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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E37CCC54EBD for ; Fri, 13 Jan 2023 03:50:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233392AbjAMDuK (ORCPT ); Thu, 12 Jan 2023 22:50:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229756AbjAMDuI (ORCPT ); Thu, 12 Jan 2023 22:50:08 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D895554703 for ; Thu, 12 Jan 2023 19:50:07 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id a4-20020a5b0004000000b006fdc6aaec4fso21742876ybp.20 for ; Thu, 12 Jan 2023 19:50:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=PpQHC4NcAeUWNMKwINV6b15y1SedzAb1MKkwfHkrc18=; b=sRVsa74aJlqP+CI0/p52Jx9L5VC+mO7wdeF4D7T+Mo1wjekmMl3RXgLkUBGj+ov+7h iqfNNV4APK79XeAWWxe975BGxAcf4PH5/fet8p2+BoKQ9ApU9VqDVk/w0QsIpAxniQPI c4zXPaeSm03ulWOiL6fqv0KI4i3Lvmk4X8aBK/v8jSbOYwCK0RylPwO7oKcc9uXsaVLl Os6NLLvPEKQGFjv1EKil1CqdjqT86lB7Q0JlZnV20/9FaGCY1zZWugPaRzdcTn6bJDU5 FqM8HbiJeD2BA5fPe9wiNAbNPJh0HpDScF044zvfsYz5SF7hO/KGAHBrZXH/Xk722/KT 9Xww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=PpQHC4NcAeUWNMKwINV6b15y1SedzAb1MKkwfHkrc18=; b=50WddlCQRp6NF7LvZYpFwUxDIWlFQfQDRXyzpbOHsxTWzzkyF6nOollmv8nO7vTRgX w2zXsJRp7iA6k5B2H6xC10Llocb9IRl/APA0CR5HOAt3m6sxo9Dd64PlWxX1L9Ym/4P0 pST+q/s5qI6sW/qaHN6HRwCTFNeeDxy6emOvkHouc/yWYSrP2vFA+O9AAzYMxku/mABI +XgoHLwvfCrg3KkZTpNeINS8tUiyPBVjZEte3wBGG7Xn/D/+vztLfOlZugxws36R5Hcx nCTanw/rCdx3piUBeSRlySH2fTIPEYFbW96vvweXKFe7Izq4K4qovcROL31JIRpFNqlH 6sxA== X-Gm-Message-State: AFqh2kr0Ux+j0Gi3D1gwre2cDNBZQ4MGcxwDalusDVr/QfQD5YMNy3ox XabLCXq2doIwv2SbziNXB1JRmLGkGDOaeQ== X-Google-Smtp-Source: AMrXdXtByGjzrtFwpkQ3ixpE9eu5GVo/M7lmKE4T2FFkjUAkJQvw/7lHXnVfIY+XJox9W/TxwJ8KB3r/Q59HNw== X-Received: from ricarkol4.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:1248]) (user=ricarkol job=sendgmr) by 2002:a25:4c81:0:b0:6f9:ece2:7b87 with SMTP id z123-20020a254c81000000b006f9ece27b87mr9161127yba.485.1673581807103; Thu, 12 Jan 2023 19:50:07 -0800 (PST) Date: Fri, 13 Jan 2023 03:49:54 +0000 In-Reply-To: <20230113035000.480021-1-ricarkol@google.com> Mime-Version: 1.0 References: <20230113035000.480021-1-ricarkol@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Message-ID: <20230113035000.480021-4-ricarkol@google.com> Subject: [PATCH 3/9] KVM: arm64: Add kvm_pgtable_stage2_split() From: Ricardo Koller To: pbonzini@redhat.com, maz@kernel.org, oupton@google.com, yuzenghui@huawei.com, dmatlack@google.com Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev, qperret@google.com, catalin.marinas@arm.com, andrew.jones@linux.dev, seanjc@google.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, eric.auger@redhat.com, gshan@redhat.com, reijiw@google.com, rananta@google.com, bgardon@google.com, ricarkol@gmail.com, Ricardo Koller Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Add a new stage2 function, kvm_pgtable_stage2_split(), for splitting a range of huge pages. This will be used for eager-splitting huge pages into PAGE_SIZE pages. The goal is to avoid having to split huge pages on write-protection faults, and instead use this function to do it ahead of time for large ranges (e.g., all guest memory in 1G chunks at a time). No functional change intended. This new function will be used in a subsequent commit. Signed-off-by: Ricardo Koller --- arch/arm64/include/asm/kvm_pgtable.h | 29 ++++++++++++ arch/arm64/kvm/hyp/pgtable.c | 67 ++++++++++++++++++++++++++++ 2 files changed, 96 insertions(+) diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index 8ad78d61af7f..5fbdc1f259fd 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -644,6 +644,35 @@ bool kvm_pgtable_stage2_is_young(struct kvm_pgtable *pgt, u64 addr); */ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size); +/** + * kvm_pgtable_stage2_split() - Split a range of huge pages into leaf PTEs pointing + * to PAGE_SIZE guest pages. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). + * @addr: Intermediate physical address from which to split. + * @size: Size of the range. + * @mc: Cache of pre-allocated and zeroed memory from which to allocate + * page-table pages. + * + * @addr and the end (@addr + @size) are effectively aligned down and up to + * the top level huge-page block size. This is an exampe using 1GB + * huge-pages and 4KB granules. + * + * [---input range---] + * : : + * [--1G block pte--][--1G block pte--][--1G block pte--][--1G block pte--] + * : : + * [--2MB--][--2MB--][--2MB--][--2MB--] + * : : + * [ ][ ][:][ ][ ][ ][ ][ ][:][ ][ ][ ] + * : : + * + * Return: 0 on success, negative error code on failure. Note that + * kvm_pgtable_stage2_split() is best effort: it tries to break as many + * blocks in the input range as allowed by the size of the memcache. It + * will fail it wasn't able to break any block. + */ +int kvm_pgtable_stage2_split(struct kvm_pgtable *pgt, u64 addr, u64 size, void *mc); + /** * kvm_pgtable_walk() - Walk a page-table. * @pgt: Page-table structure initialised by kvm_pgtable_*_init(). diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 0dee13007776..db9d1a28769b 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -1229,6 +1229,73 @@ int kvm_pgtable_stage2_create_removed(struct kvm_pgtable *pgt, return 0; } +struct stage2_split_data { + struct kvm_s2_mmu *mmu; + void *memcache; +}; + +static int stage2_split_walker(const struct kvm_pgtable_visit_ctx *ctx, + enum kvm_pgtable_walk_flags visit) +{ + struct stage2_split_data *data = ctx->arg; + struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops; + kvm_pte_t pte = ctx->old, new, *childp; + enum kvm_pgtable_prot prot; + void *mc = data->memcache; + u32 level = ctx->level; + u64 phys; + int ret; + + /* Nothing to split at the last level */ + if (level == KVM_PGTABLE_MAX_LEVELS - 1) + return 0; + + /* We only split valid block mappings */ + if (!kvm_pte_valid(pte) || kvm_pte_table(pte, ctx->level)) + return 0; + + phys = kvm_pte_to_phys(pte); + prot = kvm_pgtable_stage2_pte_prot(pte); + + ret = kvm_pgtable_stage2_create_removed(data->mmu->pgt, &new, phys, + level, prot, mc); + if (ret) + return ret; + + if (!stage2_try_break_pte(ctx, data->mmu)) { + childp = kvm_pte_follow(new, mm_ops); + kvm_pgtable_stage2_free_removed(mm_ops, childp, level); + mm_ops->put_page(childp); + return -EAGAIN; + } + + /* + * Note, the contents of the page table are guaranteed to be + * made visible before the new PTE is assigned because + * stage2_make_pte() writes the PTE using smp_store_release(). + */ + stage2_make_pte(ctx, new); + dsb(ishst); + return 0; +} + +int kvm_pgtable_stage2_split(struct kvm_pgtable *pgt, + u64 addr, u64 size, void *mc) +{ + struct stage2_split_data split_data = { + .mmu = pgt->mmu, + .memcache = mc, + }; + + struct kvm_pgtable_walker walker = { + .cb = stage2_split_walker, + .flags = KVM_PGTABLE_WALK_LEAF, + .arg = &split_data, + }; + + return kvm_pgtable_walk(pgt, addr, size, &walker); +} + int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu, struct kvm_pgtable_mm_ops *mm_ops, enum kvm_pgtable_stage2_flags flags, -- 2.39.0.314.g84b9a713c41-goog