static void clear_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr)
{
if (pud_huge(*pud)) {
pud_clear(pud);
kvm_tlb_flush_vmid_ipa(kvm, addr);
} else {
pmd_t *pmd_table = pmd_offset(pud, 0);
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)
{
if (kvm_pmd_huge(*pmd)) {
pmd_clear(pmd);
kvm_tlb_flush_vmid_ipa(kvm, addr);
} else {
pte_t *pte_table = pte_offset_kernel(pmd, 0);
pmd_clear(pmd);
kvm_tlb_flush_vmid_ipa(kvm, addr);
pte_free_kernel(NULL, pte_table);
}
put_page(virt_to_page(pmd));
}
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 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);
}
/*
* 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 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_pte_entry(struct kvm *kvm, pte_t *pte, phys_addr_t addr)
{
if (pte_present(*pte)) {
kvm_set_pte(pte, __pte(0));
put_page(virt_to_page(pte));
kvm_tlb_flush_vmid_ipa(kvm, addr);
}
}
/**
* 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));
}
/**
* 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_tlb_flush_vmid_ipa(kvm, 0); /* Invalidate TLB ALL */
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,
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;
}
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 - 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;
}
/* 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;
if (pte_present(old_pte)) {
/* Skip page table update if there is no change */
if (pte_val(old_pte) == pte_val(*new_pte))
return 0;
kvm_set_pte(pte, __pte(0));
kvm_tlb_flush_vmid_ipa(kvm, addr);
} else {
get_page(virt_to_page(pte));
}
kvm_set_pte(pte, *new_pte);
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)
{
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;
}
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);
old_pmd = *pmd;
if (pmd_present(old_pmd)) {
/*
* Multiple vcpus faulting on the same PMD entry, can
* lead to them sequentially updating the PMD with the
* same value. Following the break-before-make
* (pmd_clear() followed by tlb_flush()) process can
* hinder forward progress due to refaults generated
* on missing translations.
*
* Skip updating the page table if the entry is
* unchanged.
*/
if (pmd_val(old_pmd) == pmd_val(*new_pmd))
return 0;
/*
* 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_pfn(old_pmd) != pmd_pfn(*new_pmd));
pmd_clear(pmd);
kvm_tlb_flush_vmid_ipa(kvm, addr);
} else {
get_page(virt_to_page(pmd));
}
kvm_set_pmd(pmd, *new_pmd);
return 0;
}
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(kvm, start_pte))
clear_pmd_entry(kvm, pmd, start_addr);
}
