From patchwork Tue Aug 30 19:41:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oliver Upton X-Patchwork-Id: 12959807 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 34B43ECAAA1 for ; Tue, 30 Aug 2022 19:41:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230424AbiH3Tl5 (ORCPT ); Tue, 30 Aug 2022 15:41:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229513AbiH3Tlz (ORCPT ); Tue, 30 Aug 2022 15:41:55 -0400 Received: from out1.migadu.com (out1.migadu.com [91.121.223.63]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1650F726A0; Tue, 30 Aug 2022 12:41:54 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1661888512; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QlZz4xsWZh51ZQP7HNgRWu8mkrkQyxoC5UQCh4dA9Gc=; b=oW0OkHRXICpe1qsMt0Vkf05qJypn89W1g6AlFhTy1KOz5tK4JqHClut6fFaXYCX49Vc1QJ jhWNFu4tgN1b56RXLkVgSjCkxoSdx4TVq936DjQMlyZOnhuv8/848Ta6ygx6EIPnwQZlbP IAcGQ4HxQopueoqeyeKY2SIVQBOPmhQ= From: Oliver Upton To: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , Quentin Perret , Ricardo Koller , Reiji Watanabe , David Matlack , Ben Gardon , Paolo Bonzini , Gavin Shan , Peter Xu , Sean Christopherson , Oliver Upton Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 01/14] KVM: arm64: Add a helper to tear down unlinked stage-2 subtrees Date: Tue, 30 Aug 2022 19:41:19 +0000 Message-Id: <20220830194132.962932-2-oliver.upton@linux.dev> In-Reply-To: <20220830194132.962932-1-oliver.upton@linux.dev> References: <20220830194132.962932-1-oliver.upton@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org A subsequent change to KVM will move the tear down of an unlinked stage-2 subtree out of the critical path of the break-before-make sequence. Introduce a new helper for tearing down unlinked stage-2 subtrees. Leverage the existing stage-2 free walkers to do so, with a deep call into __kvm_pgtable_walk() as the subtree is no longer reachable from the root. Signed-off-by: Oliver Upton --- arch/arm64/include/asm/kvm_pgtable.h | 11 +++++++++++ arch/arm64/kvm/hyp/pgtable.c | 26 ++++++++++++++++++++++++++ 2 files changed, 37 insertions(+) diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index 9f339dffbc1a..d71fb92dc913 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -316,6 +316,17 @@ int __kvm_pgtable_stage2_init(struct kvm_pgtable *pgt, struct kvm_s2_mmu *mmu, */ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt); +/** + * kvm_pgtable_stage2_free_removed() - Free a removed stage-2 paging structure. + * @pgtable: Unlinked stage-2 paging structure to be freed. + * @level: Level of the stage-2 paging structure to be freed. + * @arg: Page-table structure initialised by kvm_pgtable_stage2_init*() + * + * The page-table is assumed to be unreachable by any hardware walkers prior to + * freeing and therefore no TLB invalidation is performed. + */ +void kvm_pgtable_stage2_free_removed(void *pgtable, u32 level, void *arg); + /** * kvm_pgtable_stage2_map() - Install a mapping in a guest stage-2 page-table. * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init*(). diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 2cb3867eb7c2..d8127c25424c 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -1233,3 +1233,29 @@ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt) pgt->mm_ops->free_pages_exact(pgt->pgd, pgd_sz); pgt->pgd = NULL; } + +void kvm_pgtable_stage2_free_removed(void *pgtable, u32 level, void *arg) +{ + struct kvm_pgtable *pgt = (struct kvm_pgtable *)arg; + kvm_pte_t *ptep = (kvm_pte_t *)pgtable; + struct kvm_pgtable_walker walker = { + .cb = stage2_free_walker, + .flags = KVM_PGTABLE_WALK_LEAF | + KVM_PGTABLE_WALK_TABLE_POST, + .arg = pgt->mm_ops, + }; + struct kvm_pgtable_walk_data data = { + .pgt = pgt, + .walker = &walker, + + /* + * At this point the IPA really doesn't matter, as the page + * table being traversed has already been removed from the stage + * 2. Set an appropriate range to cover the entire page table. + */ + .addr = 0, + .end = kvm_granule_size(level), + }; + + WARN_ON(__kvm_pgtable_walk(&data, ptep, level)); +}