From patchwork Mon May 15 17:30:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 13241912 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0415AC7EE2A for ; Mon, 15 May 2023 17:49:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244697AbjEORtU (ORCPT ); Mon, 15 May 2023 13:49:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244648AbjEORtE (ORCPT ); Mon, 15 May 2023 13:49:04 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 24CCC1524F for ; Mon, 15 May 2023 10:47:11 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E44D162F0A for ; Mon, 15 May 2023 17:47:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BCFEC433A1; Mon, 15 May 2023 17:47:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684172830; bh=L+vFEjrDxPHQopVHyQuoKaHYPKVgXf8Bsk3j4A6+Qig=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cKUSVc+H8T3NHRl003iPAAAC4keJaMZUXQCfZQ9TlZJatClnDKwYUw3yxnIRBMqyn Nd3dqViTExBh5aR6M6IG8PoIaboTMEfbYVF9zibyA+adLGty5ti5xDrdmXzMUR9QYp MC6TuLkeLpqsed+v0v1LLm7gEy2imvtoQbj4XTjO3mF2v5/67vsMEi/UiCNxqAqFoi MzcwRhwQekI3AUGucMExEZZ5OHZ+O4Z2csMCyT5HOAnt/kQ62HE5kCaWCWCIpquxl2 StuwMUypC3bREDbIa0g1mesDjWTrSl9F3a1Hmrvb38Qu2Ip+ALGdKiwM9d3Ddtp0dX 4VnJHUTYFQb+A== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pyc2i-00FJAF-B0; Mon, 15 May 2023 18:31:28 +0100 From: Marc Zyngier To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Alexandru Elisei , Andre Przywara , Chase Conklin , Christoffer Dall , Ganapatrao Kulkarni , Darren Hart , Jintack Lim , Russell King , Miguel Luis , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: [PATCH v10 19/59] KVM: arm64: nv: Trap EL1 VM register accesses in virtual EL2 Date: Mon, 15 May 2023 18:30:23 +0100 Message-Id: <20230515173103.1017669-20-maz@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230515173103.1017669-1-maz@kernel.org> References: <20230515173103.1017669-1-maz@kernel.org> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, alexandru.elisei@arm.com, andre.przywara@arm.com, chase.conklin@arm.com, christoffer.dall@arm.com, gankulkarni@os.amperecomputing.com, darren@os.amperecomputing.com, jintack@cs.columbia.edu, rmk+kernel@armlinux.org.uk, miguel.luis@oracle.com, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Christoffer Dall When running in virtual EL2 mode, we actually run the hardware in EL1 and therefore have to use the EL1 registers to ensure correct operation. By setting the HCR.TVM and HCR.TVRM we ensure that the virtual EL2 mode doesn't shoot itself in the foot when setting up what it believes to be a different mode's system register state (for example when preparing to switch to a VM). We can leverage the existing sysregs infrastructure to support trapped accesses to these registers. Reviewed-by: Russell King (Oracle) Reviewed-by: Alexandru Elisei Signed-off-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm64/kvm/hyp/include/hyp/switch.h | 4 +--- arch/arm64/kvm/hyp/nvhe/switch.c | 2 +- arch/arm64/kvm/hyp/vhe/switch.c | 7 ++++++- arch/arm64/kvm/sys_regs.c | 19 ++++++++++++++++--- 4 files changed, 24 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h index e78a08a72a3c..c6d62357e736 100644 --- a/arch/arm64/kvm/hyp/include/hyp/switch.h +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h @@ -119,10 +119,8 @@ static inline void __deactivate_traps_common(struct kvm_vcpu *vcpu) } } -static inline void ___activate_traps(struct kvm_vcpu *vcpu) +static inline void ___activate_traps(struct kvm_vcpu *vcpu, u64 hcr) { - u64 hcr = vcpu->arch.hcr_el2; - if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM)) hcr |= HCR_TVM; diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c index 71fa16a0dc77..7730860552da 100644 --- a/arch/arm64/kvm/hyp/nvhe/switch.c +++ b/arch/arm64/kvm/hyp/nvhe/switch.c @@ -40,7 +40,7 @@ static void __activate_traps(struct kvm_vcpu *vcpu) { u64 val; - ___activate_traps(vcpu); + ___activate_traps(vcpu, vcpu->arch.hcr_el2); __activate_traps_common(vcpu); val = vcpu->arch.cptr_el2; diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c index 3d868e84c7a0..14880c84678f 100644 --- a/arch/arm64/kvm/hyp/vhe/switch.c +++ b/arch/arm64/kvm/hyp/vhe/switch.c @@ -35,9 +35,14 @@ DEFINE_PER_CPU(unsigned long, kvm_hyp_vector); static void __activate_traps(struct kvm_vcpu *vcpu) { + u64 hcr = vcpu->arch.hcr_el2; u64 val; - ___activate_traps(vcpu); + /* Trap VM sysreg accesses if an EL2 guest is not using VHE. */ + if (vcpu_is_el2(vcpu) && !vcpu_el2_e2h_is_set(vcpu)) + hcr |= HCR_TVM | HCR_TRVM; + + ___activate_traps(vcpu, hcr); val = read_sysreg(cpacr_el1); val |= CPACR_ELx_TTA; diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index a881d5cd1671..28b882b79d3e 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -391,8 +391,15 @@ static void get_access_mask(const struct sys_reg_desc *r, u64 *mask, u64 *shift) /* * Generic accessor for VM registers. Only called as long as HCR_TVM - * is set. If the guest enables the MMU, we stop trapping the VM - * sys_regs and leave it in complete control of the caches. + * is set. + * + * This is set in two cases: either (1) we're running at vEL2, or (2) + * we're running at EL1 and the guest has its MMU off. + * + * (1) TVM/TRVM is set, as we need to virtualise some of the VM + * registers for the guest hypervisor + * (2) Once the guest enables the MMU, we stop trapping the VM sys_regs + * and leave it in complete control of the caches. */ static bool access_vm_reg(struct kvm_vcpu *vcpu, struct sys_reg_params *p, @@ -401,7 +408,13 @@ static bool access_vm_reg(struct kvm_vcpu *vcpu, bool was_enabled = vcpu_has_cache_enabled(vcpu); u64 val, mask, shift; - BUG_ON(!p->is_write); + /* We don't expect TRVM on the host */ + BUG_ON(!vcpu_is_el2(vcpu) && !p->is_write); + + if (!p->is_write) { + p->regval = vcpu_read_sys_reg(vcpu, r->reg); + return true; + } get_access_mask(r, &mask, &shift);