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 CEF25C433F5 for ; Fri, 8 Apr 2022 20:06:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239365AbiDHUIJ (ORCPT ); Fri, 8 Apr 2022 16:08:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38394 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239371AbiDHUIC (ORCPT ); Fri, 8 Apr 2022 16:08:02 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CDF34353A99 for ; Fri, 8 Apr 2022 13:05:55 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id t190-20020a25c3c7000000b006410799ab3dso2067616ybf.21 for ; Fri, 08 Apr 2022 13:05:55 -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=pAGqEnG2raRkXveZrBOcJyHPFm0QVTMkhlJQFJA6T34=; b=fkf7yOt+xD7tPoLc32dR2/1ousTpprVrbdor4w8WJ28DKGW7L4u8ZSraUcycc4uKIx qIhFw4XjsCzjNrsqJZ7FDiR7kbhNdo9HlrECBWIGZQYEgklkOp6x/7lnhjh2nr7AkBsn C9IsV/kKQ4A+DEBXdbfdSnSJyDQG963lgzXVwwu0RFUrvvAINdb93EZG4Rz+364uJ/kC ffGjkLkbzJNk2CmRiYuzdfRe8LxLAzd8qX96szw4FY/GsE2/kqQg4DTyfouy123yi6Fo 3nuCQkMf/4aVhDA2jSGy/I52QR0VqL1WXxHhBpkGiKplOyrniE2sXUjiMpHULw7lt5t0 KcEA== 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=pAGqEnG2raRkXveZrBOcJyHPFm0QVTMkhlJQFJA6T34=; b=x/0lZraI2AMGNwNJVVKGXv1N9s76Eraihw2Dz34XsXWlApiAy7EhzW8S3FgCLgTnXK 9cOKiNazHFKQza19boo8sladrg8HeOfufvc5tK7/cp/82hz03GwYGGxQY9Ot1n2idBAE erKVR+EDYTCMXZJq+zoyE7NVh9+vsJqOGmRUvsCEFfUsaMQX689qdg4PtRmSRKIRJSgB DSwCqAsTae6iu/vnwJSxzB92xN4QRJ5nTwrvtlsltcModiTf3noxB/MEk6xkk9E4eK10 MEecBCrtkSpIdLoUlPhYj6OfeTRsFVvXsLHkYsIXQvEX8FS+UUVtEb0Z2fWrMYixGz/Q t9+g== X-Gm-Message-State: AOAM531ijS3igHlo8rhYq1g+7KhekPZyumGUFE6U3k7qJEEfvsOz5ED6 SEWsAaXiWOXZA5fA0Bah5BBV/FdT2YguvD6mtQ== X-Google-Smtp-Source: ABdhPJw+e7eRfTOjt8ij1JblVkRTOiDGCo90TudLPv3hs+v+1VcmuHXfi9c5ryQLjBORNvuZhqGkr3+gBULrWSkxcA== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:f0ed:c8a:dab7:ecc2]) (user=kaleshsingh job=sendgmr) by 2002:a25:ae1c:0:b0:63d:4d85:acdc with SMTP id a28-20020a25ae1c000000b0063d4d85acdcmr15047111ybj.435.1649448355076; Fri, 08 Apr 2022 13:05:55 -0700 (PDT) Date: Fri, 8 Apr 2022 13:03:27 -0700 In-Reply-To: <20220408200349.1529080-1-kaleshsingh@google.com> Message-Id: <20220408200349.1529080-5-kaleshsingh@google.com> Mime-Version: 1.0 References: <20220408200349.1529080-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.35.1.1178.g4f1659d476-goog Subject: [PATCH v7 4/6] 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 , Andrew Walbran , Mark Rutland , Ard Biesheuvel , Masahiro Yamada , Nathan Chancellor , Changbin Du , Nick Desaulniers , 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 Tested-by: Fuad Tabba Reviewed-by: Fuad Tabba --- Changes in v7: - Add Fuad's Reviewed-by and Tested-by tags. 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); } /* -- 2.35.1.1178.g4f1659d476-goog