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-rw-r--r--arch/x86/kvm/mmu/mmu.c335
-rw-r--r--arch/x86/kvm/mmu/mmu_internal.h28
-rw-r--r--arch/x86/kvm/mmu/mmutrace.h2
-rw-r--r--arch/x86/kvm/mmu/page_track.c2
-rw-r--r--arch/x86/kvm/mmu/paging_tmpl.h28
-rw-r--r--arch/x86/kvm/mmu/spte.c40
-rw-r--r--arch/x86/kvm/mmu/spte.h35
-rw-r--r--arch/x86/kvm/mmu/tdp_iter.h2
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.c139
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.h1
10 files changed, 329 insertions, 283 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index db007a4dff..8d74bdef68 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -336,16 +336,19 @@ static int is_cpuid_PSE36(void)
#ifdef CONFIG_X86_64
static void __set_spte(u64 *sptep, u64 spte)
{
+ KVM_MMU_WARN_ON(is_ept_ve_possible(spte));
WRITE_ONCE(*sptep, spte);
}
static void __update_clear_spte_fast(u64 *sptep, u64 spte)
{
+ KVM_MMU_WARN_ON(is_ept_ve_possible(spte));
WRITE_ONCE(*sptep, spte);
}
static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
{
+ KVM_MMU_WARN_ON(is_ept_ve_possible(spte));
return xchg(sptep, spte);
}
@@ -432,8 +435,8 @@ static u64 __update_clear_spte_slow(u64 *sptep, u64 spte)
* The idea using the light way get the spte on x86_32 guest is from
* gup_get_pte (mm/gup.c).
*
- * An spte tlb flush may be pending, because kvm_set_pte_rmap
- * coalesces them and we are running out of the MMU lock. Therefore
+ * An spte tlb flush may be pending, because they are coalesced and
+ * we are running out of the MMU lock. Therefore
* we need to protect against in-progress updates of the spte.
*
* Reading the spte while an update is in progress may get the old value
@@ -567,9 +570,9 @@ static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep)
if (!is_shadow_present_pte(old_spte) ||
!spte_has_volatile_bits(old_spte))
- __update_clear_spte_fast(sptep, 0ull);
+ __update_clear_spte_fast(sptep, SHADOW_NONPRESENT_VALUE);
else
- old_spte = __update_clear_spte_slow(sptep, 0ull);
+ old_spte = __update_clear_spte_slow(sptep, SHADOW_NONPRESENT_VALUE);
if (!is_shadow_present_pte(old_spte))
return old_spte;
@@ -603,7 +606,7 @@ static u64 mmu_spte_clear_track_bits(struct kvm *kvm, u64 *sptep)
*/
static void mmu_spte_clear_no_track(u64 *sptep)
{
- __update_clear_spte_fast(sptep, 0ull);
+ __update_clear_spte_fast(sptep, SHADOW_NONPRESENT_VALUE);
}
static u64 mmu_spte_get_lockless(u64 *sptep)
@@ -831,6 +834,15 @@ static void account_shadowed(struct kvm *kvm, struct kvm_mmu_page *sp)
gfn_t gfn;
kvm->arch.indirect_shadow_pages++;
+ /*
+ * Ensure indirect_shadow_pages is elevated prior to re-reading guest
+ * child PTEs in FNAME(gpte_changed), i.e. guarantee either in-flight
+ * emulated writes are visible before re-reading guest PTEs, or that
+ * an emulated write will see the elevated count and acquire mmu_lock
+ * to update SPTEs. Pairs with the smp_mb() in kvm_mmu_track_write().
