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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 EC9B2C5CFEB for ; Wed, 11 Jul 2018 15:05:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 947AA20881 for ; Wed, 11 Jul 2018 15:05:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 947AA20881 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388894AbeGKPK2 (ORCPT ); Wed, 11 Jul 2018 11:10:28 -0400 Received: from foss.arm.com ([217.140.101.70]:38226 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732705AbeGKPK2 (ORCPT ); Wed, 11 Jul 2018 11:10:28 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EF30D7A9; Wed, 11 Jul 2018 08:05:42 -0700 (PDT) Received: from localhost (e105922-lin.cambridge.arm.com [10.1.206.33]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 705FB3F5B1; Wed, 11 Jul 2018 08:05:42 -0700 (PDT) From: Punit Agrawal To: Suzuki K Poulose Cc: kvmarm@lists.cs.columbia.edu, marc.zyngier@arm.com, linux-kernel@vger.kernel.org, will.deacon@arm.com, Russell King , Catalin Marinas , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v5 4/7] KVM: arm64: Support PUD hugepage in stage2_is_exec() References: <20180709143835.28971-1-punit.agrawal@arm.com> <20180709144124.29164-1-punit.agrawal@arm.com> <20180709144124.29164-4-punit.agrawal@arm.com> Date: Wed, 11 Jul 2018 16:05:40 +0100 In-Reply-To: (Suzuki K. Poulose's message of "Wed, 11 Jul 2018 14:41:29 +0100") Message-ID: <87a7qxq0cb.fsf@e105922-lin.cambridge.arm.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Suzuki K Poulose writes: > On 09/07/18 15:41, Punit Agrawal wrote: >> In preparation for creating PUD hugepages at stage 2, add support for >> detecting execute permissions on PUD page table entries. Faults due to >> lack of execute permissions on page table entries is used to perform >> i-cache invalidation on first execute. >> >> Provide trivial implementations of arm32 helpers to allow sharing of >> code. >> >> Signed-off-by: Punit Agrawal >> Cc: Christoffer Dall >> Cc: Marc Zyngier >> Cc: Russell King >> Cc: Catalin Marinas >> Cc: Will Deacon >> --- >> arch/arm/include/asm/kvm_mmu.h | 6 ++++ >> arch/arm64/include/asm/kvm_mmu.h | 5 +++ >> arch/arm64/include/asm/pgtable-hwdef.h | 2 ++ >> virt/kvm/arm/mmu.c | 49 +++++++++++++++++++++++--- >> 4 files changed, 57 insertions(+), 5 deletions(-) >> >> diff --git a/arch/arm/include/asm/kvm_mmu.h b/arch/arm/include/asm/kvm_mmu.h >> index c23722f75d5c..d05c8986e495 100644 >> --- a/arch/arm/include/asm/kvm_mmu.h >> +++ b/arch/arm/include/asm/kvm_mmu.h >> @@ -96,6 +96,12 @@ static inline bool kvm_s2pud_readonly(pud_t *pud) >> } >> +static inline bool kvm_s2pud_exec(pud_t *pud) >> +{ >> + BUG(); >> + return false; >> +} >> + >> static inline void kvm_set_pmd(pmd_t *pmd, pmd_t new_pmd) >> { >> *pmd = new_pmd; >> diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h >> index 84051930ddfe..15bc1be8f82f 100644 >> --- a/arch/arm64/include/asm/kvm_mmu.h >> +++ b/arch/arm64/include/asm/kvm_mmu.h >> @@ -249,6 +249,11 @@ static inline bool kvm_s2pud_readonly(pud_t *pudp) >> return kvm_s2pte_readonly((pte_t *)pudp); >> } >> +static inline bool kvm_s2pud_exec(pud_t *pudp) >> +{ >> + return !