337 lines
8.5 KiB
C
337 lines
8.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2020 Google LLC
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* Author: Quentin Perret <qperret@google.com>
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*/
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#include <linux/kvm_host.h>
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#include <asm/kvm_hyp.h>
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#include <asm/kvm_mmu.h>
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#include <asm/kvm_pgtable.h>
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#include <asm/kvm_pkvm.h>
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#include <nvhe/early_alloc.h>
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#include <nvhe/fixed_config.h>
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#include <nvhe/gfp.h>
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#include <nvhe/memory.h>
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#include <nvhe/mem_protect.h>
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#include <nvhe/mm.h>
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#include <nvhe/trap_handler.h>
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unsigned long hyp_nr_cpus;
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#define hyp_percpu_size ((unsigned long)__per_cpu_end - \
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(unsigned long)__per_cpu_start)
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static void *vmemmap_base;
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static void *hyp_pgt_base;
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static void *host_s2_pgt_base;
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static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
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static struct hyp_pool hpool;
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static int divide_memory_pool(void *virt, unsigned long size)
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{
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unsigned long vstart, vend, nr_pages;
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hyp_early_alloc_init(virt, size);
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hyp_vmemmap_range(__hyp_pa(virt), size, &vstart, &vend);
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nr_pages = (vend - vstart) >> PAGE_SHIFT;
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vmemmap_base = hyp_early_alloc_contig(nr_pages);
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if (!vmemmap_base)
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return -ENOMEM;
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nr_pages = hyp_s1_pgtable_pages();
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hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
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if (!hyp_pgt_base)
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return -ENOMEM;
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nr_pages = host_s2_pgtable_pages();
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host_s2_pgt_base = hyp_early_alloc_contig(nr_pages);
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if (!host_s2_pgt_base)
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return -ENOMEM;
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return 0;
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}
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static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
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unsigned long *per_cpu_base,
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u32 hyp_va_bits)
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{
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void *start, *end, *virt = hyp_phys_to_virt(phys);
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unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
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enum kvm_pgtable_prot prot;
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int ret, i;
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/* Recreate the hyp page-table using the early page allocator */
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hyp_early_alloc_init(hyp_pgt_base, pgt_size);
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ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
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&hyp_early_alloc_mm_ops);
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if (ret)
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return ret;
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ret = hyp_create_idmap(hyp_va_bits);
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if (ret)
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return ret;
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ret = hyp_map_vectors();
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if (ret)
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return ret;
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ret = hyp_back_vmemmap(phys, size, hyp_virt_to_phys(vmemmap_base));
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if (ret)
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return ret;
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ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
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if (ret)
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return ret;
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ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
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if (ret)
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return ret;
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ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
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if (ret)
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return ret;
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ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
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if (ret)
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return ret;
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for (i = 0; i < hyp_nr_cpus; i++) {
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struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i);
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unsigned long hyp_addr;
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start = (void *)kern_hyp_va(per_cpu_base[i]);
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end = start + PAGE_ALIGN(hyp_percpu_size);
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ret = pkvm_create_mappings(start, end, PAGE_HYP);
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if (ret)
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return ret;
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/*
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* Allocate a contiguous HYP private VA range for the stack
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* and guard page. The allocation is also aligned based on
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* the order of its size.
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*/
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ret = pkvm_alloc_private_va_range(PAGE_SIZE * 2, &hyp_addr);
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if (ret)
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return ret;
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/*
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* Since the stack grows downwards, map the stack to the page
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* at the higher address and leave the lower guard page
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* unbacked.
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*
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* Any valid stack address now has the PAGE_SHIFT bit as 1
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* and addresses corresponding to the guard page have the
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* PAGE_SHIFT bit as 0 - this is used for overflow detection.
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*/
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hyp_spin_lock(&pkvm_pgd_lock);
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ret = kvm_pgtable_hyp_map(&pkvm_pgtable, hyp_addr + PAGE_SIZE,
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PAGE_SIZE, params->stack_pa, PAGE_HYP);
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hyp_spin_unlock(&pkvm_pgd_lock);
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if (ret)
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return ret;
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/* Update stack_hyp_va to end of the stack's private VA range */
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params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE);
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}
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/*
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* Map the host's .bss and .rodata sections RO in the hypervisor, but
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* transfer the ownership from the host to the hypervisor itself to
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* make sure it can't be donated or shared with another entity.
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*
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* The ownership transition requires matching changes in the host
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* stage-2. This will be done later (see finalize_host_mappings()) once
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* the hyp_vmemmap is addressable.
