From patchwork Thu Mar 1 15:55:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 10251753 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 77EEA60211 for ; Thu, 1 Mar 2018 15:56:11 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 67DDF28618 for ; Thu, 1 Mar 2018 15:56:11 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5C12B28630; Thu, 1 Mar 2018 15:56:11 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E832828618 for ; Thu, 1 Mar 2018 15:56:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031768AbeCAP4B (ORCPT ); Thu, 1 Mar 2018 10:56:01 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:40616 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031541AbeCAPz6 (ORCPT ); Thu, 1 Mar 2018 10:55:58 -0500 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 38B281688; Thu, 1 Mar 2018 07:55:58 -0800 (PST) Received: from approximate.cambridge.arm.com (approximate.cambridge.arm.com [10.1.207.62]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6CE6F3F25C; Thu, 1 Mar 2018 07:55:56 -0800 (PST) From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu Cc: Christoffer Dall , Mark Rutland , Catalin Marinas , Will Deacon , James Morse , Steve Capper , Peter Maydell Subject: [PATCH v5 06/23] KVM: arm/arm64: Do not use kern_hyp_va() with kvm_vgic_global_state Date: Thu, 1 Mar 2018 15:55:21 +0000 Message-Id: <20180301155538.26860-7-marc.zyngier@arm.com> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20180301155538.26860-1-marc.zyngier@arm.com> References: <20180301155538.26860-1-marc.zyngier@arm.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP kvm_vgic_global_state is part of the read-only section, and is usually accessed using a PC-relative address generation (adrp + add). It is thus useless to use kern_hyp_va() on it, and actively problematic if kern_hyp_va() becomes non-idempotent. On the other hand, there is no way that the compiler is going to guarantee that such access is always PC relative. So let's bite the bullet and provide our own accessor. Signed-off-by: Marc Zyngier --- arch/arm/include/asm/kvm_mmu.h | 7 +++++++ arch/arm64/include/asm/kvm_mmu.h | 20 ++++++++++++++++++++ virt/kvm/arm/hyp/vgic-v2-sr.c | 4 ++-- 3 files changed, 29 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h index de1b919404e4..a6808d2869f5 100644 --- a/arch/arm/include/asm/kvm_mmu.h +++ b/arch/arm/include/asm/kvm_mmu.h @@ -28,6 +28,13 @@ */ #define kern_hyp_va(kva) (kva) +/* Resolving symbol addresses in a PC-relative way is easy... */ +#define hyp_symbol_addr(s) \ + ({ \ + typeof(s) *addr = &(s); \ + addr; \ + }) + /* * KVM_MMU_CACHE_MIN_PAGES is the number of stage2 page table translation levels. */ diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index e3bc1d0a5e93..7120bf3f22c7 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -110,6 +110,26 @@ static inline unsigned long __kern_hyp_va(unsigned long v) #define kern_hyp_va(v) ((typeof(v))(__kern_hyp_va((unsigned long)(v)))) +/* + * Obtain the PC-relative address of a kernel symbol + * s: symbol + * + * The goal of this macro is to return a symbol's address based on a + * PC-relative computation, as opposed to a loading the VA from a + * constant pool or something similar. This works well for HYP, as an + * absolute VA is guaranteed to be wrong. Only use this if trying to + * obtain the address of a symbol (i.e. not something you obtained by + * following a pointer). + */ +#define hyp_symbol_addr(s) \ + ({ \ + typeof(s) *addr; \ + asm volatile("adrp %0, %1\n" \ + "add %0, %0, :lo12:%1\n" \ + : "=r" (addr) : "S" (&s)); \ + addr; \ + }) + /* * We currently only support a 40bit IPA. */ diff --git a/virt/kvm/arm/hyp/vgic-v2-sr.c b/virt/kvm/arm/hyp/vgic-v2-sr.c index 4fe6e797e8b3..a6ca049d9651 100644 --- a/virt/kvm/arm/hyp/vgic-v2-sr.c +++ b/virt/kvm/arm/hyp/vgic-v2-sr.c @@ -26,7 +26,7 @@ static void __hyp_text save_elrsr(struct kvm_vcpu *vcpu, void __iomem *base) { struct vgic_v2_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v2; - int nr_lr = (kern_hyp_va(&kvm_vgic_global_state))->nr_lr; + int nr_lr = hyp_symbol_addr(kvm_vgic_global_state)->nr_lr; u32 elrsr0, elrsr1; elrsr0 = readl_relaxed(base + GICH_ELRSR0); @@ -140,7 +140,7 @@ int __hyp_text __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu) return -1; rd = kvm_vcpu_dabt_get_rd(vcpu); - addr = kern_hyp_va((kern_hyp_va(&kvm_vgic_global_state))->vcpu_base_va); + addr = kern_hyp_va(hyp_symbol_addr(kvm_vgic_global_state)->vcpu_base_va); addr += fault_ipa - vgic->vgic_cpu_base; if (kvm_vcpu_dabt_iswrite(vcpu)) {