+ */
+ smp_mb();
+
gfn = sp->gfn;
slots = kvm_memslots_for_spte_role(kvm, sp->role);
slot = __gfn_to_memslot(slots, gfn);
@@ -1448,49 +1460,11 @@ static bool __kvm_zap_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
}
static bool kvm_zap_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
- struct kvm_memory_slot *slot, gfn_t gfn, int level,
- pte_t unused)
+ struct kvm_memory_slot *slot, gfn_t gfn, int level)
{
return __kvm_zap_rmap(kvm, rmap_head, slot);
}
-static bool kvm_set_pte_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
- struct kvm_memory_slot *slot, gfn_t gfn, int level,
- pte_t pte)
-{
- u64 *sptep;
- struct rmap_iterator iter;
- bool need_flush = false;
- u64 new_spte;
- kvm_pfn_t new_pfn;
-
- WARN_ON_ONCE(pte_huge(pte));
- new_pfn = pte_pfn(pte);
-
-restart:
- for_each_rmap_spte(rmap_head, &iter, sptep) {
- need_flush = true;
-
- if (pte_write(pte)) {
- kvm_zap_one_rmap_spte(kvm, rmap_head, sptep);
- goto restart;
- } else {
- new_spte = kvm_mmu_changed_pte_notifier_make_spte(
- *sptep, new_pfn);
-
- mmu_spte_clear_track_bits(kvm, sptep);
- mmu_spte_set(sptep, new_spte);
- }
- }
-
- if (need_flush && kvm_available_flush_remote_tlbs_range()) {
- kvm_flush_remote_tlbs_gfn(kvm, gfn, level);
- return false;
- }
-
- return need_flush;
-}
-
struct slot_rmap_walk_iterator {
/* input fields. */
const struct kvm_memory_slot *slot;
@@ -1562,7 +1536,7 @@ static void slot_rmap_walk_next(struct slot_rmap_walk_iterator *iterator)
typedef bool (*rmap_handler_t)(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
struct kvm_memory_slot *slot, gfn_t gfn,
- int level, pte_t pte);
+ int level);
static __always_inline bool kvm_handle_gfn_range(struct kvm *kvm,
struct kvm_gfn_range *range,
@@ -1574,7 +1548,7 @@ static __always_inline bool kvm_handle_gfn_range(struct kvm *kvm,
for_each_slot_rmap_range(range->slot, PG_LEVEL_4K, KVM_MAX_HUGEPAGE_LEVEL,
range->start, range->end - 1, &iterator)
ret |= handler(kvm, iterator.rmap, range->slot, iterator.gfn,
- iterator.level, range->arg.pte);
+ iterator.level);
return ret;
}
@@ -1596,22 +1570,8 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
return flush;
}
-bool kvm_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
-{
- bool flush = false;
-
- if (kvm_memslots_have_rmaps(kvm))
- flush = kvm_handle_gfn_range(kvm, range, kvm_set_pte_rmap);
-
- if (tdp_mmu_enabled)
- flush |= kvm_tdp_mmu_set_spte_gfn(kvm, range);
-
- return flush;
-}
-
static bool kvm_age_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
- struct kvm_memory_slot *slot, gfn_t gfn, int level,
- pte_t unused)
+ struct kvm_memory_slot *slot, gfn_t gfn, int level)
{
u64 *sptep;
struct rmap_iterator iter;
@@ -1624,8 +1584,7 @@ static bool kvm_age_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
}
static bool kvm_test_age_rmap(struct kvm *kvm, struct kvm_rmap_head *rmap_head,
- struct kvm_memory_slot *slot, gfn_t gfn,
- int level, pte_t unused)
+ struct kvm_memory_slot *slot, gfn_t gfn, int level)
{
u64 *sptep;
struct rmap_iterator iter;
@@ -1950,7 +1909,8 @@ static bool kvm_sync_page_check(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
static int kvm_sync_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int i)
{
- if (!sp->spt[i])
+ /* sp->spt[i] has initial value of shadow page table allocation */
+ if (sp->spt[i] == SHADOW_NONPRESENT_VALUE)
return 0;
return vcpu->arch.mmu->sync_spte(vcpu, sp, i);
@@ -2514,7 +2474,7 @@ static int mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
return kvm_mmu_prepare_zap_page(kvm, child,
invalid_list);
}
- } else if (is_mmio_spte(pte)) {
+ } else if (is_mmio_spte(kvm, pte)) {
mmu_spte_clear_no_track(spte);
}
return 0;
@@ -3314,9 +3274,19 @@ static int kvm_handle_noslot_fault(struct kvm_vcpu *vcpu,
{
gva_t gva = fault->is_tdp ? 0 : fault->addr;
+ if (fault->is_private) {
+ kvm_mmu_prepare_memory_fault_exit(vcpu, fault);
+ return -EFAULT;
+ }
+
vcpu_cache_mmio_info(vcpu, gva, fault->gfn,
access & shadow_mmio_access_mask);
+ fault->slot = NULL;
