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 D4232C4338F for ; Thu, 29 Jul 2021 13:29:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B811060EBC for ; Thu, 29 Jul 2021 13:29:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238102AbhG2N3s (ORCPT ); Thu, 29 Jul 2021 09:29:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46370 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237795AbhG2N3F (ORCPT ); Thu, 29 Jul 2021 09:29:05 -0400 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD7DDC061799 for ; Thu, 29 Jul 2021 06:29:02 -0700 (PDT) Received: by mail-qv1-xf4a.google.com with SMTP id m15-20020a0cbf0f0000b02902e60d75210eso3857115qvi.19 for ; Thu, 29 Jul 2021 06:29:02 -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=t9d8PqBzyoMiv4uaDaKWmALSR0AbEM5jj3yE0ogaIjo=; b=qdH4TWs2IPN7BH6Qf64dcpE5qjfH2iCeLcZX05rnMNjDWiBnFROcDGWEe/SdMju7x/ ieDbYf7UO1Mq1ELT6YQ0XasLQyPpiRUTXjG3KEShWGZ9JFwQgDi7gkhanF3t14H2Lrym g4bXAIzrDRY7b8rE1N2wpQCdJQ3W8gXHS8E/CnjFZDjpruQc0oXYrRONUVWJjdhikTu5 ir2JnbEZXVpjouYRcMnnxiQPaEo/yNabkdYo1ggwEFlG75vu2TUW02dmBDAgZ7PyOssP 7FFDhwLvfwHe2cXVTR6aKM4U+/2gXXzCmDt3Jp5HQJXGNJ1OLuNREzhPnRzyyh3OtZkf WWqw== 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=t9d8PqBzyoMiv4uaDaKWmALSR0AbEM5jj3yE0ogaIjo=; b=uUopuDzw8lenx7VCtsaAYHzUDzohYM7BZ20C5YWqhflYtq6mLfelUjzyXS0VVZDKDF MRoBOT8nAZNrXXdPH4+Cc27sIfMhipuTXOrxthNjiI4W3ZXXL7AMfKDs97UeTnTyRW1G thvrGa5ApKBzo69RdP+tvaNNnfZt9hepJV+A1TjpJCDJ7aZlN8DxcWXuGeDrON9USDO6 0i+mv/f+xpOMlFhKKkbfrGDXb1GVd2wAt4NopcWbyuYnEg7vleIC4/1+7hBnNV5IQxc6 xBf4dvMQbb6j/idS8l1uf5oBa7Jd2uwKJsCVHeE+N1bTvwRlhW8k2aCjNVHBTzBwsRQf dnhw== X-Gm-Message-State: AOAM530xIcjsQjVwFC1Ya6k8/pFaKC8V2b6pAFAxNd+jWnGxdOzhaRmi qMjDkAXQDZ1YE9ckFdnCqjUquC9Iooff X-Google-Smtp-Source: ABdhPJxqCORnrX6VEWjxQJG0CdLIdUAJQytJlymD5vtw/Ugu5Brx5yVux+z3aZpshYRqV+Kxtuu7tq0zDGIm X-Received: from luke.lon.corp.google.com ([2a00:79e0:d:210:293a:bc89:7514:5218]) (user=qperret job=sendgmr) by 2002:ad4:5965:: with SMTP id eq5mr4814986qvb.41.1627565341803; Thu, 29 Jul 2021 06:29:01 -0700 (PDT) Date: Thu, 29 Jul 2021 14:28:14 +0100 In-Reply-To: <20210729132818.4091769-1-qperret@google.com> Message-Id: <20210729132818.4091769-18-qperret@google.com> Mime-Version: 1.0 References: <20210729132818.4091769-1-qperret@google.com> X-Mailer: git-send-email 2.32.0.432.gabb21c7263-goog Subject: [PATCH v3 17/21] KVM: arm64: Mark host bss and rodata section as shared 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 As the hypervisor maps the host's .bss and .rodata sections in its stage-1, make sure to tag them as shared in hyp and host page-tables. But since the hypervisor relies on the presence of these mappings, we cannot let the host in complete control of the memory regions -- it must not unshare or donate them to another entity for example. To prevent this, let's transfer the ownership of those ranges to the hypervisor itself, and share the pages back with the host. Signed-off-by: Quentin Perret --- arch/arm64/kvm/hyp/nvhe/setup.c | 82 +++++++++++++++++++++++++++++---- 1 file changed, 74 insertions(+), 8 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c index 0b574d106519..7f557b264f62 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -58,6 +58,7 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, { void *start, *end, *virt = hyp_phys_to_virt(phys); unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT; + enum kvm_pgtable_prot prot; int ret, i; /* Recreate the hyp page-table using the early page allocator */ @@ -83,10 +84,6 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, if (ret) return ret; - ret = pkvm_create_mappings(__start_rodata, __end_rodata, PAGE_HYP_RO); - if (ret) - return ret; - ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO); if (ret) return ret; @@ -95,10 +92,6 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, if (ret) return ret; - ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, PAGE_HYP_RO); - if (ret) - return ret; - ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP); if (ret) return ret; @@ -117,6 +110,24 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, return ret; } + /* + * Map the host's .bss and .rodata sections RO in the hypervisor, but + * transfer the ownerhsip from the host to the hypervisor itself to + * make sure it can't be donated or shared with another entity. + * + * The ownership transtion requires matching changes in the host + * stage-2. This will done later (see finalize_host_mappings()) once the + * hyp_vmemmap is addressable. + */ + prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED); + ret = pkvm_create_mappings(__start_rodata, __end_rodata, prot); + if (ret) + return ret; + + ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, prot); + if (ret) + return ret; + return 0; } @@ -148,6 +159,57 @@ static void hpool_put_page(void *addr) hyp_put_page(&hpool, addr); } +static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level, + kvm_pte_t *ptep, + enum kvm_pgtable_walk_flags flag, + void * const arg) +{ + enum kvm_pgtable_prot prot; + enum pkvm_page_state state; + kvm_pte_t pte = *ptep; + phys_addr_t phys; + + if (!kvm_pte_valid(pte)) + return 0; + + if (level != (KVM_PGTABLE_MAX_LEVELS - 1)) + return -EINVAL; + + phys = kvm_pte_to_phys(pte); + if (!addr_is_memory(phys)) + return 0; + + /* + * Adjust the host stage-2 mappings to match the ownership attributes + * configured in the hypervisor stage-1. + */ + state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(pte)); + switch (state) { + case PKVM_PAGE_OWNED: + return host_stage2_set_owner_locked(phys, phys + PAGE_SIZE, pkvm_hyp_id); + case PKVM_PAGE_SHARED_OWNED: + prot = pkvm_mkstate(KVM_PGTABLE_PROT_RWX, PKVM_PAGE_SHARED_BORROWED); + break; + case PKVM_PAGE_SHARED_BORROWED: + prot = pkvm_mkstate(KVM_PGTABLE_PROT_RWX, PKVM_PAGE_SHARED_OWNED); + break; + default: + return -EINVAL; + } + + return host_stage2_idmap_locked(phys, phys + PAGE_SIZE, prot); +} + +static int finalize_host_mappings(void) +{ + struct kvm_pgtable_walker walker = { + .cb = finalize_host_mappings_walker, + .flags = KVM_PGTABLE_WALK_LEAF, + }; + + return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits), &walker); +} + void __noreturn __pkvm_init_finalise(void) { struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data); @@ -167,6 +229,10 @@ void __noreturn __pkvm_init_finalise(void) if (ret) goto out; + ret = finalize_host_mappings(); + if (ret) + goto out; + pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) { .zalloc_page = hyp_zalloc_hyp_page, .phys_to_virt = hyp_phys_to_virt, -- 2.32.0.432.gabb21c7263-goog