From patchwork Sat Jul 22 02:22:51 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Raghavendra Rao Ananta X-Patchwork-Id: 13322718 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 8BCC2C04FDF for ; Sat, 22 Jul 2023 02:23:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229902AbjGVCXV (ORCPT ); Fri, 21 Jul 2023 22:23:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231269AbjGVCXI (ORCPT ); Fri, 21 Jul 2023 22:23:08 -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 9EE971BF4 for ; Fri, 21 Jul 2023 19:23:07 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-d05e334f436so1281371276.2 for ; Fri, 21 Jul 2023 19:23:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1689992587; x=1690597387; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=CAxgFYrkZ9qbsDUo1uJQpSTW39yNyw7CK8s0M5hY5O0=; b=3iFGmjsCWI0cSr6R+O6VEjCyfW9zvlMHhWJhG+l839P3FsYO4gL1EVp1Zvl8J5KBZm gWDHLZwbR5T/RsdaSMNr+PWsaXoHdcJclYOVj00Ryvz0JXZ4BYS8/+hx3pK8yUTJJeTo a5/Y/WZRJ+Cpgl2754cfdsBfDPMsEJuS4tz3ZfnIVNX/gGU28fvxGMohv8fTo1VivHM+ k5v3mRdaKw/ow8ksLRSjR5aq5SfbYF/x22thzHDkHXkkUesujuRvwYduBTk7tl7yPQ2N TmTvFyIwsFPUtv4YYKm+MwQFY8Nm7KPPVkWXEVgsNp0Pql6llfmedndioi5rKnBNAGiA xZPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689992587; x=1690597387; 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=CAxgFYrkZ9qbsDUo1uJQpSTW39yNyw7CK8s0M5hY5O0=; b=UVA2Ej28ncg2SNHPbMQdyktGhlBiIcd1+VwbJtkhl645uRVnWP3ZTi8FK2DANP8lpZ 9Z/+2IxEfuw30KGRRpBdJlOfo8qFobBptvhZ2ioHXXFDH9oTR5GSpw6o/xg7DfJ3mc2n 1V/7Cv6us1Gk8kpbHPmwxCcd5OIfBPNMfE6ZJkoLh7UFkXCHnjAd66TZuwiEnzctK0OA eVvkIN6LDRGd8mH51QujPTIFabUMGF/G8Oo5f/Fi+aqWPXa6NsPy05AyVp6TlTPNy+0v 7G8VOrybNBiDfhlp85IEHhQYEdXmQ4XBzd0gUEINxQ0oMUCU8eygNqeaF8mRXnoif6aF 8I4A== X-Gm-Message-State: ABy/qLbcz6euE6nyegsxauS6uslCUCyPtULbBQtpyqVu6sFr+fCGwRXW 4UCpUhtQBo+vFXYMfNKoCWH3+VLOXJUh X-Google-Smtp-Source: APBJJlGMDpIVJqpXTTAq2sIMW6qbt+e8DqurrZE8mbv8BJ0pkJpydFhWPniYpjZ4KSuFNcWAmdJj1syWWRwO X-Received: from rananta-linux.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:22b5]) (user=rananta job=sendgmr) by 2002:a25:2fd5:0:b0:cb0:e4d4:f4ff with SMTP id v204-20020a252fd5000000b00cb0e4d4f4ffmr22044ybv.3.1689992586869; Fri, 21 Jul 2023 19:23:06 -0700 (PDT) Date: Sat, 22 Jul 2023 02:22:51 +0000 In-Reply-To: <20230722022251.3446223-1-rananta@google.com> Mime-Version: 1.0 References: <20230722022251.3446223-1-rananta@google.com> X-Mailer: git-send-email 2.41.0.487.g6d72f3e995-goog Message-ID: <20230722022251.3446223-13-rananta@google.com> Subject: [PATCH v7 12/12] 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 , Reiji Watanabe , 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-mips@vger.kernel.org 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); } -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_data) +{ + bool defer_tlb_flush = __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 != 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 = 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); } 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 = ctx->arg; + struct stage2_unmap_data *unmap_data = ctx->arg; + struct kvm_pgtable *pgt = unmap_data->pgt; struct kvm_s2_mmu *mmu = pgt->mmu; struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; kvm_pte_t *childp = NULL; @@ -1098,7 +1137,7 @@ static int stage2_unmap_walker(const struct kvm_pgtable_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); 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_pgtable_visit_ctx *ctx, int kvm_pgtable_stage2_unmap(struct kvm_pgtable *pgt, u64 addr, u64 size) { + int ret; + struct stage2_unmap_data unmap_data = { + .pgt = pgt, + .defer_tlb_flush_init = __stage2_unmap_defer_tlb_flush(pgt), + }; struct kvm_pgtable_walker walker = { .cb = stage2_unmap_walker, - .arg = pgt, + .arg = &unmap_data, .flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST, }; - return kvm_pgtable_walk(pgt, addr, size, &walker); + ret = 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; } struct stage2_attr_data {