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Mon, 31 Aug 2020 12:31:34 +0000 From: Anup Patel To: Palmer Dabbelt , Palmer Dabbelt , Paul Walmsley , Albert Ou , Paolo Bonzini Cc: Alexander Graf , Atish Patra , Alistair Francis , Damien Le Moal , Anup Patel , kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel Subject: [PATCH v14 11/17] RISC-V: KVM: Implement MMU notifiers Date: Mon, 31 Aug 2020 18:00:09 +0530 Message-Id: <20200831123015.336047-12-anup.patel@wdc.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200831123015.336047-1-anup.patel@wdc.com> References: <20200831123015.336047-1-anup.patel@wdc.com> X-ClientProxiedBy: BM1PR0101CA0046.INDPRD01.PROD.OUTLOOK.COM (2603:1096:b00:1a::32) To DM6PR04MB6201.namprd04.prod.outlook.com (2603:10b6:5:127::32) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from 255.255.255.255 (255.255.255.255) by BM1PR0101CA0046.INDPRD01.PROD.OUTLOOK.COM (2603:1096:b00:1a::32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3326.19 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData: 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 X-OriginatorOrg: wdc.com X-MS-Exchange-CrossTenant-Network-Message-Id: 61c6c01b-ced0-4f50-20e6-08d84da9cc22 X-MS-Exchange-CrossTenant-AuthSource: DM6PR04MB6201.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 31 Aug 2020 12:31:34.6762 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: b61c8803-16f3-4c35-9b17-6f65f441df86 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: O763VFkfhT4EykIRCV3o91bKu9+tPC/Vk5pm0jifwVqWqnx9hG72OCUqF9VkpmloTq6CI9vpZDG8T/ThKagxHQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR04MB6092 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org This patch implements MMU notifiers for KVM RISC-V so that Guest physical address space is in-sync with Host physical address space. This will allow swapping, page migration, etc to work transparently with KVM RISC-V. Signed-off-by: Anup Patel Acked-by: Paolo Bonzini Reviewed-by: Paolo Bonzini Reviewed-by: Alexander Graf --- arch/riscv/include/asm/kvm_host.h | 7 ++ arch/riscv/kvm/Kconfig | 1 + arch/riscv/kvm/mmu.c | 144 +++++++++++++++++++++++++++++- arch/riscv/kvm/vm.c | 1 + 4 files changed, 149 insertions(+), 4 deletions(-) diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm_host.h index 5d70c8cf3733..d25f181c3433 100644 --- a/arch/riscv/include/asm/kvm_host.h +++ b/arch/riscv/include/asm/kvm_host.h @@ -203,6 +203,13 @@ static inline void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) {} static inline void kvm_arch_sched_in(struct kvm_vcpu *vcpu, int cpu) {} static inline void kvm_arch_vcpu_block_finish(struct kvm_vcpu *vcpu) {} +#define KVM_ARCH_WANT_MMU_NOTIFIER +int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, + unsigned long end, unsigned int flags); +int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte); +int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end); +int kvm_test_age_hva(struct kvm *kvm, unsigned long hva); + void __kvm_riscv_hfence_gvma_vmid_gpa(unsigned long gpa, unsigned long vmid); void __kvm_riscv_hfence_gvma_vmid(unsigned long vmid); void __kvm_riscv_hfence_gvma_gpa(unsigned long gpa); diff --git a/arch/riscv/kvm/Kconfig b/arch/riscv/kvm/Kconfig index 633063edaee8..a712bb910cda 100644 --- a/arch/riscv/kvm/Kconfig +++ b/arch/riscv/kvm/Kconfig @@ -20,6 +20,7 @@ if VIRTUALIZATION config KVM tristate "Kernel-based Virtual Machine (KVM) support (EXPERIMENTAL)" depends on RISCV_SBI && MMU + select MMU_NOTIFIER select PREEMPT_NOTIFIERS select ANON_INODES select KVM_MMIO diff --git a/arch/riscv/kvm/mmu.c b/arch/riscv/kvm/mmu.c index 35b9aabe6c57..b31db8a9f362 100644 --- a/arch/riscv/kvm/mmu.c +++ b/arch/riscv/kvm/mmu.c @@ -296,7 +296,8 @@ static void stage2_op_pte(struct kvm *kvm, gpa_t addr, } } -static void stage2_unmap_range(struct kvm *kvm, gpa_t start, gpa_t size) +static void stage2_unmap_range(struct kvm *kvm, gpa_t start, + gpa_t size, bool may_block) { int ret; pte_t *ptep; @@ -321,6 +322,13 @@ static void stage2_unmap_range(struct kvm *kvm, gpa_t start, gpa_t size) next: addr += page_size; + + /* + * If the range is too large, release the kvm->mmu_lock + * to prevent starvation and lockup detector warnings. + */ + if (may_block && addr < end) + cond_resched_lock(&kvm->mmu_lock); } } @@ -404,6 +412,38 @@ int stage2_ioremap(struct kvm *kvm, gpa_t gpa, phys_addr_t hpa, } +static int handle_hva_to_gpa(struct kvm *kvm, + unsigned long start, + unsigned long end, + int (*handler)(struct kvm *kvm, + gpa_t gpa, u64 size, + void *data), + void *data) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + int ret = 0; + + slots = kvm_memslots(kvm); + + /* we only care about the pages that