From patchwork Fri Aug 7 08:48:39 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chenyi Qiang X-Patchwork-Id: 11705173 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 418F0913 for ; Fri, 7 Aug 2020 08:47:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 300DA20855 for ; Fri, 7 Aug 2020 08:47:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728050AbgHGIq6 (ORCPT ); Fri, 7 Aug 2020 04:46:58 -0400 Received: from mga06.intel.com ([134.134.136.31]:65145 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727942AbgHGIq5 (ORCPT ); Fri, 7 Aug 2020 04:46:57 -0400 IronPort-SDR: HkTtbA8K4qqtuVg5p/uqdZhL4Go0wz8cae8WxBnLrtsUwo3fAiSGsBf4Z+0xree9sgAm7eXGM/ Xval5DkM3UdQ== X-IronPort-AV: E=McAfee;i="6000,8403,9705"; a="214565734" X-IronPort-AV: E=Sophos;i="5.75,445,1589266800"; d="scan'208";a="214565734" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Aug 2020 01:46:56 -0700 IronPort-SDR: GbC13P0kZW6dyIqBs8R85hTPlUpzOuVOCZuTKi2tyI/Zdu8WVh2ZiapSht5xQCvP9StdF92u21 mi5j/c6eWrOw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,445,1589266800"; d="scan'208";a="307317184" Received: from chenyi-pc.sh.intel.com ([10.239.159.72]) by orsmga002.jf.intel.com with ESMTP; 07 Aug 2020 01:46:54 -0700 From: Chenyi Qiang To: Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Xiaoyao Li Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC 5/7] KVM: MMU: Add support for PKS emulation Date: Fri, 7 Aug 2020 16:48:39 +0800 Message-Id: <20200807084841.7112-6-chenyi.qiang@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200807084841.7112-1-chenyi.qiang@intel.com> References: <20200807084841.7112-1-chenyi.qiang@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Advertise pkr_mask to cache the conditions where pretection key checks for supervisor pages are needed. When the accessed pages are those with a translation for which the U/S flag is 0 in at least one paging-structure entry controlling the translation, they are the supervisor pages and PKRS enforces the access rights check. Signed-off-by: Chenyi Qiang --- arch/x86/include/asm/kvm_host.h | 8 +++--- arch/x86/kvm/mmu.h | 12 ++++++--- arch/x86/kvm/mmu/mmu.c | 44 +++++++++++++++++---------------- 3 files changed, 35 insertions(+), 29 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 6b739d0d1c97..736e56e023d5 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -422,10 +422,10 @@ struct kvm_mmu { u8 permissions[16]; /* - * The pkru_mask indicates if protection key checks are needed. It - * consists of 16 domains indexed by page fault error code bits [4:1], - * with PFEC.RSVD replaced by ACC_USER_MASK from the page tables. - * Each domain has 2 bits which are ANDed with AD and WD from PKRU. + * The pkr_mask indicates if protection key checks are needed. + * It consists of 16 domains indexed by page fault error code + * bits[4:1]. Each domain has 2 bits which are ANDed with AD + * and WD from PKRU/PKRS. */ u32 pkr_mask; diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h index 7fb4c63d5704..b840b2d9ee9f 100644 --- a/arch/x86/kvm/mmu.h +++ b/arch/x86/kvm/mmu.h @@ -195,15 +195,19 @@ static inline u8 permission_fault(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, WARN_ON(pfec & (PFERR_PK_MASK | PFERR_RSVD_MASK)); if (unlikely(mmu->pkr_mask)) { u32 pkr_bits, offset; + u64 pkrs; /* - * PKRU defines 32 bits, there are 16 domains and 2 - * attribute bits per domain in pkru. pte_pkey is the - * index of the protection domain, so pte_pkey * 2 is - * is the index of the first bit for the domain. + * PKRU and PKRS both define 32 bits. There are 16 domains + * and 2 attribute bits per domain in them. pte_key is the + * index of the protection domain, so pte_pkey * 2 is the + * index of the first bit for the domain. The choice of + * PKRU and PKRS is determined by the accessed pages. */ if (pte_access & PT_USER_MASK) pkr_bits = (vcpu->arch.pkru >> (pte_pkey * 2)) & 3; + else if (!kvm_get_msr(vcpu, MSR_IA32_PKRS, &pkrs)) + pkr_bits = (pkrs >> (pte_pkey * 2)) & 3; else pkr_bits = 0; diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 333b4da739f8..845aea86b138 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -4693,28 +4693,29 @@ static void update_permission_bitmask(struct kvm_vcpu *vcpu, } /* -* PKU is an additional mechanism by which the paging controls access to -* user-mode addresses based on the value in the PKRU register. Protection -* key violations are reported through a bit in the page fault error code. +* Protection Keys (PKEY) is an additional mechanism by which +* the paging controls access to user-mode/supervisor-mode address +* based on the values in PKEY registers (PKRU/PKRS). Protection key +* violations are reported through a bit in the page fault error code. * Unlike other bits of the error code, the PK bit is not known at the * call site of e.g. gva_to_gpa; it must be computed directly in -* permission_fault based on two bits of PKRU, on some machine state (CR4, -* CR0, EFER, CPL), and on other bits of the error code and the page tables. +* permission_fault based on two bits of PKRU/PKRS, on some machine +* state (CR4, CR0, EFER, CPL), and on other bits of the error code +* and the page tables. * * In particular the following conditions come from the error code, the * page tables and the machine state: -* - PK is always zero unless CR4.PKE=1 and EFER.LMA=1 +* - PK is always zero unless CR4.PKE=1/CR4.PKS=1 and EFER.LMA=1 * - PK is always zero if RSVD=1 (reserved bit set) or F=1 (instruction fetch) -* - PK is always zero if U=0 in the page tables -* - PKRU.WD is ignored if CR0.WP=0 and the access is a supervisor access. +* - (PKRU/PKRS).WD is ignored if CR0.WP=0 and the access is a supervisor access. * -* The PKRU bitmask caches the result of these four conditions. The error -* code (minus the P bit) and the page table's U bit form an index into the -* PKRU bitmask. Two bits of the PKRU bitmask are then extracted and ANDed -* with the two bits of the PKRU register corresponding to the protection key. -* For the first three conditions above the bits will be 00, thus masking -* away both AD and WD. For all reads or if the last condition holds, WD -* only will be masked away. +* The pkr_mask caches the result of these three conditions. The error +* code (minus the P bit) forms an index into the pkr_mask. Both PKU and +* PKS shares the same bitmask. Two bits of the pkr_mask are then extracted +* and ANDed with the two bits of the PKEY register corresponding to +* the protection key. For the first two conditions above the bits will be 00, +* thus masking away both AD and WD. For all reads or if the last condition +* holds, WD only will be masked away. */ static void update_pkr_bitmask(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, bool ept) @@ -4727,8 +4728,9 @@ static void update_pkr_bitmask(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, return; } - /* PKEY is enabled only if CR4.PKE and EFER.LMA are both set. */ - if (!kvm_read_cr4_bits(vcpu, X86_CR4_PKE) || !is_long_mode(vcpu)) { + /* PKEY is enabled only if CR4.PKE/CR4.PKS and EFER.LMA are both set. */ + if ((!kvm_read_cr4_bits(vcpu, X86_CR4_PKE) && + !kvm_read_cr4_bits(vcpu, X86_CR4_PKS)) || !is_long_mode(vcpu)) { mmu->pkr_mask = 0; return; } @@ -4757,14 +4759,14 @@ static void update_pkr_bitmask(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu, check_pkey = (!ff && !rsvdf); /* - * write access is controlled by PKRU if it is a - * user access or CR0.WP = 1. + * write access is controlled by PKRU/PKRS if + * it is a user access or CR0.WP = 1. */ check_write = check_pkey && wf && (uf || wp); - /* PKRU.AD stops both read and write access. */ + /* PKRU/PKRS.AD stops both read and write access. */ pkey_bits = !!check_pkey; - /* PKRU.WD stops write access. */ + /* PKRU/PKRS.WD stops write access. */ pkey_bits |= (!!check_write) << 1; mmu->pkr_mask |= (pkey_bits & 3) << pfec;