/*
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
* Author: Christoffer Dall <c.dall@virtualopensystems.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2, as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/mman.h>
#include <linux/kvm_host.h>
#include <linux/io.h>
#include <linux/hugetlb.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_mmio.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include "trace.h"
extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];
static pgd_t *boot_hyp_pgd;
static pgd_t *hyp_pgd;
static pgd_t *merged_hyp_pgd;
static DEFINE_MUTEX(kvm_hyp_pgd_mutex);
static unsigned long hyp_idmap_start;
static unsigned long hyp_idmap_end;
static phys_addr_t hyp_idmap_vector;
#define hyp_pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t))
#define kvm_pmd_huge(_x) (pmd_huge(_x) || pmd_trans_huge(_x))
#define kvm_pud_huge(_x) pud_huge(_x)
#define KVM_S2PTE_FLAG_IS_IOMAP (1UL << 0)
#define KVM_S2_FLAG_LOGGING_ACTIVE (1UL << 1)
static bool memslot_is_logging(struct kvm_memory_slot *memslot)
{
return memslot->dirty_bitmap && !(memslot->flags & KVM_MEM_READONLY);
}
/**
* kvm_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
*/
void kvm_flush_remote_tlbs(struct kvm *kvm)
{
kvm_call_hyp(__kvm_tlb_flush_vmid, kvm);
}
static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
{
/*
* This function also gets called when dealing with HYP page
* tables. As HYP doesn't have an associated struct kvm (and
* the HYP page tables are fairly static), we don't do
* anything there.
*/
if (kvm)
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa);
}
/*
* D-Cache management functions. They take the page table entries by
* value, as they are flushing the cache using the kernel mapping (or
* kmap on 32bit).
*/
static void kvm_flush_dcache_pte(pte_t pte)
{
__kvm_flush_dcache_pte(pte);
}
static void kvm_flush_dcache_pmd(pmd_t pmd)
{
__kvm_flush_dcache_pmd(pmd);
}
static void kvm_flush_dcache_pud(pud_t pud)
{
__kvm_flush_dcache_pud(pud);
}
/**
* stage2_dissolve_pmd() - clear and flush huge PMD entry
* @kvm: pointer to kvm structure.
* @addr: IPA
* @pmd: pmd pointer for IPA
*
* Function clears a PMD entry, flushes addr 1st and 2nd stage TLBs. Marks all
* pages in the range dirty.
*/
static void stage2_dissolve_pmd(struct kvm *kvm, phys_addr_t addr, pmd_t *pmd)
{
if (!kvm_pmd_huge(*pmd))
return;
pmd_clear(pmd);
kvm_tlb_flush_vmid_ipa(kvm, addr);
put_page(virt_to_page(pmd));
}
static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
int min, int max)
{
void *page;
BUG_ON(max > KVM_NR_MEM_OBJS);
if (cache->nobjs >= min)
return 0;
while (cache->nobjs < max) {
page = (void *)__get_free_page(PGALLOC_GFP);
if (!page)
return -ENOMEM;
cache->objects[cache->nobjs++] = page;
}
return 0;
}
static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
{
while (mc->nobjs)
free_page((unsigned long)mc->objects[--mc->nobjs]);
}
static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc)
{
void *p;
BUG_ON(!mc || !mc->nobjs);
p = mc->objects[--mc->nobjs];
return p;
}
static void clear_pgd_entry(struct kvm *kvm, pgd_t *pgd, phys_addr_t addr)
{
pud_t *pud_table __maybe_unused = pud_offset(pgd, 0);
pgd_clear(pgd);
kvm_tlb_flush_vmid_ipa(kvm, addr);
pud_free(NULL, pud_table);
put_page(virt_to_page(pgd));
}
static void clear_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)
{
pmd_t *pmd_table = pmd_offset(pud, 0);
VM_BUG_ON(pud_huge(*pud));
pud_clear(pud);
kvm_tlb_flush_vmid_ipa(kvm, addr);
pmd_free(NULL, pmd_table);
put_page(virt_to_page(pud));
}
static void clear_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr)
{
pte_t *pte_table = pte_offset_kernel(pmd, 0);
VM_BUG_ON(kvm_pmd_huge(*pmd));
pmd_clear(pmd);
kvm_tlb_flush_vmid_ipa(kvm, addr);
pte_free_kernel(NULL, pte_table);
put_page(virt_to_page(pmd));
}
/*
* 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 call kvm_flush_dcache_p*() to make sure
* the IO subsystem will never hit in the cache.
*/
static void unmap_ptes(struct kvm *kvm, pmd_t *pmd,
phys_addr_t addr, phys_addr_t end)
{
phys_addr_t start_addr = addr;
pte_t *pte, *start_pte;
start_pte = pte = pte_offset_kernel(pmd, addr);
do {
if (!pte_none(*pte)) {
pte_t old_pte = *pte;
kvm_set_pte(pte, __pte(0));
kvm_tlb_flush_vmid_ipa(kvm, addr);
/* No need to invalidate the cache for device mappings */
if ((pte_val(old_pte) & PAGE_S2_DEVICE) != PAGE_S2_DEVICE)
kvm_flush_dcache_pte(old_pte);
put_page(virt_to_page(pte));
}
} while (pte++, addr += PAGE_SIZE, addr != end);
if (kvm_pte_table_empty(kvm, start_pte))
clear_pmd_entry(kvm, pmd, start_addr);
}
static void unmap_pmds(struct kvm *kvm, pud_t *pud,
phys_addr_t addr, phys_addr_t end)
{
phys_addr_t next, start_addr = addr;
pmd_t *pmd, *start_pmd;
start_pmd = pmd = pmd_offset(pud, addr);
do {
next = kvm_pmd_addr_end(addr, end);
if (!pmd_none(*pmd)) {
if (kvm_pmd_huge(*pmd)) {
pmd_t old_pmd = *pmd;
pmd_clear(pmd);
kvm_tlb_flush_vmid_ipa(kvm, addr);
kvm_flush_dcache_pmd(old_pmd);
put_page(virt_to_page(pmd));
} else {
unmap_ptes(kvm, pmd, addr, next);
}
}
} while (pmd++, addr = next, addr != end);
if (kvm_pmd_table_empty(kvm, start_pmd))
clear_pud_entry(kvm, pud, start_addr);
}
static void unmap_puds(struct kvm *kvm, pgd_t *pgd,
phys_addr_t addr, phys_addr_t end)
{
phys_addr_t next, start_addr = addr;
pud_t *pud, *start_pud;
start_pud = pud = pud_offset(pgd, addr);
do {
next = kvm_pud_addr_end(addr, end);
if (!pud_none(*pud)) {
if (pud_huge(*pud)) {
pud_t old_pud = *pud;
pud_clear(pud);
kvm_tlb_flush_vmid_ipa(kvm, addr);
kvm_flush_dcache_pud(old_pud);
put_page(virt_to_page(pud));
} else {
unmap_pmds(kvm, pud, addr, next);
}
}
} while (pud++, addr = next, addr != end);
if (kvm_pud_table_empty(kvm, start_pud))
clear_pgd_entry(kvm, pgd, start_addr);
}
static void unmap_range(struct kvm *kvm, pgd_t *pgdp,
phys_addr_t start, u64 size)
{
pgd_t *pgd;
phys_addr_t addr = start, end = start + size;
phys_addr_t next;
pgd = pgdp + kvm_pgd_index(addr);
do {
next = kvm_pgd_addr_end(addr, end);
if (!pgd_none(*pgd))
unmap_puds(kvm, pgd, addr, next);
} while (pgd++, addr = next, addr != end);
}
static void stage2_flush_ptes(struct kvm *kvm, pmd_t *pmd,
phys_addr_t addr, phys_addr_t end)
{
pte_t *pte;
pte = pte_offset_kernel(pmd, addr);
do {
if (!pte_none(*pte) &&
(pte_val(*pte) & PAGE_S2_DEVICE) != PAGE_S2_DEVICE)
kvm_flush_dcache_pte(*pte);
} while (pte++, addr += PAGE_SIZE, addr != end);
}
static void stage2_flush_pmds(struct kvm *kvm, pud_t *pud,
phys_addr_t addr, phys_addr_t end)
{
pmd_t *pmd;
phys_addr_t next;
pmd = pmd_offset(pud, addr);
do {
next = kvm_pmd_addr_end(addr, end);
if (!pmd_none(*pmd)) {
if (kvm_pmd_huge(*pmd))
kvm_flush_dcache_pmd(*pmd);
else
stage2_flush_ptes(kvm, pmd, addr, next);
}
} while (pmd++, addr = next, addr != end);
}
static void stage2_flush_puds(struct kvm *kvm, pgd_t *pgd,
phys_addr_t addr, phys_addr_t end)
{
pud_t *pud;
phys_addr_t next;
pud = pud_offset(pgd, addr);
do {
next = kvm_pud_addr_end(addr, end);
if (!pud_none(*pud)) {
if (pud_huge(*pud))
kvm_flush_dcache_pud(*pud);
else
stage2_flush_pmds(kvm, pud, addr, next);
}
} while (pud++, addr = next, addr != end);
}
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;
phys_addr_t next;
pgd_t *pgd;
pgd = kvm->arch.pgd + kvm_pgd_index(addr);
do {
next = kvm_pgd_addr_end(addr, end);
stage2_flush_puds(kvm, pgd, addr, next);
} while (pgd++, addr = next, addr != end);
}
/**
* 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;
idx = srcu_read_lock(&kvm->srcu);
spin_lock(&kvm->mmu_lock);
slots = kvm_memslots(kvm);
kvm_for_each_memslot(memslot, slots)
stage2_flush_memslot(kvm, memslot);
spin_unlock(&kvm->mmu_lock);
srcu_read_unlock(&kvm->srcu, idx);
}
/**
* free_boot_hyp_pgd - free HYP boot page tables
*
* Free the HYP boot page tables. The bounce page is also freed.
*/
void free_boot_hyp_pgd(void)
{
mutex_lock(&kvm_hyp_pgd_mutex);
if (boot_hyp_pgd) {
unmap_range(NULL, boot_hyp_pgd, hyp_idmap_start, PAGE_SIZE);
unmap_range(NULL, boot_hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
free_pages((unsigned long)boot_hyp_pgd, hyp_pgd_order);
boot_hyp_pgd = NULL;
}
if (hyp_pgd)
unmap_range(NULL, hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
mutex_unlock(&kvm_hyp_pgd_mutex);
}
/**
* free_hyp_pgds - free Hyp-mode page tables
*
* Assumes hyp_pgd is a page table used strictly in Hyp-mode and
* therefore contains either mappings in the kernel memory area (above
* PAGE_OFFSET), or device mappings in the vmalloc range (from
* VMALLOC_START to VMALLOC_END).
*
* boot_hyp_pgd should only map two pages for the init code.
