// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
* Author: Christoffer Dall <c.dall@virtualopensystems.com>
*/
#include <linux/mman.h>
#include <linux/kvm_host.h>
#include <linux/io.h>
#include <linux/hugetlb.h>
#include <linux/sched/signal.h>
#include <trace/events/kvm.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_pgtable.h>
#include <asm/kvm_ras.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/virt.h>
#include "trace.h"
static struct kvm_pgtable *hyp_pgtable;
static DEFINE_MUTEX(kvm_hyp_pgd_mutex);
static unsigned long __ro_after_init hyp_idmap_start;
static unsigned long __ro_after_init hyp_idmap_end;
static phys_addr_t __ro_after_init hyp_idmap_vector;
static unsigned long __ro_after_init io_map_base;
static phys_addr_t __stage2_range_addr_end(phys_addr_t addr, phys_addr_t end,
phys_addr_t size)
{
phys_addr_t boundary = ALIGN_DOWN(addr + size, size);
return (boundary - 1 < end - 1) ? boundary : end;
}
static phys_addr_t stage2_range_addr_end(phys_addr_t addr, phys_addr_t end)
{
phys_addr_t size = kvm_granule_size(KVM_PGTABLE_MIN_BLOCK_LEVEL);
return __stage2_range_addr_end(addr, end, size);
}
/*
* Release kvm_mmu_lock periodically if the memory region is large. Otherwise,
* we may see kernel panics with CONFIG_DETECT_HUNG_TASK,
* CONFIG_LOCKUP_DETECTOR, CONFIG_LOCKDEP. Additionally, holding the lock too
* long will also starve other vCPUs. We have to also make sure that the page
* tables are not freed while we released the lock.
*/
static int stage2_apply_range(struct kvm_s2_mmu *mmu, phys_addr_t addr,
phys_addr_t end,
int (*fn)(struct kvm_pgtable *, u64, u64),
bool resched)
{
struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
int ret;
u64 next;
do {
struct kvm_pgtable *pgt = mmu->pgt;
if (!pgt)
return -EINVAL;
next = stage2_range_addr_end(addr, end);
ret = fn(pgt, addr, next - addr);
if (ret)
break;
if (resched && next != end)
cond_resched_rwlock_write(&kvm->mmu_lock);
} while (addr = next, addr != end);
return ret;
}
#define stage2_apply_range_resched(mmu, addr, end, fn) \
stage2_apply_range(mmu, addr, end, fn, true)
/*
* Get the maximum number of page-tables pages needed to split a range
* of blocks into PAGE_SIZE PTEs. It assumes the range is already
* mapped at level 2, or at level 1 if allowed.
*/
static int kvm_mmu_split_nr_page_tables(u64 range)
{
int n = 0;
if (KVM_PGTABLE_MIN_BLOCK_LEVEL < 2)
n += DIV_ROUND_UP(range, PUD_SIZE);
n += DIV_ROUND_UP(range, PMD_SIZE);
return n;
}
static bool need_split_memcache_topup_or_resched(struct kvm *kvm)
{
struct kvm_mmu_memory_cache *cache;
u64 chunk_size, min;
if (need_resched() || rwlock_needbreak(&kvm->mmu_lock))
return true;
chunk_size = kvm->arch.mmu.split_page_chunk_size;
min = kvm_mmu_split_nr_page_tables(chunk_size);
cache = &kvm->arch.mmu.split_page_cache;
return kvm_mmu_memory_cache_nr_free_objects(cache) < min;
}
static int kvm_mmu_split_huge_pages(struct kvm *kvm, phys_addr_t addr,
phys_addr_t end)
{
struct kvm_mmu_memory_cache *cache;
struct kvm_pgtable *pgt;
int ret, cache_capacity;
u64 next, chunk_size;
lockdep_assert_held_write(&kvm->mmu_lock);
chunk_size = kvm->arch.mmu.split_page_chunk_size;
cache_capacity = kvm_mmu_split_nr_page_tables(chunk_size);
if (chunk_size == 0)
return 0;
cache = &kvm->arch.mmu.split_page_cache;
do {
if (need_split_memcache_topup_or_resched(kvm)) {
write_unlock(&kvm->mmu_lock);
cond_resched();
/* Eager page splitting is best-effort. */
ret = __kvm_mmu_topup_memory_cache(cache,
cache_capacity,
cache_capacity);
write_lock(&kvm->mmu_lock);
if (ret)
break;
}
pgt = kvm->arch.mmu.pgt;
if (!pgt)
return -EINVAL;
next = __stage2_range_addr_end(addr, end, chunk_size);
ret = kvm_pgtable_stage2_split(pgt, addr, next - addr, cache);
if (ret)
break;
} while (addr = next, addr != end);
return ret;
}
static bool memslot_is_logging(struct kvm_memory_slot *memslot)
{
return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);
}
/**
* kvm_arch_flush_remote_tlbs() - flush all VM TLB entries for v7/8
* @kvm: pointer to kvm structure.
*
* Interface to HYP function to flush all VM TLB entries
*/
int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
{
kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
return 0;
}
int kvm_arch_flush_remote_tlbs_range(struct kvm *kvm,
gfn_t gfn, u64 nr_pages)
{
kvm_tlb_flush_vmid_range(&kvm->arch.mmu,
gfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT);
return 0;
}
static bool kvm_is_device_pfn(unsigned long pfn)
{
return !pfn_is_map_memory(pfn);
}
static void *stage2_memcache_zalloc_page(void *arg)
{
struct kvm_mmu_memory_cache *mc = arg;
void *virt;
/* Allocated with __GFP_ZERO, so no need to zero */
virt = kvm_mmu_memory_cache_alloc(mc);
if (virt)
kvm_account_pgtable_pages(virt, 1);
return virt;
}
static void *kvm_host_zalloc_pages_exact(size_t size)
{
return alloc_pages_exact(size, GFP_KERNEL_ACCOUNT | __GFP_ZERO);
}
static void *kvm_s2_zalloc_pages_exact(size_t size)
{
void *virt = kvm_host_zalloc_pages_exact(size);
if (virt)
kvm_account_pgtable_pages(virt, (size >> PAGE_SHIFT));
return virt;
}
static void kvm_s2_free_pages_exact(void *virt, size_t size)
{
kvm_account_pgtable_pages(virt, -(size >> PAGE_SHIFT));
free_pages_exact(virt, size);
}
static struct kvm_pgtable_mm_ops kvm_s2_mm_ops;
static void stage2_free_unlinked_table_rcu_cb(struct rcu_head *head)
{
struct page *page = container_of(head, struct page, rcu_head);
void *pgtable = page_to_virt(page);
u32 level = page_private(page);
kvm_pgtable_stage2_free_unlinked(&kvm_s2_mm_ops, pgtable, level);
}
static void stage2_free_unlinked_table(void *addr, u32 level)
{
struct page *page = virt_to_page(addr);
set_page_private(page, (unsigned long)level);
call_rcu(&page->rcu_head, stage2_free_unlinked_table_rcu_cb);
}
static void kvm_host_get_page(void *addr)
{
get_page(virt_to_page(addr));
}
static void kvm_host_put_page(void *addr)
{
put_page(virt_to_page(addr));
}
static void kvm_s2_put_page(void *addr)
{
struct page *p = virt_to_page(addr);
/* Dropping last refcount, the page will be freed */
if (page_count(p) == 1)
kvm_account_pgtable_pages(addr, -1);
put_page(p);
}
static int kvm_host_page_count(void *addr)
{
return page_count(virt_to_page(addr));
}
static phys_addr_t kvm_host_pa(void *addr)
{
return __pa(addr);
}
static void *kvm_host_va(phys_addr_t phys)
{
return __va(phys);
}
static void clean_dcache_guest_page(void *va, size_t size)
{
__clean_dcache_guest_page(va, size);
}
static void invalidate_icache_guest_page(void *va, size_t size)
{
__invalidate_icache_guest_page(va, size);
}
/*
* Unmapping vs dcache management:
*
* If a guest maps certain memory pages as uncached, all writes will
* bypass the data cache and go directly to RAM. However, the CPUs
* can still speculate reads (not writes) and fill cache lines with
* data.
*
* Those cache lines will be *clean* cache lines though, so a
* clean+invalidate operation is equivalent to an invalidate
* operation, because no cache lines are marked dirty.
*
* Those clean cache lines could be filled prior to an uncached write
* by the guest, and the cache coherent IO subsystem would therefore
* end up writing old data to disk.
*
* This is why right after unmapping a page/section and invalidating
* the corresponding TLBs, we flush 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.
*/
/**
* unmap_stage2_range -- Clear stage2 page table entries to unmap a range
* @mmu: The KVM stage-2 MMU pointer
* @start: The intermediate physical base address of the range to unmap
* @size: The size of the area to unmap
* @may_block: Whether or not we are permitted to block
*
* Clear a range of stage-2 mappings, lowering the various ref-counts. Must
* be called while holding mmu_lock (unless for freeing the stage2 pgd before
* destroying the VM), otherwise another faulting VCPU may come in and mess
* with things behind our backs.
*/
static void __unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size,
bool may_block)
{
struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
phys_addr_t end = start + size;
lockdep_assert_held_write(&kvm->mmu_lock);
WARN_ON(size & ~PAGE_MASK);
WARN_ON(stage2_apply_range(mmu, start, end, kvm_pgtable_stage2_unmap,
may_block));
}
static void unmap_stage2_range(struct kvm_s2_mmu *mmu, phys_addr_t start, u64 size)
{
__unmap_stage2_range(mmu, start, size, true);
}
static void stage2_flush_memslot(struct kvm *kvm,
struct kvm_memory_slot *memslot)
{
phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
phys_addr_t end = addr + PAGE_SIZE * memslot->npages;
stage2_apply_range_resched(&kvm->arch.mmu, addr, end, kvm_pgtable_stage2_flush);
}
/**
* stage2_flush_vm - Invalidate cache for pages mapped in stage 2
* @kvm: The struct kvm pointer
*
* Go through the stage 2 page tables and invalidate any cache lines
* backing memory already mapped to the VM.
*/
static void stage2_flush_vm(struct kvm *kvm)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
int idx, bkt;
idx = srcu_read_lock(&kvm->srcu);
write_lock(&kvm->mmu_lock);
slots = kvm_memslots(kvm);
kvm_for_each_memslot(memslot, bkt, slots)
stage2_flush_memslot(kvm, memslot);
write_unlock(&kvm->mmu_lock);
srcu_read_unlock(&kvm->srcu, idx);
}
/**
* free_hyp_pgds - free Hyp-mode page tables
*/
void __init free_hyp_pgds(void)
{
mutex_lock(&kvm_hyp_pgd_mutex);
if (hyp_pgtable) {
kvm_pgtable_hyp_destroy(hyp_pgtable);
kfree(hyp_pgtable);
hyp_pgtable = NULL;
}
mutex_unlock(&kvm_hyp_pgd_mutex);
}
static bool kvm_host_owns_hyp_mappings(void)
{
if (is_kernel_in_hyp_mode())
return false;
if (static_branch_likely(&kvm_protected_mode_initialized))
return false;
/*
* This can happen at boot time when __create_hyp_mappings() is called
* after the hyp protection has been enabled, but the static key has
* not been flipped yet.
*/
if (!hyp_pgtable && is_protected_kvm_enabled())
return false;
WARN_ON(!hyp_pgtable);
return true;
}
int __create_hyp_mappings(unsigned long start, unsigned long size,
unsigned long phys, enum kvm_pgtable_prot prot)
{
int err;
if (WARN_ON(!kvm_host_owns_hyp_mappings()))
return -EINVAL;
mutex_lock(&kvm_hyp_pgd_mutex);
err = kvm_pgtable_hyp_map(hyp_pgtable, start, size, phys, prot);
mutex_unlock(&kvm_hyp_pgd_mutex);
return err;
}
static phys_addr_t kvm_kaddr_to_phys(void *kaddr)
{
if (!is_vmalloc_addr(kaddr)) {
BUG_ON(!virt_addr_valid(kaddr));
return __pa(kaddr);
} else {
return page_to_phys(vmalloc_to_page(kaddr)) +
offset_in_page(kaddr);
}
}
struct hyp_shared_pfn {
u64 pfn;
int count;
struct rb_node node;
};
static DEFINE_MUTEX(hyp_shared_pfns_lock);
static struct rb_root hyp_shared_pfns = RB_ROOT;
static struct hyp_shared_pfn *find_shared_pfn(u64 pfn, struct rb_node ***node,
struct rb_node **parent)
{
struct hyp_shared_pfn *this;
*node = &hyp_shared_pfns.rb_node;
*parent = NULL;
while (**node) {
this = container_of(**node, struct hyp_shared_pfn, node);
*parent = **node;
if (this->pfn < pfn)
*node = &((**node)->rb_left);
else if (this->pfn > pfn)
*node = &((**node)->rb_right);
else
return this;
}
return NULL;
}
static int share_pfn_hyp(u64 pfn)
{
struct rb_node **node, *parent;
struct hyp_shared_pfn *this;
int ret = 0;
mutex_lock(&hyp_shared_pfns_lock);
this = find_shared_pfn(pfn, &node, &parent);
if (this) {
this->count++;
goto unlock;
}
this = kzalloc(sizeof(*this), GFP_KERNEL);
if (!this) {
ret = -ENOMEM;
goto unlock;
}
this->pfn = pfn;
this->count = 1;
rb_link_node(&this->node, parent, node);
rb_insert_color(&this->node, &hyp_shared_pfns);
ret = kvm_call_hyp_nvhe(__pkvm_host_share_hyp, pfn, 1);
unlock:
mutex_unlock(&hyp_shared_pfns_lock);
return ret;
}
static int unshare_pfn_hyp(u64 pfn)
{
struct rb_node **node, *parent;
struct hyp_shared_pfn *this;
int ret = 0;
mutex_lock(&hyp_shared_pfns_lock);
this = find_shared_pfn(pfn, &node, &parent);
if (WARN_ON(!this)) {
ret = -ENOENT;
goto unlock;
}
this->count--;
if (this->count)
goto unlock;
rb_erase(&this->node, &hyp_shared_pfns);
kfree(this);
ret = kvm_call_hyp_nvhe(__pkvm_host_unshare_hyp, pfn, 1);
unlock:
mutex_unlock(&hyp_shared_pfns_lock);
return ret;
}
int kvm_share_hyp(void *from, void *to)
{
phys_addr_t start, end, cur;
u64 pfn;
int ret;
if (is_kernel_in_hyp_mode())
return 0;
/*
* The share hcall maps things in the 'fixed-offset' region of the hyp
* VA space, so we can only share physically contiguous data-structures
* for now.
*/
if (is_vmalloc_or_module_addr(from) || is_vmalloc_or_module_addr(to))
return -EINVAL;
if (kvm_host_owns_hyp_mappings())
return create_hyp_mappings(from, to, PAGE_HYP);
start = ALIGN_DOWN(__pa(from), PAGE_SIZE);
end = PAGE_ALIGN(__pa(to));
for (cur = start; cur < end; cur += PAGE_SIZE) {
pfn = __phys_to_pfn(cur);
ret = share_pfn_hyp(pfn);
if (ret)
return ret;
}
return 0;
}
void kvm_unshare_hyp(void *from, void *to)
{
phys_addr_t start, end, cur;
u64 pfn;
if (is_kernel_in_hyp_mode() || kvm_host_owns_hyp_mappings() || !from)
return;
start = ALIGN_DOWN(__pa(from), PAGE_SIZE);
end = PAGE_ALIGN(__pa(to));
for (cur = start; cur < end; cur += PAGE_SIZE) {
pfn = __phys_to_pfn(cur);
WARN_ON(unshare_pfn_hyp(pfn));
}
}
/**
* create_hyp_mappings - duplicate a kernel virtual address range in Hyp mode
* @from: The virtual kernel start address of the range
* @to: The virtual kernel end address of the range (exclusive)
* @prot: The protection to be applied to this range
*
* The same virtual address as the kernel virtual address is also used
* in Hyp-mode mapping (modulo HYP_PAGE_OFFSET) to the same underlying
* physical pages.
*/
int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot)
{
phys_addr_t phys_addr;
unsigned long virt_addr;
unsigned long start = kern_hyp_va((unsigned long)from);
unsigned long end = kern_hyp_va((unsigned long)to);
if (is_kernel_in_hyp_mode())
return 0;
if (!kvm_host_owns_hyp_mappings())
return -EPERM;
start = start & PAGE_MASK;
end = PAGE_ALIGN(end);
for (virt_addr = start; virt_addr < end; virt_addr += PAGE_SIZE) {
int err;
phys_addr = kvm_kaddr_to_phys(from + virt_addr - start);
err = __create_hyp_mappings(virt_addr, PAGE_SIZE, phys_addr,
prot);
if (err)
return err;
}
return 0;
}
static int __hyp_alloc_private_va_range(unsigned long base)
{
lockdep_assert_held(&kvm_hyp_pgd_mutex);
if (!PAGE_ALIGNED(base))
return -EINVAL;
/*
* Verify that BIT(VA_BITS - 1) hasn't been flipped by
* allocating the new area, as it would indicate we've
* overflowed the idmap/IO address range.
*/
if ((base ^ io_map_base) & BIT(VA_BITS - 1))
return -ENOMEM;
io_map_base = base;
return 0;
}
/**
* hyp_alloc_private_va_range - Allocates a private VA range.
* @size: The size of the VA range to reserve.
* @haddr: The hypervisor virtual start address of the allocation.
*
* The private virtual address (VA) range is allocated below io_map_base
* and aligned based on the order of @size.
*
* Return: 0 on success or negative error code on failure.
*/
int hyp_alloc_private_va_range(size_t size, unsigned long *haddr)
{
unsigned long base;
int ret = 0;
mutex_lock(&kvm_hyp_pgd_mutex);
/*
* This assumes that we have enough space below the idmap
* page to allocate our VAs. If not, the check in
* __hyp_alloc_private_va_range() will kick. A potential
* alternative would be to detect that overflow and switch
* to an allocation above the idmap.
*
* The allocated size is always a multiple of PAGE_SIZE.
*/
size = PAGE_ALIGN(size);
base = io_map_base - size;
ret = __hyp_alloc_private_va_range(base);
mutex_unlock(&kvm_hyp_pgd_mutex);
if (!ret)
*haddr = base;
return ret;
}
static int __create_hyp_private_mapping(phys_addr_t phys_addr, size_t size,
unsigned long *haddr,
enum kvm_pgtable_prot prot)
{
unsigned long addr;
int ret = 0;
if (!kvm_host_owns_hyp_mappings()) {
addr = kvm_call_hyp_nvhe(__pkvm_create_private_mapping,
phys_addr, size, prot);
if (IS_ERR_VALUE(addr))
return addr;
*haddr = addr;
return 0;
}
size = PAGE_ALIGN(size + offset_in_page(phys_addr));
ret = hyp_alloc_private_va_range(size, &addr);
if (ret)
return ret;
ret = __create_hyp_mappings(addr, size, phys_addr, prot);
if (ret)
return ret;
*haddr = addr + offset_in_page(phys_addr);
return ret;
}
int create_hyp_stack(phys_addr_t phys_addr, unsigned long *haddr)
{
unsigned long base;
size_t size;
int ret;
mutex_lock(&kvm_hyp_pgd_mutex);
/*
* Efficient stack verification using the PAGE_SHIFT bit implies
* an alignment of our allocation on the order of the size.
*/
size = PAGE_SIZE * 2;
base = ALIGN_DOWN(io_map_base - size, size);
ret = __hyp_alloc_private_va_range(base);
mutex_unlock(&kvm_hyp_pgd_mutex);
if (ret) {
kvm_err("Cannot allocate hyp stack guard page\n");
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.
*/
ret = __create_hyp_mappings(base + PAGE_SIZE, PAGE_SIZE, phys_addr,
PAGE_HYP);
if (ret)
kvm_err("Cannot map hyp stack\n");
*haddr = base + size;
return ret;
}
/**
* create_hyp_io_mappings - Map IO into both kernel and HYP
* @phys_addr: The physical start address which gets mapped
* @size: Size of the region being mapped
* @kaddr: Kernel VA for this mapping
* @haddr: HYP VA for this mapping
*/
int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size,
void __iomem **kaddr,
void __iomem **haddr)
{
unsigned long addr;
int ret;
if (is_protected_kvm_enabled())
return -EPERM;
*kaddr = ioremap(phys_addr, size);
if (!*kaddr)
return -ENOMEM;
if (is_kernel_in_hyp_mode()) {
*haddr = *kaddr;
return 0;
}
ret = __create_hyp_private_mapping(phys_addr, size,
&addr, PAGE_HYP_DEVICE);
if (ret) {
iounmap(*kaddr);
*kaddr = NULL;
*haddr = NULL;
return ret;
}
*haddr = (void __iomem *)addr;
return 0;
}
/**
* create_hyp_exec_mappings - Map an executable range into HYP
* @phys_addr: The physical start address which gets mapped
* @size: Size of the region being mapped
* @haddr: HYP VA for this mapping
*/
int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size,
void **haddr)
{
unsigned long addr;
int ret;
BUG_ON(is_kernel_in_hyp_mode());
ret = __create_hyp_private_mapping(phys_addr, size,
&addr, PAGE_HYP_EXEC);
if (ret) {
*haddr = NULL;
return ret;
}
*haddr = (void *)addr;
return 0;
}
static struct kvm_pgtable_mm_ops kvm_user_mm_ops = {
/* We shouldn't need any other callback to walk the PT */
.phys_to_virt = kvm_host_va,
};
static int get_user_mapping_size(struct kvm *kvm, u64 addr)
{
struct kvm_pgtable pgt = {
.pgd = (kvm_pteref_t)kvm->mm->pgd,
.ia_bits = vabits_actual,
.start_level = (KVM_PGTABLE_MAX_LEVELS -
CONFIG_PGTABLE_LEVELS),
.mm_ops = &kvm_user_mm_ops,
};
unsigned long flags;
kvm_pte_t pte = 0; /* Keep GCC quiet... */
u32 level = ~0;
int ret;
/*
* Disable IRQs so that we hazard against a concurrent
* teardown of the userspace page tables (which relies on
* IPI-ing threads).
*/
local_irq_save(flags);
ret = kvm_pgtable_get_leaf(&pgt, addr, &pte, &level);
local_irq_restore(flags);
if (ret)
return ret;
/*
* Not seeing an error, but not updating level? Something went
* deeply wrong...
*/
if (WARN_ON(level >= KVM_PGTABLE_MAX_LEVELS))
return -EFAULT;
/* Oops, the userspace PTs are gone... Replay the fault */
if (!kvm_pte_valid(pte))
return -EAGAIN;
return BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level));
}
static struct kvm_pgtable_mm_ops kvm_s2_mm_ops = {
.zalloc_page = stage2_memcache_zalloc_page,
.zalloc_pages_exact = kvm_s2_zalloc_pages_exact,
.free_pages_exact = kvm_s2_free_pages_exact,
.free_unlinked_table = stage2_free_unlinked_table,
.get_page = kvm_host_get_page,
.put_page = kvm_s2_put_page,
.page_count = kvm_host_page_count,
.phys_to_virt = kvm_host_va,
.virt_to_phys = kvm_host_pa,
.dcache_clean_inval_poc = clean_dcache_guest_page,
.icache_inval_pou = invalidate_icache_guest_page,
};
/**
* kvm_init_stage2_mmu - Initialise a S2 MMU structure
* @kvm: The pointer to the KVM structure
* @mmu: The pointer to the s2 MMU structure
* @type: The machine type of the virtual machine
*
* Allocates only the stage-2 HW PGD level table(s).
* Note we don't need locking here as this is only called when the VM is
* created, which can only be done once.
*/
int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long type)
{
u32 kvm_ipa_limit = get_kvm_ipa_limit();
int cpu, err;
struct kvm_pgtable *pgt;
u64 mmfr0, mmfr1;
u32 phys_shift;
if (type & ~KVM_VM_TYPE_ARM_IPA_SIZE_MASK)
return -EINVAL;
phys_shift = KVM_VM_TYPE_ARM_IPA_SIZE(type);
if (is_protected_kvm_enabled()) {
phys_shift = kvm_ipa_limit;
} else if (phys_shift) {
if (phys_shift > kvm_ipa_limit ||
phys_shift < ARM64_MIN_PARANGE_BITS)
return -EINVAL;
} else {
phys_shift = KVM_PHYS_SHIFT;
if (phys_shift > kvm_ipa_limit) {
pr_warn_once("%s using unsupported default IPA limit, upgrade your VMM\n",
current->comm);
return -EINVAL;
}
}
mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
kvm->arch.vtcr = kvm_get_vtcr(mmfr0, mmfr1, phys_shift);
if (mmu->pgt != NULL) {
kvm_err("kvm_arch already initialized?\n");
return -EINVAL;
}
pgt = kzalloc(sizeof(*pgt), GFP_KERNEL_ACCOUNT);
if (!pgt)
return -ENOMEM;
mmu->arch = &kvm->arch;
err = kvm_pgtable_stage2_init(pgt, mmu, &kvm_s2_mm_ops);
if (err)
goto out_free_pgtable;
mmu->last_vcpu_ran = alloc_percpu(typeof(*mmu->last_vcpu_ran));
if (!mmu->last_vcpu_ran) {
err = -ENOMEM;
goto out_destroy_pgtable;
}
for_each_possible_cpu(cpu)
*per_cpu_ptr(mmu->last_vcpu_ran, cpu) = -1;
/* The eager page splitting is disabled by default */
mmu->split_page_chunk_size = KVM_ARM_EAGER_SPLIT_CHUNK_SIZE_DEFAULT;
mmu->split_page_cache.gfp_zero = __GFP_ZERO;
mmu->pgt = pgt;
mmu->pgd_phys = __pa(pgt->pgd);
return 0;
out_destroy_pgtable:
kvm_pgtable_stage2_destroy(pgt);
out_free_pgtable:
kfree(pgt);
return err;
}
void kvm_uninit_stage2_mmu(struct kvm *kvm)
{
kvm_free_stage2_pgd(&kvm->arch.mmu);
kvm_mmu_free_memory_cache(&kvm->arch.mmu.split_page_cache);
}
static void stage2_unmap_memslot(struct kvm *kvm,
struct kvm_memory_slot *memslot)
{
hva_t hva = memslot->userspace_addr;
phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT;
phys_addr_t size = PAGE_SIZE * memslot->npages;
hva_t reg_end = hva + size;
/*
* A memory region could potentially cover multiple VMAs, and any holes
* between them, so iterate over all of them to find out if we should
* unmap any of them.
*
* +--------------------------------------------+
* +---------------+----------------+ +----------------+
* | : VMA 1 | VMA 2 | | VMA 3 : |
* +---------------+----------------+ +----------------+
* | memory region |
* +--------------------------------------------+
*/
do {
struct vm_area_struct *vma;
hva_t vm_start, vm_end;
vma = find_vma_intersection(current->mm, hva, reg_end);
if (!vma)
break;
/*
* Take the intersection of this VMA with the memory region
*/
vm_start = max(hva, vma->vm_start);
vm_end = min(reg_end, vma->vm_end);
if (!(vma->vm_flags & VM_PFNMAP)) {
gpa_t gpa = addr + (vm_start - memslot->userspace_addr);
unmap_stage2_range(&kvm->arch.mmu, gpa, vm_end - vm_start);
}
hva = vm_end;
} while (hva < reg_end);
}
/**
* stage2_unmap_vm - Unmap Stage-2 RAM mappings
* @kvm: The struct kvm pointer
*
* Go through the memregions and unmap any regular RAM
* backing memory already mapped to the VM.
*/
void stage2_unmap_vm(struct kvm *kvm)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
int idx, bkt;
idx = srcu_read_lock(&kvm->srcu);
mmap_read_lock(current->mm);
write_lock(&kvm->mmu_lock);
slots = kvm_memslots(kvm);
kvm_for_each_memslot(memslot, bkt, slots)
stage2_unmap_memslot(kvm, memslot);
write_unlock(&kvm->mmu_lock);
mmap_read_unlock(current->mm);
srcu_read_unlock(&kvm->srcu, idx);
}
void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu)
{
struct kvm *kvm = kvm_s2_mmu_to_kvm(mmu);
struct kvm_pgtable *pgt = NULL;
write_lock(&kvm->mmu_lock);
pgt = mmu->pgt;
if (pgt) {
mmu->pgd_phys = 0;
mmu->pgt = NULL;
free_percpu(mmu->last_vcpu_ran);
}
write_unlock(&kvm->mmu_lock);
if (pgt) {
kvm_pgtable_stage2_destroy(pgt);
kfree(pgt);
}
}
static void hyp_mc_free_fn(void *addr, void *unused)
{
free_page((unsigned long)addr);
}
static void *hyp_mc_alloc_fn(void *unused)
{
return (void *)__get_free_page(GFP_KERNEL_ACCOUNT);
}
void free_hyp_memcache(struct kvm_hyp_memcache *mc)
{
if (is_protected_kvm_enabled())
__free_hyp_memcache(mc, hyp_mc_free_fn,
kvm_host_va, NULL);
}
int topup_hyp_memcache(struct kvm_hyp_memcache *mc, unsigned long min_pages)
{
if (!is_protected_kvm_enabled())
return 0;
return __topup_hyp_memcache(mc, min_pages, hyp_mc_alloc_fn,
kvm_host_pa, NULL);
}
/**
* kvm_phys_addr_ioremap - map a device range to guest IPA
*
* @kvm: The KVM pointer
* @guest_ipa: The IPA at which to insert the mapping
* @pa: The physical address of the device
* @size: The size of the mapping
* @writable: Whether or not to create a writable mapping
*/
int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa,
phys_addr_t pa, unsigned long size, bool writable)
{
phys_addr_t addr;
int ret = 0;
struct kvm_mmu_memory_cache cache = { .gfp_zero = __GFP_ZERO };
struct kvm_pgtable *pgt = kvm->arch.mmu.pgt;
enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_DEVICE |
KVM_PGTABLE_PROT_R |
(writable ? KVM_PGTABLE_PROT_W : 0);
if (is_protected_kvm_enabled())
return -EPERM;
size += offset_in_page(guest_ipa);
guest_ipa &= PAGE_MASK;
for (addr = guest_ipa; addr < guest_ipa + size; addr += PAGE_SIZE) {
ret = kvm_mmu_topup_memory_cache(&cache,
kvm_mmu_cache_min_pages(kvm));
if (ret)
break;
write_lock(&kvm->mmu_lock);
ret = kvm_pgtable_stage2_map(pgt, addr, PAGE_SIZE, pa, prot,
&cache, 0);
write_unlock(&kvm->mmu_lock);
if (ret)
break;
pa += PAGE_SIZE;
}
kvm_mmu_free_memory_cache(&cache);
return ret;
}
/**
* stage2_wp_range() - write protect stage2 memory region range
* @mmu: The KVM stage-2 MMU pointer
* @addr: Start address of range
* @end: End address of range
*/
static void stage2_wp_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, phys_addr_t end)
{
stage2_apply_range_resched(mmu, addr, end, kvm_pgtable_stage2_wrprotect);
}
/**
* kvm_mmu_wp_memory_region() - write protect stage 2 entries for memory slot
* @kvm: The KVM pointer
* @slot: The memory slot to write protect
*
* Called to start logging dirty pages after memory region
* KVM_MEM_LOG_DIRTY_PAGES operation is called. After this function returns
* all present PUD, PMD and PTEs are write protected in the memory region.
* Afterwards read of dirty page log can be called.
*
* Acquires kvm_mmu_lock. Called with kvm->slots_lock mutex acquired,
* serializing operations for VM memory regions.
*/
static void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot)
{
struct kvm_memslots *slots = kvm_memslots(kvm);
struct kvm_memory_slot *memslot = id_to_memslot(slots, slot);
phys_addr_t start, end;
if (WARN_ON_ONCE(!memslot))
return;
start = memslot->base_gfn << PAGE_SHIFT;
end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
write_lock(&kvm->mmu_lock);
stage2_wp_range(&kvm->arch.mmu, start, end);
write_unlock(&kvm->mmu_lock);
kvm_flush_remote_tlbs_memslot(kvm, memslot);
}
/**
* kvm_mmu_split_memory_region() - split the stage 2 blocks into PAGE_SIZE
* pages for memory slot
* @kvm: The KVM pointer
* @slot: The memory slot to split
*
* Acquires kvm->mmu_lock. Called with kvm->slots_lock mutex acquired,
* serializing operations for VM memory regions.
*/
static void kvm_mmu_split_memory_region(struct kvm *kvm, int slot)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
phys_addr_t start, end;
lockdep_assert_held(&kvm->slots_lock);
slots = kvm_memslots(kvm);
memslot = id_to_memslot(slots, slot);
start = memslot->base_gfn << PAGE_SHIFT;
end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
write_lock(&kvm->mmu_lock);
kvm_mmu_split_huge_pages(kvm, start, end);
write_unlock(&kvm->mmu_lock);
}
/*
* kvm_arch_mmu_enable_log_dirty_pt_masked() - enable dirty logging for selected pages.
* @kvm: The KVM pointer
* @slot: The memory slot associated with mask
* @gfn_offset: The gfn offset in memory slot
* @mask: The mask of pages at offset 'gfn_offset' in this memory
* slot to enable dirty logging on
*
* Writes protect selected pages to enable dirty logging, and then
* splits them to PAGE_SIZE. Caller must acquire kvm->mmu_lock.
*/
void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t gfn_offset, unsigned long mask)
{
phys_addr_t base_gfn = slot->base_gfn + gfn_offset;
phys_addr_t start = (base_gfn + __ffs(mask)) << PAGE_SHIFT;
phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT;
lockdep_assert_held_write(&kvm->mmu_lock);
stage2_wp_range(&kvm->arch.mmu, start, end);
/*
* Eager-splitting is done when manual-protect is set. We
* also check for initially-all-set because we can avoid
* eager-splitting if initially-all-set is false.
* Initially-all-set equal false implies that huge-pages were
* already split when enabling dirty logging: no need to do it
* again.
*/
if (kvm_dirty_log_manual_protect_and_init_set(kvm))
kvm_mmu_split_huge_pages(kvm, start, end);
}
static void kvm_send_hwpoison_signal(unsigned long address, short lsb)
{
send_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, current);
}
static bool fault_supports_stage2_huge_mapping(struct kvm_memory_slot *memslot,
unsigned long hva,
unsigned long map_size)
{
gpa_t gpa_start;
hva_t uaddr_start, uaddr_end;
size_t size;
/* The memslot and the VMA are guaranteed to be aligned to PAGE_SIZE */
if (map_size == PAGE_SIZE)
return true;
size = memslot->npages * PAGE_SIZE;
gpa_start = memslot->base_gfn << PAGE_SHIFT;
uaddr_start = memslot->userspace_addr;
uaddr_end = uaddr_start + size;
/*
* Pages belonging to memslots that don't have the same alignment
* within a PMD/PUD for userspace and IPA cannot be mapped with stage-2
* PMD/PUD entries, because we'll end up mapping the wrong pages.
*
* Consider a layout like the following:
*
* memslot->userspace_addr:
* +-----+--------------------+--------------------+---+
* |abcde|fgh Stage-1 block | Stage-1 block tv|xyz|
* +-----+--------------------+--------------------+---+
*
* memslot->base_gfn << PAGE_SHIFT:
* +---+--------------------+--------------------+-----+
* |abc|def Stage-2 block | Stage-2 block |tvxyz|
* +---+--------------------+--------------------+-----+
*
* If we create those stage-2 blocks, we'll end up with this incorrect
* mapping:
* d -> f
* e -> g
* f -> h
*/
if ((gpa_start & (map_size - 1)) != (uaddr_start & (map_size - 1)))
return false;
/*
* Next, let's make sure we're not trying to map anything not covered
* by the memslot. This means we have to prohibit block size mappings
* for the beginning and end of a non-block aligned and non-block sized
* memory slot (illustrated by the head and tail parts of the
* userspace view above containing pages 'abcde' and 'xyz',
* respectively).
*
* Note that it doesn't matter if we do the check using the
* userspace_addr or the base_gfn, as both are equally aligned (per
* the check above) and equally sized.
*/
return (hva & ~(map_size - 1)) >= uaddr_start &&
(hva & ~(map_size - 1)) + map_size <= uaddr_end;
}
/*
* Check if the given hva is backed by a transparent huge page (THP) and
* whether it can be mapped using block mapping in stage2. If so, adjust
* the stage2 PFN and IPA accordingly. Only PMD_SIZE THPs are currently
* supported. This will need to be updated to support other THP sizes.
*
* Returns the size of the mapping.
*/
static long
transparent_hugepage_adjust(struct kvm *kvm, struct kvm_memory_slot *memslot,
unsigned long hva, kvm_pfn_t *pfnp,
phys_addr_t *ipap)
{
kvm_pfn_t pfn = *pfnp;
/*
* Make sure the adjustment is done only for THP pages. Also make
* sure that the HVA and IPA are sufficiently aligned and that the
* block map is contained within the memslot.
*/
if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE)) {
int sz = get_user_mapping_size(kvm, hva);
if (sz < 0)
return sz;
if (sz < PMD_SIZE)
return PAGE_SIZE;
/*
* The address we faulted on is backed by a transparent huge
* page. However, because we map the compound huge page and
* not the individual tail page, we need to transfer the
* refcount to the head page. We have to be careful that the
* THP doesn't start to split while we are adjusting the
* refcounts.
*
* We are sure this doesn't happen, because mmu_invalidate_retry
* was successful and we are holding the mmu_lock, so if this
* THP is trying to split, it will be blocked in the mmu
* notifier before touching any of the pages, specifically
* before being able to call __split_huge_page_refcount().
*
* We can therefore safely transfer the refcount from PG_tail
* to PG_head and switch the pfn from a tail page to the head
* page accordingly.
*/
*ipap &= PMD_MASK;
kvm_release_pfn_clean(pfn);
pfn &= ~(PTRS_PER_PMD - 1);
get_page(pfn_to_page(pfn));
*pfnp = pfn;
return PMD_SIZE;
}
/* Use page mapping if we cannot use block mapping. */
return PAGE_SIZE;
}
static int get_vma_page_shift(struct vm_area_struct *vma, unsigned long hva)
{
unsigned long pa;
if (is_vm_hugetlb_page(vma) && !(vma->vm_flags & VM_PFNMAP))
return huge_page_shift(hstate_vma(vma));
if (!(vma->vm_flags & VM_PFNMAP))
return PAGE_SHIFT;
VM_BUG_ON(is_vm_hugetlb_page(vma));
pa = (vma->vm_pgoff << PAGE_SHIFT) + (hva - vma->vm_start);
#ifndef __PAGETABLE_PMD_FOLDED
if ((hva & (PUD_SIZE - 1)) == (pa & (PUD_SIZE - 1)) &&
ALIGN_DOWN(hva, PUD_SIZE) >= vma->vm_start &&
ALIGN(hva, PUD_SIZE) <= vma->vm_end)
return PUD_SHIFT;
#endif
if ((hva & (PMD_SIZE - 1)) == (pa & (PMD_SIZE - 1)) &&
ALIGN_DOWN(hva, PMD_SIZE) >= vma->vm_start &&
ALIGN(hva, PMD_SIZE) <= vma->vm_end)
return PMD_SHIFT;
return PAGE_SHIFT;
}
/*
* The page will be mapped in stage 2 as Normal Cacheable, so the VM will be
* able to see the page's tags and therefore they must be initialised first. If
* PG_mte_tagged is set, tags have already been initialised.