(READ_ONCE(pud_val(*pudp)) & PUD_S2_XN); >> +} >> + >> static inline bool kvm_page_empty(void *ptr) >> { >> struct page *ptr_page = virt_to_page(ptr); >> diff --git a/arch/arm64/include/asm/pgtable-hwdef.h b/arch/arm64/include/asm/pgtable-hwdef.h >> index fd208eac9f2a..10ae592b78b8 100644 >> --- a/arch/arm64/include/asm/pgtable-hwdef.h >> +++ b/arch/arm64/include/asm/pgtable-hwdef.h >> @@ -193,6 +193,8 @@ >> #define PMD_S2_RDWR (_AT(pmdval_t, 3) << 6) /* HAP[2:1] */ >> #define PMD_S2_XN (_AT(pmdval_t, 2) << 53) /* XN[1:0] */ >> +#define PUD_S2_XN (_AT(pudval_t, 2) << 53) /* XN[1:0] >> */ >> + >> /* >> * Memory Attribute override for Stage-2 (MemAttr[3:0]) >> */ >> diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c >> index ed8f8271c389..e73909a31e02 100644 >> --- a/virt/kvm/arm/mmu.c >> +++ b/virt/kvm/arm/mmu.c >> @@ -1038,23 +1038,62 @@ static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache >> return 0; >> } >> -static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr) >> +/* >> + * stage2_get_leaf_entry - walk the stage2 VM page tables and return >> + * true if a valid and present leaf-entry is found. A pointer to the >> + * leaf-entry is returned in the appropriate level variable - pudpp, >> + * pmdpp, ptepp. >> + */ >> +static bool stage2_get_leaf_entry(struct kvm *kvm, phys_addr_t addr, >> + pud_t **pudpp, pmd_t **pmdpp, pte_t **ptepp) >> { >> + pud_t *pudp; >> pmd_t *pmdp; >> pte_t *ptep; > > nit: As mentioned in the other thread, you may initialize the reference > pointers to NULL to make sure we start clean and avoid the initialization > everywhere this is called. I took the approach to not touch the pointers unless they are being assigned a valid pointer. I'll initialise the incoming pointers (p*dpp) before proceeding with the table walk. Thanks, Punit > >> - pmdp = stage2_get_pmd(kvm, NULL, addr); >> + pudp = stage2_get_pud(kvm, NULL, addr); >> + if (!pudp || pud_none(*pudp) || !pud_present(*pudp)) >> + return false; >> + >> + if (pud_huge(*pudp)) { >> + *pudpp = pudp; >> + return true; >> + } >> + >> + pmdp = stage2_pmd_offset(pudp, addr); >> if (!pmdp || pmd_none(*pmdp) || !pmd_present(*pmdp)) >> return false; >> - if (pmd_thp_or_huge(*pmdp)) >> - return kvm_s2pmd_exec(pmdp); >> + if (pmd_thp_or_huge(*pmdp)) { >> + *pmdpp = pmdp; >> + return true; >> + } >> ptep = pte_offset_kernel(pmdp, addr); >> if (!ptep || pte_none(*ptep) || !pte_present(*ptep)) >> return false; >> - return kvm_s2pte_exec(ptep); >> + *ptepp = ptep; >> + return true; >> +} >> + >> +static bool stage2_is_exec(struct kvm *kvm, phys_addr_t addr) >> +{ >> + pud_t *pudp = NULL; >> + pmd_t *pmdp = NULL; >> + pte_t *ptep = NULL; >> + bool found; >> + >> + found = stage2_get_leaf_entry(kvm, addr, &pudp, &pmdp, &ptep); >> + if (!found) >> + return false; >> + >> + if (pudp) >> + return kvm_s2pud_exec(pudp); >> + else if (pmdp) >> + return kvm_s2pmd_exec(pmdp); >> + else >> + return kvm_s2pte_exec(ptep); >> } > > Reviewed-by: Suzuki K Poulose > _______________________________________________ > kvmarm mailing list > kvmarm@lists.cs.columbia.edu > https://lists.cs.columbia.edu/mailman/listinfo/kvmarm