now forcefully enable ptrauth and may cause some error message in failure. Did I interpret something different from your last suggestion[1]? Actually we can skip with --enable-ptrauth and have just 2 option, * By default enable ptrauth if system supports it. * --disable-ptrauth: useful to migrate non-ptrauth guests on ptrauth hosts [1]:https://lkml.org/lkml/2019/4/5/171 Thanks, Amit Daniel > > You could try to be more explicit about what happens in these cases, but > I'm not sure it's worth it given the state of the existing code. > > [...] > > Cheers > ---Dave > _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99BF6C282DA for ; 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Wed, 17 Apr 2019 05:36:14 -0700 (PDT) Subject: Re: [kvmtool PATCH v9 5/5] KVM: arm/arm64: Add a vcpu feature for pointer authentication To: Dave Martin References: <1555039236-10608-1-git-send-email-amit.kachhap@arm.com> <1555039236-10608-6-git-send-email-amit.kachhap@arm.com> <20190416163221.GY3567@e103592.cambridge.arm.com> From: Amit Daniel Kachhap Message-ID: <364bccb9-a818-3cad-1885-724781b99c9e@arm.com> Date: Wed, 17 Apr 2019 18:06:11 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190416163221.GY3567@e103592.cambridge.arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190417_053618_366089_C5101A55 X-CRM114-Status: GOOD ( 25.05 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marc Zyngier , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Kristina Martsenko , Ramana Radhakrishnan , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 4/16/19 10:02 PM, Dave Martin wrote: > On Fri, Apr 12, 2019 at 08:50:36AM +0530, Amit Daniel Kachhap wrote: >> This patch adds a runtime capabality for KVM tool to enable Arm64 8.3 >> Pointer Authentication in guest kernel. Two vcpu features >> KVM_ARM_VCPU_PTRAUTH_[ADDRESS/GENERIC] are supplied together to enable >> Pointer Authentication in KVM guest after checking the capability. >> >> Command line options --enable-ptrauth and --disable-ptrauth are added >> to use this feature. However, if those options are not provided then >> also this feature is enabled if host supports this capability. >> >> The macros defined in the headers are not in sync and should be replaced >> from the upstream. >> >> Signed-off-by: Amit Daniel Kachhap >> --- >> Changes since v8: >> * Added option --enable-ptrauth and --disable-ptrauth to use ptrauth. Also >> enable ptrauth if no option provided and Host supports ptrauth. [Dave Martin] >> * The macro definition are not linear as the kvmtool is not synchronised with the >> kernel changes present in kvmarm/next tree. >> >> arm/aarch32/include/kvm/kvm-cpu-arch.h | 1 + >> arm/aarch64/include/asm/kvm.h | 2 ++ >> arm/aarch64/include/kvm/kvm-config-arch.h | 6 +++++- >> arm/aarch64/include/kvm/kvm-cpu-arch.h | 2 ++ >> arm/include/arm-common/kvm-config-arch.h | 2 ++ >> arm/kvm-cpu.c | 11 +++++++++++ >> include/linux/kvm.h | 2 ++ >> 7 files changed, 25 insertions(+), 1 deletion(-) >> >> diff --git a/arm/aarch32/include/kvm/kvm-cpu-arch.h b/arm/aarch32/include/kvm/kvm-cpu-arch.h >> index d28ea67..520ea76 100644 >> --- a/arm/aarch32/include/kvm/kvm-cpu-arch.h >> +++ b/arm/aarch32/include/kvm/kvm-cpu-arch.h >> @@ -13,4 +13,5 @@ >> #define ARM_CPU_ID 0, 0, 0 >> #define ARM_CPU_ID_MPIDR 5 >> >> +#define ARM_VCPU_PTRAUTH_FEATURE 0 >> #endif /* KVM__KVM_CPU_ARCH_H */ >> diff --git a/arm/aarch64/include/asm/kvm.h b/arm/aarch64/include/asm/kvm.h >> index 97c3478..a2546e6 100644 >> --- a/arm/aarch64/include/asm/kvm.h >> +++ b/arm/aarch64/include/asm/kvm.h >> @@ -102,6 +102,8 @@ struct kvm_regs { >> #define KVM_ARM_VCPU_EL1_32BIT 1 /* CPU running a 32bit VM */ >> #define KVM_ARM_VCPU_PSCI_0_2 2 /* CPU uses PSCI v0.2 */ >> #define KVM_ARM_VCPU_PMU_V3 3 /* Support guest PMUv3 */ >> +#define KVM_ARM_VCPU_PTRAUTH_ADDRESS 5 /* CPU uses address pointer authentication */ >> +#define KVM_ARM_VCPU_PTRAUTH_GENERIC 6 /* CPU uses generic pointer authentication */ >> >> struct kvm_vcpu_init { >> __u32 target; >> diff --git a/arm/aarch64/include/kvm/kvm-config-arch.h b/arm/aarch64/include/kvm/kvm-config-arch.h >> index 04be43d..0279b13 100644 >> --- a/arm/aarch64/include/kvm/kvm-config-arch.h >> +++ b/arm/aarch64/include/kvm/kvm-config-arch.h >> @@ -8,7 +8,11 @@ >> "Create PMUv3 device"), \ >> OPT_U64('\0', "kaslr-seed", &(cfg)->kaslr_seed, \ >> "Specify random seed for Kernel Address Space " \ >> - "Layout Randomization (KASLR)"), >> + "Layout Randomization (KASLR)"), \ >> + OPT_BOOLEAN('\0', "enable-ptrauth", &(cfg)->enable_ptrauth, \ >> + "Enables pointer authentication"), \ >> + OPT_BOOLEAN('\0', "disable-ptrauth", &(cfg)->disable_ptrauth, \ >> + "Disables pointer authentication"), >> >> #include "arm-common/kvm-config-arch.h" >> >> diff --git a/arm/aarch64/include/kvm/kvm-cpu-arch.h b/arm/aarch64/include/kvm/kvm-cpu-arch.h >> index a9d8563..fcc2107 100644 >> --- a/arm/aarch64/include/kvm/kvm-cpu-arch.h >> +++ b/arm/aarch64/include/kvm/kvm-cpu-arch.h >> @@ -17,4 +17,6 @@ >> #define ARM_CPU_CTRL 3, 0, 1, 0 >> #define ARM_CPU_CTRL_SCTLR_EL1 0 >> >> +#define ARM_VCPU_PTRAUTH_FEATURE ((1UL << KVM_ARM_VCPU_PTRAUTH_ADDRESS) \ >> + | (1UL << KVM_ARM_VCPU_PTRAUTH_GENERIC)) >> #endif /* KVM__KVM_CPU_ARCH_H */ >> diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h >> index 5734c46..1b4287d 100644 >> --- a/arm/include/arm-common/kvm-config-arch.h >> +++ b/arm/include/arm-common/kvm-config-arch.h >> @@ -10,6 +10,8 @@ struct kvm_config_arch { >> bool aarch32_guest; >> bool has_pmuv3; >> u64 kaslr_seed; >> + bool enable_ptrauth; >> + bool disable_ptrauth; >> enum irqchip_type irqchip; >> u64 fw_addr; >> }; >> diff --git a/arm/kvm-cpu.c b/arm/kvm-cpu.c >> index 7780251..a45a649 100644 >> --- a/arm/kvm-cpu.c >> +++ b/arm/kvm-cpu.c >> @@ -69,6 +69,17 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id) >> } >> >> /* >> + * Always enable Pointer Authentication if requested. If system supports >> + * this extension then also enable it by default provided no disable >> + * request present. >> + */ >> + if ((kvm->cfg.arch.enable_ptrauth) || > > Nit: redundant () ok. > >> + (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) && > > Funny indentation? ok will align it. > >> + kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC) && >> + !kvm->cfg.arch.disable_ptrauth)) >> + vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE; >> + > > Hmm, we have some weird behaviours here: --enable-ptrauth > --disable-ptrauth will result in us trying to enable it, and May be 1 more check can be added here like, if (kvm->cfg.arch.enable_ptrauth && kvm->cfg.arch.disable_ptrauth) { print_err("Only 1 option should be supplied\n"); ret -EINVAL; } > --enable-ptrauth without the required caps will result in an unhelpful > "Unable to initialise vcpu" error message. I'm not sure this is a > whole lot worse than the way other options behave today, though. Since now ptrauth is enabled by default if system supports it even though it is not explicitly requested. so I thought --enable-ptrauth option has to now forcefully enable ptrauth and may cause some error message in failure. Did I interpret something different from your last suggestion[1]? Actually we can skip with --enable-ptrauth and have just 2 option, * By default enable ptrauth if system supports it. * --disable-ptrauth: useful to migrate non-ptrauth guests on ptrauth hosts [1]:https://lkml.org/lkml/2019/4/5/171 Thanks, Amit Daniel > > You could try to be more explicit about what happens in these cases, but > I'm not sure it's worth it given the state of the existing code. > > [...] > > Cheers > ---Dave > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel