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 B6479C433FE for ; Mon, 14 Mar 2022 20:04:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244882AbiCNUFq (ORCPT ); Mon, 14 Mar 2022 16:05:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233116AbiCNUFo (ORCPT ); Mon, 14 Mar 2022 16:05:44 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2270E26CD for ; Mon, 14 Mar 2022 13:04:34 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id l19-20020a252513000000b00629235aacb2so14826706ybl.13 for ; Mon, 14 Mar 2022 13:04:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=wcrKUjLTdB/HMJdpeOMPENhm20Kul5UdkQa5+z1O4C4=; b=ly66flbISMQbhQBRlyU0Ey6SFlvMFzMx+MCgdnpmKL7gbVZVnWJLeZ+eBkxab3u2uQ /BAPbfsTDdal7NC9tiorOpcTnS1SPCwqZUI5C63IE+zdaccPQGfmYSxoacTwGxFep/2p sYVB6HiHODgLOoNDiEG83gzblrNaMgs4O6zNyjkLeAiPKK3DV/bg6YbvMdHsVKlKv7KY 550C2M5Wqi0qqi2+Rf5QnAcPMwneFdc65JXbl6PhmeS78GfP9FQWcDKMbAEnn8H1+9ZJ SCEW87y7rwuaOAGH1aDA7RKYVL+X6hcCfbwXAskLXQyF15WTxFS95qoyIpo7yUBKpcK4 iU7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=wcrKUjLTdB/HMJdpeOMPENhm20Kul5UdkQa5+z1O4C4=; b=Fde8Jh66XTZ0KqGSM6XQYHbtNsnOA+m6zlmWtEslAQHnjaDWmiTt4WqCyLFZb3fx80 hjeOIPbDaVG71s2qpLUMuEFsaViuxl5P92ikr90ww6A7WhgTNw9pRfxhdqbidpOgufU7 FeZEpzy2zpdR/c8ZzKSGcPS/0aDmvGsr47jCTI4vyrDtJI4ZnhKmNtTc9tXjyx/HAu+4 JJRoyQru8/nv+A88kYRgigtfdh7QEA1FtBWOOP9E/IqIRZ6RUgIHEIBeTPCIbkVVwbLS lOv4GgDh6sAHGNumw2qllZOnGBId8rtI/VQ3AJfCJMCUdZa/RNIahVcSmP67r4DVP5s5 tYuA== X-Gm-Message-State: AOAM532QPXVJqkNa5R5GowqSxkvDtnQMD2oxaU+dXfcrZFQt+nyAo5eb zg/tzOrDKMTCwWNXlvDykcRV82PywyvLnBm5/w== X-Google-Smtp-Source: ABdhPJzCQjLXyp0zrSq0fPr0qCvgIfWkpLUI1kq/oOWycXP2KR703/KzwXb0OI2paMiDufMo2S2nH7jF9T3m4zbQpw== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:500a:9ac2:e73e:69e3]) (user=kaleshsingh job=sendgmr) by 2002:a81:9c4c:0:b0:2dc:ba4:4ee with SMTP id n12-20020a819c4c000000b002dc0ba404eemr20662044ywa.248.1647288273266; Mon, 14 Mar 2022 13:04:33 -0700 (PDT) Date: Mon, 14 Mar 2022 13:01:13 -0700 In-Reply-To: <20220314200148.2695206-1-kaleshsingh@google.com> Message-Id: <20220314200148.2695206-5-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220314200148.2695206-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.723.g4982287a31-goog Subject: [PATCH v6 4/8] KVM: arm64: Add guard pages for pKVM (protected nVHE) hypervisor stack From: Kalesh Singh Cc: will@kernel.org, maz@kernel.org, qperret@google.com, tabba@google.com, surenb@google.com, kernel-team@android.com, Kalesh Singh , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Mark Rutland , Mark Brown , Masami Hiramatsu , Peter Collingbourne , "Madhavan T. Venkataraman" , Andrew Scull , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Map the stack pages in the flexible private VA range and allocate guard pages below the stack as unbacked VA space. The stack is aligned so that any valid stack address has PAGE_SHIFT bit as 1 - this is used for overflow detection (implemented in a subsequent patch in the series) Signed-off-by: Kalesh Singh --- Changes in v6: - Update call to pkvm_alloc_private_va_range() (return val and params) Changes in v5: - Use a single allocation for stack and guard pages to ensure they are contiguous, per Marc Changes in v4: - Replace IS_ERR_OR_NULL check with IS_ERR check now that pkvm_alloc_private_va_range() returns an error for null pointer, per Fuad Changes in v3: - Handle null ptr in IS_ERR_OR_NULL checks, per Mark arch/arm64/kvm/hyp/nvhe/setup.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c index 27af337f9fea..e8d4ea2fcfa0 100644 --- a/arch/arm64/kvm/hyp/nvhe/setup.c +++ b/arch/arm64/kvm/hyp/nvhe/setup.c @@ -99,17 +99,42 @@ static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size, return ret; for (i = 0; i < hyp_nr_cpus; i++) { + struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i); + unsigned long hyp_addr; + start = (void *)kern_hyp_va(per_cpu_base[i]); end = start + PAGE_ALIGN(hyp_percpu_size); ret = pkvm_create_mappings(start, end, PAGE_HYP); if (ret) return ret; - end = (void *)per_cpu_ptr(&kvm_init_params, i)->stack_hyp_va; - start = end - PAGE_SIZE; - ret = pkvm_create_mappings(start, end, PAGE_HYP); + /* + * Allocate a contiguous HYP private VA range for the stack + * and guard page. The allocation is also aligned based on + * the order of its size. + */ + ret = pkvm_alloc_private_va_range(PAGE_SIZE * 2, &hyp_addr); + if (ret) + return ret; + + /* + * Since the stack grows downwards, map the stack to the page + * at the higher address and leave the lower guard page + * unbacked. + * + * Any valid stack address now has the PAGE_SHIFT bit as 1 + * and addresses corresponding to the guard page have the + * PAGE_SHIFT bit as 0 - this is used for overflow detection. + */ + hyp_spin_lock(&pkvm_pgd_lock); + ret = kvm_pgtable_hyp_map(&pkvm_pgtable, hyp_addr + PAGE_SIZE, + PAGE_SIZE, params->stack_pa, PAGE_HYP); + hyp_spin_unlock(&pkvm_pgd_lock); if (ret) return ret; + + /* Update stack_hyp_va to end of the stack's private VA range */ + params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE); } /* -- 2.35.1.723.g4982287a31-goog