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=-9.1 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_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 09452C10F0E for ; Thu, 18 Apr 2019 16:09:56 +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 C72D72171F for ; Thu, 18 Apr 2019 16:09:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="tbwSqZ5N" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C72D72171F 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:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=sdI/j7xNeVBfLATZZSy6tyM+IsZz5MivCdYqZVE/jVM=; b=tbwSqZ5N0Qd8FnY+3yGYWNnC49 nWo+dVLdRfCgVjMJbhD594ToKNZTYdOYzVp+IPjnitqS8oXTSkKFlQBi+rkaFzJG7W5qeQHiEDJ/x C67MChHi2dP9yTJVMBnA7c2EfNGsW91TdPFrp1mTBmdGlVfj9PIAFerTFdV21yUui8zNJoMgMndQD oPcp3Yz/nrz9yuB5TW1RPmg9MCf1sr38i6BtyUOlZmEk4kBwiES8PGD9x/krE+jav2ANXKSWNGdKp WR4a6Ec46Rs5SzivDjdj71pNv2VGPWp6awhAWZu0ANFab3SNkbiOFO/yepxSGVz0Ae2sOzXr5hC86 1RV6yPDg==; 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 1hH9bf-0008Ff-NQ; Thu, 18 Apr 2019 16:09:47 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hH9aH-0006N0-T9 for linux-arm-kernel@lists.infradead.org; Thu, 18 Apr 2019 16:08:26 +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 8454F169E; Thu, 18 Apr 2019 09:08:21 -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 444FE3F5AF; Thu, 18 Apr 2019 09:08:19 -0700 (PDT) From: Dave Martin To: kvmarm@lists.cs.columbia.edu Subject: [PATCH v2 10/14] KVM: arm64/sve: Explain validity checks in set_sve_vls() Date: Thu, 18 Apr 2019 17:07:07 +0100 Message-Id: <1555603631-8107-11-git-send-email-Dave.Martin@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1555603631-8107-1-git-send-email-Dave.Martin@arm.com> References: <1555603631-8107-1-git-send-email-Dave.Martin@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190418_090822_699028_CC10E7E8 X-CRM114-Status: GOOD ( 12.87 ) 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: Peter Maydell , Okamoto Takayuki , Christoffer Dall , Ard Biesheuvel , Marc Zyngier , Catalin Marinas , Will Deacon , Andrew Jones , Zhang Lei , Julien Grall , =?UTF-8?q?Alex=20Benn=C3=A9e?= , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 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 Correct virtualization of SVE relies for correctness on code in set_sve_vls() that verifies consistency between the set of vector lengths requested by userspace and the set of vector lengths available on the host. However, the purpose of this code is not obvious, and not likely to be apparent at all to people who do not have detailed knowledge of the SVE system-level architecture. This patch adds a suitable comment to explain what these checks are for. No functional change. Suggested-by: Andrew Jones Signed-off-by: Dave Martin Reviewed-by: Andrew Jones --- arch/arm64/kvm/guest.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 5bb909c..3ae2f82 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -264,6 +264,13 @@ static int set_sve_vls(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg) if (max_vq > sve_vq_from_vl(kvm_sve_max_vl)) return -EINVAL; + /* + * Vector lengths supported by the host can't currently be + * hidden from the guest individually: instead we can only set a + * maxmium via ZCR_EL2.LEN. So, make sure the available vector + * lengths match the set requested exactly up to the requested + * maximum: + */ for (vq = SVE_VQ_MIN; vq <= max_vq; ++vq) if (vq_present(&vqs, vq) != sve_vq_available(vq)) return -EINVAL; -- 2.1.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel