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 mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BAE4C433EF for ; Mon, 14 Mar 2022 20:03:59 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id F337F49ECC; Mon, 14 Mar 2022 16:03:58 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@google.com Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id uYqmUSzvA5mP; Mon, 14 Mar 2022 16:03:57 -0400 (EDT) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id C2F2A49EC2; Mon, 14 Mar 2022 16:03:57 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id C4963404CD for ; Mon, 14 Mar 2022 16:03:56 -0400 (EDT) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ZlTjJUEu8EEy for ; Mon, 14 Mar 2022 16:03:55 -0400 (EDT) Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id A396E4086D for ; Mon, 14 Mar 2022 16:03:55 -0400 (EDT) Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-2d61f6c1877so141225777b3.15 for ; Mon, 14 Mar 2022 13:03:55 -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=KBKuM8nQbHEsk5KoB9KDoIyUXnj0iRI96x05Zc5GVwU=; b=pSlak9X+zf0pVcMyDGHXsdj/0ZvCoyfAdmZkLL2IoXQ/eoplgnCHVzUHV6625bNCMO 5W/FfGYImrd/5arptPi/Rh1DZ3oNGT2WHcLtPHwLYae1RG+2+WzzpSLpx2IBnWYENwKv olSKeenA96Zm6AESUkoS6AaJro4cv3oA8G58W7nRuRrabP+0XkTX3+FgmM2KLrYrKfxI fh3CE8qwaMgsfxjjWdwl2sVShwIJXNUkC9SCrJe9gGVTROtWlcut+zWSPLRbuIgzhnlp LaMbeaJkLAlGGeT8FDnOUeP6d721ULqiYxQkoP6I2jelyXGKa7OrDJwlWFpyCLR4N3P3 sZSA== 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=KBKuM8nQbHEsk5KoB9KDoIyUXnj0iRI96x05Zc5GVwU=; b=shpHkzhKjvaXcBHKk0Tta1rN5h0mlXDRyrei0gZy6sR/tTH4ky6tGHMi1kd1l65pZb pAOSDWSMzc27x6CqowTU3BGRI7Tm36xeNQwCM9pk/BZcindFksGfZRahoncZVZkwKDb6 bNVxtsi7NytkmWEQg2sOSll59j5dM8t6PUuoNtRWsSEagKiyYhioZIKwdR0KsXGj0r7t UVKf4LchD5S1MBehSasDH0sKodxuLKUO3B4KHuw6v83UFbNpONuXsWLUGWyftcwQnvWY 6vaFrNUGiVbFHAXjgVONtvpAgEhteHPDmydhmkxzgjsD3b1rZZYDhw5dKTTocYxrtQow WeOg== X-Gm-Message-State: AOAM5331J403bBswDe9s0rlk6CUeIcDk6MpeFhd0bqD8W56JCL2lryWy a4HyaS1Fs4mVbTg3pvXj1d8yfLX7audnh1q63w== X-Google-Smtp-Source: ABdhPJy9MIn39nszadJy4TGmciC+Phtwg3irGAJ8Z0MmmzIQBmJ0g8Fd8p3i/9X7ZdC1H/f6r8RSPw1B8z+qXReY+g== X-Received: from kaleshsingh.mtv.corp.google.com ([2620:15c:211:200:500a:9ac2:e73e:69e3]) (user=kaleshsingh job=sendgmr) by 2002:a0d:e244:0:b0:2db:d6a8:14c9 with SMTP id l65-20020a0de244000000b002dbd6a814c9mr21314233ywe.402.1647288235164; Mon, 14 Mar 2022 13:03:55 -0700 (PDT) Date: Mon, 14 Mar 2022 13:01:12 -0700 In-Reply-To: <20220314200148.2695206-1-kaleshsingh@google.com> Message-Id: <20220314200148.2695206-4-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 3/8] KVM: arm64: Add guard pages for KVM nVHE hypervisor stack From: Kalesh Singh Cc: Catalin Marinas , will@kernel.org, kvmarm@lists.cs.columbia.edu, Andrew Walbran , maz@kernel.org, "Madhavan T. Venkataraman" , kernel-team@android.com, Stephen Boyd , surenb@google.com, Mark Brown , Peter Collingbourne , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Masami Hiramatsu X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu 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 hyp_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 hyp_alloc_private_va_range() returns an error for null pointer, per Fuad - Format comments to < 80 cols, per Fuad Changes in v3: - Handle null ptr in IS_ERR_OR_NULL checks, per Mark arch/arm64/include/asm/kvm_asm.h | 1 + arch/arm64/include/asm/kvm_mmu.h | 3 +++ arch/arm64/kvm/arm.c | 39 +++++++++++++++++++++++++++++--- arch/arm64/kvm/mmu.c | 4 ++-- 4 files changed, 42 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index d5b0386ef765..2e277f2ed671 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -169,6 +169,7 @@ struct kvm_nvhe_init_params { unsigned long tcr_el2; unsigned long tpidr_el2; unsigned long stack_hyp_va; + unsigned long stack_pa; phys_addr_t pgd_pa; unsigned long hcr_el2; unsigned long vttbr; diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index 3cc9aa25f510..967a9ea9a47b 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -116,6 +116,9 @@ alternative_cb_end #include #include +extern struct kvm_pgtable *hyp_pgtable; +extern struct mutex kvm_hyp_pgd_mutex; + void kvm_update_va_mask(struct alt_instr *alt, __le32 *origptr, __le32 *updptr, int nr_inst); void kvm_compute_layout(void); diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 4dca6ffd03d4..72be7e695d8d 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1538,7 +1538,6 @@ static void cpu_prepare_hyp_mode(int cpu) tcr |= (idmap_t0sz & GENMASK(TCR_TxSZ_WIDTH - 1, 0)) << TCR_T0SZ_OFFSET; params->tcr_el2 = tcr; - params->stack_hyp_va = kern_hyp_va(per_cpu(kvm_arm_hyp_stack_page, cpu) + PAGE_SIZE); params->pgd_pa = kvm_mmu_get_httbr(); if (is_protected_kvm_enabled()) params->hcr_el2 = HCR_HOST_NVHE_PROTECTED_FLAGS; @@ -1987,14 +1986,48 @@ static int init_hyp_mode(void) * Map the Hyp stack pages */ for_each_possible_cpu(cpu) { + struct kvm_nvhe_init_params *params = per_cpu_ptr_nvhe_sym(kvm_init_params, cpu); char *stack_page = (char *)per_cpu(kvm_arm_hyp_stack_page, cpu); - err = create_hyp_mappings(stack_page, stack_page + PAGE_SIZE, - PAGE_HYP); + unsigned long hyp_addr; + /* + * 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. + */ + err = hyp_alloc_private_va_range(PAGE_SIZE * 2, &hyp_addr); + if (err) { + kvm_err("Cannot allocate hyp stack guard page\n"); + goto out_err; + } + + /* + * 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. + */ + mutex_lock(&kvm_hyp_pgd_mutex); + err = kvm_pgtable_hyp_map(hyp_pgtable, hyp_addr + PAGE_SIZE, + PAGE_SIZE, __pa(stack_page), PAGE_HYP); + mutex_unlock(&kvm_hyp_pgd_mutex); if (err) { kvm_err("Cannot map hyp stack\n"); goto out_err; } + + /* + * Save the stack PA in nvhe_init_params. This will be needed + * to recreate the stack mapping in protected nVHE mode. + * __hyp_pa() won't do the right thing there, since the stack + * has been mapped in the flexible private VA space. + */ + params->stack_pa = __pa(stack_page); + + params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE); } for_each_possible_cpu(cpu) { diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 7326d683c500..9bfc6d8f3c49 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -22,8 +22,8 @@ #include "trace.h" -static struct kvm_pgtable *hyp_pgtable; -static DEFINE_MUTEX(kvm_hyp_pgd_mutex); +struct kvm_pgtable *hyp_pgtable; +DEFINE_MUTEX(kvm_hyp_pgd_mutex); static unsigned long hyp_idmap_start; static unsigned long hyp_idmap_end; -- 2.35.1.723.g4982287a31-goog _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm