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=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 4A93EC43381 for ; Tue, 26 Feb 2019 16:32:45 +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 156472184D for ; Tue, 26 Feb 2019 16:32:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="WAoi+7GU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 156472184D 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-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=/nQ5tS/BPYzVZaredljQRr54ht0vaAJUyeai8cPwn9U=; b=WAoi+7GUrZL69WvSikFb4T95n yJ0gUH/q/SAenv1oqP7CWh5ImQMy4IHulHOe0xJC/zqUHLtIYoGfRuZdrZ6xPDw70WU0UjMj2HZJ9 2XoP6Uoq9vctowQ2Zw3P334YcDurbfSaJj+HE2xpwsRNtphEW1uLdGXSFn8tY9mCVjIJ1vH/xRqMB uioosy308MmyHoywrD+wY/M3b9+eXr4mWebj8buoQu9EDX1cyyYlLLfVvktfDyDtl+YJL7As0rT8s sZ4jmJEQFm02qGsQd4Uqz8WwNiSpd28NY2KLsbBr1upxr3vMKJXtHwslH6+ycl08ZzVkCt5P7D/uk fXmH3fiaQ==; 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 1gyfen-0005lT-RZ; Tue, 26 Feb 2019 16:32:37 +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 1gyfek-0005kw-K0 for linux-arm-kernel@lists.infradead.org; Tue, 26 Feb 2019 16:32:36 +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 135BD80D; Tue, 26 Feb 2019 08:32:34 -0800 (PST) Received: from [10.1.196.50] (e108454-lin.cambridge.arm.com [10.1.196.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D212D3F738; Tue, 26 Feb 2019 08:32:31 -0800 (PST) Subject: Re: [PATCH v5 13/26] KVM: arm64/sve: System register context switch and access support To: Dave Martin , kvmarm@lists.cs.columbia.edu References: <1550519559-15915-1-git-send-email-Dave.Martin@arm.com> <1550519559-15915-14-git-send-email-Dave.Martin@arm.com> From: Julien Grall Message-ID: <8a0e6089-b77b-151b-eacd-34ad13f39ac6@arm.com> Date: Tue, 26 Feb 2019 16:32:30 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <1550519559-15915-14-git-send-email-Dave.Martin@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190226_083234_664725_500CE2F1 X-CRM114-Status: GOOD ( 17.78 ) 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 , Zhang Lei , =?UTF-8?Q?Alex_Benn=c3=a9e?= , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Dave, On 18/02/2019 19:52, Dave Martin wrote: > @@ -1091,6 +1088,95 @@ static int reg_from_user(u64 *val, const void __user *uaddr, u64 id); > static int reg_to_user(void __user *uaddr, const u64 *val, u64 id); > static u64 sys_reg_to_index(const struct sys_reg_desc *reg); > > +static unsigned int sve_restrictions(const struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *rd) > +{ > + return vcpu_has_sve(vcpu) ? 0 : REG_NO_USER | REG_NO_GUEST; > +} > + > +static unsigned int sve_id_restrictions(const struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *rd) > +{ > + return vcpu_has_sve(vcpu) ? 0 : REG_NO_USER; > +} > + > +static int get_zcr_el1(struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *rd, > + const struct kvm_one_reg *reg, void __user *uaddr) > +{ > + if (WARN_ON(!vcpu_has_sve(vcpu))) > + return -ENOENT; > + > + return reg_to_user(uaddr, &vcpu->arch.ctxt.sys_regs[ZCR_EL1], > + reg->id); > +} > + > +static int set_zcr_el1(struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *rd, > + const struct kvm_one_reg *reg, void __user *uaddr) > +{ > + if (WARN_ON(!vcpu_has_sve(vcpu))) > + return -ENOENT; > + > + return reg_from_user(&vcpu->arch.ctxt.sys_regs[ZCR_EL1], uaddr, > + reg->id); > +} > + > +/* Generate the emulated ID_AA64ZFR0_EL1 value exposed to the guest */ > +static u64 guest_id_aa64zfr0_el1(const struct kvm_vcpu *vcpu) > +{ > + if (!vcpu_has_sve(vcpu)) > + return 0; > + > + return read_sanitised_ftr_reg(SYS_ID_AA64ZFR0_EL1); > +} > + > +static bool access_id_aa64zfr0_el1(struct kvm_vcpu *vcpu, > + struct sys_reg_params *p, > + const struct sys_reg_desc *rd) > +{ > + if (p->is_write) > + return write_to_read_only(vcpu, p, rd); > + > + p->regval = guest_id_aa64zfr0_el1(vcpu); > + return true; > +} > + > +static int get_id_aa64zfr0_el1(struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *rd, > + const struct kvm_one_reg *reg, void __user *uaddr) > +{ > + u64 val; > + > + if (!vcpu_has_sve(vcpu)) > + return -ENOENT; > + > + val = guest_id_aa64zfr0_el1(vcpu); > + return reg_to_user(uaddr, &val, reg->id); > +} > + > +static int set_id_aa64zfr0_el1(struct kvm_vcpu *vcpu, > + const struct sys_reg_desc *rd, > + const struct kvm_one_reg *reg, void __user *uaddr) > +{ > + const u64 id = sys_reg_to_index(rd); > + int err; > + u64 val; > + > + if (!vcpu_has_sve(vcpu)) > + return -ENOENT; > + > + err = reg_from_user(&val, uaddr, id); > + if (err) > + return err; > + > + /* This is what we mean by invariant: you can't change it. */ > + if (val != guest_id_aa64zfr0_el1(vcpu)) > + return -EINVAL; > + > + return 0; > +} We seem to already have code for handling invariant registers as well as reading ID register. I guess the only reason you can't use them is because of the check the vcpu is using SVE. However, AFAICT the restrictions callback would prevent you to enter the {get, set}_id if the vCPU does not support SVE. So the check should not be reachable. Did I miss anything? Cheers, -- Julien Grall _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel