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 6B434C64E7D for ; Tue, 17 Nov 2020 18:16:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1284E2466D for ; Tue, 17 Nov 2020 18:16:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="H5BJeQDN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730810AbgKQSQi (ORCPT ); Tue, 17 Nov 2020 13:16:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730801AbgKQSQh (ORCPT ); Tue, 17 Nov 2020 13:16:37 -0500 Received: from mail-wr1-x449.google.com (mail-wr1-x449.google.com [IPv6:2a00:1450:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC42FC0617A6 for ; Tue, 17 Nov 2020 10:16:36 -0800 (PST) Received: by mail-wr1-x449.google.com with SMTP id 91so13039772wrk.17 for ; Tue, 17 Nov 2020 10:16:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=ku0UFgVufHs9v1IJuu4Ni7X8qoCAXYV3NVQ1AKXoaAA=; b=H5BJeQDNLb++2xZvg4tH88cc0a517Nx1EBbTKeYIiv7k2xmQWwSp58eVZTiebUdyMG +g9ZeTElu3osA0nWOAV/aPjF1sobwPu1mjr/Dc4ZR36cFV5rLKkzslvkaXdW4CLYUChE nsu09uy4ADkg28f4TLlCpZGieLbT7PYoNhrfsiVb3HuoZcGEbh4XzBqyFM2bwNG3qIfY hH/rYe/JYRFiC/HTk4i7mRnSpAofJBPD+hamGi87aZT+MwV5MFfE4MgTO4nNxijcnPew C0S1hc2bUUhl2BBBC+fbW8SxHu46dT+sn/YDa0tekeckiqLhsPvIgfkzwciINYE0N9jK cxtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ku0UFgVufHs9v1IJuu4Ni7X8qoCAXYV3NVQ1AKXoaAA=; b=O8b3fWaSYGmGEykY7o2IVhsR75lD84ru13dJm++DMc6LLRxhp5DTrdfZ1sj4o1qhkX ef3J3PdOjnaFaPySKZVBQksQnaIHIcyZScARKXt3FOj2EIa6DE+D4ZJrGtYVyLXRPwk7 qyoOpuURdzXbM221SKegMZTksMvBMuBUfpq1yazfLfTgabxP/HDWzJZwV3av318V+Scb BqXXs7nO9DKI48ow30gGvtpfF7W/JDpn6dG0WCnwg9fxwfqLIYKxfmUMNiE5EGC+mw3q e90C/d4gCHtAi9tLPLXeFtyVYHEFf70yRmb9EGjIJy9deB2pmB0eWB2s+US5cAtqxrdc VWkA== X-Gm-Message-State: AOAM533Ug3gvzy1xSmsZ9qx7aK4r7qxWFhcqrU+MDFRZC3vQ2xwsK4Lh rSLoWGdS+oN4AkWT/5iTdEp8D6Xa1TMb X-Google-Smtp-Source: ABdhPJxGgMTS1HY9eY7+MyhEXSMxE4MyyZGir1Tn8gNiQHb8pv7qDl59xEr1Ob0B7Wzc6Bbww1Gn9i2dBo1H Sender: "qperret via sendgmr" X-Received: from luke.lon.corp.google.com ([2a00:79e0:d:210:f693:9fff:fef4:a7ef]) (user=qperret job=sendgmr) by 2002:a1c:398a:: with SMTP id g132mr368672wma.51.1605636995303; Tue, 17 Nov 2020 10:16:35 -0800 (PST) Date: Tue, 17 Nov 2020 18:15:47 +0000 In-Reply-To: <20201117181607.1761516-1-qperret@google.com> Message-Id: <20201117181607.1761516-8-qperret@google.com> Mime-Version: 1.0 References: <20201117181607.1761516-1-qperret@google.com> X-Mailer: git-send-email 2.29.2.299.gdc1121823c-goog Subject: [RFC PATCH 07/27] KVM: arm64: Introduce a BSS section for use at Hyp From: Quentin Perret To: Catalin Marinas , Will Deacon , Marc Zyngier , James Morse , Julien Thierry , Suzuki K Poulose , Rob Herring , Frank Rowand Cc: "moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)" , open list , "open list:KERNEL VIRTUAL MACHINE FOR ARM64 (KVM/arm64)" , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE" , kernel-team@android.com, android-kvm@google.com, Quentin Perret Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Currently, the hyp code cannot make full use of a bss, as the kernel section is mapped read-only. While this mapping could simply be changed to read-write, it would intermingle even more the hyp and kernel state than they currently are. Instead, introduce a __hyp_bss section, that uses reserved pages, and create the appropriate RW hyp mappings during KVM init. Signed-off-by: Quentin Perret --- arch/arm64/include/asm/sections.h | 1 + arch/arm64/kernel/vmlinux.lds.S | 7 +++++++ arch/arm64/kvm/arm.c | 11 +++++++++++ arch/arm64/kvm/hyp/nvhe/hyp.lds.S | 1 + 4 files changed, 20 insertions(+) diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h index 8ff579361731..f58cf493de16 100644 --- a/arch/arm64/include/asm/sections.h +++ b/arch/arm64/include/asm/sections.h @@ -12,6 +12,7 @@ extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[]; extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[]; extern char __hyp_text_start[], __hyp_text_end[]; extern char __hyp_data_ro_after_init_start[], __hyp_data_ro_after_init_end[]; +extern char __hyp_bss_start[], __hyp_bss_end[]; extern char __idmap_text_start[], __idmap_text_end[]; extern char __initdata_begin[], __initdata_end[]; extern char __inittext_begin[], __inittext_end[]; diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index 4382b5d0645d..ded78a25365d 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -8,6 +8,13 @@ #define RO_EXCEPTION_TABLE_ALIGN 8 #define RUNTIME_DISCARD_EXIT +#define BSS_FIRST_SECTIONS \ + . = ALIGN(PAGE_SIZE); \ + __hyp_bss_start = .; \ + *(.hyp.bss) \ + . = ALIGN(PAGE_SIZE); \ + __hyp_bss_end = .; + #include #include #include diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 7335eb4fb0bd..882eb383bd75 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1709,7 +1709,18 @@ static int init_hyp_mode(void) goto out_err; } + /* + * .hyp.bss is placed at the beginning of the .bss section, so map that + * part RW, and the rest RO as the hyp shouldn't be touching it. + */ err = create_hyp_mappings(kvm_ksym_ref(__bss_start), + kvm_ksym_ref(__hyp_bss_end), PAGE_HYP); + if (err) { + kvm_err("Cannot map hyp bss section: %d\n", err); + goto out_err; + } + + err = create_hyp_mappings(kvm_ksym_ref(__hyp_bss_end), kvm_ksym_ref(__bss_stop), PAGE_HYP_RO); if (err) { kvm_err("Cannot map bss section\n"); diff --git a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S index 5d76ff2ba63e..dc281d90063e 100644 --- a/arch/arm64/kvm/hyp/nvhe/hyp.lds.S +++ b/arch/arm64/kvm/hyp/nvhe/hyp.lds.S @@ -17,4 +17,5 @@ SECTIONS { PERCPU_INPUT(L1_CACHE_BYTES) } HYP_SECTION(.data..ro_after_init) + HYP_SECTION(.bss) } -- 2.29.2.299.gdc1121823c-goog