From nobody Sun Feb 8 15:58:46 2026 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 83221EB64DC for ; Sat, 15 Jul 2023 00:54:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231352AbjGOAy5 (ORCPT ); Fri, 14 Jul 2023 20:54:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230111AbjGOAyg (ORCPT ); Fri, 14 Jul 2023 20:54:36 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10F323ABC for ; Fri, 14 Jul 2023 17:54:23 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-bd69bb4507eso2085727276.2 for ; Fri, 14 Jul 2023 17:54:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689382462; x=1689987262; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=wUK72LErj/cW/DTmM0D0+KH5bgl9rti1KYfAR7QuG/E=; b=sshR00+aAtBOwWYiCZGAYpO4fnVVTo5dI2raRcizF4Tm6lh+XV/lYXfBQd4dBrS+qm i9fl23qrXjR5kHI3koSQi2N0fvB1mruZ7myfnUZdtau2iBmAY25ul9EC/XtB0oyjhP+j DPSRaMZQvinCY+Tx+9uroryxalSjGSfC6ZTutGuMfsHVSZXDnWp3lgux9oekKpiJWkDd LnpF26hYxlw4oSLziHYFF2uWUIJeHfOhfTzx5I6iySyI2QIpX/VckMtq2Y1BylDNSPF6 bZiFVMVdblBlMiDEWAav1nw/+iNW2eGy7WyE50JOnaa7KlDcyD+Jv7AkWo7c1CCRY5dH jolA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689382462; x=1689987262; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=wUK72LErj/cW/DTmM0D0+KH5bgl9rti1KYfAR7QuG/E=; b=DmfdJQIs8wk3n45xFdR9AQbA8hjAetyetOYKu24FDxIAIrjlEcQvcx4yHOXXTHJHkT 1VrNPqvSzB7MlS6i9gVmQLrpKhX+ukKDWhKzozk40vFei7751rSJEl9nUlW64GrIpEpx AgkQKotdS1i5qiJNL4c7T/9dEV+DfeSnPEeM2ZSVLQC9ijQWS73sDPgckSrGtghkMkh/ 1uPwPAdh2XvHCr7x1iI64Pa15slwlOB7v/mtbIALw2a/rZk2zfRkobgXecu/T3IzQbV7 F96Ie2vw5boVEBk498bxLRhNw2Kw5k7rHj5z4dy4RKLtSDi8psxHWSlTUteNZv9dd22T WUTw== X-Gm-Message-State: ABy/qLZMlWEIZN9s0ZaE03a5dpkxn1yjbJx2l2+7+CqZU7DavAM5h0Fk 8clrFkTknvspPIDPctQkF8Co1X/kApww X-Google-Smtp-Source: APBJJlE0qITDo/wAXwRSd8iXWERdmKc71Dhpe2SjiRxhIc+LHhnKc3gfGxQ/Ra7EcVIhEZwkmD1LWTU7Ye9M X-Received: from rananta-linux.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:22b5]) (user=rananta job=sendgmr) by 2002:a25:32c2:0:b0:c62:5700:6520 with SMTP id y185-20020a2532c2000000b00c6257006520mr34849yby.3.1689382462727; Fri, 14 Jul 2023 17:54:22 -0700 (PDT) Date: Sat, 15 Jul 2023 00:54:05 +0000 In-Reply-To: <20230715005405.3689586-1-rananta@google.com> Mime-Version: 1.0 References: <20230715005405.3689586-1-rananta@google.com> X-Mailer: git-send-email 2.41.0.455.g037347b96a-goog Message-ID: <20230715005405.3689586-12-rananta@google.com> Subject: [PATCH v6 11/11] KVM: arm64: Use TLBI range-based intructions for unmap From: Raghavendra Rao Ananta To: Oliver Upton , Marc Zyngier , James Morse , Suzuki K Poulose Cc: Paolo Bonzini , Sean Christopherson , Huacai Chen , Zenghui Yu , Anup Patel , Atish Patra , Jing Zhang , Colton Lewis , Raghavendra Rao Anata , David Matlack , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The current implementation of the stage-2 unmap walker traverses the given range and, as a part of break-before-make, performs TLB invalidations with a DSB for every PTE. A multitude of this combination could cause a performance bottleneck on some systems. Hence, if the system supports FEAT_TLBIRANGE, defer the TLB invalidations until the entire walk is finished, and then use range-based instructions to invalidate the TLBs in one go. Condition deferred TLB invalidation on the system supporting FWB, as the optimization is entirely pointless when the unmap walker needs to perform CMOs. Rename stage2_put_pte() to stage2_unmap_put_pte() as the function now serves the stage-2 unmap walker specifically, rather than acting generic. Signed-off-by: Raghavendra Rao Ananta --- arch/arm64/kvm/hyp/pgtable.c | 67 +++++++++++++++++++++++++++++++----- 1 file changed, 58 insertions(+), 9 deletions(-) diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 5ef098af1736..cf88933a2ea0 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -831,16 +831,54 @@ static void stage2_make_pte(const struct kvm_pgtable_= visit_ctx *ctx, kvm_pte_t n smp_store_release(ctx->ptep, new); } =20 -static void stage2_put_pte(const struct kvm_pgtable_visit_ctx *ctx, struct= kvm_s2_mmu *mmu, - struct kvm_pgtable_mm_ops *mm_ops) +struct stage2_unmap_data { + struct kvm_pgtable *pgt; + bool defer_tlb_flush_init; +}; + +static bool __stage2_unmap_defer_tlb_flush(struct kvm_pgtable *pgt) +{ + /* + * If FEAT_TLBIRANGE is implemented, defer the individual + * TLB invalidations until the entire walk is finished, and + * then use the range-based TLBI instructions to do the + * invalidations. Condition deferred TLB invalidation on the + * system supporting FWB, as the optimization is entirely + * pointless when the unmap walker needs to perform CMOs. + */ + return system_supports_tlb_range() && stage2_has_fwb(pgt); +} + +static bool stage2_unmap_defer_tlb_flush(struct stage2_unmap_data *unmap_d= ata) +{ + bool defer_tlb_flush =3D __stage2_unmap_defer_tlb_flush(unmap_data->pgt); + + /* + * Since __stage2_unmap_defer_tlb_flush() is based on alternative + * patching and the TLBIs' operations behavior depend on this, + * track if there's any change in the state during the unmap sequence. + */ + WARN_ON(unmap_data->defer_tlb_flush_init !=3D defer_tlb_flush); + return defer_tlb_flush; +} + +static void stage2_unmap_put_pte(const struct kvm_pgtable_visit_ctx *ctx, + struct kvm_s2_mmu *mmu, + struct kvm_pgtable_mm_ops *mm_ops) { + struct stage2_unmap_data *unmap_data =3D ctx->arg; + /* - * Clear the existing PTE, and perform break-before-make with - * TLB maintenance if it was valid. + * Clear the existing PTE, and perform break-before-make if it was + * valid. Depending on the system support, the TLB maintenance for + * the same can be deferred until the entire unmap is completed. */ if (kvm_pte_valid(ctx->old)) { kvm_clear_pte(ctx->ptep); - kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, ctx->addr, ctx->level); + + if (!stage2_unmap_defer_tlb_flush(unmap_data)) + kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, mmu, + ctx->addr, ctx->level); } =20 mm_ops->put_page(ctx->ptep); @@ -1070,7 +1108,8 @@ int kvm_pgtable_stage2_set_owner(struct kvm_pgtable *= pgt, u64 addr, u64 size, static int stage2_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx, enum kvm_pgtable_walk_flags visit) { - struct kvm_pgtable *pgt =3D ctx->arg; + struct stage2_unmap_data *unmap_data =3D ctx->arg; + struct kvm_pgtable *pgt =3D unmap_data->pgt; struct kvm_s2_mmu *mmu =3D pgt->mmu; struct kvm_pgtable_mm_ops *mm_ops =3D ctx->mm_ops; kvm_pte_t *childp =3D NULL; @@ -1098,7 +1137,7 @@ static int stage2_unmap_walker(const struct kvm_pgtab= le_visit_ctx *ctx, * block entry and rely on the remaining portions being faulted * back lazily. */ - stage2_put_pte(ctx, mmu, mm_ops); + stage2_unmap_put_pte(ctx, mmu, mm_ops); =20 if (need_flush && mm_ops->dcache_clean_inval_poc) mm_ops->dcache_clean_inval_poc(kvm_pte_follow(ctx->old, mm_ops), @@ -1112,13 +1151,23 @@ static int stage2_unmap_walker(const struct kvm_pgt= able_visit_ctx *ctx, =20 int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size) { + int ret; + struct stage2_unmap_data unmap_data =3D { + .pgt =3D pgt, + .defer_tlb_flush_init =3D __stage2_unmap_defer_tlb_flush(pgt), + }; struct kvm_pgtable_walker walker =3D { .cb =3D stage2_unmap_walker, - .arg =3D pgt, + .arg =3D &unmap_data, .flags =3D KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, }; =20 - return kvm_pgtable_walk(pgt, addr, size, &walker); + ret =3D kvm_pgtable_walk(pgt, addr, size, &walker); + if (stage2_unmap_defer_tlb_flush(&unmap_data)) + /* Perform the deferred TLB invalidations */ + kvm_tlb_flush_vmid_range(pgt->mmu, addr, size); + + return ret; } =20 struct stage2_attr_data { --=20 2.41.0.455.g037347b96a-goog