From mboxrd@z Thu Jan 1 00:00:00 1970 From: Amit Daniel Kachhap Subject: Re: [kvmtool PATCH v10 5/5] KVM: arm/arm64: Add a vcpu feature for pointer authentication Date: Wed, 24 Apr 2019 12:32:22 +0530 Message-ID: <3b7bafc9-5d6a-7845-ef1f-577ea59000e2@arm.com> References: <1555994558-26349-1-git-send-email-amit.kachhap@arm.com> <1555994558-26349-6-git-send-email-amit.kachhap@arm.com> <20190423154625.GP3567@e103592.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190423154625.GP3567@e103592.cambridge.arm.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: kvmarm@lists.cs.columbia.edu Hi, On 4/23/19 9:16 PM, Dave Martin wrote: > On Tue, Apr 23, 2019 at 10:12:38AM +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 v9: >> * Added a error check for both enable-ptrauth and disable-ptrauth >> option. >> * Make the error explicit when enable-ptrauth is provided [Dave Martin]. >> >> 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 | 20 ++++++++++++++++++-- >> include/linux/kvm.h | 2 ++ >> 7 files changed, 32 insertions(+), 3 deletions(-) >> >> 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..acd1d5f 100644 >> --- a/arm/kvm-cpu.c >> +++ b/arm/kvm-cpu.c >> @@ -68,6 +68,18 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id) >> vcpu_init.features[0] |= (1UL << KVM_ARM_VCPU_PSCI_0_2); >> } >> >> + /* Check Pointer Authentication command line arguments. */ >> + if (kvm->cfg.arch.enable_ptrauth && kvm->cfg.arch.disable_ptrauth) >> + die("Both enable-ptrauth and disable-ptrauth option cannot be present"); > > Preferably, print the leading dashes, the same as the user would see > on the command line (e.g., --enable-ptrauth, --disable-ptrauth). > > For brevity, we could write something like: > > die("--enable-ptrauth conflicts with --disable-ptrauth"); > >> + /* >> + * Always enable Pointer Authentication if system supports >> + * this extension unless disable-ptrauth option is present. >> + */ >> + if (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) && >> + kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC) && >> + !kvm->cfg.arch.disable_ptrauth) >> + vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE; >> + >> /* >> * If the preferred target ioctl is successful then >> * use preferred target else try each and every target type >> @@ -106,8 +118,12 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id) >> die("Unable to find matching target"); >> } >> >> - if (err || target->init(vcpu)) >> - die("Unable to initialise vcpu"); >> + if (err || target->init(vcpu)) { >> + if (kvm->cfg.arch.enable_ptrauth) >> + die("Unable to initialise vcpu with pointer authentication feature"); > > We don't special-case this error message for any other feature yet: > there are a variety of reasons why we might have failed, so suggesting > that the failure is something to do with ptrauth may be misleading to > the user. > > If we want to be more informative, we could do something like the > following: > > bool supported; > > supported = kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) && > kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC); > > if (kvm->cfg.arch.enable_ptrauth && !supported) > die("--enable-ptrauth not supported on this host"); > > if (supported && !kvm->cfg.arch.disable_ptrauth) > vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE; > > /* ... */ > > if (err || target->init(vcpu)) > die("Unable to initialise vcpu"); > > We don't do this for any other feature today, but since it helps the > user to understand what went wrong it's probably a good idea. Yes this is more clear. As Mark has picked the core guest ptrauth patches. I will post this changes as standalone. Thanks, Amit Daniel > > [...] > > 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 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 9465BC10F11 for ; Wed, 24 Apr 2019 07:02:35 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 1EC7320878 for ; Wed, 24 Apr 2019 07:02:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1EC7320878 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 79D8D4A445; Wed, 24 Apr 2019 03:02:34 -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 EQUuIDCa41gv; Wed, 24 Apr 2019 03:02:31 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 108394A481; Wed, 24 Apr 2019 03:02:31 