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=-8.5 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,USER_AGENT_MUTT 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 2C6B4C282DA for ; Wed, 17 Apr 2019 15:38:18 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EE58C20674 for ; Wed, 17 Apr 2019 15:38:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ojDsAz6S" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EE58C20674 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=VK9RVjZBy+PY/UpJWCCRLRmet2AtQztRaha8xBfyk1w=; b=ojDsAz6SYN8l4/ kS5s8izc2qzsXbOJiJeQNQmFhqcrXBkNFXQPf/NFoIiPdzwvjfHuzZFl3GoTN2B2A2J1YJuaNVYlE WxInR7kr949trxnQEm12FdT/B4KkwLxKrKfDl6cuKYgz48xIVyFNvUM1Q8Mao3ZcOMvfbG0iv15li DgSsRAjA8YSAdG2IHvq5DWK+FsY5Jdxl7NQRRvCM/b+pjRYP3lU1hgBUcyj6BizKQiX7dcMcG0OQO LTpYzjk/QRh2KTMkUKalMnqqD8aWsrh5f4EolDofZj+wG5zHwLpLJfqJl2lyc3JIfWhpmDX46/9gk pS76ZL27DrdKtDYsAzKw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGmdX-0006Wg-D5; Wed, 17 Apr 2019 15:38:11 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hGmdU-0006WJ-Gm for linux-arm-kernel@lists.infradead.org; Wed, 17 Apr 2019 15:38:10 +0000 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 E93C4A78; Wed, 17 Apr 2019 08:38:06 -0700 (PDT) Received: from e103592.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 408363F557; Wed, 17 Apr 2019 08:38:05 -0700 (PDT) Date: Wed, 17 Apr 2019 16:38:02 +0100 From: Dave Martin To: Amit Daniel Kachhap Subject: Re: [kvmtool PATCH v9 5/5] KVM: arm/arm64: Add a vcpu feature for pointer authentication Message-ID: <20190417153802.GD3567@e103592.cambridge.arm.com> 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> <364bccb9-a818-3cad-1885-724781b99c9e@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <364bccb9-a818-3cad-1885-724781b99c9e@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190417_083808_571165_9C465F0A X-CRM114-Status: GOOD ( 25.23 ) 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Apr 17, 2019 at 06:06:11PM +0530, Amit Daniel Kachhap wrote: > 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"); Sure, but we should indicate which actual options conflicted. > 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]? No, this is what I meant. > 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 I think --enable-ptrauth is still useful: with --disable-ptrauth, ptrauth is definitely turned off; with --enable-ptrauth, ptrauth is definitely turned on (or we refuse to start the guest at all); with neither, ptrauth is on for the guest if the host supports it. Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel