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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 79E8BC07E9D for ; Mon, 19 Jul 2021 10:48:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6936D60FF4 for ; Mon, 19 Jul 2021 10:48:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236544AbhGSKHk (ORCPT ); Mon, 19 Jul 2021 06:07:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236718AbhGSKHU (ORCPT ); Mon, 19 Jul 2021 06:07:20 -0400 Received: from mail-wm1-x349.google.com (mail-wm1-x349.google.com [IPv6:2a00:1450:4864:20::349]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 690C1C061574 for ; Mon, 19 Jul 2021 02:55:56 -0700 (PDT) Received: by mail-wm1-x349.google.com with SMTP id z127-20020a1c7e850000b02901e46e4d52c0so3813095wmc.6 for ; Mon, 19 Jul 2021 03:48:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=jCVZUl7mrKXhOgc92CUwmjy/8GLL8qBZeqvKPdsULBo=; b=Iv6HLotZSYKnqU+lUooERsXuSEAWx3VwKrcAVoV7fvzbOe+NzdG1VEHTwtAWje0rIB FBjobDwaueZrOJExzeI7sdg7O2/F4Y5IOMh136apaQCyUSWAEPqaYj8KLp39ymbgQFzN AyCeCZTZKejh/1vxFoUB+cZ5GImkWfPknL6py9BFxSeKNLh1bEqTIwkkWL6/9QrqiZhx bufScWZMa+3N64Gm/bfzeL1huLY0dIepVZRrRZvKUeSf1CMleCvkwSbfE+lOV7YzkSqj LXRGJqpFmm/qRenArrM8tK3lx0xGKtC867Gs8dXTkq9S3SqJLJMrrTHmRgHEhXRK2f7q F7Jw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=jCVZUl7mrKXhOgc92CUwmjy/8GLL8qBZeqvKPdsULBo=; b=A30IYn/8SzTjoePmot+h718IaM3vCLCDj6GUWD73k6T5VUbVIcpTRUnQvTbUNYxQQd yuvt5ycn+1YOEbAPaXzWiy1sgHZINv6PEC4Uc+1V10ThRyx2HL+GtxQ4bRfkW6jm1fiZ OoZyxe9RLwvQXEaqnos6Qu311Rs1xigTKxXURDP9ycCme9h8gR+m1N0svq2ZPWgVsScf cJ6CopRA1X1W40bzJ34J48pLFJWGIz5gzIXp1Q85h2ugZBsYj77q5NqgaOmjqhh8ZzSa MY8qZH5SE23681DrXextGMYKbC20+mR8dE1ysR3iCkEPNv6lQxW+hMwKgIW6jWn14bOw tA6g== X-Gm-Message-State: AOAM531+22opVYbxh12aDO54F/QaY9JEcmc8iTxgBuwwuggF9LJCFQyb RJlY7HKmxqo5TE9s7e5ePtJttLonHlsq X-Google-Smtp-Source: ABdhPJzWhrN0PU3u2TAQJIPoHRtvJQ+RMyNfI8W8ip/YuHiS+H6N8RNCyCq0QLT9GDqXoBSdi1WyWB01xUsv X-Received: from luke.lon.corp.google.com ([2a00:79e0:d:210:1a96:a43f:6c2e:bb5a]) (user=qperret job=sendgmr) by 2002:a05:600c:287:: with SMTP id 7mr25592126wmk.1.1626691679361; Mon, 19 Jul 2021 03:47:59 -0700 (PDT) Date: Mon, 19 Jul 2021 11:47:29 +0100 In-Reply-To: <20210719104735.3681732-1-qperret@google.com> Message-Id: <20210719104735.3681732-9-qperret@google.com> Mime-Version: 1.0 References: <20210719104735.3681732-1-qperret@google.com> X-Mailer: git-send-email 2.32.0.402.g57bb445576-goog Subject: [PATCH 08/14] KVM: arm64: Add support for tagging shared pages in page-table From: Quentin Perret To: maz@kernel.org, james.morse@arm.com, alexandru.elisei@arm.com, suzuki.poulose@arm.com, catalin.marinas@arm.com, will@kernel.org Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, ardb@kernel.org, qwandor@google.com, tabba@google.com, dbrazdil@google.com, kernel-team@android.com, Quentin Perret Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The hypervisor will soon be in charge of tracking ownership of all memory pages in the system. The current page-tracking infrastructure at EL2 only allows binary states: a page is either owned or not by an entity. But a number of use-cases will require more complex states for pages that are shared between two entities (host, hypervisor, or guests). In preparation for supporting these use-cases, introduce in the KVM page-table library some infrastructure allowing to tag shared pages using ignored bits (a.k.a. software bits) in PTEs. Signed-off-by: Quentin Perret --- arch/arm64/include/asm/kvm_pgtable.h | 5 +++++ arch/arm64/kvm/hyp/pgtable.c | 25 +++++++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index dd72653314c7..f6d3d5c8910d 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -81,6 +81,8 @@ enum kvm_pgtable_stage2_flags { * @KVM_PGTABLE_PROT_W: Write permission. * @KVM_PGTABLE_PROT_R: Read permission. * @KVM_PGTABLE_PROT_DEVICE: Device attributes. + * @KVM_PGTABLE_STATE_SHARED: Page shared with another entity. + * @KVM_PGTABLE_STATE_BORROWED: Page borrowed from another entity. */ enum kvm_pgtable_prot { KVM_PGTABLE_PROT_X = BIT(0), @@ -88,6 +90,9 @@ enum kvm_pgtable_prot { KVM_PGTABLE_PROT_R = BIT(2), KVM_PGTABLE_PROT_DEVICE = BIT(3), + + KVM_PGTABLE_STATE_SHARED = BIT(4), + KVM_PGTABLE_STATE_BORROWED = BIT(5), }; #define KVM_PGTABLE_PROT_RW (KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W) diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index 5bdbe7a31551..51598b79dafc 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -211,6 +211,29 @@ static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id) return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id); } +static kvm_pte_t pte_ignored_bit_prot(enum kvm_pgtable_prot prot) +{ + kvm_pte_t ignored_bits = 0; + + /* + * Ignored bits 0 and 1 are reserved to track the memory ownership + * state of each page: + * 00: The page is owned solely by the page-table owner. + * 01: The page is owned by the page-table owner, but is shared + * with another entity. + * 10: The page is shared with, but not owned by the page-table owner. + * 11: Reserved for future use (lending). + */ + if (prot & KVM_PGTABLE_STATE_SHARED) { + if (prot & KVM_PGTABLE_STATE_BORROWED) + ignored_bits |= BIT(1); + else + ignored_bits |= BIT(0); + } + + return FIELD_PREP(KVM_PTE_LEAF_ATTR_IGNORED, ignored_bits); +} + static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data, u64 addr, u32 level, kvm_pte_t *ptep, enum kvm_pgtable_walk_flags flag) @@ -357,6 +380,7 @@ static int hyp_set_prot_attr(enum kvm_pgtable_prot prot, kvm_pte_t *ptep) attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_AP, ap); attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S1_SH, sh); attr |= KVM_PTE_LEAF_ATTR_LO_S1_AF; + attr |= pte_ignored_bit_prot(prot); *ptep = attr; return 0; @@ -558,6 +582,7 @@ static int stage2_set_prot_attr(struct kvm_pgtable *pgt, enum kvm_pgtable_prot p attr |= FIELD_PREP(KVM_PTE_LEAF_ATTR_LO_S2_SH, sh); attr |= KVM_PTE_LEAF_ATTR_LO_S2_AF; + attr |= pte_ignored_bit_prot(prot); *ptep = attr; return 0; -- 2.32.0.402.g57bb445576-goog