*
* The race in the test/set of the PG_mte_tagged flag is handled by:
* - preventing VM_SHARED mappings in a memslot with MTE preventing two VMs
* racing to santise the same page
* - mmap_lock protects between a VM faulting a page in and the VMM performing
* an mprotect() to add VM_MTE
*/
static void sanitise_mte_tags(struct kvm *kvm, kvm_pfn_t pfn,
unsigned long size)
{
unsigned long i, nr_pages = size >> PAGE_SHIFT;
struct page *page = pfn_to_page(pfn);
if (!kvm_has_mte(kvm))
return;
for (i = 0; i < nr_pages; i++, page++) {
if (try_page_mte_tagging(page)) {
mte_clear_page_tags(page_address(page));
set_page_mte_tagged(page);
}
}
}
static bool kvm_vma_mte_allowed(struct vm_area_struct *vma)
{
return vma->vm_flags & VM_MTE_ALLOWED;
}
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
struct kvm_memory_slot *memslot, unsigned long hva,
unsigned long fault_status)
{
int ret = 0;
bool write_fault, writable, force_pte = false;
bool exec_fault, mte_allowed;
bool device = false;
unsigned long mmu_seq;
struct kvm *kvm = vcpu->kvm;
struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
struct vm_area_struct *vma;
short vma_shift;
gfn_t gfn;
kvm_pfn_t pfn;
bool logging_active = memslot_is_logging(memslot);
unsigned long fault_level = kvm_vcpu_trap_get_fault_level(vcpu);
long vma_pagesize, fault_granule;
enum kvm_pgtable_prot prot = KVM_PGTABLE_PROT_R;
struct kvm_pgtable *pgt;
fault_granule = 1UL << ARM64_HW_PGTABLE_LEVEL_SHIFT(fault_level);
write_fault = kvm_is_write_fault(vcpu);
exec_fault = kvm_vcpu_trap_is_exec_fault(vcpu);
VM_BUG_ON(write_fault && exec_fault);
if (fault_status == ESR_ELx_FSC_PERM && !write_fault && !exec_fault) {
kvm_err("Unexpected L2 read permission error\n");
return -EFAULT;
}
/*
* Permission faults just need to update the existing leaf entry,
* and so normally don't require allocations from the memcache. The
* only exception to this is when dirty logging is enabled at runtime
* and a write fault needs to collapse a block entry into a table.
*/
if (fault_status != ESR_ELx_FSC_PERM ||
(logging_active && write_fault)) {
ret = kvm_mmu_topup_memory_cache(memcache,
kvm_mmu_cache_min_pages(kvm));
if (ret)
return ret;
}
/*
* Let's check if we will get back a huge page backed by hugetlbfs, or
* get block mapping for device MMIO region.
*/
mmap_read_lock(current->mm);
vma = vma_lookup(current->mm, hva);
if (unlikely(!vma)) {
kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
mmap_read_unlock(current->mm);
return -EFAULT;
}
/*
* logging_active is guaranteed to never be true for VM_PFNMAP
* memslots.
*/
if (logging_active) {
force_pte = true;
vma_shift = PAGE_SHIFT;
} else {
vma_shift = get_vma_page_shift(vma, hva);
}
switch (vma_shift) {
#ifndef __PAGETABLE_PMD_FOLDED
case PUD_SHIFT:
if (fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
break;
fallthrough;
#endif
case CONT_PMD_SHIFT:
vma_shift = PMD_SHIFT;
fallthrough;
case PMD_SHIFT:
if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE))
break;
fallthrough;
case CONT_PTE_SHIFT:
vma_shift = PAGE_SHIFT;
force_pte = true;
fallthrough;
case PAGE_SHIFT:
break;
default:
WARN_ONCE(1, "Unknown vma_shift %d", vma_shift);
}
vma_pagesize = 1UL << vma_shift;
if (vma_pagesize == PMD_SIZE || vma_pagesize == PUD_SIZE)
fault_ipa &= ~(vma_pagesize - 1);
gfn = fault_ipa >> PAGE_SHIFT;
mte_allowed = kvm_vma_mte_allowed(vma);
/* Don't use the VMA after the unlock -- it may have vanished */
vma = NULL;
/*
* Read mmu_invalidate_seq so that KVM can detect if the results of
* vma_lookup() or __gfn_to_pfn_memslot() become stale prior to
* acquiring kvm->mmu_lock.
*
* Rely on mmap_read_unlock() for an implicit smp_rmb(), which pairs
* with the smp_wmb() in kvm_mmu_invalidate_end().
*/
mmu_seq = vcpu->kvm->mmu_invalidate_seq;
mmap_read_unlock(current->mm);
pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL,
write_fault, &writable, NULL);
if (pfn == KVM_PFN_ERR_HWPOISON) {
kvm_send_hwpoison_signal(hva, vma_shift);
return 0;
}
if (is_error_noslot_pfn(pfn))
return -EFAULT;
if (kvm_is_device_pfn(pfn)) {
/*
* If the page was identified as device early by looking at
* the VMA flags, vma_pagesize is already representing the
* largest quantity we can map. If instead it was mapped
* via gfn_to_pfn_prot(), vma_pagesize is set to PAGE_SIZE
* and must not be upgraded.
*
* In both cases, we don't let transparent_hugepage_adjust()
* change things at the last minute.
*/
device = true;
} else if (logging_active && !write_fault) {
/*
* Only actually map the page as writable if this was a write
* fault.
*/
writable = false;
}
if (exec_fault && device)
return -ENOEXEC;
read_lock(&kvm->mmu_lock);
pgt = vcpu->arch.hw_mmu->pgt;
if (mmu_invalidate_retry(kvm, mmu_seq))
goto out_unlock;
/*
* If we are not forced to use page mapping, check if we are
* backed by a THP and thus use block mapping if possible.
*/
if (vma_pagesize == PAGE_SIZE && !(force_pte || device)) {
if (fault_status == ESR_ELx_FSC_PERM &&
fault_granule > PAGE_SIZE)
vma_pagesize = fault_granule;
else
vma_pagesize = transparent_hugepage_adjust(kvm, memslot,
hva, &pfn,
&fault_ipa);
if (vma_pagesize < 0) {
ret = vma_pagesize;
goto out_unlock;
}
}
if (fault_status != ESR_ELx_FSC_PERM && !device && kvm_has_mte(kvm)) {
/* Check the VMM hasn't introduced a new disallowed VMA */
if (mte_allowed) {
sanitise_mte_tags(kvm, pfn, vma_pagesize);
} else {
ret = -EFAULT;
goto out_unlock;
}
}
if (writable)
prot |= KVM_PGTABLE_PROT_W;
if (exec_fault)
prot |= KVM_PGTABLE_PROT_X;
if (device)
prot |= KVM_PGTABLE_PROT_DEVICE;
else if (cpus_have_const_cap(ARM64_HAS_CACHE_DIC))
prot |= KVM_PGTABLE_PROT_X;
/*
* Under the premise of getting a FSC_PERM fault, we just need to relax
* permissions only if vma_pagesize equals fault_granule. Otherwise,
* kvm_pgtable_stage2_map() should be called to change block size.
*/
if (fault_status == ESR_ELx_FSC_PERM && vma_pagesize == fault_granule)
ret = kvm_pgtable_stage2_relax_perms(pgt, fault_ipa, prot);
else
ret = kvm_pgtable_stage2_map(pgt, fault_ipa, vma_pagesize,
__pfn_to_phys(pfn), prot,
memcache,
KVM_PGTABLE_WALK_HANDLE_FAULT |
KVM_PGTABLE_WALK_SHARED);
/* Mark the page dirty only if the fault is handled successfully */
if (writable && !ret) {
kvm_set_pfn_dirty(pfn);
mark_page_dirty_in_slot(kvm, memslot, gfn);
}
out_unlock:
read_unlock(&kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return ret != -EAGAIN ? ret : 0;
}
/* Resolve the access fault by making the page young again. */
static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
{
kvm_pte_t pte;
struct kvm_s2_mmu *mmu;
trace_kvm_access_fault(fault_ipa);
read_lock(&vcpu->kvm->mmu_lock);
mmu = vcpu->arch.hw_mmu;
pte = kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa);
read_unlock(&vcpu->kvm->mmu_lock);
if (kvm_pte_valid(pte))
kvm_set_pfn_accessed(kvm_pte_to_pfn(pte));
}
/**
* kvm_handle_guest_abort - handles all 2nd stage aborts
* @vcpu: the VCPU pointer
*
* Any abort that gets to the host is almost guaranteed to be caused by a
* missing second stage translation table entry, which can mean that either the
* guest simply needs more memory and we must allocate an appropriate page or it
* can mean that the guest tried to access I/O memory, which is emulated by user
* space. The distinction is based on the IPA causing the fault and whether this
* memory region has been registered as standard RAM by user space.
*/
int kvm_handle_guest_abort(struct kvm_vcpu *vcpu)
{
unsigned long fault_status;
phys_addr_t fault_ipa;
struct kvm_memory_slot *memslot;
unsigned long hva;
bool is_iabt, write_fault, writable;
gfn_t gfn;
int ret, idx;
fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
is_iabt = kvm_vcpu_trap_is_iabt(vcpu);
if (fault_status == ESR_ELx_FSC_FAULT) {
/* Beyond sanitised PARange (which is the IPA limit) */
if (fault_ipa >= BIT_ULL(get_kvm_ipa_limit())) {
kvm_inject_size_fault(vcpu);
return 1;
}
/* Falls between the IPA range and the PARange? */
if (fault_ipa >= BIT_ULL(vcpu->arch.hw_mmu->pgt->ia_bits)) {
fault_ipa |= kvm_vcpu_get_hfar(vcpu) & GENMASK(11, 0);
if (is_iabt)
kvm_inject_pabt(vcpu, fault_ipa);
else
kvm_inject_dabt(vcpu, fault_ipa);
return 1;
}
}
/* Synchronous External Abort? */
if (kvm_vcpu_abt_issea(vcpu)) {
/*
* For RAS the host kernel may handle this abort.
* There is no need to pass the error into the guest.
*/
if (kvm_handle_guest_sea(fault_ipa, kvm_vcpu_get_esr(vcpu)))
kvm_inject_vabt(vcpu);
return 1;
}
trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_esr(vcpu),
kvm_vcpu_get_hfar(vcpu), fault_ipa);
/* Check the stage-2 fault is trans. fault or write fault */
if (fault_status != ESR_ELx_FSC_FAULT &&
fault_status != ESR_ELx_FSC_PERM &&
fault_status != ESR_ELx_FSC_ACCESS) {
kvm_err("Unsupported FSC: EC=%#x xFSC=%#lx ESR_EL2=%#lx\n",
kvm_vcpu_trap_get_class(vcpu),
(unsigned long)kvm_vcpu_trap_get_fault(vcpu),
(unsigned long)kvm_vcpu_get_esr(vcpu));
return -EFAULT;
}
idx = srcu_read_lock(&vcpu->kvm->srcu);
gfn = fault_ipa >> PAGE_SHIFT;
memslot = gfn_to_memslot(vcpu->kvm, gfn);
hva = gfn_to_hva_memslot_prot(memslot, gfn, &writable);
write_fault = kvm_is_write_fault(vcpu);
if (kvm_is_error_hva(hva) || (write_fault && !writable)) {
/*
* The guest has put either its instructions or its page-tables
* somewhere it shouldn't have. Userspace won't be able to do
* anything about this (there's no syndrome for a start), so
* re-inject the abort back into the guest.
*/
if (is_iabt) {
ret = -ENOEXEC;
goto out;
}
if (kvm_vcpu_abt_iss1tw(vcpu)) {
kvm_inject_dabt(vcpu, kvm_vcpu_get_hfar(vcpu));
ret = 1;
goto out_unlock;
}
/*
* Check for a cache maintenance operation. Since we
* ended-up here, we know it is outside of any memory
* slot. But we can't find out if that is for a device,
* or if the guest is just being stupid. The only thing
* we know for sure is that this range cannot be cached.
*
* So let's assume that the guest is just being
* cautious, and skip the instruction.
*/
if (kvm_is_error_hva(hva) && kvm_vcpu_dabt_is_cm(vcpu)) {
kvm_incr_pc(vcpu);
ret = 1;
goto out_unlock;
}
/*
* The IPA is reported as [MAX:12], so we need to
* complement it with the bottom 12 bits from the
* faulting VA. This is always 12 bits, irrespective
* of the page size.
*/
fault_ipa |= kvm_vcpu_get_hfar(vcpu) & ((1 << 12) - 1);
ret = io_mem_abort(vcpu, fault_ipa);
goto out_unlock;
}
/* Userspace should not be able to register out-of-bounds IPAs */
VM_BUG_ON(fault_ipa >= kvm_phys_size(vcpu->kvm));
if (fault_status == ESR_ELx_FSC_ACCESS) {
handle_access_fault(vcpu, fault_ipa);
ret = 1;
goto out_unlock;
}
ret = user_mem_abort(vcpu, fault_ipa, memslot, hva, fault_status);
if (ret == 0)
ret = 1;
out:
if (ret == -ENOEXEC) {
kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu));
ret = 1;
}
out_unlock:
srcu_read_unlock(&vcpu->kvm->srcu, idx);
return ret;
}
bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
{
if (!kvm->arch.mmu.pgt)
return false;
__unmap_stage2_range(&kvm->arch.mmu, range->start << PAGE_SHIFT,
(range->end - range->start) << PAGE_SHIFT,
range->may_block);
return false;
}
bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
kvm_pfn_t pfn = pte_pfn(range->arg.pte);
if (!kvm->arch.mmu.pgt)
return false;
WARN_ON(range->end - range->start != 1);
/*
* If the page isn't tagged, defer to user_mem_abort() for sanitising
* the MTE tags. The S2 pte should have been unmapped by
* mmu_notifier_invalidate_range_end().
*/
if (kvm_has_mte(kvm) && !page_mte_tagged(pfn_to_page(pfn)))
return false;
/*
* We've moved a page around, probably through CoW, so let's treat
* it just like a translation fault and the map handler will clean
* the cache to the PoC.
*
* The MMU notifiers will have unmapped a huge PMD before calling
* ->change_pte() (which in turn calls kvm_set_spte_gfn()) and
* therefore we never need to clear out a huge PMD through this
* calling path and a memcache is not required.
*/
kvm_pgtable_stage2_map(kvm->arch.mmu.pgt, range->start << PAGE_SHIFT,
PAGE_SIZE, __pfn_to_phys(pfn),
KVM_PGTABLE_PROT_R, NULL, 0);
return false;
}
bool kvm_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
u64 size = (range->end - range->start) << PAGE_SHIFT;
if (!kvm->arch.mmu.pgt)
return false;
return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
range->start << PAGE_SHIFT,
size, true);
}
bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
{
u64 size = (range->end - range->start) << PAGE_SHIFT;
if (!kvm->arch.mmu.pgt)
return false;
return kvm_pgtable_stage2_test_clear_young(kvm->arch.mmu.pgt,
range->start << PAGE_SHIFT,
size, false);
}
phys_addr_t kvm_mmu_get_httbr(void)
{
return __pa(hyp_pgtable->pgd);
}
phys_addr_t kvm_get_idmap_vector(void)
{
return hyp_idmap_vector;
}
static int kvm_map_idmap_text(void)
{
unsigned long size = hyp_idmap_end - hyp_idmap_start;
int err = __create_hyp_mappings(hyp_idmap_start, size, hyp_idmap_start,
PAGE_HYP_EXEC);
if (err)
kvm_err("Failed to idmap %lx-%lx\n",
hyp_idmap_start, hyp_idmap_end);
return err;
}
static void *kvm_hyp_zalloc_page(void *arg)
{
return (void *)get_zeroed_page(GFP_KERNEL);
}
static struct kvm_pgtable_mm_ops kvm_hyp_mm_ops = {
.zalloc_page = kvm_hyp_zalloc_page,
.get_page = kvm_host_get_page,
.put_page = kvm_host_put_page,
.phys_to_virt = kvm_host_va,
.virt_to_phys = kvm_host_pa,
};
int __init kvm_mmu_init(u32 *hyp_va_bits)
{
int err;
u32 idmap_bits;
u32 kernel_bits;
hyp_idmap_start = __pa_symbol(__hyp_idmap_text_start);
hyp_idmap_start = ALIGN_DOWN(hyp_idmap_start, PAGE_SIZE);
hyp_idmap_end = __pa_symbol(__hyp_idmap_text_end);
hyp_idmap_end = ALIGN(hyp_idmap_end, PAGE_SIZE);
hyp_idmap_vector = __pa_symbol(__kvm_hyp_init);
/*
* We rely on the linker script to ensure at build time that the HYP
* init code does not cross a page boundary.
*/
BUG_ON((hyp_idmap_start ^ (hyp_idmap_end - 1)) & PAGE_MASK);
/*
* The ID map may be configured to use an extended virtual address
* range. This is only the case if system RAM is out of range for the
* currently configured page size and VA_BITS_MIN, in which case we will
* also need the extended virtual range for the HYP ID map, or we won't
* be able to enable the EL2 MMU.
*
* However, in some cases the ID map may be configured for fewer than
* the number of VA bits used by the regular kernel stage 1. This
* happens when VA_BITS=52 and the kernel image is placed in PA space
* below 48 bits.
*
* At EL2, there is only one TTBR register, and we can't switch between
* translation tables *and* update TCR_EL2.T0SZ at the same time. Bottom
* line: we need to use the extended range with *both* our translation
* tables.
*
* So use the maximum of the idmap VA bits and the regular kernel stage
* 1 VA bits to assure that the hypervisor can both ID map its code page
* and map any kernel memory.
*/
idmap_bits = 64 - ((idmap_t0sz & TCR_T0SZ_MASK) >> TCR_T0SZ_OFFSET);
kernel_bits = vabits_actual;
*hyp_va_bits = max(idmap_bits, kernel_bits);
kvm_debug("Using %u-bit virtual addresses at EL2\n", *hyp_va_bits);
kvm_debug("IDMAP page: %lx\n", hyp_idmap_start);
kvm_debug("HYP VA range: %lx:%lx\n",
kern_hyp_va(PAGE_OFFSET),
kern_hyp_va((unsigned long)high_memory - 1));
if (hyp_idmap_start >= kern_hyp_va(PAGE_OFFSET) &&
hyp_idmap_start < kern_hyp_va((unsigned long)high_memory - 1) &&
hyp_idmap_start != (unsigned long)__hyp_idmap_text_start) {
/*
* The idmap page is intersecting with the VA space,
* it is not safe to continue further.
*/
kvm_err("IDMAP intersecting with HYP VA, unable to continue\n");
err = -EINVAL;
goto out;
}
hyp_pgtable = kzalloc(sizeof(*hyp_pgtable), GFP_KERNEL);
if (!hyp_pgtable) {
kvm_err("Hyp mode page-table not allocated\n");
err = -ENOMEM;
goto out;
}
err = kvm_pgtable_hyp_init(hyp_pgtable, *hyp_va_bits, &kvm_hyp_mm_ops);
if (err)
goto out_free_pgtable;
err = kvm_map_idmap_text();
if (err)
goto out_destroy_pgtable;
io_map_base = hyp_idmap_start;
return 0;
out_destroy_pgtable:
kvm_pgtable_hyp_destroy(hyp_pgtable);
out_free_pgtable:
kfree(hyp_pgtable);
hyp_pgtable = NULL;
out:
return err;
}
void kvm_arch_commit_memory_region(struct kvm *kvm,
struct kvm_memory_slot *old,
const struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
bool log_dirty_pages = new && new->flags & KVM_MEM_LOG_DIRTY_PAGES;
/*
* At this point memslot has been committed and there is an
* allocated dirty_bitmap[], dirty pages will be tracked while the
* memory slot is write protected.
*/
if (log_dirty_pages) {
if (change == KVM_MR_DELETE)
return;
/*
* Huge and normal pages are write-protected and split
* on either of these two cases:
*
* 1. with initial-all-set: gradually with CLEAR ioctls,
*/
if (kvm_dirty_log_manual_protect_and_init_set(kvm))
return;
/*
* or
* 2. without initial-all-set: all in one shot when
* enabling dirty logging.
*/
kvm_mmu_wp_memory_region(kvm, new->id);
kvm_mmu_split_memory_region(kvm, new->id);
} else {
/*
* Free any leftovers from the eager page splitting cache. Do
* this when deleting, moving, disabling dirty logging, or
* creating the memslot (a nop). Doing it for deletes makes
* sure we don't leak memory, and there's no need to keep the
* cache around for any of the other cases.
*/
kvm_mmu_free_memory_cache(&kvm->arch.mmu.split_page_cache);
}
}
int kvm_arch_prepare_memory_region(struct kvm *kvm,
const struct kvm_memory_slot *old,
struct kvm_memory_slot *new,
enum kvm_mr_change change)
{
hva_t hva, reg_end;
int ret = 0;
if (change != KVM_MR_CREATE && change != KVM_MR_MOVE &&
change != KVM_MR_FLAGS_ONLY)
return 0;
/*
* Prevent userspace from creating a memory region outside of the IPA
* space addressable by the KVM guest IPA space.
*/
if ((new->base_gfn + new->npages) > (kvm_phys_size(kvm) >> PAGE_SHIFT))
return -EFAULT;
hva = new->userspace_addr;
reg_end = hva + (new->npages << PAGE_SHIFT);
mmap_read_lock(current->mm);
/*
* A memory region could potentially cover multiple VMAs, and any holes
* between them, so iterate over all of them.
*
* +--------------------------------------------+
* +---------------+----------------+ +----------------+
* | : VMA 1 | VMA 2 | | VMA 3 : |
* +---------------+----------------+ +----------------+
* | memory region |
* +--------------------------------------------+
*/
do {
struct vm_area_struct *vma;
vma = find_vma_intersection(current->mm, hva, reg_end);
if (!vma)
break;
if (kvm_has_mte(kvm) && !kvm_vma_mte_allowed(vma)) {
ret = -EINVAL;
break;
}
if (vma->vm_flags & VM_PFNMAP) {
/* IO region dirty page logging not allowed */
if (new->flags & KVM_MEM_LOG_DIRTY_PAGES) {
ret = -EINVAL;
break;
}
}
hva = min(reg_end, vma->vm_end);
} while (hva < reg_end);
mmap_read_unlock(current->mm);
return ret;
}
void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *slot)
{
}
void kvm_arch_memslots_updated(struct kvm *kvm, u64 gen)
{
}
void kvm_arch_flush_shadow_all(struct kvm *kvm)
{
kvm_uninit_stage2_mmu(kvm);
}
void kvm_arch_flush_shadow_memslot(struct kvm *kvm,
struct kvm_memory_slot *slot)
{
gpa_t gpa = slot->base_gfn << PAGE_SHIFT;
phys_addr_t size = slot->npages << PAGE_SHIFT;
write_lock(&kvm->mmu_lock);
unmap_stage2_range(&kvm->arch.mmu, gpa, size);
write_unlock(&kvm->mmu_lock);
}
/*
* See note at ARMv7 ARM B1.14.4 (TL;DR: S/W ops are not easily virtualized).
*
* Main problems:
* - S/W ops are local to a CPU (not broadcast)
* - We have line migration behind our back (speculation)
* - System caches don't support S/W at all (damn!)
*
* In the face of the above, the best we can do is to try and convert
* S/W ops to VA ops. Because the guest is not allowed to infer the
* S/W to PA mapping, it can only use S/W to nuke the whole cache,
* which is a rather good thing for us.
*
* Also, it is only used when turning caches on/off ("The expected
* usage of the cache maintenance instructions that operate by set/way
* is associated with the cache maintenance instructions associated
* with the powerdown and powerup of caches, if this is required by
* the implementation.").
*
* We use the following policy:
*
* - If we trap a S/W operation, we enable VM trapping to detect
* caches being turned on/off, and do a full clean.
*
* - We flush the caches on both caches being turned on and off.
*
* - Once the caches are enabled, we stop trapping VM ops.
*/
void kvm_set_way_flush(struct kvm_vcpu *vcpu)
{
unsigned long hcr = *vcpu_hcr(vcpu);
/*
* If this is the first time we do a S/W operation
* (i.e. HCR_TVM not set) flush the whole memory, and set the
* VM trapping.
*
* Otherwise, rely on the VM trapping to wait for the MMU +
* Caches to be turned off. At that point, we'll be able to
* clean the caches again.
*/
if (!(hcr & HCR_TVM)) {
trace_kvm_set_way_flush(*vcpu_pc(vcpu),
vcpu_has_cache_enabled(vcpu));
stage2_flush_vm(vcpu->kvm);
*vcpu_hcr(vcpu) = hcr | HCR_TVM;
}
}
void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled)
{
bool now_enabled = vcpu_has_cache_enabled(vcpu);
/*
* If switching the MMU+caches on, need to invalidate the caches.
* If switching it off, need to clean the caches.
* Clean + invalidate does the trick always.
*/
if (now_enabled != was_enabled)
stage2_flush_vm(vcpu->kvm);
/* Caches are now on, stop trapping VM ops (until a S/W op) */
if (now_enabled)
*vcpu_hcr(vcpu) &= ~HCR_TVM;
trace_kvm_toggle_cache(*vcpu_pc(vcpu), was_enabled, now_enabled);
}