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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 372ABC41621 for ; Mon, 15 Mar 2021 14:06:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F282864F26 for ; Mon, 15 Mar 2021 14:06:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233996AbhCOOGI (ORCPT ); Mon, 15 Mar 2021 10:06:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:36764 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233410AbhCOOBj (ORCPT ); Mon, 15 Mar 2021 10:01:39 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5178F64DAD; Mon, 15 Mar 2021 14:01:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615816874; bh=gOIejV+/bBiUcgMjnZ/TDR9kYFEXWqR+mNLQGCWAF98=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o1DECGyckVcKlXdEsjXkgV4nvm8Aoxz80U22mSiC2VDtknRyC7DfT2H6jQM8XWciG DrqFjebQClQk0FNcTxb+33c/W7t/vTRazBuxNmyc3kso2RtxhsBDyYw9I1eZRTGGth sAYmOheuxXLOMTHIGs1o6BnZs3INtFfeQHrb/fzI= From: gregkh@linuxfoundation.org To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Zyngier , Will Deacon , Catalin Marinas Subject: [PATCH 5.4 164/168] KVM: arm64: Ensure I-cache isolation between vcpus of a same VM Date: Mon, 15 Mar 2021 14:56:36 +0100 Message-Id: <20210315135555.752583848@linuxfoundation.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210315135550.333963635@linuxfoundation.org> References: <20210315135550.333963635@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Greg Kroah-Hartman From: Marc Zyngier Commit 01dc9262ff5797b675c32c0c6bc682777d23de05 upstream. It recently became apparent that the ARMv8 architecture has interesting rules regarding attributes being used when fetching instructions if the MMU is off at Stage-1. In this situation, the CPU is allowed to fetch from the PoC and allocate into the I-cache (unless the memory is mapped with the XN attribute at Stage-2). If we transpose this to vcpus sharing a single physical CPU, it is possible for a vcpu running with its MMU off to influence another vcpu running with its MMU on, as the latter is expected to fetch from the PoU (and self-patching code doesn't flush below that level). In order to solve this, reuse the vcpu-private TLB invalidation code to apply the same policy to the I-cache, nuking it every time the vcpu runs on a physical CPU that ran another vcpu of the same VM in the past. This involve renaming __kvm_tlb_flush_local_vmid() to __kvm_flush_cpu_context(), and inserting a local i-cache invalidation there. Cc: stable@vger.kernel.org Signed-off-by: Marc Zyngier Acked-by: Will Deacon Acked-by: Catalin Marinas Link: https://lore.kernel.org/r/20210303164505.68492-1-maz@kernel.org [maz: added 32bit ARM support] Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman --- arch/arm/include/asm/kvm_asm.h | 2 +- arch/arm/kvm/hyp/tlb.c | 3 ++- arch/arm64/include/asm/kvm_asm.h | 2 +- arch/arm64/kvm/hyp/tlb.c | 3 ++- virt/kvm/arm/arm.c | 8 +++++++- 5 files changed, 13 insertions(+), 5 deletions(-) --- a/arch/arm/include/asm/kvm_asm.h +++ b/arch/arm/include/asm/kvm_asm.h @@ -56,7 +56,7 @@ extern char __kvm_hyp_init_end[]; extern void __kvm_flush_vm_context(void); extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa); extern void __kvm_tlb_flush_vmid(struct kvm *kvm); -extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu); +extern void __kvm_flush_cpu_context(struct kvm_vcpu *vcpu); extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high); --- a/arch/arm/kvm/hyp/tlb.c +++ b/arch/arm/kvm/hyp/tlb.c @@ -45,7 +45,7 @@ void __hyp_text __kvm_tlb_flush_vmid_ipa __kvm_tlb_flush_vmid(kvm); } -void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu) +void __hyp_text __kvm_flush_cpu_context(struct kvm_vcpu *vcpu) { struct kvm *kvm = kern_hyp_va(kern_hyp_va(vcpu)->kvm); @@ -54,6 +54,7 @@ void __hyp_text __kvm_tlb_flush_local_vm isb(); write_sysreg(0, TLBIALL); + write_sysreg(0, ICIALLU); dsb(nsh); isb(); --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -60,7 +60,7 @@ extern char __kvm_hyp_vector[]; extern void __kvm_flush_vm_context(void); extern void __kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa); extern void __kvm_tlb_flush_vmid(struct kvm *kvm); -extern void __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu); +extern void __kvm_flush_cpu_context(struct kvm_vcpu *vcpu); extern void __kvm_timer_set_cntvoff(u32 cntvoff_low, u32 cntvoff_high); --- a/arch/arm64/kvm/hyp/tlb.c +++ b/arch/arm64/kvm/hyp/tlb.c @@ -182,7 +182,7 @@ void __hyp_text __kvm_tlb_flush_vmid(str __tlb_switch_to_host(kvm, &cxt); } -void __hyp_text __kvm_tlb_flush_local_vmid(struct kvm_vcpu *vcpu) +void __hyp_text __kvm_flush_cpu_context(struct kvm_vcpu *vcpu) { struct kvm *kvm = kern_hyp_va(kern_hyp_va(vcpu)->kvm); struct tlb_inv_context cxt; @@ -191,6 +191,7 @@ void __hyp_text __kvm_tlb_flush_local_vm __tlb_switch_to_guest(kvm, &cxt); __tlbi(vmalle1); + asm volatile("ic iallu"); dsb(nsh); isb(); --- a/virt/kvm/arm/arm.c +++ b/virt/kvm/arm/arm.c @@ -373,11 +373,17 @@ void kvm_arch_vcpu_load(struct kvm_vcpu cpu_data = this_cpu_ptr(&kvm_host_data); /* + * We guarantee that both TLBs and I-cache are private to each + * vcpu. If detecting that a vcpu from the same VM has + * previously run on the same physical CPU, call into the + * hypervisor code to nuke the relevant contexts. + * + * We might get preempted before the vCPU actually runs, but * We might get preempted before the vCPU actually runs, but * over-invalidation doesn't affect correctness. */ if (*last_ran != vcpu->vcpu_id) { - kvm_call_hyp(__kvm_tlb_flush_local_vmid, vcpu); + kvm_call_hyp(__kvm_flush_cpu_context, vcpu); *last_ran = vcpu->vcpu_id; }