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=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=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 6D1E6C10F0D for ; Tue, 19 Mar 2019 08:31:47 +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 3E5772075E for ; Tue, 19 Mar 2019 08:31:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="lF1Ggl3z" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E5772075E 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=Htk93ynE3isjPi/gMZONAmHMwIqb4guOsF1YmRmw6Z8=; b=lF1Ggl3zveSyzPoKslEPj2uJ4f UTY94IBwp5pfFzsubI5r9eSbf7b1QmDSOSTjY+2cRh5CYvipB7uIY+GOTIelsHFW0e0GI7DfhTsIJ eBn6KCD354LiJwrZ94vnLeDH+iJqjtT0DVVhYycIPUYZ30/Y6nKk3LodaEgoVWOkOdn9LtDBzJcyi zbzJO0QXrlOhZEN4pbmSQIDE8RRXrgqXdbFvllIPO9s2UwY29kkC0W+/1ynOPVdO5ooIMKX+wyX/H t19tCt1w5bX5bnR1pug7Y7KfK/TlZLTU1Ms02f43SSMC+2lg6wKEOMsAeOjGs7GxvkCbpREooIffW 1qJSBBTg==; 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 1h6A9v-0006Pr-7o; Tue, 19 Mar 2019 08:31:43 +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 1h6A9X-0005yE-Sg for linux-arm-kernel@lists.infradead.org; Tue, 19 Mar 2019 08:31:25 +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 93FFE174E; Tue, 19 Mar 2019 01:31:19 -0700 (PDT) Received: from a075553-lin.blr.arm.com (a075553-lin.blr.arm.com [10.162.0.144]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5BCED3F59C; Tue, 19 Mar 2019 01:31:15 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v7 2/10] KVM: arm64: Support runtime sysreg visibility filtering Date: Tue, 19 Mar 2019 14:00:35 +0530 Message-Id: <1552984243-7689-3-git-send-email-amit.kachhap@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1552984243-7689-1-git-send-email-amit.kachhap@arm.com> References: <1552984243-7689-1-git-send-email-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190319_013120_470394_12021F97 X-CRM114-Status: GOOD ( 20.50 ) 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: Mark Rutland , Andrew Jones , Julien Thierry , Marc Zyngier , Catalin Marinas , Will Deacon , Christoffer Dall , Kristina Martsenko , kvmarm@lists.cs.columbia.edu, James Morse , Ramana Radhakrishnan , Amit Daniel Kachhap , Dave Martin , linux-kernel@vger.kernel.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 From: Dave Martin Some optional features of the Arm architecture add new system registers that are not present in the base architecture. Where these features are optional for the guest, the visibility of these registers may need to depend on some runtime configuration, such as a flag passed to KVM_ARM_VCPU_INIT. For example, ZCR_EL1 and ID_AA64ZFR0_EL1 need to be hidden if SVE is not enabled for the guest, even though these registers may be present in the hardware and visible to the host at EL2. Adding special-case checks all over the place for individual registers is going to get messy as the number of conditionally- visible registers grows. In order to help solve this problem, this patch adds a new sysreg method restrictions() that can be used to hook in any needed runtime visibility checks. This method can currently return REG_NO_USER to inhibit enumeration and ioctl access to the register for userspace, and REG_NO_GUEST to inhibit runtime access by the guest using MSR/MRS. This allows a conditionally modified view of individual system registers such as the CPU ID registers, in addition to completely hiding register where appropriate. Signed-off-by: Dave Martin --- arch/arm64/kvm/sys_regs.c | 24 +++++++++++++++++++++--- arch/arm64/kvm/sys_regs.h | 13 +++++++++++++ 2 files changed, 34 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index a5d14b5..75942f6 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1927,6 +1927,12 @@ static void perform_access(struct kvm_vcpu *vcpu, { trace_kvm_sys_access(*vcpu_pc(vcpu), params, r); + /* Check for regs disabled by runtime config */ + if (restrictions(vcpu, r) & REG_NO_GUEST) { + kvm_inject_undefined(vcpu); + return; + } + /* * Not having an accessor means that we have configured a trap * that we don't know how to handle. This certainly qualifies @@ -2438,6 +2444,10 @@ int kvm_arm_sys_reg_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg if (!r) return get_invariant_sys_reg(reg->id, uaddr); + /* Check for regs disabled by runtime config */ + if (restrictions(vcpu, r) & REG_NO_USER) + return -ENOENT; + if (r->get_user) return (r->get_user)(vcpu, r, reg, uaddr); @@ -2459,6 +2469,10 @@ int kvm_arm_sys_reg_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg if (!r) return set_invariant_sys_reg(reg->id, uaddr); + /* Check for regs disabled by runtime config */ + if (restrictions(vcpu, r) & REG_NO_USER) + return -ENOENT; + if (r->set_user) return (r->set_user)(vcpu, r, reg, uaddr); @@ -2515,7 +2529,8 @@ static bool copy_reg_to_user(const struct sys_reg_desc *reg, u64 __user **uind) return true; } -static int walk_one_sys_reg(const struct sys_reg_desc *rd, +static int walk_one_sys_reg(const struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd, u64 __user **uind, unsigned int *total) { @@ -2526,6 +2541,9 @@ static int walk_one_sys_reg(const struct sys_reg_desc *rd, if (!(rd->reg || rd->get_user)) return 0; + if (restrictions(vcpu, rd) & REG_NO_USER) + return 0; + if (!copy_reg_to_user(rd, uind)) return -EFAULT; @@ -2554,9 +2572,9 @@ static int walk_sys_regs(struct kvm_vcpu *vcpu, u64 __user *uind) int cmp = cmp_sys_reg(i1, i2); /* target-specific overrides generic entry. */ if (cmp <= 0) - err = walk_one_sys_reg(i1, &uind, &total); + err = walk_one_sys_reg(vcpu, i1, &uind, &total); else - err = walk_one_sys_reg(i2, &uind, &total); + err = walk_one_sys_reg(vcpu, i2, &uind, &total); if (err) return err; diff --git a/arch/arm64/kvm/sys_regs.h b/arch/arm64/kvm/sys_regs.h index 3b1bc7f..b9dd4a9 100644 --- a/arch/arm64/kvm/sys_regs.h +++ b/arch/arm64/kvm/sys_regs.h @@ -64,8 +64,15 @@ struct sys_reg_desc { const struct kvm_one_reg *reg, void __user *uaddr); int (*set_user)(struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd, const struct kvm_one_reg *reg, void __user *uaddr); + + /* Return mask of REG_* runtime restriction flags */ + unsigned int (*restrictions)(const struct kvm_vcpu *vcpu, + const struct sys_reg_desc *rd); }; +#define REG_NO_USER (1 << 0) /* hidden from userspace ioctl interface */ +#define REG_NO_GUEST (1 << 1) /* hidden from guest */ + static inline void print_sys_reg_instr(const struct sys_reg_params *p) { /* Look, we even formatted it for you to paste into the table! */ @@ -102,6 +109,12 @@ static inline void reset_val(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r __vcpu_sys_reg(vcpu, r->reg) = r->val; } +static inline unsigned int restrictions(const struct kvm_vcpu *vcpu, + const struct sys_reg_desc *r) +{ + return unlikely(r->restrictions) ? r->restrictions(vcpu, r) : 0; +} + static inline int cmp_sys_reg(const struct sys_reg_desc *i1, const struct sys_reg_desc *i2) { -- 2.7.4 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel