blob: 27e381c9da6c24bbdc3e7e59d9dda0b59a005ebf [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
#include "mmu.h"
#include "mmu_internal.h"
#include "mmutrace.h"
#include "tdp_iter.h"
#include "tdp_mmu.h"
#include "spte.h"
#ifdef CONFIG_X86_64
static bool __read_mostly tdp_mmu_enabled = false;
module_param_named(tdp_mmu, tdp_mmu_enabled, bool, 0644);
#endif
static bool is_tdp_mmu_enabled(void)
{
#ifdef CONFIG_X86_64
return tdp_enabled && READ_ONCE(tdp_mmu_enabled);
#else
return false;
#endif /* CONFIG_X86_64 */
}
/* Initializes the TDP MMU for the VM, if enabled. */
void kvm_mmu_init_tdp_mmu(struct kvm *kvm)
{
if (!is_tdp_mmu_enabled())
return;
/* This should not be changed for the lifetime of the VM. */
kvm->arch.tdp_mmu_enabled = true;
INIT_LIST_HEAD(&kvm->arch.tdp_mmu_roots);
INIT_LIST_HEAD(&kvm->arch.tdp_mmu_pages);
}
void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm)
{
if (!kvm->arch.tdp_mmu_enabled)
return;
WARN_ON(!list_empty(&kvm->arch.tdp_mmu_roots));
}
#define for_each_tdp_mmu_root(_kvm, _root) \
list_for_each_entry(_root, &_kvm->arch.tdp_mmu_roots, link)
bool is_tdp_mmu_root(struct kvm *kvm, hpa_t hpa)
{
struct kvm_mmu_page *sp;
sp = to_shadow_page(hpa);
return sp->tdp_mmu_page && sp->root_count;
}
static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
gfn_t start, gfn_t end, bool can_yield);
void kvm_tdp_mmu_free_root(struct kvm *kvm, struct kvm_mmu_page *root)
{
gfn_t max_gfn = 1ULL << (boot_cpu_data.x86_phys_bits - PAGE_SHIFT);
lockdep_assert_held(&kvm->mmu_lock);
WARN_ON(root->root_count);
WARN_ON(!root->tdp_mmu_page);
list_del(&root->link);
zap_gfn_range(kvm, root, 0, max_gfn, false);
free_page((unsigned long)root->spt);
kmem_cache_free(mmu_page_header_cache, root);
}
static union kvm_mmu_page_role page_role_for_level(struct kvm_vcpu *vcpu,
int level)
{
union kvm_mmu_page_role role;
role = vcpu->arch.mmu->mmu_role.base;
role.level = level;
role.direct = true;
role.gpte_is_8_bytes = true;
role.access = ACC_ALL;
return role;
}
static struct kvm_mmu_page *alloc_tdp_mmu_page(struct kvm_vcpu *vcpu, gfn_t gfn,
int level)
{
struct kvm_mmu_page *sp;
sp = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_page_header_cache);
sp->spt = kvm_mmu_memory_cache_alloc(&vcpu->arch.mmu_shadow_page_cache);
set_page_private(virt_to_page(sp->spt), (unsigned long)sp);
sp->role.word = page_role_for_level(vcpu, level).word;
sp->gfn = gfn;
sp->tdp_mmu_page = true;
return sp;
}
static struct kvm_mmu_page *get_tdp_mmu_vcpu_root(struct kvm_vcpu *vcpu)
{
union kvm_mmu_page_role role;
struct kvm *kvm = vcpu->kvm;
struct kvm_mmu_page *root;
role = page_role_for_level(vcpu, vcpu->arch.mmu->shadow_root_level);
spin_lock(&kvm->mmu_lock);
/* Check for an existing root before allocating a new one. */
for_each_tdp_mmu_root(kvm, root) {
if (root->role.word == role.word) {
kvm_mmu_get_root(kvm, root);
spin_unlock(&kvm->mmu_lock);
return root;
}
}
root = alloc_tdp_mmu_page(vcpu, 0, vcpu->arch.mmu->shadow_root_level);
root->root_count = 1;
list_add(&root->link, &kvm->arch.tdp_mmu_roots);
spin_unlock(&kvm->mmu_lock);
return root;
}
hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu)
{
struct kvm_mmu_page *root;
root = get_tdp_mmu_vcpu_root(vcpu);
if (!root)
return INVALID_PAGE;
return __pa(root->spt);
}
static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
u64 old_spte, u64 new_spte, int level);
static int kvm_mmu_page_as_id(struct kvm_mmu_page *sp)
{
return sp->role.smm ? 1 : 0;
}
static void handle_changed_spte_acc_track(u64 old_spte, u64 new_spte, int level)
{
bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte);
if (!is_shadow_present_pte(old_spte) || !is_last_spte(old_spte, level))
return;
if (is_accessed_spte(old_spte) &&
(!is_accessed_spte(new_spte) || pfn_changed))
kvm_set_pfn_accessed(spte_to_pfn(old_spte));
}
static void handle_changed_spte_dirty_log(struct kvm *kvm, int as_id, gfn_t gfn,
u64 old_spte, u64 new_spte, int level)
{
bool pfn_changed;
struct kvm_memory_slot *slot;
if (level > PG_LEVEL_4K)
return;
pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte);
if ((!is_writable_pte(old_spte) || pfn_changed) &&
is_writable_pte(new_spte)) {
slot = __gfn_to_memslot(__kvm_memslots(kvm, as_id), gfn);
mark_page_dirty_in_slot(slot, gfn);
}
}
/**
* handle_changed_spte - handle bookkeeping associated with an SPTE change
* @kvm: kvm instance
* @as_id: the address space of the paging structure the SPTE was a part of
* @gfn: the base GFN that was mapped by the SPTE
* @old_spte: The value of the SPTE before the change
* @new_spte: The value of the SPTE after the change
* @level: the level of the PT the SPTE is part of in the paging structure
*
* Handle bookkeeping that might result from the modification of a SPTE.
* This function must be called for all TDP SPTE modifications.
*/
static void __handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
u64 old_spte, u64 new_spte, int level)
{
bool was_present = is_shadow_present_pte(old_spte);
bool is_present = is_shadow_present_pte(new_spte);
bool was_leaf = was_present && is_last_spte(old_spte, level);
bool is_leaf = is_present && is_last_spte(new_spte, level);
bool pfn_changed = spte_to_pfn(old_spte) != spte_to_pfn(new_spte);
u64 *pt;
struct kvm_mmu_page *sp;
u64 old_child_spte;
int i;
WARN_ON(level > PT64_ROOT_MAX_LEVEL);
WARN_ON(level < PG_LEVEL_4K);
WARN_ON(gfn & (KVM_PAGES_PER_HPAGE(level) - 1));
/*
* If this warning were to trigger it would indicate that there was a
* missing MMU notifier or a race with some notifier handler.
* A present, leaf SPTE should never be directly replaced with another
* present leaf SPTE pointing to a differnt PFN. A notifier handler
* should be zapping the SPTE before the main MM's page table is
* changed, or the SPTE should be zeroed, and the TLBs flushed by the
* thread before replacement.
*/
if (was_leaf && is_leaf && pfn_changed) {
pr_err("Invalid SPTE change: cannot replace a present leaf\n"
"SPTE with another present leaf SPTE mapping a\n"
"different PFN!\n"
"as_id: %d gfn: %llx old_spte: %llx new_spte: %llx level: %d",
as_id, gfn, old_spte, new_spte, level);
/*
* Crash the host to prevent error propagation and guest data
* courruption.
*/
BUG();
}
if (old_spte == new_spte)
return;
/*
* The only times a SPTE should be changed from a non-present to
* non-present state is when an MMIO entry is installed/modified/
* removed. In that case, there is nothing to do here.
*/
if (!was_present && !is_present) {
/*
* If this change does not involve a MMIO SPTE, it is
* unexpected. Log the change, though it should not impact the
* guest since both the former and current SPTEs are nonpresent.
*/
if (WARN_ON(!is_mmio_spte(old_spte) && !is_mmio_spte(new_spte)))
pr_err("Unexpected SPTE change! Nonpresent SPTEs\n"
"should not be replaced with another,\n"
"different nonpresent SPTE, unless one or both\n"
"are MMIO SPTEs.\n"
"as_id: %d gfn: %llx old_spte: %llx new_spte: %llx level: %d",
as_id, gfn, old_spte, new_spte, level);
return;
}
if (was_leaf && is_dirty_spte(old_spte) &&
(!is_dirty_spte(new_spte) || pfn_changed))
kvm_set_pfn_dirty(spte_to_pfn(old_spte));
/*
* Recursively handle child PTs if the change removed a subtree from
* the paging structure.
*/
if (was_present && !was_leaf && (pfn_changed || !is_present)) {
pt = spte_to_child_pt(old_spte, level);
sp = sptep_to_sp(pt);
list_del(&sp->link);
if (sp->lpage_disallowed)
unaccount_huge_nx_page(kvm, sp);
for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
old_child_spte = READ_ONCE(*(pt + i));
WRITE_ONCE(*(pt + i), 0);
handle_changed_spte(kvm, as_id,
gfn + (i * KVM_PAGES_PER_HPAGE(level - 1)),
old_child_spte, 0, level - 1);
}
kvm_flush_remote_tlbs_with_address(kvm, gfn,
KVM_PAGES_PER_HPAGE(level));
free_page((unsigned long)pt);
kmem_cache_free(mmu_page_header_cache, sp);
}
}
static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
u64 old_spte, u64 new_spte, int level)
{
__handle_changed_spte(kvm, as_id, gfn, old_spte, new_spte, level);
handle_changed_spte_acc_track(old_spte, new_spte, level);
handle_changed_spte_dirty_log(kvm, as_id, gfn, old_spte,
new_spte, level);
}
static inline void __tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter,
u64 new_spte, bool record_acc_track,
bool record_dirty_log)
{
u64 *root_pt = tdp_iter_root_pt(iter);
struct kvm_mmu_page *root = sptep_to_sp(root_pt);
int as_id = kvm_mmu_page_as_id(root);
WRITE_ONCE(*iter->sptep, new_spte);
__handle_changed_spte(kvm, as_id, iter->gfn, iter->old_spte, new_spte,
iter->level);
if (record_acc_track)
handle_changed_spte_acc_track(iter->old_spte, new_spte,
iter->level);
if (record_dirty_log)
handle_changed_spte_dirty_log(kvm, as_id, iter->gfn,
iter->old_spte, new_spte,
iter->level);
}
static inline void tdp_mmu_set_spte(struct kvm *kvm, struct tdp_iter *iter,
u64 new_spte)
{
__tdp_mmu_set_spte(kvm, iter, new_spte, true, true);
}
static inline void tdp_mmu_set_spte_no_acc_track(struct kvm *kvm,
struct tdp_iter *iter,
u64 new_spte)
{
__tdp_mmu_set_spte(kvm, iter, new_spte, false, true);
}
static inline void tdp_mmu_set_spte_no_dirty_log(struct kvm *kvm,
struct tdp_iter *iter,
u64 new_spte)
{
__tdp_mmu_set_spte(kvm, iter, new_spte, true, false);
}
#define tdp_root_for_each_pte(_iter, _root, _start, _end) \
for_each_tdp_pte(_iter, _root->spt, _root->role.level, _start, _end)
#define tdp_root_for_each_leaf_pte(_iter, _root, _start, _end) \
tdp_root_for_each_pte(_iter, _root, _start, _end) \
if (!is_shadow_present_pte(_iter.old_spte) || \
!is_last_spte(_iter.old_spte, _iter.level)) \
continue; \
else
#define tdp_mmu_for_each_pte(_iter, _mmu, _start, _end) \
for_each_tdp_pte(_iter, __va(_mmu->root_hpa), \
_mmu->shadow_root_level, _start, _end)
/*
* Flush the TLB if the process should drop kvm->mmu_lock.
* Return whether the caller still needs to flush the tlb.
*/
static bool tdp_mmu_iter_flush_cond_resched(struct kvm *kvm, struct tdp_iter *iter)
{
if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
kvm_flush_remote_tlbs(kvm);
cond_resched_lock(&kvm->mmu_lock);
tdp_iter_refresh_walk(iter);
return false;
} else {
return true;
}
}
static void tdp_mmu_iter_cond_resched(struct kvm *kvm, struct tdp_iter *iter)
{
if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
cond_resched_lock(&kvm->mmu_lock);
tdp_iter_refresh_walk(iter);
}
}
/*
* Tears down the mappings for the range of gfns, [start, end), and frees the
* non-root pages mapping GFNs strictly within that range. Returns true if
* SPTEs have been cleared and a TLB flush is needed before releasing the
* MMU lock.
* If can_yield is true, will release the MMU lock and reschedule if the
* scheduler needs the CPU or there is contention on the MMU lock. If this
* function cannot yield, it will not release the MMU lock or reschedule and
* the caller must ensure it does not supply too large a GFN range, or the
* operation can cause a soft lockup.
*/
static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
gfn_t start, gfn_t end, bool can_yield)
{
struct tdp_iter iter;
bool flush_needed = false;
tdp_root_for_each_pte(iter, root, start, end) {
if (!is_shadow_present_pte(iter.old_spte))
continue;
/*
* If this is a non-last-level SPTE that covers a larger range
* than should be zapped, continue, and zap the mappings at a
* lower level.
*/
if ((iter.gfn < start ||
iter.gfn + KVM_PAGES_PER_HPAGE(iter.level) > end) &&
!is_last_spte(iter.old_spte, iter.level))
continue;
tdp_mmu_set_spte(kvm, &iter, 0);
if (can_yield)
flush_needed = tdp_mmu_iter_flush_cond_resched(kvm, &iter);
else
flush_needed = true;
}
return flush_needed;
}
/*
* Tears down the mappings for the range of gfns, [start, end), and frees the
* non-root pages mapping GFNs strictly within that range. Returns true if
* SPTEs have been cleared and a TLB flush is needed before releasing the
* MMU lock.
*/
bool kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, gfn_t start, gfn_t end)
{
struct kvm_mmu_page *root;
bool flush = false;
for_each_tdp_mmu_root(kvm, root) {
/*
* Take a reference on the root so that it cannot be freed if
* this thread releases the MMU lock and yields in this loop.
*/
kvm_mmu_get_root(kvm, root);
flush |= zap_gfn_range(kvm, root, start, end, true);
kvm_mmu_put_root(kvm, root);
}
return flush;
}
void kvm_tdp_mmu_zap_all(struct kvm *kvm)
{
gfn_t max_gfn = 1ULL << (boot_cpu_data.x86_phys_bits - PAGE_SHIFT);
bool flush;
flush = kvm_tdp_mmu_zap_gfn_range(kvm, 0, max_gfn);
if (flush)
kvm_flush_remote_tlbs(kvm);
}
/*
* Installs a last-level SPTE to handle a TDP page fault.
* (NPT/EPT violation/misconfiguration)
*/
static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu, int write,
int map_writable,
struct tdp_iter *iter,
kvm_pfn_t pfn, bool prefault)
{
u64 new_spte;
int ret = 0;
int make_spte_ret = 0;
if (unlikely(is_noslot_pfn(pfn))) {
new_spte = make_mmio_spte(vcpu, iter->gfn, ACC_ALL);
trace_mark_mmio_spte(iter->sptep, iter->gfn, new_spte);
} else
make_spte_ret = make_spte(vcpu, ACC_ALL, iter->level, iter->gfn,
pfn, iter->old_spte, prefault, true,
map_writable, !shadow_accessed_mask,
&new_spte);
if (new_spte == iter->old_spte)
ret = RET_PF_SPURIOUS;
else
tdp_mmu_set_spte(vcpu->kvm, iter, new_spte);
/*
* If the page fault was caused by a write but the page is write
* protected, emulation is needed. If the emulation was skipped,
* the vCPU would have the same fault again.
*/
if (make_spte_ret & SET_SPTE_WRITE_PROTECTED_PT) {
if (write)
ret = RET_PF_EMULATE;
kvm_make_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu);
}
/* If a MMIO SPTE is installed, the MMIO will need to be emulated. */
if (unlikely(is_mmio_spte(new_spte)))
ret = RET_PF_EMULATE;
trace_kvm_mmu_set_spte(iter->level, iter->gfn, iter->sptep);
if (!prefault)
vcpu->stat.pf_fixed++;
return ret;
}
/*
* Handle a TDP page fault (NPT/EPT violation/misconfiguration) by installing
* page tables and SPTEs to translate the faulting guest physical address.
*/
int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
int map_writable, int max_level, kvm_pfn_t pfn,
bool prefault)
{
bool nx_huge_page_workaround_enabled = is_nx_huge_page_enabled();
bool write = error_code & PFERR_WRITE_MASK;
bool exec = error_code & PFERR_FETCH_MASK;
bool huge_page_disallowed = exec && nx_huge_page_workaround_enabled;
struct kvm_mmu *mmu = vcpu->arch.mmu;
struct tdp_iter iter;
struct kvm_mmu_page *sp;
u64 *child_pt;
u64 new_spte;
int ret;
gfn_t gfn = gpa >> PAGE_SHIFT;
int level;
int req_level;
if (WARN_ON(!VALID_PAGE(vcpu->arch.mmu->root_hpa)))
return RET_PF_RETRY;
if (WARN_ON(!is_tdp_mmu_root(vcpu->kvm, vcpu->arch.mmu->root_hpa)))
return RET_PF_RETRY;
level = kvm_mmu_hugepage_adjust(vcpu, gfn, max_level, &pfn,
huge_page_disallowed, &req_level);
trace_kvm_mmu_spte_requested(gpa, level, pfn);
tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) {
if (nx_huge_page_workaround_enabled)
disallowed_hugepage_adjust(iter.old_spte, gfn,
iter.level, &pfn, &level);
if (iter.level == level)
break;
/*
* If there is an SPTE mapping a large page at a higher level
* than the target, that SPTE must be cleared and replaced
* with a non-leaf SPTE.
*/
if (is_shadow_present_pte(iter.old_spte) &&
is_large_pte(iter.old_spte)) {
tdp_mmu_set_spte(vcpu->kvm, &iter, 0);
kvm_flush_remote_tlbs_with_address(vcpu->kvm, iter.gfn,
KVM_PAGES_PER_HPAGE(iter.level));
/*
* The iter must explicitly re-read the spte here
* because the new value informs the !present
* path below.
*/
iter.old_spte = READ_ONCE(*iter.sptep);
}
if (!is_shadow_present_pte(iter.old_spte)) {
sp = alloc_tdp_mmu_page(vcpu, iter.gfn, iter.level);
list_add(&sp->link, &vcpu->kvm->arch.tdp_mmu_pages);
child_pt = sp->spt;
clear_page(child_pt);
new_spte = make_nonleaf_spte(child_pt,
!shadow_accessed_mask);
trace_kvm_mmu_get_page(sp, true);
if (huge_page_disallowed && req_level >= iter.level)
account_huge_nx_page(vcpu->kvm, sp);
tdp_mmu_set_spte(vcpu->kvm, &iter, new_spte);
}
}
if (WARN_ON(iter.level != level))
return RET_PF_RETRY;
ret = tdp_mmu_map_handle_target_level(vcpu, write, map_writable, &iter,
pfn, prefault);
return ret;
}
static int kvm_tdp_mmu_handle_hva_range(struct kvm *kvm, unsigned long start,
unsigned long end, unsigned long data,
int (*handler)(struct kvm *kvm, struct kvm_memory_slot *slot,
struct kvm_mmu_page *root, gfn_t start,
gfn_t end, unsigned long data))
{
struct kvm_memslots *slots;
struct kvm_memory_slot *memslot;
struct kvm_mmu_page *root;
int ret = 0;
int as_id;
for_each_tdp_mmu_root(kvm, root) {
/*
* Take a reference on the root so that it cannot be freed if
* this thread releases the MMU lock and yields in this loop.
*/
kvm_mmu_get_root(kvm, root);
as_id = kvm_mmu_page_as_id(root);
slots = __kvm_memslots(kvm, as_id);
kvm_for_each_memslot(memslot, slots) {
unsigned long hva_start, hva_end;
gfn_t gfn_start, 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_start = hva_to_gfn_memslot(hva_start, memslot);
gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot);
ret |= handler(kvm, memslot, root, gfn_start,
gfn_end, data);
}
kvm_mmu_put_root(kvm, root);
}
return ret;
}
static int zap_gfn_range_hva_wrapper(struct kvm *kvm,
struct kvm_memory_slot *slot,
struct kvm_mmu_page *root, gfn_t start,
gfn_t end, unsigned long unused)
{
return zap_gfn_range(kvm, root, start, end, false);
}
int kvm_tdp_mmu_zap_hva_range(struct kvm *kvm, unsigned long start,
unsigned long end)
{
return kvm_tdp_mmu_handle_hva_range(kvm, start, end, 0,
zap_gfn_range_hva_wrapper);
}
/*
* Mark the SPTEs range of GFNs [start, end) unaccessed and return non-zero
* if any of the GFNs in the range have been accessed.
*/
static int age_gfn_range(struct kvm *kvm, struct kvm_memory_slot *slot,
struct kvm_mmu_page *root, gfn_t start, gfn_t end,
unsigned long unused)
{
struct tdp_iter iter;
int young = 0;
u64 new_spte = 0;
tdp_root_for_each_leaf_pte(iter, root, start, end) {
/*
* If we have a non-accessed entry we don't need to change the
* pte.
*/
if (!is_accessed_spte(iter.old_spte))
continue;
new_spte = iter.old_spte;
if (spte_ad_enabled(new_spte)) {
clear_bit((ffs(shadow_accessed_mask) - 1),
(unsigned long *)&new_spte);
} else {
/*
* Capture the dirty status of the page, so that it doesn't get
* lost when the SPTE is marked for access tracking.
*/
if (is_writable_pte(new_spte))
kvm_set_pfn_dirty(spte_to_pfn(new_spte));
new_spte = mark_spte_for_access_track(new_spte);
}
new_spte &= ~shadow_dirty_mask;
tdp_mmu_set_spte_no_acc_track(kvm, &iter, new_spte);
young = 1;
}
return young;
}
int kvm_tdp_mmu_age_hva_range(struct kvm *kvm, unsigned long start,
unsigned long end)
{
return kvm_tdp_mmu_handle_hva_range(kvm, start, end, 0,
age_gfn_range);
}
static int test_age_gfn(struct kvm *kvm, struct kvm_memory_slot *slot,
struct kvm_mmu_page *root, gfn_t gfn, gfn_t unused,
unsigned long unused2)
{
struct tdp_iter iter;
tdp_root_for_each_leaf_pte(iter, root, gfn, gfn + 1)
if (is_accessed_spte(iter.old_spte))
return 1;
return 0;
}
int kvm_tdp_mmu_test_age_hva(struct kvm *kvm, unsigned long hva)
{
return kvm_tdp_mmu_handle_hva_range(kvm, hva, hva + 1, 0,
test_age_gfn);
}
/*
* Handle the changed_pte MMU notifier for the TDP MMU.
* data is a pointer to the new pte_t mapping the HVA specified by the MMU
* notifier.
* Returns non-zero if a flush is needed before releasing the MMU lock.
*/
static int set_tdp_spte(struct kvm *kvm, struct kvm_memory_slot *slot,
struct kvm_mmu_page *root, gfn_t gfn, gfn_t unused,
unsigned long data)
{
struct tdp_iter iter;
pte_t *ptep = (pte_t *)data;
kvm_pfn_t new_pfn;
u64 new_spte;
int need_flush = 0;
WARN_ON(pte_huge(*ptep));
new_pfn = pte_pfn(*ptep);
tdp_root_for_each_pte(iter, root, gfn, gfn + 1) {
if (iter.level != PG_LEVEL_4K)
continue;
if (!is_shadow_present_pte(iter.old_spte))
break;
tdp_mmu_set_spte(kvm, &iter, 0);
kvm_flush_remote_tlbs_with_address(kvm, iter.gfn, 1);
if (!pte_write(*ptep)) {
new_spte = kvm_mmu_changed_pte_notifier_make_spte(
iter.old_spte, new_pfn);
tdp_mmu_set_spte(kvm, &iter, new_spte);
}
need_flush = 1;
}
if (need_flush)
kvm_flush_remote_tlbs_with_address(kvm, gfn, 1);
return 0;
}
int kvm_tdp_mmu_set_spte_hva(struct kvm *kvm, unsigned long address,
pte_t *host_ptep)
{
return kvm_tdp_mmu_handle_hva_range(kvm, address, address + 1,
(unsigned long)host_ptep,
set_tdp_spte);
}
/*
* Remove write access from all the SPTEs mapping GFNs [start, end). If
* skip_4k is set, SPTEs that map 4k pages, will not be write-protected.
* Returns true if an SPTE has been changed and the TLBs need to be flushed.
*/
static bool wrprot_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
gfn_t start, gfn_t end, int min_level)
{
struct tdp_iter iter;
u64 new_spte;
bool spte_set = false;
BUG_ON(min_level > KVM_MAX_HUGEPAGE_LEVEL);
for_each_tdp_pte_min_level(iter, root->spt, root->role.level,
min_level, start, end) {
if (!is_shadow_present_pte(iter.old_spte) ||
!is_last_spte(iter.old_spte, iter.level))
continue;
new_spte = iter.old_spte & ~PT_WRITABLE_MASK;
tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte);
spte_set = true;
tdp_mmu_iter_cond_resched(kvm, &iter);
}
return spte_set;
}
/*
* Remove write access from all the SPTEs mapping GFNs in the memslot. Will
* only affect leaf SPTEs down to min_level.
* Returns true if an SPTE has been changed and the TLBs need to be flushed.
*/
bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm, struct kvm_memory_slot *slot,
int min_level)
{
struct kvm_mmu_page *root;
int root_as_id;
bool spte_set = false;
for_each_tdp_mmu_root(kvm, root) {
root_as_id = kvm_mmu_page_as_id(root);
if (root_as_id != slot->as_id)
continue;
/*
* Take a reference on the root so that it cannot be freed if
* this thread releases the MMU lock and yields in this loop.
*/
kvm_mmu_get_root(kvm, root);
spte_set |= wrprot_gfn_range(kvm, root, slot->base_gfn,
slot->base_gfn + slot->npages, min_level);
kvm_mmu_put_root(kvm, root);
}
return spte_set;
}
/*
* Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If
* AD bits are enabled, this will involve clearing the dirty bit on each SPTE.
* If AD bits are not enabled, this will require clearing the writable bit on
* each SPTE. Returns true if an SPTE has been changed and the TLBs need to
* be flushed.
*/
static bool clear_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
gfn_t start, gfn_t end)
{
struct tdp_iter iter;
u64 new_spte;
bool spte_set = false;
tdp_root_for_each_leaf_pte(iter, root, start, end) {
if (spte_ad_need_write_protect(iter.old_spte)) {
if (is_writable_pte(iter.old_spte))
new_spte = iter.old_spte & ~PT_WRITABLE_MASK;
else
continue;
} else {
if (iter.old_spte & shadow_dirty_mask)
new_spte = iter.old_spte & ~shadow_dirty_mask;
else
continue;
}
tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte);
spte_set = true;
tdp_mmu_iter_cond_resched(kvm, &iter);
}
return spte_set;
}
/*
* Clear the dirty status of all the SPTEs mapping GFNs in the memslot. If
* AD bits are enabled, this will involve clearing the dirty bit on each SPTE.
* If AD bits are not enabled, this will require clearing the writable bit on
* each SPTE. Returns true if an SPTE has been changed and the TLBs need to
* be flushed.
*/
bool kvm_tdp_mmu_clear_dirty_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
{
struct kvm_mmu_page *root;
int root_as_id;
bool spte_set = false;
for_each_tdp_mmu_root(kvm, root) {
root_as_id = kvm_mmu_page_as_id(root);
if (root_as_id != slot->as_id)
continue;
/*
* Take a reference on the root so that it cannot be freed if
* this thread releases the MMU lock and yields in this loop.
*/
kvm_mmu_get_root(kvm, root);
spte_set |= clear_dirty_gfn_range(kvm, root, slot->base_gfn,
slot->base_gfn + slot->npages);
kvm_mmu_put_root(kvm, root);
}
return spte_set;
}
/*
* Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is
* set in mask, starting at gfn. The given memslot is expected to contain all
* the GFNs represented by set bits in the mask. If AD bits are enabled,
* clearing the dirty status will involve clearing the dirty bit on each SPTE
* or, if AD bits are not enabled, clearing the writable bit on each SPTE.
*/
static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root,
gfn_t gfn, unsigned long mask, bool wrprot)
{
struct tdp_iter iter;
u64 new_spte;
tdp_root_for_each_leaf_pte(iter, root, gfn + __ffs(mask),
gfn + BITS_PER_LONG) {
if (!mask)
break;
if (iter.level > PG_LEVEL_4K ||
!(mask & (1UL << (iter.gfn - gfn))))
continue;
if (wrprot || spte_ad_need_write_protect(iter.old_spte)) {
if (is_writable_pte(iter.old_spte))
new_spte = iter.old_spte & ~PT_WRITABLE_MASK;
else
continue;
} else {
if (iter.old_spte & shadow_dirty_mask)
new_spte = iter.old_spte & ~shadow_dirty_mask;
else
continue;
}
tdp_mmu_set_spte_no_dirty_log(kvm, &iter, new_spte);
mask &= ~(1UL << (iter.gfn - gfn));
}
}
/*
* Clears the dirty status of all the 4k SPTEs mapping GFNs for which a bit is
* set in mask, starting at gfn. The given memslot is expected to contain all
* the GFNs represented by set bits in the mask. If AD bits are enabled,
* clearing the dirty status will involve clearing the dirty bit on each SPTE
* or, if AD bits are not enabled, clearing the writable bit on each SPTE.
*/
void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t gfn, unsigned long mask,
bool wrprot)
{
struct kvm_mmu_page *root;
int root_as_id;
lockdep_assert_held(&kvm->mmu_lock);
for_each_tdp_mmu_root(kvm, root) {
root_as_id = kvm_mmu_page_as_id(root);
if (root_as_id != slot->as_id)
continue;
clear_dirty_pt_masked(kvm, root, gfn, mask, wrprot);
}
}
/*
* Set the dirty status of all the SPTEs mapping GFNs in the memslot. This is
* only used for PML, and so will involve setting the dirty bit on each SPTE.
* Returns true if an SPTE has been changed and the TLBs need to be flushed.
*/
static bool set_dirty_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
gfn_t start, gfn_t end)
{
struct tdp_iter iter;
u64 new_spte;
bool spte_set = false;
tdp_root_for_each_pte(iter, root, start, end) {
if (!is_shadow_present_pte(iter.old_spte))
continue;
new_spte = iter.old_spte | shadow_dirty_mask;
tdp_mmu_set_spte(kvm, &iter, new_spte);
spte_set = true;
tdp_mmu_iter_cond_resched(kvm, &iter);
}
return spte_set;
}
/*
* Set the dirty status of all the SPTEs mapping GFNs in the memslot. This is
* only used for PML, and so will involve setting the dirty bit on each SPTE.
* Returns true if an SPTE has been changed and the TLBs need to be flushed.
*/
bool kvm_tdp_mmu_slot_set_dirty(struct kvm *kvm, struct kvm_memory_slot *slot)
{
struct kvm_mmu_page *root;
int root_as_id;
bool spte_set = false;
for_each_tdp_mmu_root(kvm, root) {
root_as_id = kvm_mmu_page_as_id(root);
if (root_as_id != slot->as_id)
continue;
/*
* Take a reference on the root so that it cannot be freed if
* this thread releases the MMU lock and yields in this loop.
*/
kvm_mmu_get_root(kvm, root);
spte_set |= set_dirty_gfn_range(kvm, root, slot->base_gfn,
slot->base_gfn + slot->npages);
kvm_mmu_put_root(kvm, root);
}
return spte_set;
}
/*
* Clear non-leaf entries (and free associated page tables) which could
* be replaced by large mappings, for GFNs within the slot.
*/
static void zap_collapsible_spte_range(struct kvm *kvm,
struct kvm_mmu_page *root,
gfn_t start, gfn_t end)
{
struct tdp_iter iter;
kvm_pfn_t pfn;
bool spte_set = false;
tdp_root_for_each_pte(iter, root, start, end) {
if (!is_shadow_present_pte(iter.old_spte) ||
is_last_spte(iter.old_spte, iter.level))
continue;
pfn = spte_to_pfn(iter.old_spte);
if (kvm_is_reserved_pfn(pfn) ||
!PageTransCompoundMap(pfn_to_page(pfn)))
continue;
tdp_mmu_set_spte(kvm, &iter, 0);
spte_set = tdp_mmu_iter_flush_cond_resched(kvm, &iter);
}
if (spte_set)
kvm_flush_remote_tlbs(kvm);
}
/*
* Clear non-leaf entries (and free associated page tables) which could
* be replaced by large mappings, for GFNs within the slot.
*/
void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
const struct kvm_memory_slot *slot)
{
struct kvm_mmu_page *root;
int root_as_id;
for_each_tdp_mmu_root(kvm, root) {
root_as_id = kvm_mmu_page_as_id(root);
if (root_as_id != slot->as_id)
continue;
/*
* Take a reference on the root so that it cannot be freed if
* this thread releases the MMU lock and yields in this loop.
*/
kvm_mmu_get_root(kvm, root);
zap_collapsible_spte_range(kvm, root, slot->base_gfn,
slot->base_gfn + slot->npages);
kvm_mmu_put_root(kvm, root);
}
}
/*
* Removes write access on the last level SPTE mapping this GFN and unsets the
* SPTE_MMU_WRITABLE bit to ensure future writes continue to be intercepted.
* Returns true if an SPTE was set and a TLB flush is needed.
*/
static bool write_protect_gfn(struct kvm *kvm, struct kvm_mmu_page *root,
gfn_t gfn)
{
struct tdp_iter iter;
u64 new_spte;
bool spte_set = false;
tdp_root_for_each_leaf_pte(iter, root, gfn, gfn + 1) {
if (!is_writable_pte(iter.old_spte))
break;
new_spte = iter.old_spte &
~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE);
tdp_mmu_set_spte(kvm, &iter, new_spte);
spte_set = true;
}
return spte_set;
}
/*
* Removes write access on the last level SPTE mapping this GFN and unsets the
* SPTE_MMU_WRITABLE bit to ensure future writes continue to be intercepted.
* Returns true if an SPTE was set and a TLB flush is needed.
*/
bool kvm_tdp_mmu_write_protect_gfn(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn)
{
struct kvm_mmu_page *root;
int root_as_id;
bool spte_set = false;
lockdep_assert_held(&kvm->mmu_lock);
for_each_tdp_mmu_root(kvm, root) {
root_as_id = kvm_mmu_page_as_id(root);
if (root_as_id != slot->as_id)
continue;
spte_set |= write_protect_gfn(kvm, root, gfn);
}
return spte_set;
}
/*
* Return the level of the lowest level SPTE added to sptes.
* That SPTE may be non-present.
*/
int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes)
{
struct tdp_iter iter;
struct kvm_mmu *mmu = vcpu->arch.mmu;
int leaf = vcpu->arch.mmu->shadow_root_level;
gfn_t gfn = addr >> PAGE_SHIFT;
tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) {
leaf = iter.level;
sptes[leaf - 1] = iter.old_spte;
}
return leaf;
}