linux/arch/arm/kvm/mmu.c
Ard Biesheuvel a7d079cea2 ARM/arm64: KVM: fix use of WnR bit in kvm_is_write_fault()
The ISS encoding for an exception from a Data Abort has a WnR
bit[6] that indicates whether the Data Abort was caused by a
read or a write instruction. While there are several fields
in the encoding that are only valid if the ISV bit[24] is set,
WnR is not one of them, so we can read it unconditionally.

Instead of fixing both implementations of kvm_is_write_fault()
in place, reimplement it just once using kvm_vcpu_dabt_iswrite(),
which already does the right thing with respect to the WnR bit.
Also fix up the callers to pass 'vcpu'

Acked-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Acked-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2014-09-11 11:31:13 +01:00

1167 lines
30 KiB
C

/*
* 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 DEFINE_MUTEX(kvm_hyp_pgd_mutex);
static void *init_bounce_page;
static unsigned long hyp_idmap_start;
static unsigned long hyp_idmap_end;
static phys_addr_t hyp_idmap_vector;
#define pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t))
#define kvm_pmd_huge(_x) (pmd_huge(_x) || pmd_trans_huge(_x))
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);
}
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));
}
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)) {
kvm_set_pte(pte, __pte(0));
put_page(virt_to_page(pte));
kvm_tlb_flush_vmid_ipa(kvm, addr);
}
} while (pte++, addr += PAGE_SIZE, addr != end);
if (kvm_pte_table_empty(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_clear(pmd);
kvm_tlb_flush_vmid_ipa(kvm, addr);
put_page(virt_to_page(pmd));
} else {
unmap_ptes(kvm, pmd, addr, next);
}
}
} while (pmd++, addr = next, addr != end);
if (kvm_pmd_table_empty(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_clear(pud);
kvm_tlb_flush_vmid_ipa(kvm, addr);
put_page(virt_to_page(pud));
} else {
unmap_pmds(kvm, pud, addr, next);
}
}
} while (pud++, addr = next, addr != end);
if (kvm_pud_table_empty(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 + pgd_index(addr);
do {
next = kvm_pgd_addr_end(addr, end);
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)) {
hva_t hva = gfn_to_hva(kvm, addr >> PAGE_SHIFT);
kvm_flush_dcache_to_poc((void*)hva, PAGE_SIZE);
}
} 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)) {
hva_t hva = gfn_to_hva(kvm, addr >> PAGE_SHIFT);
kvm_flush_dcache_to_poc((void*)hva, PMD_SIZE);
} 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)) {
hva_t hva = gfn_to_hva(kvm, addr >> PAGE_SHIFT);
kvm_flush_dcache_to_poc((void*)hva, PUD_SIZE);
} 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 + 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.
*/
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, pgd_order);
boot_hyp_pgd = NULL;
}
if (hyp_pgd)
unmap_range(NULL, hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE);
free_page((unsigned long)init_bounce_page);
init_bounce_page = NULL;
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, pgd_order);
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_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;
mutex_lock(&kvm_hyp_pgd_mutex);
addr = start & PAGE_MASK;
end = PAGE_ALIGN(end);
do {
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);
get_page(virt_to_page(pud));
kvm_flush_dcache_to_poc(pud, sizeof(*pud));
}
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;
} 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);
}
/**
* 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;
memset(pgd, 0, PTRS_PER_S2_PGD * sizeof(pgd_t));
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);
}
/**
* 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 pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache,
phys_addr_t addr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pgd = kvm->arch.pgd + pgd_index(addr);
pud = pud_offset(pgd, 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, bool iomap)
{
pmd_t *pmd;
pte_t *pte, old_pte;
/* Create stage-2 page table mapping - Level 1 */
pmd = stage2_get_pmd(kvm, cache, addr);
if (!pmd) {
/*
* Ignore calls from kvm_set_spte_hva for unallocated
* address ranges.
*/
return 0;
}
/* 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)
{
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);
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 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 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;
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(&current->mm->mmap_sem);
vma = find_vma_intersection(current->mm, hva, hva + 1);
if (is_vm_hugetlb_page(vma)) {
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(&current->mm->mmap_sem);
/* 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(kvm, gfn, write_fault, &writable);
if (is_error_pfn(pfn))
return -EFAULT;
if (kvm_is_mmio_pfn(pfn))
mem_type = PAGE_S2_DEVICE;
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);
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, hva & PMD_MASK, PMD_SIZE);
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);
}
coherent_cache_guest_page(vcpu, hva, PAGE_SIZE);
ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte,
mem_type == PAGE_S2_DEVICE);
}
out_unlock:
spin_unlock(&kvm->mmu_lock);
kvm_release_pfn_clean(pfn);
return ret;
}
/**
* 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(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;
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;
}
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 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);
}
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)
{
return virt_to_phys(hyp_pgd);
}
phys_addr_t kvm_mmu_get_boot_httbr(void)
{
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);
if ((hyp_idmap_start ^ hyp_idmap_end) & PAGE_MASK) {
/*
* Our init code is crossing a page boundary. Allocate
* a bounce page, copy the code over and use that.
*/
size_t len = __hyp_idmap_text_end - __hyp_idmap_text_start;
phys_addr_t phys_base;
init_bounce_page = (void *)__get_free_page(GFP_KERNEL);
if (!init_bounce_page) {
kvm_err("Couldn't allocate HYP init bounce page\n");
err = -ENOMEM;
goto out;
}
memcpy(init_bounce_page, __hyp_idmap_text_start, len);
/*
* Warning: the code we just copied to the bounce page
* must be flushed to the point of coherency.
* Otherwise, the data may be sitting in L2, and HYP
* mode won't be able to observe it as it runs with
* caches off at that point.
*/
kvm_flush_dcache_to_poc(init_bounce_page, len);
phys_base = kvm_virt_to_phys(init_bounce_page);
hyp_idmap_vector += phys_base - hyp_idmap_start;
hyp_idmap_start = phys_base;
hyp_idmap_end = phys_base + len;
kvm_info("Using HYP init bounce page @%lx\n",
(unsigned long)phys_base);
}
hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, pgd_order);
boot_hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 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;
}
/* 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)
{
gpa_t gpa = old->base_gfn << PAGE_SHIFT;
phys_addr_t size = old->npages << PAGE_SHIFT;
if (change == KVM_MR_DELETE || change == KVM_MR_MOVE) {
spin_lock(&kvm->mmu_lock);
unmap_stage2_range(kvm, gpa, size);
spin_unlock(&kvm->mmu_lock);
}
}
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)
{
return 0;
}
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)
{
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)
{
}