From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Martin Subject: [PATCH 14/14] KVM: arm64: Clarify access behaviour for out-of-range SVE register slice IDs Date: Fri, 12 Apr 2019 17:28:18 +0100 Message-ID: <1555086498-26691-15-git-send-email-Dave.Martin@arm.com> References: <1555086498-26691-1-git-send-email-Dave.Martin@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 240FF4A4B9 for ; Fri, 12 Apr 2019 12:29:41 -0400 (EDT) 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 Gm9y36FERm2t for ; Fri, 12 Apr 2019 12:29:39 -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 391D64A47E for ; Fri, 12 Apr 2019 12:29:39 -0400 (EDT) In-Reply-To: <1555086498-26691-1-git-send-email-Dave.Martin@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: kvmarm@lists.cs.columbia.edu Cc: Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , Zhang Lei , Julien Grall , linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu The existing documentation for which SVE register slice IDs are considered out-of-range, and what happens when userspace tries to access them, is cryptic. This patch rewords the text with the aim of making it a bit easier to understand. No functional change. Suggested-by: Andrew Jones Signed-off-by: Dave Martin --- Documentation/virtual/kvm/api.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 74c51c7..91cb12a 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2159,8 +2159,9 @@ arm64 SVE registers have the following bit patterns: 0x6050 0000 0015 060 FFR bits[256*slice + 255 : 256*slice] 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register -Access to slices beyond the maximum vector length configured for the -vcpu (i.e., where 16 * slice >= max_vq (**)) will fail with ENOENT. +Access to register IDs where 2048 * slice >= 128 * max_vq will fail with +ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit +quadwords: see (**) below. These registers are only accessible on vcpus for which SVE is enabled. See KVM_ARM_VCPU_INIT for details. -- 2.1.4 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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 D4F06C10F14 for ; Fri, 12 Apr 2019 16:29:44 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id 91A102077C for ; Fri, 12 Apr 2019 16:29:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 91A102077C 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 486914A4DE; Fri, 12 Apr 2019 12:29:44 -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 qExDRKsr9xJd; Fri, 12 Apr 2019 12:29:42 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 8B3CA4A4E5; Fri, 12 Apr 2019 12:29:42 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 240FF4A4B9 for ; Fri, 12 Apr 2019 12:29:41 -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 Gm9y36FERm2t for ; Fri, 12 Apr 2019 12:29:39 -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 391D64A47E for ; Fri, 12 Apr 2019 12:29:39 -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 B9879168F; Fri, 12 Apr 2019 09:29:38 -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 ESMTPA id 766E73F718; Fri, 12 Apr 2019 09:29:36 -0700 (PDT) From: Dave Martin To: kvmarm@lists.cs.columbia.edu Subject: [PATCH 14/14] KVM: arm64: Clarify access behaviour for out-of-range SVE register slice IDs Date: Fri, 12 Apr 2019 17:28:18 +0100 Message-Id: <1555086498-26691-15-git-send-email-Dave.Martin@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1555086498-26691-1-git-send-email-Dave.Martin@arm.com> References: <1555086498-26691-1-git-send-email-Dave.Martin@arm.com> Cc: Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , Zhang Lei , Julien Grall , 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: , MIME-Version: 1.0 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: <20190412162818.EZMSwOzZMPdJe5B3k2G4UaVo4DHPlV1WwO-9nradcvA@z> The existing documentation for which SVE register slice IDs are considered out-of-range, and what happens when userspace tries to access them, is cryptic. This patch rewords the text with the aim of making it a bit easier to understand. No functional change. Suggested-by: Andrew Jones Signed-off-by: Dave Martin --- Documentation/virtual/kvm/api.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 74c51c7..91cb12a 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -2159,8 +2159,9 @@ arm64 SVE registers have the following bit patterns: 0x6050 0000 0015 060 FFR bits[256*slice + 255 : 256*slice] 0x6060 0000 0015 ffff KVM_REG_ARM64_SVE_VLS pseudo-register -Access to slices beyond the maximum vector length configured for the -vcpu (i.e., where 16 * slice >= max_vq (**)) will fail with ENOENT. +Access to register IDs where 2048 * slice >= 128 * max_vq will fail with +ENOENT. max_vq is the vcpu's maximum supported vector length in 128-bit +quadwords: see (**) below. These registers are only accessible on vcpus for which SVE is enabled. See KVM_ARM_VCPU_INIT for details. -- 2.1.4 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm