diff options
Diffstat (limited to 'arch/arm64/kvm/pkvm.c')
| -rw-r--r-- | arch/arm64/kvm/pkvm.c | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c new file mode 100644 index 0000000000..6ff3ec18c9 --- /dev/null +++ b/arch/arm64/kvm/pkvm.c @@ -0,0 +1,263 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2020 - Google LLC + * Author: Quentin Perret <qperret@google.com> + */ + +#include <linux/init.h> +#include <linux/kmemleak.h> +#include <linux/kvm_host.h> +#include <linux/memblock.h> +#include <linux/mutex.h> +#include <linux/sort.h> + +#include <asm/kvm_pkvm.h> + +#include "hyp_constants.h" + +DEFINE_STATIC_KEY_FALSE(kvm_protected_mode_initialized); + +static struct memblock_region *hyp_memory = kvm_nvhe_sym(hyp_memory); +static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr); + +phys_addr_t hyp_mem_base; +phys_addr_t hyp_mem_size; + +static int cmp_hyp_memblock(const void *p1, const void *p2) +{ + const struct memblock_region *r1 = p1; + const struct memblock_region *r2 = p2; + + return r1->base < r2->base ? -1 : (r1->base > r2->base); +} + +static void __init sort_memblock_regions(void) +{ + sort(hyp_memory, + *hyp_memblock_nr_ptr, + sizeof(struct memblock_region), + cmp_hyp_memblock, + NULL); +} + +static int __init register_memblock_regions(void) +{ + struct memblock_region *reg; + + for_each_mem_region(reg) { + if (*hyp_memblock_nr_ptr >= HYP_MEMBLOCK_REGIONS) + return -ENOMEM; + + hyp_memory[*hyp_memblock_nr_ptr] = *reg; + (*hyp_memblock_nr_ptr)++; + } + sort_memblock_regions(); + + return 0; +} + +void __init kvm_hyp_reserve(void) +{ + u64 hyp_mem_pages = 0; + int ret; + + if (!is_hyp_mode_available() || is_kernel_in_hyp_mode()) + return; + + if (kvm_get_mode() != KVM_MODE_PROTECTED) + return; + + ret = register_memblock_regions(); + if (ret) { + *hyp_memblock_nr_ptr = 0; + kvm_err("Failed to register hyp memblocks: %d\n", ret); + return; + } + + hyp_mem_pages += hyp_s1_pgtable_pages(); + hyp_mem_pages += host_s2_pgtable_pages(); + hyp_mem_pages += hyp_vm_table_pages(); + hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE); + hyp_mem_pages += hyp_ffa_proxy_pages(); + + /* + * Try to allocate a PMD-aligned region to reduce TLB pressure once + * this is unmapped from the host stage-2, and fallback to PAGE_SIZE. + */ + hyp_mem_size = hyp_mem_pages << PAGE_SHIFT; + hyp_mem_base = memblock_phys_alloc(ALIGN(hyp_mem_size, PMD_SIZE), + PMD_SIZE); + if (!hyp_mem_base) + hyp_mem_base = memblock_phys_alloc(hyp_mem_size, PAGE_SIZE); + else + hyp_mem_size = ALIGN(hyp_mem_size, PMD_SIZE); + + if (!hyp_mem_base) { + kvm_err("Failed to reserve hyp memory\n"); + return; + } + + kvm_info("Reserved %lld MiB at 0x%llx\n", hyp_mem_size >> 20, + hyp_mem_base); +} + +/* + * Allocates and donates memory for hypervisor VM structs at EL2. + * + * Allocates space for the VM state, which includes the hyp vm as well as + * the hyp vcpus. + * + * Stores an opaque handler in the kvm struct for future reference. + * + * Return 0 on success, negative error code on failure. + */ +static int __pkvm_create_hyp_vm(struct kvm *host_kvm) +{ + size_t pgd_sz, hyp_vm_sz, hyp_vcpu_sz; + struct kvm_vcpu *host_vcpu; + pkvm_handle_t handle; + void *pgd, *hyp_vm; + unsigned long idx; + int ret; + + if (host_kvm->created_vcpus < 1) + return -EINVAL; + + pgd_sz = kvm_pgtable_stage2_pgd_size(host_kvm->arch.vtcr); + + /* + * The PGD pages will be reclaimed using a hyp_memcache which implies + * page granularity. So, use alloc_pages_exact() to get individual + * refcounts. + */ + pgd = alloc_pages_exact(pgd_sz, GFP_KERNEL_ACCOUNT); + if (!pgd) + return -ENOMEM; + + /* Allocate memory to donate to hyp for vm and vcpu pointers. */ + hyp_vm_sz = PAGE_ALIGN(size_add(PKVM_HYP_VM_SIZE, + size_mul(sizeof(void *), + host_kvm->created_vcpus))); + hyp_vm = alloc_pages_exact(hyp_vm_sz, GFP_KERNEL_ACCOUNT); + if (!hyp_vm) { + ret = -ENOMEM; + goto free_pgd; + } + + /* Donate the VM memory to hyp and let hyp initialize it. */ + ret = kvm_call_hyp_nvhe(__pkvm_init_vm, host_kvm, hyp_vm, pgd); + if (ret < 0) + goto free_vm; + + handle = ret; + + host_kvm->arch.pkvm.handle = handle; + + /* Donate memory for the vcpus at hyp and initialize it. */ + hyp_vcpu_sz = PAGE_ALIGN(PKVM_HYP_VCPU_SIZE); + kvm_for_each_vcpu(idx, host_vcpu, host_kvm) { + void *hyp_vcpu; + + /* Indexing of the vcpus to be sequential starting at 0. */ + if (WARN_ON(host_vcpu->vcpu_idx != idx)) { + ret = -EINVAL; + goto destroy_vm; + } + + hyp_vcpu = alloc_pages_exact(hyp_vcpu_sz, GFP_KERNEL_ACCOUNT); + if (!hyp_vcpu) { + ret = -ENOMEM; + goto destroy_vm; + } + + ret = kvm_call_hyp_nvhe(__pkvm_init_vcpu, handle, host_vcpu, + hyp_vcpu); + if (ret) { + free_pages_exact(hyp_vcpu, hyp_vcpu_sz); + goto destroy_vm; + } + } + + return 0; + +destroy_vm: + pkvm_destroy_hyp_vm(host_kvm); + return ret; +free_vm: + free_pages_exact(hyp_vm, hyp_vm_sz); +free_pgd: + free_pages_exact(pgd, pgd_sz); + return ret; +} + +int pkvm_create_hyp_vm(struct kvm *host_kvm) +{ + int ret = 0; + + mutex_lock(&host_kvm->lock); + if (!host_kvm->arch.pkvm.handle) + ret = __pkvm_create_hyp_vm(host_kvm); + mutex_unlock(&host_kvm->lock); + + return ret; +} + +void pkvm_destroy_hyp_vm(struct kvm *host_kvm) +{ + if (host_kvm->arch.pkvm.handle) { + WARN_ON(kvm_call_hyp_nvhe(__pkvm_teardown_vm, + host_kvm->arch.pkvm.handle)); + } + + host_kvm->arch.pkvm.handle = 0; + free_hyp_memcache(&host_kvm->arch.pkvm.teardown_mc); +} + +int pkvm_init_host_vm(struct kvm *host_kvm) +{ + mutex_init(&host_kvm->lock); + return 0; +} + +static void __init _kvm_host_prot_finalize(void *arg) +{ + int *err = arg; + + if (WARN_ON(kvm_call_hyp_nvhe(__pkvm_prot_finalize))) + WRITE_ONCE(*err, -EINVAL); +} + +static int __init pkvm_drop_host_privileges(void) +{ + int ret = 0; + + /* + * Flip the static key upfront as that may no longer be possible + * once the host stage 2 is installed. + */ + static_branch_enable(&kvm_protected_mode_initialized); + on_each_cpu(_kvm_host_prot_finalize, &ret, 1); + return ret; +} + +static int __init finalize_pkvm(void) +{ + int ret; + + if (!is_protected_kvm_enabled() || !is_kvm_arm_initialised()) + return 0; + + /* + * Exclude HYP sections from kmemleak so that they don't get peeked + * at, which would end badly once inaccessible. + */ + kmemleak_free_part(__hyp_bss_start, __hyp_bss_end - __hyp_bss_start); + kmemleak_free_part_phys(hyp_mem_base, hyp_mem_size); + + ret = pkvm_drop_host_privileges(); + if (ret) + pr_err("Failed to finalize Hyp protection: %d\n", ret); + + return ret; +} +device_initcall_sync(finalize_pkvm); |