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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 0653FC10F13 for ; Tue, 16 Apr 2019 16:32:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D11C320821 for ; Tue, 16 Apr 2019 16:32:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729924AbfDPQcR (ORCPT ); Tue, 16 Apr 2019 12:32:17 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:59366 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726647AbfDPQcR (ORCPT ); Tue, 16 Apr 2019 12:32:17 -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 9D23080D; Tue, 16 Apr 2019 09:32:16 -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 F07A53F59C; Tue, 16 Apr 2019 09:32:14 -0700 (PDT) Date: Tue, 16 Apr 2019 17:32:12 +0100 From: Dave Martin To: Amit Daniel Kachhap 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 Subject: Re: [PATCH v9 4/5] KVM: arm64: Add capability to advertise ptrauth for guest Message-ID: <20190416163212.GX3567@e103592.cambridge.arm.com> References: <1555039236-10608-1-git-send-email-amit.kachhap@arm.com> <1555039236-10608-5-git-send-email-amit.kachhap@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1555039236-10608-5-git-send-email-amit.kachhap@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 12, 2019 at 08:50:35AM +0530, Amit Daniel Kachhap wrote: > This patch advertises the capability of two cpu feature called address > pointer authentication and generic pointer authentication. These > capabilities depend upon system support for pointer authentication and > VHE mode. > > The current arm64 KVM partially implements pointer authentication and > support of address/generic authentication are tied together. However, > separate ABI requirements for both of them is added so that any future > isolated implementation will not require any ABI changes. > > Signed-off-by: Amit Daniel Kachhap > Cc: Mark Rutland > Cc: Marc Zyngier > Cc: Christoffer Dall > Cc: kvmarm@lists.cs.columbia.edu > --- > Changes since v8: > * Keep the capability check same for the 2 vcpu ptrauth features. [Dave Martin] > > Documentation/virtual/kvm/api.txt | 2 ++ > arch/arm64/kvm/reset.c | 5 +++++ > include/uapi/linux/kvm.h | 2 ++ > 3 files changed, 9 insertions(+) > > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt > index 9d202f4..56021d0 100644 > --- a/Documentation/virtual/kvm/api.txt > +++ b/Documentation/virtual/kvm/api.txt > @@ -2756,9 +2756,11 @@ Possible features: > - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication > for the CPU and supported only on arm64 architecture. > Must be requested if KVM_ARM_VCPU_PTRAUTH_GENERIC is also requested. > + Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. What if KVM_CAP_ARM_PTRAUTH_ADDRESS is absent and KVM_ARM_VCPU_PTRAUTH_GENERIC is requested? By these rules, we have a contradiction: userspace both must request and must not request KVM_ARM_VCPU_PTRAUTH_ADDRESS. We could qualify as follows: Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. Must be requested if KVM_CAP_ARM_PTRAUTH_ADDRESS is present and KVM_ARM_VCPU_PTRAUTH_GENERIC is also requested. > - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication > for the CPU and supported only on arm64 architecture. > Must be requested if KVM_ARM_VCPU_PTRAUTH_ADDRESS is also requested. > + Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. Similarly. Or, we go back to having a single cap and a single feature, and add more caps/features later on if we decide it's possible to support address/generic auth separately later on. Otherwise, we end up with complex rules that can't be tested. This is a high price to pay for forwards compatibility: userspace's conformance to the rules can't be fully tested, so there's a fair chance it won't work properly anyway when hardware/KVM with just one auth type appears. [...] Thoughts? 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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, 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 3A65BC10F14 for ; Tue, 16 Apr 2019 16:32:21 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id CAE7120821 for ; Tue, 16 Apr 2019 16:32:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CAE7120821 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 4DF9C4A506; Tue, 16 Apr 2019 12:32:20 -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 5Ph4u2uxx20F; Tue, 16 Apr 2019 12:32:18 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id EAB3D4A4D4; Tue, 16 Apr 2019 12:32:18 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 835244A4CC for ; Tue, 16 Apr 2019 12:32:18 -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 tEjcoi+bJxub for ; Tue, 16 Apr 2019 12:32:17 -0400 (EDT) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 2C2CC4A4A3 for ; Tue, 16 Apr 2019 12:32:17 -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 9D23080D; Tue, 16 Apr 2019 09:32:16 -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 F07A53F59C; Tue, 16 Apr 2019 09:32:14 -0700 (PDT) Date: Tue, 16 Apr 2019 17:32:12 +0100 From: Dave Martin To: Amit Daniel Kachhap Subject: Re: [PATCH v9 4/5] KVM: arm64: Add capability to advertise ptrauth for guest Message-ID: <20190416163212.GX3567@e103592.cambridge.arm.com> References: <1555039236-10608-1-git-send-email-amit.kachhap@arm.com> <1555039236-10608-5-git-send-email-amit.kachhap@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1555039236-10608-5-git-send-email-amit.kachhap@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) 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-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu Message-ID: <20190416163212.v6fRpUZK5kZZZ-vLaM0-mMIcz-O8olnPUkMhuJXBy08@z> On Fri, Apr 12, 2019 at 08:50:35AM +0530, Amit Daniel Kachhap wrote: > This patch advertises the capability of two cpu feature called address > pointer authentication and generic pointer authentication. These > capabilities depend upon system support for pointer authentication and > VHE mode. > > The current arm64 KVM partially implements pointer authentication and > support of address/generic authentication are tied together. However, > separate ABI requirements for both of them is added so that any future > isolated implementation will not require any ABI changes. > > Signed-off-by: Amit Daniel Kachhap > Cc: Mark Rutland > Cc: Marc Zyngier > Cc: Christoffer Dall > Cc: kvmarm@lists.cs.columbia.edu > --- > Changes since v8: > * Keep the capability check same for the 2 vcpu ptrauth features. [Dave Martin] > > Documentation/virtual/kvm/api.txt | 2 ++ > arch/arm64/kvm/reset.c | 5 +++++ > include/uapi/linux/kvm.h | 2 ++ > 3 files changed, 9 insertions(+) > > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt > index 9d202f4..56021d0 100644 > --- a/Documentation/virtual/kvm/api.txt > +++ b/Documentation/virtual/kvm/api.txt > @@ -2756,9 +2756,11 @@ Possible features: > - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication > for the CPU and supported only on arm64 architecture. > Must be requested if KVM_ARM_VCPU_PTRAUTH_GENERIC is also requested. > + Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. What if KVM_CAP_ARM_PTRAUTH_ADDRESS is absent and KVM_ARM_VCPU_PTRAUTH_GENERIC is requested? By these rules, we have a contradiction: userspace both must request and must not request KVM_ARM_VCPU_PTRAUTH_ADDRESS. We could qualify as follows: Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. Must be requested if KVM_CAP_ARM_PTRAUTH_ADDRESS is present and KVM_ARM_VCPU_PTRAUTH_GENERIC is also requested. > - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication > for the CPU and supported only on arm64 architecture. > Must be requested if KVM_ARM_VCPU_PTRAUTH_ADDRESS is also requested. > + Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. Similarly. Or, we go back to having a single cap and a single feature, and add more caps/features later on if we decide it's possible to support address/generic auth separately later on. Otherwise, we end up with complex rules that can't be tested. This is a high price to pay for forwards compatibility: userspace's conformance to the rules can't be fully tested, so there's a fair chance it won't work properly anyway when hardware/KVM with just one auth type appears. [...] Thoughts? 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=-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,URIBL_BLOCKED,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 2825EC10F13 for ; Tue, 16 Apr 2019 16:32:26 +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 E83262087C for ; Tue, 16 Apr 2019 16:32:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ZIymziUj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E83262087C 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=nNxEtcx4BmMEt4/Y9edUkrSiFA7Nk15lSvWxOdkkFuQ=; b=ZIymziUj0TAiLg MoB6BwiWsO9C82PiMqQQQ0BGJN9kNOChL8kfN1S7BYUCea9sDG1VPOCthx9eDq4fPA7iSiUS3aKZe yltg/5ent1UXK8Q0WZBi8QOEkO6DgIBQyy0HzBI7J5d7WurVivSvJkUw8R0m5adQE5SkImGqH1h6C aklAR2uMjGdHPsQw4+eNVCaXhfOmwG1a6gNb7foNUIcLnNJUsYZFrNmxHYyUvGHYDuZdyQRjeGNt1 PASGNnyw2iStZzfyZQ/PlnWB568fA8Mlt7bxVUQZc6dlnImO0G7QHoZmngyi/pthpFl25zQejx1me 67YGeXqidxYnnjUy2NuQ==; 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 1hGR0O-0004Jf-Pf; Tue, 16 Apr 2019 16:32:20 +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 1hGR0L-0004JJ-4w for linux-arm-kernel@lists.infradead.org; Tue, 16 Apr 2019 16:32:18 +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 9D23080D; Tue, 16 Apr 2019 09:32:16 -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 F07A53F59C; Tue, 16 Apr 2019 09:32:14 -0700 (PDT) Date: Tue, 16 Apr 2019 17:32:12 +0100 From: Dave Martin To: Amit Daniel Kachhap Subject: Re: [PATCH v9 4/5] KVM: arm64: Add capability to advertise ptrauth for guest Message-ID: <20190416163212.GX3567@e103592.cambridge.arm.com> References: <1555039236-10608-1-git-send-email-amit.kachhap@arm.com> <1555039236-10608-5-git-send-email-amit.kachhap@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1555039236-10608-5-git-send-email-amit.kachhap@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-20190416_093217_196610_4E4FAAB5 X-CRM114-Status: GOOD ( 19.66 ) 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 Fri, Apr 12, 2019 at 08:50:35AM +0530, Amit Daniel Kachhap wrote: > This patch advertises the capability of two cpu feature called address > pointer authentication and generic pointer authentication. These > capabilities depend upon system support for pointer authentication and > VHE mode. > > The current arm64 KVM partially implements pointer authentication and > support of address/generic authentication are tied together. However, > separate ABI requirements for both of them is added so that any future > isolated implementation will not require any ABI changes. > > Signed-off-by: Amit Daniel Kachhap > Cc: Mark Rutland > Cc: Marc Zyngier > Cc: Christoffer Dall > Cc: kvmarm@lists.cs.columbia.edu > --- > Changes since v8: > * Keep the capability check same for the 2 vcpu ptrauth features. [Dave Martin] > > Documentation/virtual/kvm/api.txt | 2 ++ > arch/arm64/kvm/reset.c | 5 +++++ > include/uapi/linux/kvm.h | 2 ++ > 3 files changed, 9 insertions(+) > > diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt > index 9d202f4..56021d0 100644 > --- a/Documentation/virtual/kvm/api.txt > +++ b/Documentation/virtual/kvm/api.txt > @@ -2756,9 +2756,11 @@ Possible features: > - KVM_ARM_VCPU_PTRAUTH_ADDRESS: Enables Address Pointer authentication > for the CPU and supported only on arm64 architecture. > Must be requested if KVM_ARM_VCPU_PTRAUTH_GENERIC is also requested. > + Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. What if KVM_CAP_ARM_PTRAUTH_ADDRESS is absent and KVM_ARM_VCPU_PTRAUTH_GENERIC is requested? By these rules, we have a contradiction: userspace both must request and must not request KVM_ARM_VCPU_PTRAUTH_ADDRESS. We could qualify as follows: Depends on KVM_CAP_ARM_PTRAUTH_ADDRESS. Must be requested if KVM_CAP_ARM_PTRAUTH_ADDRESS is present and KVM_ARM_VCPU_PTRAUTH_GENERIC is also requested. > - KVM_ARM_VCPU_PTRAUTH_GENERIC: Enables Generic Pointer authentication > for the CPU and supported only on arm64 architecture. > Must be requested if KVM_ARM_VCPU_PTRAUTH_ADDRESS is also requested. > + Depends on KVM_CAP_ARM_PTRAUTH_GENERIC. Similarly. Or, we go back to having a single cap and a single feature, and add more caps/features later on if we decide it's possible to support address/generic auth separately later on. Otherwise, we end up with complex rules that can't be tested. This is a high price to pay for forwards compatibility: userspace's conformance to the rules can't be fully tested, so there's a fair chance it won't work properly anyway when hardware/KVM with just one auth type appears. [...] Thoughts? Cheers ---Dave _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel