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=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 8F87AC43214 for ; Fri, 6 Aug 2021 11:31:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E6AB611BF for ; Fri, 6 Aug 2021 11:31:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245409AbhHFLbs (ORCPT ); Fri, 6 Aug 2021 07:31:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:56006 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239694AbhHFLbr (ORCPT ); Fri, 6 Aug 2021 07:31:47 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5675761050; Fri, 6 Aug 2021 11:31:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628249491; bh=M9UB+bjgdI6GkTumogq6PmtB5wmIP3agM0PRxyG7pzs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d99YBEzt7kgHJGXAqHCa0xdR9wp3Ia4JNvUYZgbwVAnr1+j3UI7DUz5N/PnFO6Dvg G/Lel3sJ23OXZk2Rqp91807gWTJ4dR+VLIEOnSvxWOGZeztENE1OjfljYjyA/G3ODJ H6ZBhMl8nIivSnxz9anaDw2QHJorMpPn+SZSFQID2kI0OWOUAblpuTjb86R1qCQuCn WHzUrXMvfiGIu9Z7hJMuCa5zZDQ9LcsPsrWomvQtBQvamPwpSj23f1IKKIyIH+H6PS aY3vnrawjp509cZqN4+n3o0fiBn8yWn0OZpnCN51tw7UuA/BV5ohyjzaJHtvTfbsNr KADY24c/a0nSw== From: Will Deacon To: linux-arm-kernel@lists.infradead.org Cc: kernel-team@android.com, Will Deacon , Catalin Marinas , Marc Zyngier , Jade Alglave , Shameer Kolothum , kvmarm@lists.cs.columbia.edu, linux-arch@vger.kernel.org Subject: [PATCH 4/4] KVM: arm64: Upgrade VMID accesses to {READ,WRITE}_ONCE Date: Fri, 6 Aug 2021 12:31:08 +0100 Message-Id: <20210806113109.2475-6-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210806113109.2475-1-will@kernel.org> References: <20210806113109.2475-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org From: Marc Zyngier Since TLB invalidation can run in parallel with VMID allocation, we need to be careful and avoid any sort of load/store tearing. Use {READ,WRITE}_ONCE consistently to avoid any surprise. Cc: Catalin Marinas Cc: Jade Alglave Cc: Shameer Kolothum Signed-off-by: Marc Zyngier Signed-off-by: Will Deacon --- arch/arm64/include/asm/kvm_mmu.h | 7 ++++++- arch/arm64/kvm/arm.c | 2 +- arch/arm64/kvm/hyp/nvhe/mem_protect.c | 4 ++-- arch/arm64/kvm/mmu.c | 2 +- 4 files changed, 10 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 934ef0deff9f..5828dd8fa738 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -252,6 +252,11 @@ static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa, #define kvm_phys_to_vttbr(addr) phys_to_ttbr(addr) +/* + * When this is (directly or indirectly) used on the TLB invalidation + * path, we rely on a previously issued DSB so that page table updates + * and VMID reads are correctly ordered. + */ static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu) { struct kvm_vmid *vmid = &mmu->vmid; @@ -259,7 +264,7 @@ static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu) u64 cnp = system_supports_cnp() ? VTTBR_CNP_BIT : 0; baddr = mmu->pgd_phys; - vmid_field = (u64)vmid->vmid << VTTBR_VMID_SHIFT; + vmid_field = (u64)READ_ONCE(vmid->vmid) << VTTBR_VMID_SHIFT; return kvm_phys_to_vttbr(baddr) | vmid_field | cnp; } diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index e9a2b8f27792..658f76067f46 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -571,7 +571,7 @@ static void update_vmid(struct kvm_vmid *vmid) kvm_call_hyp(__kvm_flush_vm_context); } - vmid->vmid = kvm_next_vmid; + WRITE_ONCE(vmid->vmid, kvm_next_vmid); kvm_next_vmid++; kvm_next_vmid &= (1 << kvm_get_vmid_bits()) - 1; diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index d4e74ca7f876..55ae97a144b8 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -109,8 +109,8 @@ int kvm_host_prepare_stage2(void *pgt_pool_base) mmu->pgd_phys = __hyp_pa(host_kvm.pgt.pgd); mmu->arch = &host_kvm.arch; mmu->pgt = &host_kvm.pgt; - mmu->vmid.vmid_gen = 0; - mmu->vmid.vmid = 0; + WRITE_ONCE(mmu->vmid.vmid_gen, 0); + WRITE_ONCE(mmu->vmid.vmid, 0); return 0; } diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 3155c9e778f0..b1a6eaec28ff 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -485,7 +485,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu) mmu->arch = &kvm->arch; mmu->pgt = pgt; mmu->pgd_phys = __pa(pgt->pgd); - mmu->vmid.vmid_gen = 0; + WRITE_ONCE(mmu->vmid.vmid_gen, 0); return 0; out_destroy_pgtable: -- 2.32.0.605.g8dce9f2422-goog