From patchwork Mon Aug 13 14:57:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 10564351 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4457617E1 for ; Mon, 13 Aug 2018 14:59:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 331362942A for ; Mon, 13 Aug 2018 14:59:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 262E729432; Mon, 13 Aug 2018 14:59:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5B35E2942A for ; Mon, 13 Aug 2018 14:59:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=X809E7yBK1COE3PT+dH73ItMRphiaQtp6hPUd2G4sc4=; b=a5Rvz26FYSMMhkkuu/5I1n06Xj sUCpOyVTIyvGzkW4iv06EpfOxHF2E/giDVnmeaA5BrQfot6j4LaFxc+uzodqtHReaPzXhDVNlEeZ9 IR0gT2afXRdYeQJcVWNJCHFoAhCS5HsK59dmigCsKs244WbkI3llAi8rhP0ybUzjZvtBMpwFYxnvF XOpRw+NClOE3GIslbToP6W5yi3ZsZrP5wJTfh11oC99vGDK89wQ9ScVs1HcmZ7KSLU/pd837Dr4Tp eIXWxS1yexV/zQ7ma5xGX9xzGJ/KN8ctz+/2zIOPQJilqMVfIDAXm6ZkYp0gbDkz6b6n42T+Yu1mT YUJvcGIQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fpEJj-00063B-Iq; Mon, 13 Aug 2018 14:59:35 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fpEJA-0005Mr-V2 for linux-arm-kernel@lists.infradead.org; Mon, 13 Aug 2018 14:59:04 +0000 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 EAA00ED1; Mon, 13 Aug 2018 07:58:52 -0700 (PDT) Received: from approximate.Emea.Arm.com (approximate.Emea.Arm.com [10.4.13.119]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D60B93F5D0; Mon, 13 Aug 2018 07:58:49 -0700 (PDT) From: Marc Zyngier To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Subject: [PATCH 01/37] arm64: KVM: Add support for Stage-2 control of memory types and cacheability Date: Mon, 13 Aug 2018 15:57:19 +0100 Message-Id: <20180813145755.16566-2-marc.zyngier@arm.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180813145755.16566-1-marc.zyngier@arm.com> References: <20180813145755.16566-1-marc.zyngier@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180813_075901_022485_041D528B X-CRM114-Status: GOOD ( 22.03 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Andrew Jones , Kees Cook , kvm@vger.kernel.org, "Gustavo A . R . Silva" , Andre Przywara , Punit Agrawal , Christoffer Dall , Dongjiu Geng , Jia He , Eric Auger , James Morse , Catalin Marinas , Suzuki Poulose , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Up to ARMv8.3, the combinaison of Stage-1 and Stage-2 attributes results in the strongest attribute of the two stages. This means that the hypervisor has to perform quite a lot of cache maintenance just in case the guest has some non-cacheable mappings around. ARMv8.4 solves this problem by offering a different mode (FWB) where Stage-2 has total control over the memory attribute (this is limited to systems where both I/O and instruction fetches are coherent with the dcache). This is achieved by having a different set of memory attributes in the page tables, and a new bit set in HCR_EL2. On such a system, we can then safely sidestep any form of dcache management. Acked-by: Catalin Marinas Reviewed-by: Christoffer Dall Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/cpucaps.h | 3 ++- arch/arm64/include/asm/kvm_arm.h | 1 + arch/arm64/include/asm/kvm_emulate.h | 2 ++ arch/arm64/include/asm/kvm_mmu.h | 27 +++++++++++++++++++++------ arch/arm64/include/asm/memory.h | 7 +++++++ arch/arm64/include/asm/pgtable-prot.h | 14 ++++++++++++-- arch/arm64/include/asm/sysreg.h | 1 + arch/arm64/kernel/cpufeature.c | 20 ++++++++++++++++++++ virt/kvm/arm/mmu.c | 4 ++++ 9 files changed, 70 insertions(+), 9 deletions(-) diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index 8a699c708fc9..ed84d6536830 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -49,7 +49,8 @@ #define ARM64_HAS_CACHE_DIC 28 #define ARM64_HW_DBM 29 #define ARM64_SSBD 30 +#define ARM64_HAS_STAGE2_FWB 31 -#define ARM64_NCAPS 31 +#define ARM64_NCAPS 32 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/kvm_arm.h b/arch/arm64/include/asm/kvm_arm.h index 6dd285e979c9..aa45df752a16 100644 --- a/arch/arm64/include/asm/kvm_arm.h +++ b/arch/arm64/include/asm/kvm_arm.h @@ -23,6 +23,7 @@ #include /* Hyp Configuration Register (HCR) bits */ +#define HCR_FWB (UL(1) << 46) #define HCR_TEA (UL(1) << 37) #define HCR_TERR (UL(1) << 36) #define HCR_TLOR (UL(1) << 35) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 1dab3a984608..dd98fdf33d99 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -63,6 +63,8 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) /* trap error record accesses */ vcpu->arch.hcr_el2 |= HCR_TERR; } + if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) + vcpu->arch.hcr_el2 |= HCR_FWB; if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) vcpu->arch.hcr_el2 &= ~HCR_RW; diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index fb9a7127bb75..bac9f016736b 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -267,6 +267,15 @@ static inline void __clean_dcache_guest_page(kvm_pfn_t pfn, unsigned long size) { void *va = page_address(pfn_to_page(pfn)); + /* + * With FWB, we ensure that the guest always accesses memory using + * cacheable attributes, and we don't have to clean to PoC when + * faulting in pages. Furthermore, FWB implies IDC, so cleaning to + * PoU is not required either in this case. + */ + if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) + return; + kvm_flush_dcache_to_poc(va, size); } @@ -287,20 +296,26 @@ static inline void __invalidate_icache_guest_page(kvm_pfn_t pfn, static inline void __kvm_flush_dcache_pte(pte_t pte) { - struct page *page = pte_page(pte); - kvm_flush_dcache_to_poc(page_address(page), PAGE_SIZE); + if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) { + struct page *page = pte_page(pte); + kvm_flush_dcache_to_poc(page_address(page), PAGE_SIZE); + } } static inline void __kvm_flush_dcache_pmd(pmd_t pmd) { - struct page *page = pmd_page(pmd); - kvm_flush_dcache_to_poc(page_address(page), PMD_SIZE); + if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) { + struct page *page = pmd_page(pmd); + kvm_flush_dcache_to_poc(page_address(page), PMD_SIZE); + } } static inline void __kvm_flush_dcache_pud(pud_t pud) { - struct page *page = pud_page(pud); - kvm_flush_dcache_to_poc(page_address(page), PUD_SIZE); + if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) { + struct page *page = pud_page(pud); + kvm_flush_dcache_to_poc(page_address(page), PUD_SIZE); + } } #define kvm_virt_to_phys(x) __pa_symbol(x) diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 49d99214f43c..b96442960aea 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -155,6 +155,13 @@ #define MT_S2_NORMAL 0xf #define MT_S2_DEVICE_nGnRE 0x1 +/* + * Memory types for Stage-2 translation when ID_AA64MMFR2_EL1.FWB is 0001 + * Stage-2 enforces Normal-WB and Device-nGnRE + */ +#define MT_S2_FWB_NORMAL 6 +#define MT_S2_FWB_DEVICE_nGnRE 1 + #ifdef CONFIG_ARM64_4K_PAGES #define IOREMAP_MAX_ORDER (PUD_SHIFT) #else diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h index 108ecad7acc5..c66c3047400e 100644 --- a/arch/arm64/include/asm/pgtable-prot.h +++ b/arch/arm64/include/asm/pgtable-prot.h @@ -67,8 +67,18 @@ #define PAGE_HYP_RO __pgprot(_HYP_PAGE_DEFAULT | PTE_HYP | PTE_RDONLY | PTE_HYP_XN) #define PAGE_HYP_DEVICE __pgprot(PROT_DEVICE_nGnRE | PTE_HYP) -#define PAGE_S2 __pgprot(_PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY | PTE_S2_XN) -#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_S2_XN) +#define PAGE_S2_MEMATTR(attr) \ + ({ \ + u64 __val; \ + if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) \ + __val = PTE_S2_MEMATTR(MT_S2_FWB_ ## attr); \ + else \ + __val = PTE_S2_MEMATTR(MT_S2_ ## attr); \ + __val; \ + }) + +#define PAGE_S2 __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(NORMAL) | PTE_S2_RDONLY | PTE_S2_XN) +#define PAGE_S2_DEVICE __pgprot(_PROT_DEFAULT | PAGE_S2_MEMATTR(DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_S2_XN) #define PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_VALID) | PTE_PROT_NONE | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN) #define PAGE_SHARED __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index a8f84812c6e8..98af0b37fb31 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -576,6 +576,7 @@ #define ID_AA64MMFR1_VMIDBITS_16 2 /* id_aa64mmfr2 */ +#define ID_AA64MMFR2_FWB_SHIFT 40 #define ID_AA64MMFR2_AT_SHIFT 32 #define ID_AA64MMFR2_LVA_SHIFT 16 #define ID_AA64MMFR2_IESB_SHIFT 12 diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index f24892a40d2c..d58d1f0abe16 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -192,6 +192,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = { }; static const struct arm64_ftr_bits ftr_id_aa64mmfr2[] = { + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_FWB_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_AT_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_LVA_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR2_IESB_SHIFT, 4, 0), @@ -1026,6 +1027,14 @@ static void cpu_copy_el2regs(const struct arm64_cpu_capabilities *__unused) } #endif +static void cpu_has_fwb(const struct arm64_cpu_capabilities *__unused) +{ + u64 val = read_sysreg_s(SYS_CLIDR_EL1); + + /* Check that CLIDR_EL1.LOU{U,IS} are both 0 */ + WARN_ON(val & (7 << 27 | 7 << 21)); +} + static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "GIC system register CPU interface", @@ -1182,6 +1191,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cache_dic, }, + { + .desc = "Stage-2 Force Write-Back", + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .capability = ARM64_HAS_STAGE2_FWB, + .sys_reg = SYS_ID_AA64MMFR2_EL1, + .sign = FTR_UNSIGNED, + .field_pos = ID_AA64MMFR2_FWB_SHIFT, + .min_field_value = 1, + .matches = has_cpuid_feature, + .cpu_enable = cpu_has_fwb, + }, #ifdef CONFIG_ARM64_HW_AFDBM { /* diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c index 1d90d79706bd..ea7314296ad1 100644 --- a/virt/kvm/arm/mmu.c +++ b/virt/kvm/arm/mmu.c @@ -196,6 +196,10 @@ static void clear_stage2_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr * This is why right after unmapping a page/section and invalidating * the corresponding TLBs, we call kvm_flush_dcache_p*() to make sure * the IO subsystem will never hit in the cache. + * + * This is all avoided on systems that have ARM64_HAS_STAGE2_FWB, as + * we then fully enforce cacheability of RAM, no matter what the guest + * does. */ static void unmap_stage2_ptes(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr, phys_addr_t end)