blob: 110f04627785c8dd0dccebbd2cd674478b255e7b [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2020 Google LLC
* Author: Quentin Perret <qperret@google.com>
*/
#include <linux/kvm_host.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_pgtable.h>
#include <asm/kvm_pkvm.h>
#include <nvhe/early_alloc.h>
#include <nvhe/fixed_config.h>
#include <nvhe/gfp.h>
#include <nvhe/memory.h>
#include <nvhe/mem_protect.h>
#include <nvhe/mm.h>
#include <nvhe/pkvm.h>
#include <nvhe/trap_handler.h>
unsigned long hyp_nr_cpus;
#define hyp_percpu_size ((unsigned long)__per_cpu_end - \
(unsigned long)__per_cpu_start)
static void *vmemmap_base;
static void *vm_table_base;
static void *hyp_pgt_base;
static void *host_s2_pgt_base;
static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
static struct hyp_pool hpool;
static int divide_memory_pool(void *virt, unsigned long size)
{
unsigned long nr_pages;
hyp_early_alloc_init(virt, size);
nr_pages = hyp_vmemmap_pages(sizeof(struct hyp_page));
vmemmap_base = hyp_early_alloc_contig(nr_pages);
if (!vmemmap_base)
return -ENOMEM;
nr_pages = hyp_vm_table_pages();
vm_table_base = hyp_early_alloc_contig(nr_pages);
if (!vm_table_base)
return -ENOMEM;
nr_pages = hyp_s1_pgtable_pages();
hyp_pgt_base = hyp_early_alloc_contig(nr_pages);
if (!hyp_pgt_base)
return -ENOMEM;
nr_pages = host_s2_pgtable_pages();
host_s2_pgt_base = hyp_early_alloc_contig(nr_pages);
if (!host_s2_pgt_base)
return -ENOMEM;
return 0;
}
static int recreate_hyp_mappings(phys_addr_t phys, unsigned long size,
unsigned long *per_cpu_base,
u32 hyp_va_bits)
{
void *start, *end, *virt = hyp_phys_to_virt(phys);
unsigned long pgt_size = hyp_s1_pgtable_pages() << PAGE_SHIFT;
enum kvm_pgtable_prot prot;
int ret, i;
/* Recreate the hyp page-table using the early page allocator */
hyp_early_alloc_init(hyp_pgt_base, pgt_size);
ret = kvm_pgtable_hyp_init(&pkvm_pgtable, hyp_va_bits,
&hyp_early_alloc_mm_ops);
if (ret)
return ret;
ret = hyp_create_idmap(hyp_va_bits);
if (ret)
return ret;
ret = hyp_map_vectors();
if (ret)
return ret;
ret = hyp_back_vmemmap(hyp_virt_to_phys(vmemmap_base));
if (ret)
return ret;
ret = pkvm_create_mappings(__hyp_text_start, __hyp_text_end, PAGE_HYP_EXEC);
if (ret)
return ret;
ret = pkvm_create_mappings(__hyp_rodata_start, __hyp_rodata_end, PAGE_HYP_RO);
if (ret)
return ret;
ret = pkvm_create_mappings(__hyp_bss_start, __hyp_bss_end, PAGE_HYP);
if (ret)
return ret;
ret = pkvm_create_mappings(virt, virt + size, PAGE_HYP);
if (ret)
return ret;
for (i = 0; i < hyp_nr_cpus; i++) {
struct kvm_nvhe_init_params *params = per_cpu_ptr(&kvm_init_params, i);
unsigned long hyp_addr;
start = (void *)kern_hyp_va(per_cpu_base[i]);
end = start + PAGE_ALIGN(hyp_percpu_size);
ret = pkvm_create_mappings(start, end, PAGE_HYP);
if (ret)
return ret;
/*
* Allocate a contiguous HYP private VA range for the stack
* and guard page. The allocation is also aligned based on
* the order of its size.
*/
ret = pkvm_alloc_private_va_range(PAGE_SIZE * 2, &hyp_addr);
if (ret)
return ret;
/*
* Since the stack grows downwards, map the stack to the page
* at the higher address and leave the lower guard page
* unbacked.
*
* Any valid stack address now has the PAGE_SHIFT bit as 1
* and addresses corresponding to the guard page have the
* PAGE_SHIFT bit as 0 - this is used for overflow detection.
*/
hyp_spin_lock(&pkvm_pgd_lock);
ret = kvm_pgtable_hyp_map(&pkvm_pgtable, hyp_addr + PAGE_SIZE,
PAGE_SIZE, params->stack_pa, PAGE_HYP);
hyp_spin_unlock(&pkvm_pgd_lock);
if (ret)
return ret;
/* Update stack_hyp_va to end of the stack's private VA range */
params->stack_hyp_va = hyp_addr + (2 * PAGE_SIZE);
}
/*
* Map the host sections RO in the hypervisor, but transfer the
* ownership from the host to the hypervisor itself to make sure they
* can't be donated or shared with another entity.
*
* The ownership transition requires matching changes in the host
* stage-2. This will be done later (see finalize_host_mappings()) once
* the hyp_vmemmap is addressable.
*/
prot = pkvm_mkstate(PAGE_HYP_RO, PKVM_PAGE_SHARED_OWNED);
ret = pkvm_create_mappings(&kvm_vgic_global_state,
&kvm_vgic_global_state + 1, prot);
if (ret)
return ret;
return 0;
}
static void update_nvhe_init_params(void)
{
struct kvm_nvhe_init_params *params;
unsigned long i;
for (i = 0; i < hyp_nr_cpus; i++) {
params = per_cpu_ptr(&kvm_init_params, i);
params->pgd_pa = __hyp_pa(pkvm_pgtable.pgd);
dcache_clean_inval_poc((unsigned long)params,
(unsigned long)params + sizeof(*params));
}
}
static void *hyp_zalloc_hyp_page(void *arg)
{
return hyp_alloc_pages(&hpool, 0);
}
static void hpool_get_page(void *addr)
{
hyp_get_page(&hpool, addr);
}
static void hpool_put_page(void *addr)
{
hyp_put_page(&hpool, addr);
}
static int fix_host_ownership_walker(const struct kvm_pgtable_visit_ctx *ctx,
enum kvm_pgtable_walk_flags visit)
{
enum kvm_pgtable_prot prot;
enum pkvm_page_state state;
phys_addr_t phys;
if (!kvm_pte_valid(ctx->old))
return 0;
if (ctx->level != (KVM_PGTABLE_MAX_LEVELS - 1))
return -EINVAL;
phys = kvm_pte_to_phys(ctx->old);
if (!addr_is_memory(phys))
return -EINVAL;
/*
* Adjust the host stage-2 mappings to match the ownership attributes
* configured in the hypervisor stage-1.
*/
state = pkvm_getstate(kvm_pgtable_hyp_pte_prot(ctx->old));
switch (state) {
case PKVM_PAGE_OWNED:
return host_stage2_set_owner_locked(phys, PAGE_SIZE, PKVM_ID_HYP);
case PKVM_PAGE_SHARED_OWNED:
prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_BORROWED);
break;
case PKVM_PAGE_SHARED_BORROWED:
prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, PKVM_PAGE_SHARED_OWNED);
break;
default:
return -EINVAL;
}
return host_stage2_idmap_locked(phys, PAGE_SIZE, prot);
}
static int fix_hyp_pgtable_refcnt_walker(const struct kvm_pgtable_visit_ctx *ctx,
enum kvm_pgtable_walk_flags visit)
{
/*
* Fix-up the refcount for the page-table pages as the early allocator
* was unable to access the hyp_vmemmap and so the buddy allocator has
* initialised the refcount to '1'.
*/
if (kvm_pte_valid(ctx->old))
ctx->mm_ops->get_page(ctx->ptep);
return 0;
}
static int fix_host_ownership(void)
{
struct kvm_pgtable_walker walker = {
.cb = fix_host_ownership_walker,
.flags = KVM_PGTABLE_WALK_LEAF,
};
int i, ret;
for (i = 0; i < hyp_memblock_nr; i++) {
struct memblock_region *reg = &hyp_memory[i];
u64 start = (u64)hyp_phys_to_virt(reg->base);
ret = kvm_pgtable_walk(&pkvm_pgtable, start, reg->size, &walker);
if (ret)
return ret;
}
return 0;
}
static int fix_hyp_pgtable_refcnt(void)
{
struct kvm_pgtable_walker walker = {
.cb = fix_hyp_pgtable_refcnt_walker,
.flags = KVM_PGTABLE_WALK_LEAF | KVM_PGTABLE_WALK_TABLE_POST,
.arg = pkvm_pgtable.mm_ops,
};
return kvm_pgtable_walk(&pkvm_pgtable, 0, BIT(pkvm_pgtable.ia_bits),
&walker);
}
void __noreturn __pkvm_init_finalise(void)
{
struct kvm_host_data *host_data = this_cpu_ptr(&kvm_host_data);
struct kvm_cpu_context *host_ctxt = &host_data->host_ctxt;
unsigned long nr_pages, reserved_pages, pfn;
int ret;
/* Now that the vmemmap is backed, install the full-fledged allocator */
pfn = hyp_virt_to_pfn(hyp_pgt_base);
nr_pages = hyp_s1_pgtable_pages();
reserved_pages = hyp_early_alloc_nr_used_pages();
ret = hyp_pool_init(&hpool, pfn, nr_pages, reserved_pages);
if (ret)
goto out;
ret = kvm_host_prepare_stage2(host_s2_pgt_base);
if (ret)
goto out;
pkvm_pgtable_mm_ops = (struct kvm_pgtable_mm_ops) {
.zalloc_page = hyp_zalloc_hyp_page,
.phys_to_virt = hyp_phys_to_virt,
.virt_to_phys = hyp_virt_to_phys,
.get_page = hpool_get_page,
.put_page = hpool_put_page,
.page_count = hyp_page_count,
};
pkvm_pgtable.mm_ops = &pkvm_pgtable_mm_ops;
ret = fix_host_ownership();
if (ret)
goto out;
ret = fix_hyp_pgtable_refcnt();
if (ret)
goto out;
ret = hyp_create_pcpu_fixmap();
if (ret)
goto out;
pkvm_hyp_vm_table_init(vm_table_base);
out:
/*
* We tail-called to here from handle___pkvm_init() and will not return,
* so make sure to propagate the return value to the host.
*/
cpu_reg(host_ctxt, 1) = ret;
__host_enter(host_ctxt);
}
int __pkvm_init(phys_addr_t phys, unsigned long size, unsigned long nr_cpus,
unsigned long *per_cpu_base, u32 hyp_va_bits)
{
struct kvm_nvhe_init_params *params;
void *virt = hyp_phys_to_virt(phys);
void (*fn)(phys_addr_t params_pa, void *finalize_fn_va);
int ret;
BUG_ON(kvm_check_pvm_sysreg_table());
if (!PAGE_ALIGNED(phys) || !PAGE_ALIGNED(size))
return -EINVAL;
hyp_spin_lock_init(&pkvm_pgd_lock);
hyp_nr_cpus = nr_cpus;
ret = divide_memory_pool(virt, size);
if (ret)
return ret;
ret = recreate_hyp_mappings(phys, size, per_cpu_base, hyp_va_bits);
if (ret)
return ret;
update_nvhe_init_params();
/* Jump in the idmap page to switch to the new page-tables */
params = this_cpu_ptr(&kvm_init_params);
fn = (typeof(fn))__hyp_pa(__pkvm_init_switch_pgd);
fn(__hyp_pa(params), __pkvm_init_finalise);
unreachable();
}