the guest sees */ + kvm_for_each_memslot(memslot, slots) { + unsigned long hva_start, hva_end; + gfn_t gpa; + + hva_start = max(start, memslot->userspace_addr); + hva_end = min(end, memslot->userspace_addr + + (memslot->npages << PAGE_SHIFT)); + if (hva_start >= hva_end) + continue; + + gpa = hva_to_gfn_memslot(hva_start, memslot) << PAGE_SHIFT; + ret |= handler(kvm, gpa, (u64)(hva_end - hva_start), data); + } + + return ret; +} + void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn_offset, @@ -549,7 +589,7 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, spin_lock(&kvm->mmu_lock); if (ret) stage2_unmap_range(kvm, mem->guest_phys_addr, - mem->memory_size); + mem->memory_size, false); spin_unlock(&kvm->mmu_lock); out: @@ -557,6 +597,96 @@ int kvm_arch_prepare_memory_region(struct kvm *kvm, return ret; } +static int kvm_unmap_hva_handler(struct kvm *kvm, + gpa_t gpa, u64 size, void *data) +{ + unsigned int flags = *(unsigned int *)data; + bool may_block = flags & MMU_NOTIFIER_RANGE_BLOCKABLE; + + stage2_unmap_range(kvm, gpa, size, may_block); + return 0; +} + +int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, + unsigned long end, unsigned int flags) +{ + if (!kvm->arch.pgd) + return 0; + + handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, &flags); + return 0; +} + +static int kvm_set_spte_handler(struct kvm *kvm, + gpa_t gpa, u64 size, void *data) +{ + pte_t *pte = (pte_t *)data; + + WARN_ON(size != PAGE_SIZE); + stage2_set_pte(kvm, 0, NULL, gpa, pte); + + return 0; +} + +int kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte) +{ + unsigned long end = hva + PAGE_SIZE; + kvm_pfn_t pfn = pte_pfn(pte); + pte_t stage2_pte; + + if (!kvm->arch.pgd) + return 0; + + stage2_pte = pfn_pte(pfn, PAGE_WRITE_EXEC); + handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &stage2_pte); + + return 0; +} + +static int kvm_age_hva_handler(struct kvm *kvm, + gpa_t gpa, u64 size, void *data) +{ + pte_t *ptep; + u32 ptep_level = 0; + + WARN_ON(size != PAGE_SIZE && size != PMD_SIZE && size != PGDIR_SIZE); + + if (!stage2_get_leaf_entry(kvm, gpa, &ptep, &ptep_level)) + return 0; + + return ptep_test_and_clear_young(NULL, 0, ptep); +} + +int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end) +{ + if (!kvm->arch.pgd) + return 0; + + return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL); +} + +static int kvm_test_age_hva_handler(struct kvm *kvm, + gpa_t gpa, u64 size, void *data) +{ + pte_t *ptep; + u32 ptep_level = 0; + + WARN_ON(size != PAGE_SIZE && size != PMD_SIZE); + if (!stage2_get_leaf_entry(kvm, gpa, &ptep, &ptep_level)) + return 0; + + return pte_young(*ptep); +} + +int kvm_test_age_hva(struct kvm *kvm, unsigned long hva) +{ + if (!kvm->arch.pgd) + return 0; + + return handle_hva_to_gpa(kvm, hva, hva, + kvm_test_age_hva_handler, NULL); +} + int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, struct kvm_memory_slot *memslot, gpa_t gpa, unsigned long hva, bool is_write) @@ -571,7 +701,7 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, struct kvm_mmu_page_cache *pcache = &vcpu->arch.mmu_page_cache; bool logging = (memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY)) ? true : false; - unsigned long vma_pagesize; + unsigned long vma_pagesize, mmu_seq; mmap_read_lock(current->mm); @@ -610,6 +740,8 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, return ret; } + mmu_seq = kvm->mmu_notifier_seq; + hfn = gfn_to_pfn_prot(kvm, gfn, is_write, &writeable); if (hfn == KVM_PFN_ERR_HWPOISON) { send_sig_mceerr(BUS_MCEERR_AR, (void __user *)hva, @@ -628,6 +760,9 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, spin_lock(&kvm->mmu_lock); + if (mmu_notifier_retry(kvm, mmu_seq)) + goto out_unlock; + if (writeable) { kvm_set_pfn_dirty(hfn); mark_page_dirty(kvm, gfn); @@ -641,6 +776,7 @@ int kvm_riscv_stage2_map(struct kvm_vcpu *vcpu, if (ret) kvm_err("Failed to map in stage2\n"); +out_unlock: spin_unlock(&kvm->mmu_lock); kvm_set_pfn_accessed(hfn); kvm_release_pfn_clean(hfn); @@ -674,7 +810,7 @@ void kvm_riscv_stage2_free_pgd(struct kvm *kvm) spin_lock(&kvm->mmu_lock); if (kvm->arch.pgd) { - stage2_unmap_range(kvm, 0UL, stage2_gpa_size); + stage2_unmap_range(kvm, 0UL, stage2_gpa_size, false); pgd = READ_ONCE(kvm->arch.pgd); kvm->arch.pgd = NULL; kvm->arch.pgd_phys = 0; diff --git a/arch/riscv/kvm/vm.c b/arch/riscv/kvm/vm.c index 6cde69a82252..00a1a88008be 100644 --- a/arch/riscv/kvm/vm.c +++ b/arch/riscv/kvm/vm.c @@ -49,6 +49,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) case KVM_CAP_IOEVENTFD: case KVM_CAP_DEVICE_CTRL: case KVM_CAP_USER_MEMORY: + case KVM_CAP_SYNC_MMU: case KVM_CAP_DESTROY_MEMORY_REGION_WORKS: case KVM_CAP_ONE_REG: case KVM_CAP_READONLY_MEM: