From patchwork Tue Nov 10 14:42:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nikos Nikoleris X-Patchwork-Id: 11894465 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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 89420C388F7 for ; Tue, 10 Nov 2020 14:42:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3D56D20678 for ; Tue, 10 Nov 2020 14:42:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731036AbgKJOmh (ORCPT ); Tue, 10 Nov 2020 09:42:37 -0500 Received: from foss.arm.com ([217.140.110.172]:56828 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730059AbgKJOmg (ORCPT ); Tue, 10 Nov 2020 09:42:36 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 29FE21063; Tue, 10 Nov 2020 06:42:36 -0800 (PST) Received: from camtx2.cambridge.arm.com (camtx2.cambridge.arm.com [10.1.7.22]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F1E1B3F718; Tue, 10 Nov 2020 06:42:34 -0800 (PST) From: Nikos Nikoleris To: kvm@vger.kernel.org Cc: mark.rutland@arm.com, jade.alglave@arm.com, luc.maranget@inria.fr, andre.przywara@arm.com, alexandru.elisei@arm.com, drjones@redhat.com, Luc Maranget Subject: [kvm-unit-tests PATCH v2 1/2] arm: Add mmu_get_pte() to the MMU API Date: Tue, 10 Nov 2020 14:42:05 +0000 Message-Id: <20201110144207.90693-2-nikos.nikoleris@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201110144207.90693-1-nikos.nikoleris@arm.com> References: <20201110144207.90693-1-nikos.nikoleris@arm.com> X-ARM-No-Footer: FoSSMail Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Luc Maranget Add the mmu_get_pte() function that allows a test to get a pointer to the PTE for a valid virtual address. Return NULL if the MMU is off. Signed-off-by: Nikos Nikoleris Signed-off-by: Luc Maranget Co-Developed-by: Nikos Nikoleris Reviewed-by: Andrew Jones Reviewed-by: Alexandru Elisei --- lib/arm/asm/mmu-api.h | 1 + lib/arm/mmu.c | 32 +++++++++++++++++++++----------- 2 files changed, 22 insertions(+), 11 deletions(-) diff --git a/lib/arm/asm/mmu-api.h b/lib/arm/asm/mmu-api.h index 2bbe1fa..3d04d03 100644 --- a/lib/arm/asm/mmu-api.h +++ b/lib/arm/asm/mmu-api.h @@ -22,5 +22,6 @@ extern void mmu_set_range_sect(pgd_t *pgtable, uintptr_t virt_offset, extern void mmu_set_range_ptes(pgd_t *pgtable, uintptr_t virt_offset, phys_addr_t phys_start, phys_addr_t phys_end, pgprot_t prot); +extern pteval_t *mmu_get_pte(pgd_t *pgtable, uintptr_t vaddr); extern void mmu_clear_user(pgd_t *pgtable, unsigned long vaddr); #endif diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c index d937f20..e58da10 100644 --- a/lib/arm/mmu.c +++ b/lib/arm/mmu.c @@ -212,15 +212,21 @@ unsigned long __phys_to_virt(phys_addr_t addr) return addr; } -void mmu_clear_user(pgd_t *pgtable, unsigned long vaddr) +pteval_t *mmu_get_pte(pgd_t *pgtable, uintptr_t vaddr) { + /* + * NOTE: The Arm architecture requires the use of a + * break-before-make sequence before making any changes to + * PTEs (Arm ARM D5-2669 for AArch64, B3-1378 for AArch32). + */ + pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; if (!mmu_enabled()) - return; + return NULL; pgd = pgd_offset(pgtable, vaddr); assert(pgd_valid(*pgd)); @@ -229,17 +235,21 @@ void mmu_clear_user(pgd_t *pgtable, unsigned long vaddr) pmd = pmd_offset(pud, vaddr); assert(pmd_valid(*pmd)); - if (pmd_huge(*pmd)) { - pmd_t entry = __pmd(pmd_val(*pmd) & ~PMD_SECT_USER); - WRITE_ONCE(*pmd, entry); - goto out_flush_tlb; - } + if (pmd_huge(*pmd)) + return &pmd_val(*pmd); pte = pte_offset(pmd, vaddr); assert(pte_valid(*pte)); - pte_t entry = __pte(pte_val(*pte) & ~PTE_USER); - WRITE_ONCE(*pte, entry); -out_flush_tlb: - flush_tlb_page(vaddr); + return &pte_val(*pte); +} + +void mmu_clear_user(pgd_t *pgtable, unsigned long vaddr) +{ + pteval_t *p_pte = mmu_get_pte(pgtable, vaddr); + if (p_pte) { + pteval_t entry = *p_pte & ~PTE_USER; + WRITE_ONCE(*p_pte, entry); + flush_tlb_page(vaddr); + } }