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*/
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prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED);
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ret = pkvm_create_mappings(__start_rodata, __end_rodata, prot);
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if (ret)
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return ret;
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ret = pkvm_create_mappings(__hyp_bss_end, __bss_stop, prot);
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if (ret)
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return ret;
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return 0;
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}
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static void update_nvhe_init_params(void)
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{
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struct kvm_nvhe_init_params *params;
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unsigned long i;
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for (i = 0; i < hyp_nr_cpus; i++) {
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params = per_cpu_ptr(&kvm_init_params, i);
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params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
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dcache_clean_inval_poc((unsigned long)params,
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(unsigned long)params + sizeof(*params));
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}
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}
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static void *hyp_zalloc_hyp_page(void *arg)
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{
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return hyp_alloc_pages(&hpool, 0);
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}
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static void hpool_get_page(void *addr)
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{
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hyp_get_page(&hpool, addr);
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}
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static void hpool_put_page(void *addr)
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{
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hyp_put_page(&hpool, addr);
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}
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static int finalize_host_mappings_walker(u64 addr, u64 end, u32 level,
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kvm_pte_t *ptep,
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enum kvm_pgtable_walk_flags flag,
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void * const arg)
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{
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struct kvm_pgtable_mm_ops *mm_ops = arg;
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enum kvm_pgtable_prot prot;
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enum pkvm_page_state state;
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kvm_pte_t pte = *ptep;
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phys_addr_t phys;
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if (!kvm_pte_valid(pte))
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return 0;
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/*
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* Fix-up the refcount for the page-table pages as the early allocator
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* was unable to access the hyp_vmemmap and so the buddy allocator has
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* initialised the refcount to '1'.
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*/
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mm_ops->get_page(ptep);
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if (flag != KVM_PGTABLE_WALK_LEAF)
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return 0;
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if (level != (KVM_PGTABLE_MAX_LEVELS - 1))
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return -EINVAL;
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phys = kvm_pte_to_phys(pte);
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if (!addr_is_memory(phys))
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return -EINVAL;
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/*
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* Adjust the host stage-2 mappings to match the ownership attributes
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* configured in the hypervisor stage-1.
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*/
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state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(pte));
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switch (state) {
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case PKVM_PAGE_OWNED:
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return host_stage2_set_owner_locked(phys, PAGE_SIZE, pkvm_hyp_id);
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case PKVM_PAGE_SHARED_OWNED:
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prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED);
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break;
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case PKVM_PAGE_SHARED_BORROWED:
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prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED);
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break;
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default:
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return -EINVAL;
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}
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return host_stage2_idmap_locked(phys, PAGE_SIZE, prot);
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}
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static int finalize_host_mappings(void)
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{
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struct kvm_pgtable_walker walker = {
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.cb = finalize_host_mappings_walker,
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.flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
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.arg = pkvm_pgtable.mm_ops,
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};
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int i, ret;
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for (i = 0; i < hyp_memblock_nr; i++) {
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struct memblock_region *reg = &hyp_memory[i];
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u64 start = (u64)hyp_phys_to_virt(reg->base);
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ret = kvm_pgtable_walk(&pkvm_pgtable, start, reg->size, &walker);
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if (ret)
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return ret;
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}
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return 0;
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}
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void __noreturn __pkvm_init_finalise(void)
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{
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struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
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struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt;
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unsigned long nr_pages, reserved_pages, pfn;
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int ret;
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/* Now that the vmemmap is backed, install the full-fledged allocator */
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pfn = hyp_virt_to_pfn(hyp_pgt_base);
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nr_pages = hyp_s1_pgtable_pages();
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reserved_pages = hyp_early_alloc_nr_used_pages();
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ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
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if (ret)
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goto out;
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ret = kvm_host_prepare_stage2(host_s2_pgt_base);
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if (ret)
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goto out;
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pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
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.zalloc_page = hyp_zalloc_hyp_page,
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.phys_to_virt = hyp_phys_to_virt,
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.virt_to_phys = hyp_virt_to_phys,
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.get_page = hpool_get_page,
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.put_page = hpool_put_page,
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.page_count = hyp_page_count,
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};
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pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
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ret = finalize_host_mappings();
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if (ret)
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goto out;
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out:
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/*
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* We tail-called to here from handle___pkvm_init() and will not return,
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* so make sure to propagate the return value to the host.
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*/
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cpu_reg(host_ctxt, 1) = ret;
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__host_enter(host_ctxt);
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}
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int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
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unsigned long *per_cpu_base, u32 hyp_va_bits)
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{
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struct kvm_nvhe_init_params *params;
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void *virt = hyp_phys_to_virt(phys);
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void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
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int ret;
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BUG_ON(kvm_check_pvm_sysreg_table());
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if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
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return -EINVAL;
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hyp_spin_lock_init(&pkvm_pgd_lock);
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hyp_nr_cpus = nr_cpus;
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ret = divide_memory_pool(virt, size);
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if (ret)
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return ret;
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ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
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if (ret)
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return ret;
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update_nvhe_init_params();
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/* Jump in the idmap page to switch to the new page-tables */
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params = this_cpu_ptr(&kvm_init_params);
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fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
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fn(__hyp_pa(params), __pkvm_init_finalise);
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unreachable();
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}
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