*/
void free_hyp_pgds(void)
{
unsigned long addr;
free_boot_hyp_pgd();
mutex_lock(&kvm_hyp_pgd_mutex);
if (hyp_pgd) {
for (addr = PAGE_OFFSET; virt_addr_valid(addr); addr += PGDIR_SIZE)
unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE);
for (addr = VMALLOC_START; is_vmalloc_addr((void*)addr); addr += PGDIR_SIZE)
unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE);
free_pages((unsigned long)hyp_pgd, hyp_pgd_order);
hyp_pgd = NULL;
}
if (merged_hyp_pgd) {
clear_page(merged_hyp_pgd);
free_page((unsigned long)merged_hyp_pgd);
merged_hyp_pgd = NULL;
}
mutex_unlock(&kvm_hyp_pgd_mutex);
}
static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start,
unsigned long end, unsigned long pfn,
pgprot_t prot)
{
pte_t *pte;
unsigned long addr;
addr = start;
do {
pte = pte_offset_kernel(pmd, addr);
kvm_set_pte(pte, pfn_pte(pfn, prot));
get_page(virt_to_page(pte));
kvm_flush_dcache_to_poc(pte, sizeof(*pte));
pfn++;
} while (addr += PAGE_SIZE, addr != end);
}
static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start,
unsigned long end, unsigned long pfn,
pgprot_t prot)
{
pmd_t *pmd;
pte_t *pte;
unsigned long addr, next;
addr = start;
do {
pmd = pmd_offset(pud, addr);
BUG_ON(pmd_sect(*pmd));
if (pmd_none(*pmd)) {
pte = pte_alloc_one_kernel(NULL, addr);
if (!pte) {
kvm_err("Cannot allocate Hyp pte\n");
return -ENOMEM;
}
pmd_populate_kernel(NULL, pmd, pte);
get_page(virt_to_page(pmd));
kvm_flush_dcache_to_poc(pmd, sizeof(*pmd));
}
next = pmd_addr_end(addr, end);
create_hyp_pte_mappings(pmd, addr, next, pfn, prot);
pfn += (next - addr) >> PAGE_SHIFT;
} while (addr = next, addr != end);
return 0;
}
static int create_hyp_pud_mappings(pgd_t *pgd, unsigned long start,
unsigned long end, unsigned long pfn,
pgprot_t prot)
{
pud_t *pud;
pmd_t *pmd;
unsigned long addr, next;
int ret;
addr = start;
do {
pud = pud_offset(pgd, addr);
if (pud_none_or_clear_bad(pud)) {
pmd = pmd_alloc_one(NULL, addr);
if (!pmd) {
kvm_err("Cannot allocate Hyp pmd\n");
return -ENOMEM;
}
pud_populate(NULL, pud, pmd);
get_page(virt_to_page(pud));
kvm_flush_dcache_to_poc(pud, sizeof(*pud));
}
next = pud_addr_end(addr, end);
ret = create_hyp_pmd_mappings(pud, addr, next, pfn, prot);
if (ret)
return ret;
pfn += (next - addr) >> PAGE_SHIFT;
} while (addr = next, addr != end);
return 0;
}
static int __create_hyp_mappings(pgd_t *pgdp,
unsigned long start, unsigned long end,
unsigned long pfn, pgprot_t prot)
{
pgd_t *pgd;
pud_t *pud;
unsigned long addr, next;
int err = 0;
mutex_lock(&kvm_hyp_pgd_mutex);
addr = start & PAGE_MASK;
end = PAGE_ALIGN(end);
do {
pgd = pgdp + pgd_index(addr);
if (pgd_none(*pgd)) {
pud = pud_alloc_one(NULL, addr);
if (!pud) {
kvm_err("Cannot allocate Hyp pud\n");
err = -ENOMEM;
goto out;
}
pgd_populate(NULL, pgd, pud);
get_page(virt_to_page(pgd));
kvm_flush_dcache_to_poc(pgd, sizeof(*pgd));
}
next = pgd_addr_end(addr, end);
err = create_hyp_pud_mappings(pgd, addr, next, pfn, prot);
if (err)
goto out;
pfn += (next - addr) >> PAGE_SHIFT;
} while (addr = next, addr != end);
out:
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);
}
}
/**
* 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)
*
* 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)
{
phys_addr_t phys_addr;
unsigned long virt_addr;
unsigned long start = KERN_TO_HYP((unsigned long)from);
unsigned long end = KERN_TO_HYP((unsigned long)to);
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(hyp_pgd, virt_addr,
virt_addr + PAGE_SIZE,
__phys_to_pfn(phys_addr),
PAGE_HYP);
if (err)
return err;
}
return 0;
}
/**
* create_hyp_io_mappings - duplicate a kernel IO mapping into Hyp mode
* @from: The kernel start VA of the range
* @to: The kernel end VA of the range (exclusive)
* @phys_addr: The physical start address which gets mapped
*
* The resulting HYP VA is the same as the kernel VA, modulo
* HYP_PAGE_OFFSET.
*/
int create_hyp_io_mappings(void *from, void *to, phys_addr_t phys_addr)
{
unsigned long start = KERN_TO_HYP((unsigned long)from);
unsigned long end = KERN_TO_HYP((unsigned long)to);
/* Check for a valid kernel IO mapping */
if (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1))
return -EINVAL;
return __create_hyp_mappings(hyp_pgd, start, end,
__phys_to_pfn(phys_addr), PAGE_HYP_DEVICE);
}
/* Free the HW pgd, one page at a time */
static void kvm_free_hwpgd(void *hwpgd)
{
free_pages_exact(hwpgd, kvm_get_hwpgd_size());
}
/* Allocate the HW PGD, making sure that each page gets its own refcount */
static void *kvm_alloc_hwpgd(void)
{
unsigned int size = kvm_get_hwpgd_size();
return alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
}
/**
* kvm_alloc_stage2_pgd - allocate level-1 table for stage-2 translation.
* @kvm: The KVM struct pointer for the VM.
*
* Allocates the 1st level table only of size defined by S2_PGD_ORDER (can
* support either full 40-bit input addresses or limited to 32-bit input
* addresses). Clears the allocated pages.
*
* 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_alloc_stage2_pgd(struct kvm *kvm)
{
pgd_t *pgd;
void *hwpgd;
if (kvm->arch.pgd != NULL) {
kvm_err("kvm_arch already initialized?\n");
return -EINVAL;
}
hwpgd = kvm_alloc_hwpgd();
if (!hwpgd)
return -ENOMEM;
/* When the kernel uses more levels of page tables than the
* guest, we allocate a fake PGD and pre-populate it to point
* to the next-level page table, which will be the real
* initial page table pointed to by the VTTBR.
*
* When KVM_PREALLOC_LEVEL==2, we allocate a single page for
* the PMD and the kernel will use folded pud.
* When KVM_PREALLOC_LEVEL==1, we allocate 2 consecutive PUD
* pages.
*/
if (KVM_PREALLOC_LEVEL > 0) {
int i;
/*
* Allocate fake pgd for the page table manipulation macros to
* work. This is not used by the hardware and we have no
* alignment requirement for this allocation.
*/
pgd = (pgd_t *)kmalloc(PTRS_PER_S2_PGD * sizeof(pgd_t),
GFP_KERNEL | __GFP_ZERO);
if (!pgd) {
kvm_free_hwpgd(hwpgd);
return -ENOMEM;
}
/* Plug the HW PGD into the fake one. */
for (i = 0; i < PTRS_PER_S2_PGD; i++) {
if (KVM_PREALLOC_LEVEL == 1)
pgd_populate(NULL, pgd + i,
(pud_t *)hwpgd + i * PTRS_PER_PUD);
else if (KVM_PREALLOC_LEVEL == 2)
pud_populate(NULL, pud_offset(pgd, 0) + i,
(pmd_t *)hwpgd + i * PTRS_PER_PMD);
}
} else {
/*
* Allocate actual first-level Stage-2 page table used by the
* hardware for Stage-2 page table walks.
*/
pgd = (pgd_t *)hwpgd;
}
kvm_clean_pgd(pgd);
kvm->arch.pgd = pgd;
return 0;
}
/**
* unmap_stage2_range -- Clear stage2 page table entries to unmap a range
* @kvm: The VM pointer
* @start: The intermediate physical base address of the range to unmap
* @size: The size of the area to unmap
*
* 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 *kvm, phys_addr_t start, u64 size)
{
unmap_range(kvm, kvm->arch.pgd, start, size);
}
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 = find_vma(current->mm, hva);
hva_t vm_start, vm_end;
if (!vma || vma->vm_start >= reg_end)
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, 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 reguler 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;
idx = srcu_read_lock(&kvm->srcu);
spin_lock(&kvm->mmu_lock);
slots = kvm_memslots(kvm);
kvm_for_each_memslot(memslot, slots)
stage2_unmap_memslot(kvm, memslot);
spin_unlock(&kvm->mmu_lock);
srcu_read_unlock(&kvm->srcu, idx);
}
/**
* kvm_free_stage2_pgd - free all stage-2 tables
* @kvm: The KVM struct pointer for the VM.
*
* Walks the level-1 page table pointed to by kvm->arch.pgd and frees all
* underlying level-2 and level-3 tables before freeing the actual level-1 table
* and setting the struct pointer to NULL.
*
* Note we don't need locking here as this is only called when the VM is
* destroyed, which can only be done once.
*/
void kvm_free_stage2_pgd(struct kvm *kvm)
{
if (kvm->arch.pgd == NULL)
return;
unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE);
kvm_free_hwpgd(kvm_get_hwpgd(kvm));
if (KVM_PREALLOC_LEVEL > 0)
kfree(kvm->arch.pgd);
kvm->arch.pgd = NULL;
}
static pud_t *stage2_get_pud(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
phys_addr_t addr)
{
pgd_t *pgd;
pud_t *pud;
pgd = kvm->arch.pgd + kvm_pgd_index(addr);
if (WARN_ON(pgd_none(*pgd))) {
if (!cache)
return NULL;
pud = mmu_memory_cache_alloc(cache);
pgd_populate(NULL, pgd, pud);
get_page(virt_to_page(pgd));
}
return pud_offset(pgd, addr);
}
static pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
phys_addr_t addr)
{
pud_t *pud;
pmd_t *pmd;
pud = stage2_get_pud(kvm, cache, addr);
if (pud_none(*pud)) {
if (!cache)
return NULL;
pmd = mmu_memory_cache_alloc(cache);
pud_populate(NULL, pud, pmd);
get_page(virt_to_page(pud));
}
return pmd_offset(pud, addr);
}
static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache
*cache, phys_addr_t addr, const pmd_t *new_pmd)
{
pmd_t *pmd, old_pmd;
pmd = stage2_get_pmd(kvm, cache, addr);
VM_BUG_ON(!pmd);
/*
* Mapping in huge pages should only happen through a fault. If a
* page is merged into a transparent huge page, the individual
* subpages of that huge page should be unmapped through MMU
* notifiers before we get here.
*
* Merging of CompoundPages is not supported; they should become
* splitting first, unmapped, merged, and mapped back in on-demand.
*/
VM_BUG_ON(pmd_present(*pmd) && pmd_pfn(*pmd) != pmd_pfn(*new_pmd));
old_pmd = *pmd;
kvm_set_pmd(pmd, *new_pmd);
if (pmd_present(old_pmd))
kvm_tlb_flush_vmid_ipa(kvm, addr);
else
get_page(virt_to_page(pmd));
return 0;
}
static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
phys_addr_t addr, const pte_t *new_pte,
unsigned long flags)
{
pmd_t *pmd;
pte_t *pte, old_pte;
bool iomap = flags & KVM_S2PTE_FLAG_IS_IOMAP;
bool logging_active = flags & KVM_S2_FLAG_LOGGING_ACTIVE;
VM_BUG_ON(logging_active && !cache);
/* Create stage-2 page table mapping - Levels 0 and 1 */
pmd = stage2_get_pmd(kvm, cache, addr);
if (!pmd) {
/*
* Ignore calls from kvm_set_spte_hva for unallocated
* address ranges.
*/
return 0;
}
/*
* While dirty page logging - dissolve huge PMD, then continue on to
* allocate page.
*/
if (logging_active)
stage2_dissolve_pmd(kvm, addr, pmd);
/* Create stage-2 page mappings - Level 2 */
if (pmd_none(*pmd)) {
if (!cache)
return 0; /* ignore calls from kvm_set_spte_hva */
pte = mmu_memory_cache_alloc(cache);
kvm_clean_pte(pte);
pmd_populate_kernel(NULL, pmd, pte);
get_page(virt_to_page(pmd));
}
pte = pte_offset_kernel(pmd, addr);
if (iomap && pte_present(*pte))
return -EFAULT;
/* Create 2nd stage page table mapping - Level 3 */
old_pte = *pte;
kvm_set_pte(pte, *new_pte);
if (pte_present(old_pte))
kvm_tlb_flush_vmid_ipa(kvm, addr);
else
get_page(virt_to_page(pte));
return 0;
}
/**
* 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
*/
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, end;
int ret = 0;
unsigned long pfn;
struct kvm_mmu_memory_cache cache = { 0, };
end = (guest_ipa + size + PAGE_SIZE - 1) & PAGE_MASK;
pfn = __phys_to_pfn(pa);
for (addr = guest_ipa; addr < end; addr += PAGE_SIZE) {
pte_t pte = pfn_pte(pfn, PAGE_S2_DEVICE);
if (writable)
kvm_set_s2pte_writable(&pte);
ret = mmu_topup_memory_cache(&cache, KVM_MMU_CACHE_MIN_PAGES,
KVM_NR_MEM_OBJS);
if (ret)
goto out;
spin_lock(&kvm->mmu_lock);
ret = stage2_set_pte(kvm, &cache, addr, &pte,
KVM_S2PTE_FLAG_IS_IOMAP);
spin_unlock(&kvm->mmu_lock);
if (ret)
goto out;
pfn++;
}
out:
mmu_free_memory_cache(&cache);
return ret;
}
static bool transparent_hugepage_adjust(pfn_t *pfnp, phys_addr_t *ipap)
{
pfn_t pfn = *pfnp;
gfn_t gfn = *ipap >> PAGE_SHIFT;
if (PageTransCompound(pfn_to_page(pfn))) {
unsigned long mask;
/*
* 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_notifier_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.
*/
mask = PTRS_PER_PMD - 1;
VM_BUG_ON((gfn & mask) != (pfn & mask));
if (pfn & mask) {
*ipap &= PMD_MASK;
kvm_release_pfn_clean(pfn);
pfn &= ~mask;
kvm_get_pfn(pfn);
*pfnp = pfn;
}
return true;
}
return false;
}
static bool kvm_is_write_fault(struct kvm_vcpu *vcpu)
{
if (kvm_vcpu_trap_is_iabt(vcpu))
return false;
return kvm_vcpu_dabt_iswrite(vcpu);
}
static bool kvm_is_device_pfn(unsigned long pfn)
{
return !pfn_valid(pfn);
}
/**
* stage2_wp_ptes - write protect PMD range
* @pmd: pointer to pmd entry
* @addr: range start address
* @end: range end address
*/
static void stage2_wp_ptes(pmd_t *pmd, phys_addr_t addr, phys_addr_t end)
{
pte_t *pte;
pte = pte_offset_kernel(pmd, addr);
do {
if (!pte_none(*pte)) {
if (!kvm_s2pte_readonly(pte))
kvm_set_s2pte_readonly(pte);
}
} while (pte++, addr += PAGE_SIZE, addr != end);
}
/**
* stage2_wp_pmds - write protect PUD range
* @pud: pointer to pud entry
* @addr: range start address
* @end: range end address
*/
static void stage2_wp_pmds(pud_t *pud, phys_addr_t addr, phys_addr_t end)
{
pmd_t *pmd;
phys_addr_t next;
pmd = pmd_offset(pud, addr);
do {
next = kvm_pmd_addr_end(addr, end);
if (!pmd_none(*pmd)) {
if (kvm_pmd_huge(*pmd)) {
if (!kvm_s2pmd_readonly(pmd))
kvm_set_s2pmd_readonly(pmd);
} else {
stage2_wp_ptes(pmd, addr, next);
}
}
} while (pmd++, addr = next, addr != end);
}
/**
* stage2_wp_puds - write protect PGD range
* @pgd: pointer to pgd entry
* @addr: range start address
* @end: range end address
*
* Process PUD entries, for a huge PUD we cause a panic.
*/
static void stage2_wp_puds(pgd_t *pgd, phys_addr_t addr, phys_addr_t end)
{
pud_t *pud;
phys_addr_t next;
pud = pud_offset(pgd, addr);
do {
next = kvm_pud_addr_end(addr, end);
if (!pud_none(*pud)) {
/* TODO:PUD not supported, revisit later if supported */
BUG_ON(kvm_pud_huge(*pud));
stage2_wp_pmds(pud, addr, next);
}
} while (pud++, addr = next, addr != end);
}
/**
* stage2_wp_range() - write protect stage2 memory region range
* @kvm: The KVM pointer
* @addr: Start address of range
* @end: End address of range
*/
static void stage2_wp_range(struct kvm *kvm, phys_addr_t addr, phys_addr_t end)
{
pgd_t *pgd;
phys_addr_t next;
pgd = kvm->arch.pgd + kvm_pgd_index(addr);
do {
/*
* 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.
*/
if (need_resched() || spin_needbreak(&kvm->mmu_lock))
cond_resched_lock(&kvm->mmu_lock);
next = kvm_pgd_addr_end(addr, end);
if (pgd_present(*pgd))
stage2_wp_puds(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
}
/**
* 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 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.
*/
void kvm_mmu_wp_memory_region(struct kvm *kvm, int slot)
{
struct kvm_memory_slot *memslot = id_to_memslot(kvm->memslots, slot);
phys_addr_t start = memslot->base_gfn << PAGE_SHIFT;
phys_addr_t end = (memslot->base_gfn + memslot->npages) << PAGE_SHIFT;
spin_lock(&kvm->mmu_lock);
stage2_wp_range(kvm, start, end);
spin_unlock(&kvm->mmu_lock);
kvm_flush_remote_tlbs(kvm);
}
/**
* kvm_mmu_write_protect_pt_masked() - write protect dirty pages
* @kvm: The KVM pointer
* @slot: The memory slot associated with mask
* @gfn_offset: The gfn offset in memory slot
* @mask: The mask of dirty pages at offset 'gfn_offset' in this memory
* slot to be write protected
*
* Walks bits set in mask write protects the associated pte's. Caller must
* acquire kvm_mmu_lock.
*/
static void kvm_mmu_write_protect_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;
stage2_wp_range(kvm, start, end);
}
/*
* kvm_arch_mmu_enable_log_dirty_pt_masked - enable dirty logging for selected
* dirty pages.
*
* It calls kvm_mmu_write_protect_pt_masked to write protect selected pages to
* enable dirty logging for them.
*/
void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t gfn_offset, unsigned long mask)
{
kvm_mmu_write_protect_pt_masked(kvm, slot, gfn_offset, mask);
}
static void coherent_cache_guest_page(struct kvm_vcpu *vcpu, pfn_t pfn,
unsigned long size, bool uncached)
{
__coherent_cache_guest_page(vcpu, pfn, size, uncached);
}
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;
bool write_fault, writable, hugetlb = false, force_pte = false;
unsigned long mmu_seq;
gfn_t gfn = fault_ipa >> PAGE_SHIFT;
struct kvm *kvm = vcpu->kvm;
struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
struct vm_area_struct *vma;
pfn_t pfn;
pgprot_t mem_type = PAGE_S2;
bool fault_ipa_uncached;
bool logging_active = memslot_is_logging(memslot);
unsigned long flags = 0;
write_fault = kvm_is_write_fault(vcpu);
if (fault_status == FSC_PERM && !write_fault) {
kvm_err("Unexpected L2 read permission error\n");
return -EFAULT;
}
/* Let's check if we will get back a huge page backed by hugetlbfs */
down_read(¤t->mm->mmap_sem);
vma = find_vma_intersection(current->mm, hva, hva + 1);
if (unlikely(!vma)) {
kvm_err("Failed to find VMA for hva 0x%lx\n", hva);
up_read(¤t->mm->mmap_sem);
return -EFAULT;
}
if (is_vm_hugetlb_page(vma) && !logging_active) {
hugetlb = true;
gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT;
} else {
/*
* Pages belonging to memslots that don't have the same
* alignment for userspace and IPA cannot be mapped using
* block descriptors even if the pages belong to a THP for
* the process, because the stage-2 block descriptor will
* cover more than a single THP and we loose atomicity for
* unmapping, updates, and splits of the THP or other pages
* in the stage-2 block range.
*/
if ((memslot->userspace_addr & ~PMD_MASK) !=
((memslot->base_gfn << PAGE_SHIFT) & ~PMD_MASK))
force_pte = true;
}
up_read(¤t->mm->mmap_sem);
/* We need minimum second+third level pages */
ret = mmu_topup_memory_cache(memcache, KVM_MMU_CACHE_MIN_PAGES,
KVM_NR_MEM_OBJS);
if (ret)
return ret;
mmu_seq = vcpu->kvm->mmu_notifier_seq;
/*
* Ensure the read of mmu_notifier_seq happens before we call
* gfn_to_pfn_prot (which calls get_user_pages), so that we don't risk
* the page we just got a reference to gets unmapped before we have a
* chance to grab the mmu_lock, which ensure that if the page gets
* unmapped afterwards, the call to kvm_unmap_hva will take it away
* from us again properly. This smp_rmb() interacts with the smp_wmb()
* in kvm_mmu_notifier_invalidate_<page|range_end>.
*/
smp_rmb();
pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writable);
if (is_error_pfn(pfn))
return -EFAULT;
if (kvm_is_device_pfn(pfn)) {
mem_type = PAGE_S2_DEVICE;
flags |= KVM_S2PTE_FLAG_IS_IOMAP;
} else if (logging_active) {
/*
* Faults on pages in a memslot with logging enabled
* should not be mapped with huge pages (it introduces churn
* and performance degradation), so force a pte mapping.
*/
force_pte = true;
flags |= KVM_S2_FLAG_LOGGING_ACTIVE;
/*
* Only actually map the page as writable if this was a write
* fault.
*/
if (!write_fault)
writable = false;
}
spin_lock(&kvm->mmu_lock);
if (mmu_notifier_retry(kvm, mmu_seq))
goto out_unlock;
if (!hugetlb && !force_pte)
hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa);
fault_ipa_uncached = memslot->flags & KVM_MEMSLOT_INCOHERENT;
if (hugetlb) {
pmd_t new_pmd = pfn_pmd(pfn, mem_type);
new_pmd = pmd_mkhuge(new_pmd);
if (writable) {
kvm_set_s2pmd_writable(&new_pmd);
kvm_set_pfn_dirty(pfn);
}
coherent_cache_guest_page(vcpu, pfn, PMD_SIZE, fault_ipa_uncached);
ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd);
} else {
pte_t new_pte = pfn_pte(pfn, mem_type);
if (writable) {
kvm_set_s2pte_writable(&new_pte);
kvm_set_pfn_dirty(pfn);
mark_page_dirty(kvm, gfn);
}
coherent_cache_guest_page(vcpu, pfn, PAGE_SIZE, fault_ipa_uncached);
ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, flags);
}
out_unlock:
spin_unlock(&kvm->mmu_lock);
kvm_set_pfn_accessed(pfn);
kvm_release_pfn_clean(pfn);
return ret;
}
/*
* Resolve the access fault by making the page young again.
* Note that because the faulting entry is guaranteed not to be
* cached in the TLB, we don't need to invalidate anything.
*/
static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa)
{
pmd_t *pmd;
pte_t *pte;
pfn_t pfn;
bool pfn_valid = false;
trace_kvm_access_fault(fault_ipa);
spin_lock(&vcpu->kvm->mmu_lock);
pmd = stage2_get_pmd(vcpu->kvm, NULL, fault_ipa);
if (!pmd || pmd_none(*pmd)) /* Nothing there */
goto out;
if (kvm_pmd_huge(*pmd)) { /* THP, HugeTLB */
*pmd = pmd_mkyoung(*pmd);
pfn = pmd_pfn(*pmd);
pfn_valid = true;
goto out;
}
pte = pte_offset_kernel(pmd, fault_ipa);
if (pte_none(*pte)) /* Nothing there either */
goto out;
*pte = pte_mkyoung(*pte); /* Just a page... */
pfn = pte_pfn(*pte);
pfn_valid = true;
out:
spin_unlock(&vcpu->kvm->mmu_lock);
if (pfn_valid)
kvm_set_pfn_accessed(pfn);
}
/**
* kvm_handle_guest_abort - handles all 2nd stage aborts
* @vcpu: the VCPU pointer
* @run: the kvm_run structure
*
* 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, struct kvm_run *run)
{
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;
is_iabt = kvm_vcpu_trap_is_iabt(vcpu);
fault_ipa = kvm_vcpu_get_fault_ipa(vcpu);
trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_hsr(vcpu),
kvm_vcpu_get_hfar(vcpu), fault_ipa);
/* Check the stage-2 fault is trans. fault or write fault */
fault_status = kvm_vcpu_trap_get_fault_type(vcpu);
if (fault_status != FSC_FAULT && fault_status != FSC_PERM &&
fault_status != 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_hsr(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)) {
if (is_iabt) {
/* Prefetch Abort on I/O address */
kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(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, run, fault_ipa);
goto out_unlock;
}
/* Userspace should not be able to register out-of-bounds IPAs */
VM_BUG_ON(fault_ipa >= KVM_PHYS_SIZE);
if (fault_status == 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_unlock:
srcu_read_unlock(&vcpu->kvm->srcu, idx);
return ret;
}
static int handle_hva_to_gpa(struct kvm *kvm,
unsigned long start,
unsigned long end,
int (*handler)(struct kvm *kvm,
gpa_t gpa, void *data),
void *data)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
int ret = 0;
slots = kvm_memslots(kvm);
/* we only care about the pages that the guest sees */
kvm_for_each_memslot(memslot, slots) {
unsigned long hva_start, hva_end;
gfn_t gfn, gfn_end;
hva_start = max(start, memslot->userspace_addr);
hva_end = min(end, memslot->userspace_addr +
(memslot->npages << PAGE_SHIFT));
if (hva_start >= hva_end)
continue;
/*
* {gfn(page) | page intersects with [hva_start, hva_end)} =
* {gfn_start, gfn_start+1, ..., gfn_end-1}.
*/
gfn = hva_to_gfn_memslot(hva_start, memslot);
gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
for (; gfn < gfn_end; ++gfn) {
gpa_t gpa = gfn << PAGE_SHIFT;
ret |= handler(kvm, gpa, data);
}
}
return ret;
}
static int kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, void *data)
{
unmap_stage2_range(kvm, gpa, PAGE_SIZE);
return 0;
}
int kvm_unmap_hva(struct kvm *kvm, unsigned long hva)
{
unsigned long end = hva + PAGE_SIZE;
if (!kvm->arch.pgd)
return 0;
trace_kvm_unmap_hva(hva);
handle_hva_to_gpa(kvm, hva, end, &kvm_unmap_hva_handler, NULL);
return 0;
}
int kvm_unmap_hva_range(struct kvm *kvm,
unsigned long start, unsigned long end)
{
if (!kvm->arch.pgd)
return 0;
trace_kvm_unmap_hva_range(start, end);
handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL);
return 0;
}
static int kvm_set_spte_handler(struct kvm *kvm, gpa_t gpa, void *data)
{
pte_t *pte = (pte_t *)data;
/*
* We can always call stage2_set_pte with KVM_S2PTE_FLAG_LOGGING_ACTIVE
* flag clear because MMU notifiers will have unmapped a huge PMD before
* calling ->change_pte() (which in turn calls kvm_set_spte_hva()) and
* therefore stage2_set_pte() never needs to clear out a huge PMD
* through this calling path.
*/
stage2_set_pte(kvm, NULL, gpa, pte, 0);
return 0;
}
void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte)
{
unsigned long end = hva + PAGE_SIZE;
pte_t stage2_pte;
if (!kvm->arch.pgd)
return;
trace_kvm_set_spte_hva(hva);
stage2_pte = pfn_pte(pte_pfn(pte), PAGE_S2);
handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &stage2_pte);
}
static int kvm_age_hva_handler(struct kvm *kvm, gpa_t gpa, void *data)
{
pmd_t *pmd;
pte_t *pte;
pmd = stage2_get_pmd(kvm, NULL, gpa);
if (!pmd || pmd_none(*pmd)) /* Nothing there */
return 0;
if (kvm_pmd_huge(*pmd)) { /* THP, HugeTLB */
if (pmd_young(*pmd)) {
*pmd = pmd_mkold(*pmd);
return 1;
}
return 0;
}
pte = pte_offset_kernel(pmd, gpa);
if (pte_none(*pte))
return 0;
if (pte_young(*pte)) {
*pte = pte_mkold(*pte); /* Just a page... */
return 1;
}
return 0;
}
static int kvm_test_age_hva_handler(struct kvm *kvm, gpa_t gpa, void *data)
{
pmd_t *pmd;
pte_t *pte;
pmd = stage2_get_pmd(kvm, NULL, gpa);
if (!pmd || pmd_none(*pmd)) /* Nothing there */
return 0;
if (kvm_pmd_huge(*pmd)) /* THP, HugeTLB */
return pmd_young(*pmd);
pte = pte_offset_kernel(pmd, gpa);
if (!pte_none(*pte)) /* Just a page... */
return pte_young(*pte);
return 0;
}
int kvm_age_hva(struct kvm *kvm, unsigned long start, unsigned long end)
{
trace_kvm_age_hva(start, end);
return handle_hva_to_gpa(kvm, start, end, kvm_age_hva_handler, NULL);
}
int kvm_test_age_hva(struct kvm *kvm, unsigned long hva)
{
trace_kvm_test_age_hva(hva);
return handle_hva_to_gpa(kvm, hva, hva, kvm_test_age_hva_handler, NULL);
}
void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu)
{
mmu_free_memory_cache(&vcpu->arch.mmu_page_cache);
}
phys_addr_t kvm_mmu_get_httbr(void)
{
if (__kvm_cpu_uses_extended_idmap())
return virt_to_phys(merged_hyp_pgd);
else
return virt_to_phys(hyp_pgd);
}
phys_addr_t kvm_mmu_get_boot_httbr(void)
{
if (__kvm_cpu_uses_extended_idmap())
return virt_to_phys(merged_hyp_pgd);
else
return virt_to_phys(boot_hyp_pgd);
}
phys_addr_t kvm_get_idmap_vector(void)
{
return hyp_idmap_vector;
}
int kvm_mmu_init(void)
{
int err;
hyp_idmap_start = kvm_virt_to_phys(__hyp_idmap_text_start);
hyp_idmap_end = kvm_virt_to_phys(__hyp_idmap_text_end);
hyp_idmap_vector = kvm_virt_to_phys(__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);
hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, hyp_pgd_order);
boot_hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, hyp_pgd_order);
if (!hyp_pgd || !boot_hyp_pgd) {
kvm_err("Hyp mode PGD not allocated\n");
err = -ENOMEM;
goto out;
}
/* Create the idmap in the boot page tables */
err = __create_hyp_mappings(boot_hyp_pgd,
hyp_idmap_start, hyp_idmap_end,
__phys_to_pfn(hyp_idmap_start),
PAGE_HYP);
if (err) {
kvm_err("Failed to idmap %lx-%lx\n",
hyp_idmap_start, hyp_idmap_end);
goto out;
}
if (__kvm_cpu_uses_extended_idmap()) {
merged_hyp_pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
if (!merged_hyp_pgd) {
kvm_err("Failed to allocate extra HYP pgd\n");
goto out;
}
__kvm_extend_hypmap(boot_hyp_pgd, hyp_pgd, merged_hyp_pgd,
hyp_idmap_start);
return 0;
}
/* Map the very same page at the trampoline VA */
err = __create_hyp_mappings(boot_hyp_pgd,
TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE,
__phys_to_pfn(hyp_idmap_start),
PAGE_HYP);
if (err) {
kvm_err("Failed to map trampoline @%lx into boot HYP pgd\n",
TRAMPOLINE_VA);
goto out;
}
/* Map the same page again into the runtime page tables */
err = __create_hyp_mappings(hyp_pgd,
TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE,
__phys_to_pfn(hyp_idmap_start),
PAGE_HYP);
if (err) {
kvm_err("Failed to map trampoline @%lx into runtime HYP pgd\n",
TRAMPOLINE_VA);
goto out;
}
return 0;
out:
free_hyp_pgds();
return err;
}
void kvm_arch_commit_memory_region(struct kvm *kvm,
struct kvm_userspace_memory_region *mem,
const struct kvm_memory_slot *old,
enum kvm_mr_change change)
{
/*
* At this point memslot has been committed and there is an
* allocated dirty_bitmap[], dirty pages will be be tracked while the
* memory slot is write protected.
*/
if (change != KVM_MR_DELETE && mem->flags & KVM_MEM_LOG_DIRTY_PAGES)
kvm_mmu_wp_memory_region(kvm, mem->slot);
}
int kvm_arch_prepare_memory_region(struct kvm *kvm,
struct kvm_memory_slot *memslot,
struct kvm_userspace_memory_region *mem,
enum kvm_mr_change change)
{
hva_t hva = mem->userspace_addr;
hva_t reg_end = hva + mem->memory_size;
bool writable = !(mem->flags & KVM_MEM_READONLY);
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 (memslot->base_gfn + memslot->npages >=
(KVM_PHYS_SIZE >> PAGE_SHIFT))
return -EFAULT;
/*
* A memory region could potentially cover multiple VMAs, and any holes
* between them, so iterate over all of them to find out if we can map
* any of them right now.
*
* +--------------------------------------------+
* +---------------+----------------+ +----------------+
* | : VMA 1 | VMA 2 | | VMA 3 : |
* +---------------+----------------+ +----------------+
* | memory region |
* +--------------------------------------------+
*/
do {
struct vm_area_struct *vma = find_vma(current->mm, hva);
hva_t vm_start, vm_end;
if (!vma || vma->vm_start >= reg_end)
break;
/*
* Mapping a read-only VMA is only allowed if the
* memory region is configured as read-only.
*/
if (writable && !(vma->vm_flags & VM_WRITE)) {
ret = -EPERM;
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 = mem->guest_phys_addr +
(vm_start - mem->userspace_addr);
phys_addr_t pa = (vma->vm_pgoff << PAGE_SHIFT) +
vm_start - vma->vm_start;
/* IO region dirty page logging not allowed */
if (memslot->flags & KVM_MEM_LOG_DIRTY_PAGES)
return -EINVAL;
ret = kvm_phys_addr_ioremap(kvm, gpa, pa,
vm_end - vm_start,
writable);
if (ret)
break;
}
hva = vm_end;
} while (hva < reg_end);
if (change == KVM_MR_FLAGS_ONLY)
return ret;
spin_lock(&kvm->mmu_lock);
if (ret)
unmap_stage2_range(kvm, mem->guest_phys_addr, mem->memory_size);
else
stage2_flush_memslot(kvm, memslot);
spin_unlock(&kvm->mmu_lock);
return ret;
}
void kvm_arch_free_memslot(struct kvm *kvm, struct kvm_memory_slot *free,
struct kvm_memory_slot *dont)
{
}
int kvm_arch_create_memslot(struct kvm *kvm, struct kvm_memory_slot *slot,
unsigned long npages)
{
/*
* Readonly memslots are not incoherent with the caches by definition,
* but in practice, they are used mostly to emulate ROMs or NOR flashes
* that the guest may consider devices and hence map as uncached.
* To prevent incoherency issues in these cases, tag all readonly
* regions as incoherent.
*/
if (slot->flags & KVM_MEM_READONLY)
slot->flags |= KVM_MEMSLOT_INCOHERENT;
return 0;
}
void kvm_arch_memslots_updated(struct kvm *kvm)
{
}
void kvm_arch_flush_shadow_all(struct kvm *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;
spin_lock(&kvm->mmu_lock);
unmap_stage2_range(kvm, gpa, size);
spin_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_get_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_set_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_set_hcr(vcpu, vcpu_get_hcr(vcpu) & ~HCR_TVM);
trace_kvm_toggle_cache(*vcpu_pc(vcpu), was_enabled, now_enabled);
}