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2593D4A445 for ; Wed, 24 Apr 2019 03:02:30 -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 O2009u7obwd9 for ; Wed, 24 Apr 2019 03:02:28 -0400 (EDT) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 5E6D24A41C for ; Wed, 24 Apr 2019 03:02:28 -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 BBB1115A2; Wed, 24 Apr 2019 00:02:27 -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 36F533F238; Wed, 24 Apr 2019 00:02:24 -0700 (PDT) Subject: Re: [kvmtool PATCH v10 5/5] KVM: arm/arm64: Add a vcpu feature for pointer authentication To: Dave Martin References: <1555994558-26349-1-git-send-email-amit.kachhap@arm.com> <1555994558-26349-6-git-send-email-amit.kachhap@arm.com> <20190423154625.GP3567@e103592.cambridge.arm.com> From: Amit Daniel Kachhap Message-ID: <3b7bafc9-5d6a-7845-ef1f-577ea59000e2@arm.com> Date: Wed, 24 Apr 2019 12:32:22 +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: <20190423154625.GP3567@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: <20190424070222.pfPVczJ9xet-2tUMjE0mFLEVIG9mnMOAphVHq6OPLT0@z> Hi, On 4/23/19 9:16 PM, Dave Martin wrote: > On Tue, Apr 23, 2019 at 10:12:38AM +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 v9: >> * Added a error check for both enable-ptrauth and disable-ptrauth >> option. >> * Make the error explicit when enable-ptrauth is provided [Dave Martin]. >> >> 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 | 20 ++++++++++++++++++-- >> include/linux/kvm.h | 2 ++ >> 7 files changed, 32 insertions(+), 3 deletions(-) >> >> 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..acd1d5f 100644 >> --- a/arm/kvm-cpu.c >> +++ b/arm/kvm-cpu.c >> @@ -68,6 +68,18 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id) >> vcpu_init.features[0] |= (1UL << KVM_ARM_VCPU_PSCI_0_2); >> } >> >> + /* Check Pointer Authentication command line arguments. */ >> + if (kvm->cfg.arch.enable_ptrauth && kvm->cfg.arch.disable_ptrauth) >> + die("Both enable-ptrauth and disable-ptrauth option cannot be present"); > > Preferably, print the leading dashes, the same as the user would see > on the command line (e.g., --enable-ptrauth, --disable-ptrauth). > > For brevity, we could write something like: > > die("--enable-ptrauth conflicts with --disable-ptrauth"); > >> + /* >> + * Always enable Pointer Authentication if system supports >> + * this extension unless disable-ptrauth option is present. >> + */ >> + if (kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) && >> + kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC) && >> + !kvm->cfg.arch.disable_ptrauth) >> + vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE; >> + >> /* >> * If the preferred target ioctl is successful then >> * use preferred target else try each and every target type >> @@ -106,8 +118,12 @@ struct kvm_cpu *kvm_cpu__arch_init(struct kvm *kvm, unsigned long cpu_id) >> die("Unable to find matching target"); >> } >> >> - if (err || target->init(vcpu)) >> - die("Unable to initialise vcpu"); >> + if (err || target->init(vcpu)) { >> + if (kvm->cfg.arch.enable_ptrauth) >> + die("Unable to initialise vcpu with pointer authentication feature"); > > We don't special-case this error message for any other feature yet: > there are a variety of reasons why we might have failed, so suggesting > that the failure is something to do with ptrauth may be misleading to > the user. > > If we want to be more informative, we could do something like the > following: > > bool supported; > > supported = kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_ADDRESS) && > kvm__supports_extension(kvm, KVM_CAP_ARM_PTRAUTH_GENERIC); > > if (kvm->cfg.arch.enable_ptrauth && !supported) > die("--enable-ptrauth not supported on this host"); > > if (supported && !kvm->cfg.arch.disable_ptrauth) > vcpu_init.features[0] |= ARM_VCPU_PTRAUTH_FEATURE; > > /* ... */ > > if (err || target->init(vcpu)) > die("Unable to initialise vcpu"); > > We don't do this for any other feature today, but since it helps the > user to understand what went wrong it's probably a good idea. Yes this is more clear. As Mark has picked the core guest ptrauth patches. I will post this changes as standalone. Thanks, Amit Daniel > > [...] > > Cheers > ---Dave > _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm