/*
* 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 <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 DEFINE_MUTEX(kvm_hyp_pgd_mutex);
static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
{
kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa);
}
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 free_ptes(pmd_t *pmd, unsigned long addr)
{
pte_t *pte;
unsigned int i;
for (i = 0; i < PTRS_PER_PMD; i++, addr += PMD_SIZE) {
if (!pmd_none(*pmd) && pmd_table(*pmd)) {
pte = pte_offset_kernel(pmd, addr);
pte_free_kernel(NULL, pte);
}
pmd++;
}
}
static void free_hyp_pgd_entry(unsigned long addr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
unsigned long hyp_addr = KERN_TO_HYP(addr);
pgd = hyp_pgd + pgd_index(hyp_addr);
pud = pud_offset(pgd, hyp_addr);
if (pud_none(*pud))
return;
BUG_ON(pud_bad(*pud));
pmd = pmd_offset(pud, hyp_addr);
free_ptes(pmd, addr);
pmd_free(NULL, pmd);
pud_clear(pud);
}
/**
* free_hyp_pmds - free a Hyp-mode level-2 tables and child level-3 tables
*
* Assumes this 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).
*/
void free_hyp_pmds(void)
{
unsigned long addr;
mutex_lock(&kvm_hyp_pgd_mutex);
for (addr = PAGE_OFFSET; virt_addr_valid(addr); addr += PGDIR_SIZE)
free_hyp_pgd_entry(addr);
for (addr = VMALLOC_START; is_vmalloc_addr((void*)addr); addr += PGDIR_SIZE)
free_hyp_pgd_entry(addr);
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;
for (addr = start; addr < end; addr += PAGE_SIZE) {
pte = pte_offset_kernel(pmd, addr);
kvm_set_pte(pte, pfn_pte(pfn, prot));
pfn++;
}
}
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;
for (addr = start; addr < end; addr = next) {
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);
}
next = pmd_addr_end(addr, end);
create_hyp_pte_mappings(pmd, addr, next, pfn, prot);
pfn += (next - addr) >> PAGE_SHIFT;
}
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;
pmd_t *pmd;
unsigned long addr, next;
int err = 0;
if (start >= end)
return -EINVAL;
mutex_lock(&kvm_hyp_pgd_mutex);
for (addr = start & PAGE_MASK; addr < end; addr = next) {
pgd = pgdp + pgd_index(addr);
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");
err = -ENOMEM;
goto out;
}
pud_populate(NULL, pud, pmd);
}
next = pgd_addr_end(addr, end);
err = create_hyp_pmd_mappings(pud, addr, next, pfn, prot);
if (err)
goto out;
pfn += (next - addr) >> PAGE_SHIFT;
}
out:
mutex_unlock(&kvm_hyp_pgd_mutex);
return err;
}
/**
* 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.
*
* Note: Wrapping around zero in the "to" address is not supported.
*/
int create_hyp_mappings(void *from, void *to)
{
unsigned long phys_addr = virt_to_phys(from);
unsigned long start = KERN_TO_HYP((unsigned long)from);
unsigned long end = KERN_TO_HYP((unsigned long)to);
/* Check for a valid kernel memory mapping */
if (!virt_addr_valid(from) || !virt_addr_valid(to - 1))
return -EINVAL;
return __create_hyp_mappings(hyp_pgd, start, end,
__phys_to_pfn(phys_addr), PAGE_HYP);
}
/**
* 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);
}
/**
* 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;
if (kvm->arch.pgd != NULL) {
kvm_err("kvm_arch already initialized?\n");
return -EINVAL;
}
pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, S2_PGD_ORDER);
if (!pgd)
return -ENOMEM;
/* stage-2 pgd must be aligned to its size */
VM_BUG_ON((unsigned long)pgd & (S2_PGD_SIZE - 1));
memset(pgd, 0, PTRS_PER_S2_PGD * sizeof(pgd_t));
kvm_clean_pgd(pgd);
kvm->arch.pgd = pgd;
return 0;
}
static void clear_pud_entry(pud_t *pud)
{
pmd_t *pmd_table = pmd_offset(pud, 0);
pud_clear(pud);
pmd_free(NULL, pmd_table);
put_page(virt_to_page(pud));
}
static void clear_pmd_entry(pmd_t *pmd)
{
pte_t *pte_table = pte_offset_kernel(pmd, 0);
pmd_clear(pmd);
pte_free_kernel(NULL, pte_table);
put_page(virt_to_page(pmd));
}
static bool pmd_empty(pmd_t *pmd)
{
struct page *pmd_page = virt_to_page(pmd);
return page_count(pmd_page) == 1;
}
static void clear_pte_entry(pte_t *pte)
{
if (pte_present(*pte)) {
kvm_set_pte(pte, __pte(0));
put_page(virt_to_page(pte));
}
}
static bool pte_empty(pte_t *pte)
{
struct page *pte_page = virt_to_page(pte);
return page_count(pte_page) == 1;
}
/**
* 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)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
phys_addr_t addr = start, end = start + size;
u64 range;
while (addr < end) {
pgd = kvm->arch.pgd + pgd_index(addr);
pud = pud_offset(pgd, addr);
if (pud_none(*pud)) {
addr += PUD_SIZE;
continue;
}
pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd)) {
addr += PMD_SIZE;
continue;
}
pte = pte_offset_kernel(pmd, addr);
clear_pte_entry(pte);
range = PAGE_SIZE;
/* If we emptied the pte, walk back up the ladder */
if (pte_empty(pte)) {
clear_pmd_entry(pmd);
range = PMD_SIZE;
if (pmd_empty(pmd)) {
clear_pud_entry(pud);
range = PUD_SIZE;
}
}
addr += range;
}
}
/**
* 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);
free_pages((unsigned long)kvm->arch.pgd, S2_PGD_ORDER);
kvm->arch.pgd = NULL;
}
static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
phys_addr_t addr, const pte_t *new_pte, bool iomap)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte, old_pte;
/* Create 2nd stage page table mapping - Level 1 */
pgd = kvm->arch.pgd + pgd_index(addr);
pud = pud_offset(pgd, addr);
if (pud_none(*pud)) {
if (!cache)
return 0; /* ignore calls from kvm_set_spte_hva */
pmd = mmu_memory_cache_alloc(cache);
pud_populate(NULL, pud, pmd);
get_page(virt_to_page(pud));
}
pmd = pmd_offset(pud, addr);
/* Create 2nd stage page table mapping - 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)
{
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);
kvm_set_s2pte_writable(&pte);
ret = mmu_topup_memory_cache(&cache, 2, 2);
if (ret)
goto out;
spin_lock(&kvm->mmu_lock);
ret = stage2_set_pte(kvm, &cache, addr, &pte, true);
spin_unlock(&kvm->mmu_lock);
if (ret)
goto out;
pfn++;
}
out:
mmu_free_memory_cache(&cache);
return ret;
}
static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
gfn_t gfn, struct kvm_memory_slot *memslot,
unsigned long fault_status)
{
pte_t new_pte;
pfn_t pfn;
int ret;
bool write_fault, writable;
unsigned long mmu_seq;
struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache;
write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu));
if (fault_status == FSC_PERM && !write_fault) {
kvm_err("Unexpected L2 read permission error\n");
return -EFAULT;
}
/* We need minimum second+third level pages */
ret = mmu_topup_memory_cache(memcache, 2, 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(vcpu->kvm, gfn, write_fault, &writable);
if (is_error_pfn(pfn))
return -EFAULT;
new_pte = pfn_pte(pfn, PAGE_S2);
coherent_icache_guest_page(vcpu->kvm, gfn);
spin_lock(&vcpu->kvm->mmu_lock);
if (mmu_notifier_retry(vcpu->kvm, mmu_seq))
goto out_unlock;
if (writable) {
kvm_set_s2pte_writable(&new_pte);
kvm_set_pfn_dirty(pfn);
}
stage2_set_pte(vcpu->kvm, memcache, fault_ipa, &new_pte, false);
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return 0;
}
/**
* 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;
bool is_iabt;
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(vcpu);
if (fault_status != FSC_FAULT && fault_status != FSC_PERM) {
kvm_err("Unsupported fault status: EC=%#x DFCS=%#lx\n",
kvm_vcpu_trap_get_class(vcpu), fault_status);
return -EFAULT;
}
idx = srcu_read_lock(&vcpu->kvm->srcu);
gfn = fault_ipa >> PAGE_SHIFT;
if (!kvm_is_visible_gfn(vcpu->kvm, gfn)) {
if (is_iabt) {
/* Prefetch Abort on I/O address */
kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu));
ret = 1;
goto out_unlock;
}
if (fault_status != FSC_FAULT) {
kvm_err("Unsupported fault status on io memory: %#lx\n",
fault_status);
ret = -EFAULT;
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;
}
memslot = gfn_to_memslot(vcpu->kvm, gfn);
ret = user_mem_abort(vcpu, fault_ipa, gfn, memslot, fault_status);
if (ret == 0)
ret = 1;
out_unlock:
srcu_read_unlock(&vcpu->kvm->srcu, idx);
return ret;
}
static void handle_hva_to_gpa(struct kvm *kvm,
unsigned long start,
unsigned long end,
void (*handler)(struct kvm *kvm,
gpa_t gpa, void *data),
void *data)
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
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;
handler(kvm, gpa, data);
}
}
}
static void kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, void *data)
{
unmap_stage2_range(kvm, gpa, PAGE_SIZE);
kvm_tlb_flush_vmid_ipa(kvm, gpa);
}
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 void kvm_set_spte_handler(struct kvm *kvm, gpa_t gpa, void *data)
{
pte_t *pte = (pte_t *)data;
stage2_set_pte(kvm, NULL, gpa, pte, false);
}
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);
}
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)
{
VM_BUG_ON(!virt_addr_valid(hyp_pgd));
return virt_to_phys(hyp_pgd);
}
int kvm_mmu_init(void)
{
if (!hyp_pgd) {
kvm_err("Hyp mode PGD not allocated\n");
return -ENOMEM;
}
return 0;
}
/**
* kvm_clear_idmap - remove all idmaps from the hyp pgd
*
* Free the underlying pmds for all pgds in range and clear the pgds (but
* don't free them) afterwards.
*/
void kvm_clear_hyp_idmap(void)
{
unsigned long addr, end;
unsigned long next;
pgd_t *pgd = hyp_pgd;
pud_t *pud;
pmd_t *pmd;
addr = virt_to_phys(__hyp_idmap_text_start);
end = virt_to_phys(__hyp_idmap_text_end);
pgd += pgd_index(addr);
do {
next = pgd_addr_end(addr, end);
if (pgd_none_or_clear_bad(pgd))
continue;
pud = pud_offset(pgd, addr);
pmd = pmd_offset(pud, addr);
pud_clear(pud);
kvm_clean_pmd_entry(pmd);
pmd_free(NULL, (pmd_t *)((unsigned long)pmd & PAGE_MASK));
} while (pgd++, addr = next, addr < end);
}