+ fault->pfn = KVM_PFN_NOSLOT;
+ fault->map_writable = false;
+ fault->hva = KVM_HVA_ERR_BAD;
+
/*
* If MMIO caching is disabled, emulate immediately without
* touching the shadow page tables as attempting to install an
@@ -4134,23 +4104,31 @@ static int get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes, int *root_level
return leaf;
}
-/* return true if reserved bit(s) are detected on a valid, non-MMIO SPTE. */
-static bool get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr, u64 *sptep)
+static int get_sptes_lockless(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes,
+ int *root_level)
{
- u64 sptes[PT64_ROOT_MAX_LEVEL + 1];
- struct rsvd_bits_validate *rsvd_check;
- int root, leaf, level;
- bool reserved = false;
+ int leaf;
walk_shadow_page_lockless_begin(vcpu);
if (is_tdp_mmu_active(vcpu))
- leaf = kvm_tdp_mmu_get_walk(vcpu, addr, sptes, &root);
+ leaf = kvm_tdp_mmu_get_walk(vcpu, addr, sptes, root_level);
else
- leaf = get_walk(vcpu, addr, sptes, &root);
+ leaf = get_walk(vcpu, addr, sptes, root_level);
walk_shadow_page_lockless_end(vcpu);
+ return leaf;
+}
+/* return true if reserved bit(s) are detected on a valid, non-MMIO SPTE. */
+static bool get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr, u64 *sptep)
+{
+ u64 sptes[PT64_ROOT_MAX_LEVEL + 1];
+ struct rsvd_bits_validate *rsvd_check;
+ int root, leaf, level;
+ bool reserved = false;
+
+ leaf = get_sptes_lockless(vcpu, addr, sptes, &root);
if (unlikely(leaf < 0)) {
*sptep = 0ull;
return reserved;
@@ -4196,7 +4174,7 @@ static int handle_mmio_page_fault(struct kvm_vcpu *vcpu, u64 addr, bool direct)
if (WARN_ON_ONCE(reserved))
return -EINVAL;
- if (is_mmio_spte(spte)) {
+ if (is_mmio_spte(vcpu->kvm, spte)) {
gfn_t gfn = get_mmio_spte_gfn(spte);
unsigned int access = get_mmio_spte_access(spte);
@@ -4259,24 +4237,28 @@ static u32 alloc_apf_token(struct kvm_vcpu *vcpu)
return (vcpu->arch.apf.id++ << 12) | vcpu->vcpu_id;
}
-static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
- gfn_t gfn)
+static bool kvm_arch_setup_async_pf(struct kvm_vcpu *vcpu,
+ struct kvm_page_fault *fault)
{
struct kvm_arch_async_pf arch;
arch.token = alloc_apf_token(vcpu);
- arch.gfn = gfn;
+ arch.gfn = fault->gfn;
+ arch.error_code = fault->error_code;
arch.direct_map = vcpu->arch.mmu->root_role.direct;
arch.cr3 = kvm_mmu_get_guest_pgd(vcpu, vcpu->arch.mmu);
- return kvm_setup_async_pf(vcpu, cr2_or_gpa,
- kvm_vcpu_gfn_to_hva(vcpu, gfn), &arch);
+ return kvm_setup_async_pf(vcpu, fault->addr,
+ kvm_vcpu_gfn_to_hva(vcpu, fault->gfn), &arch);
}
void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
{
int r;
+ if (WARN_ON_ONCE(work->arch.error_code & PFERR_PRIVATE_ACCESS))
+ return;
+
if ((vcpu->arch.mmu->root_role.direct != work->arch.direct_map) ||
work->wakeup_all)
return;
@@ -4289,7 +4271,7 @@ void kvm_arch_async_page_ready(struct kvm_vcpu *vcpu, struct kvm_async_pf *work)
work->arch.cr3 != kvm_mmu_get_guest_pgd(vcpu, vcpu->arch.mmu))
return;
- kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, 0, true, NULL);
+ kvm_mmu_do_page_fault(vcpu, work->cr2_or_gpa, work->arch.error_code, true, NULL);
}
static inline u8 kvm_max_level_for_order(int order)
@@ -4309,14 +4291,6 @@ static inline u8 kvm_max_level_for_order(int order)
return PG_LEVEL_4K;
}
-static void kvm_mmu_prepare_memory_fault_exit(struct kvm_vcpu *vcpu,
- struct kvm_page_fault *fault)
-{
- kvm_prepare_memory_fault_exit(vcpu, fault->gfn << PAGE_SHIFT,
- PAGE_SIZE, fault->write, fault->exec,
- fault->is_private);
-}
-
static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu,
struct kvm_page_fault *fault)
{
@@ -4343,48 +4317,15 @@ static int kvm_faultin_pfn_private(struct kvm_vcpu *vcpu,
static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
{
- struct kvm_memory_slot *slot = fault->slot;
bool async;
- /*
- * Retry the page fault if the gfn hit a memslot that is being deleted
- * or moved. This ensures any existing SPTEs for the old memslot will
- * be zapped before KVM inserts a new MMIO SPTE for the gfn.
- */
- if (slot && (slot->flags & KVM_MEMSLOT_INVALID))
- return RET_PF_RETRY;
-
- if (!kvm_is_visible_memslot(slot)) {
- /* Don't expose private memslots to L2. */
- if (is_guest_mode(vcpu)) {
- fault->slot = NULL;
- fault->pfn = KVM_PFN_NOSLOT;
- fault->map_writable = false;
- return RET_PF_CONTINUE;
- }
- /*
- * If the APIC access page exists but is disabled, go directly
- * to emulation without caching the MMIO access or creating a
- * MMIO SPTE. That way the cache doesn't need to be purged
- * when the AVIC is re-enabled.
- */
- if (slot && slot->id == APIC_ACCESS_PAGE_PRIVATE_MEMSLOT &&
- !kvm_apicv_activated(vcpu->kvm))
- return RET_PF_EMULATE;
- }
-
- if (fault->is_private != kvm_mem_is_private(vcpu->kvm, fault->gfn)) {
- kvm_mmu_prepare_memory_fault_exit(vcpu, fault);
- return -EFAULT;
- }
-
if (fault->is_private)
return kvm_faultin_pfn_private(vcpu, fault);
async = false;
- fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, false, &async,
- fault->write, &fault->map_writable,
- &fault->hva);
+ fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, false, false,
+ &async, fault->write,
+ &fault->map_writable, &fault->hva);
if (!async)
return RET_PF_CONTINUE; /* *pfn has correct page already */
@@ -4394,7 +4335,7 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
trace_kvm_async_pf_repeated_fault(fault->addr, fault->gfn);
kvm_make_request(KVM_REQ_APF_HALT, vcpu);
return RET_PF_RETRY;
- } else if (kvm_arch_setup_async_pf(vcpu, fault->addr, fault->gfn)) {
+ } else if (kvm_arch_setup_async_pf(vcpu, fault)) {
return RET_PF_RETRY;
}
}
@@ -4404,21 +4345,73 @@ static int __kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
* to wait for IO. Note, gup always bails if it is unable to quickly
* get a page and a fatal signal, i.e. SIGKILL, is pending.
*/
- fault->pfn = __gfn_to_pfn_memslot(slot, fault->gfn, false, true, NULL,
- fault->write, &fault->map_writable,
- &fault->hva);
+ fault->pfn = __gfn_to_pfn_memslot(fault->slot, fault->gfn, false, true,
+ NULL, fault->write,
+ &fault->map_writable, &fault->hva);
return RET_PF_CONTINUE;
}
static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
unsigned int access)
{
+ struct kvm_memory_slot *slot = fault->slot;
int ret;
+ /*
+ * Note that the mmu_invalidate_seq also serves to detect a concurrent
+ * change in attributes. is_page_fault_stale() will detect an
+ * invalidation relate to fault->fn and resume the guest without
+ * installing a mapping in the page tables.
+ */
fault->mmu_seq = vcpu->kvm->mmu_invalidate_seq;
smp_rmb();
/*
+ * Now that we have a snapshot of mmu_invalidate_seq we can check for a
+ * private vs. shared mismatch.
+ */
+ if (fault->is_private != kvm_mem_is_private(vcpu->kvm, fault->gfn)) {
+ kvm_mmu_prepare_memory_fault_exit(vcpu, fault);
+ return -EFAULT;
+ }
+
+ if (unlikely(!slot))
+ return kvm_handle_noslot_fault(vcpu, fault, access);
+
+ /*
+ * Retry the page fault if the gfn hit a memslot that is being deleted
+ * or moved. This ensures any existing SPTEs for the old memslot will
+ * be zapped before KVM inserts a new MMIO SPTE for the gfn.
+ */
+ if (slot->flags & KVM_MEMSLOT_INVALID)
+ return RET_PF_RETRY;
+
+ if (slot->id == APIC_ACCESS_PAGE_PRIVATE_MEMSLOT) {
+ /*
+ * Don't map L1's APIC access page into L2, KVM doesn't support
+ * using APICv/AVIC to accelerate L2 accesses to L1's APIC,
+ * i.e. the access needs to be emulated. Emulating access to
+ * L1's APIC is also correct if L1 is accelerating L2's own
+ * virtual APIC, but for some reason L1 also maps _L1's_ APIC
+ * into L2. Note, vcpu_is_mmio_gpa() always treats access to
+ * the APIC as MMIO. Allow an MMIO SPTE to be created, as KVM
+ * uses different roots for L1 vs. L2, i.e. there is no danger
+ * of breaking APICv/AVIC for L1.
+ */
+ if (is_guest_mode(vcpu))
+ return kvm_handle_noslot_fault(vcpu, fault, access);
+
+ /*
+ * If the APIC access page exists but is disabled, go directly
+ * to emulation without caching the MMIO access or creating a
+ * MMIO SPTE. That way the cache doesn't need to be purged
+ * when the AVIC is re-enabled.
+ */
+ if (!kvm_apicv_activated(vcpu->kvm))
+ return RET_PF_EMULATE;
+ }
+
+ /*
* Check for a relevant mmu_notifier invalidation event before getting
* the pfn from the primary MMU, and before acquiring mmu_lock.
*
@@ -4439,8 +4432,7 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
* *guaranteed* to need to retry, i.e. waiting until mmu_lock is held
* to detect retry guarantees the worst case latency for the vCPU.
*/
- if (fault->slot &&
- mmu_invalidate_retry_gfn_unsafe(vcpu->kvm, fault->mmu_seq, fault->gfn))
+ if (mmu_invalidate_retry_gfn_unsafe(vcpu->kvm, fault->mmu_seq, fault->gfn))
return RET_PF_RETRY;
ret = __kvm_faultin_pfn(vcpu, fault);
@@ -4450,7 +4442,7 @@ static int kvm_faultin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault,
if (unlikely(is_error_pfn(fault->pfn)))
return kvm_handle_error_pfn(vcpu, fault);
- if (unlikely(!fault->slot))
+ if (WARN_ON_ONCE(!fault->slot || is_noslot_pfn(fault->pfn)))
return kvm_handle_noslot_fault(vcpu, fault, access);
/*
@@ -4561,6 +4553,16 @@ int kvm_handle_page_fault(struct kvm_vcpu *vcpu, u64 error_code,
if (WARN_ON_ONCE(fault_address >> 32))
return -EFAULT;
#endif
+ /*
+ * Legacy #PF exception only have a 32-bit error code. Simply drop the
+ * upper bits as KVM doesn't use them for #PF (because they are never
+ * set), and to ensure there are no collisions with KVM-defined bits.
+ */
+ if (WARN_ON_ONCE(error_code >> 32))
+ error_code = lower_32_bits(error_code);
+
+ /* Ensure the above sanity check also covers KVM-defined flags. */
+ BUILD_BUG_ON(lower_32_bits(PFERR_SYNTHETIC_MASK));
vcpu->arch.l1tf_flush_l1d = true;
if (!flags) {
@@ -4812,7 +4814,7 @@ EXPORT_SYMBOL_GPL(kvm_mmu_new_pgd);
static bool sync_mmio_spte(struct kvm_vcpu *vcpu, u64 *sptep, gfn_t gfn,
unsigned int access)
{
- if (unlikely(is_mmio_spte(*sptep))) {
+ if (unlikely(is_mmio_spte(vcpu->kvm, *sptep))) {
if (gfn != get_mmio_spte_gfn(*sptep)) {
mmu_spte_clear_no_track(sptep);
return true;
@@ -5322,6 +5324,11 @@ static inline int kvm_mmu_get_tdp_level(struct kvm_vcpu *vcpu)
return max_tdp_level;
}
+u8 kvm_mmu_get_max_tdp_level(void)
+{
+ return tdp_root_level ? tdp_root_level : max_tdp_level;
+}
+
static union kvm_mmu_page_role
kvm_calc_tdp_mmu_root_page_role(struct kvm_vcpu *vcpu,
union kvm_cpu_role cpu_role)
@@ -5802,10 +5809,15 @@ void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
bool flush = false;
/*
- * If we don't have indirect shadow pages, it means no page is
- * write-protected, so we can exit simply.
+ * When emulating guest writes, ensure the written value is visible to
+ * any task that is handling page faults before checking whether or not
+ * KVM is shadowing a guest PTE. This ensures either KVM will create
+ * the correct SPTE in the page fault handler, or this task will see
+ * a non-zero indirect_shadow_pages. Pairs with the smp_mb() in
+ * account_shadowed().
*/
- if (!READ_ONCE(vcpu->kvm->arch.indirect_shadow_pages))
+ smp_mb();
+ if (!vcpu->kvm->arch.indirect_shadow_pages)
return;
write_lock(&vcpu->kvm->mmu_lock);
@@ -5846,30 +5858,35 @@ int noinline kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, u64 err
int r, emulation_type = EMULTYPE_PF;
bool direct = vcpu->arch.mmu->root_role.direct;
- /*
- * IMPLICIT_ACCESS is a KVM-defined flag used to correctly perform SMAP
- * checks when emulating instructions that triggers implicit access.
- * WARN if hardware generates a fault with an error code that collides
- * with the KVM-defined value. Clear the flag and continue on, i.e.
- * don't terminate the VM, as KVM can't possibly be relying on a flag
- * that KVM doesn't know about.
- */
- if (WARN_ON_ONCE(error_code & PFERR_IMPLICIT_ACCESS))
- error_code &= ~PFERR_IMPLICIT_ACCESS;
-
if (WARN_ON_ONCE(!VALID_PAGE(vcpu->arch.mmu->root.hpa)))
return RET_PF_RETRY;
+ /*
+ * Except for reserved faults (emulated MMIO is shared-only), set the
+ * PFERR_PRIVATE_ACCESS flag for software-protected VMs based on the gfn's
+ * current attributes, which are the source of truth for such VMs. Note,
+ * this wrong for nested MMUs as the GPA is an L2 GPA, but KVM doesn't
+ * currently supported nested virtualization (among many other things)
+ * for software-protected VMs.
+ */
+ if (IS_ENABLED(CONFIG_KVM_SW_PROTECTED_VM) &&
+ !(error_code & PFERR_RSVD_MASK) &&
+ vcpu->kvm->arch.vm_type == KVM_X86_SW_PROTECTED_VM &&
+ kvm_mem_is_private(vcpu->kvm, gpa_to_gfn(cr2_or_gpa)))
+ error_code |= PFERR_PRIVATE_ACCESS;
+
r = RET_PF_INVALID;
if (unlikely(error_code & PFERR_RSVD_MASK)) {
+ if (WARN_ON_ONCE(error_code & PFERR_PRIVATE_ACCESS))
+ return -EFAULT;
+
r = handle_mmio_page_fault(vcpu, cr2_or_gpa, direct);
if (r == RET_PF_EMULATE)
goto emulate;
}
if (r == RET_PF_INVALID) {
- r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa,
- lower_32_bits(error_code), false,
+ r = kvm_mmu_do_page_fault(vcpu, cr2_or_gpa, error_code, false,
&emulation_type);
if (KVM_BUG_ON(r == RET_PF_INVALID, vcpu->kvm))
return -EIO;
@@ -5912,6 +5929,22 @@ emulate:
}
EXPORT_SYMBOL_GPL(kvm_mmu_page_fault);
+void kvm_mmu_print_sptes(struct kvm_vcpu *vcpu, gpa_t gpa, const char *msg)
+{
+ u64 sptes[PT64_ROOT_MAX_LEVEL + 1];
+ int root_level, leaf, level;
+
+ leaf = get_sptes_lockless(vcpu, gpa, sptes, &root_level);
+ if (unlikely(leaf < 0))
+ return;
+
+ pr_err("%s %llx", msg, gpa);
+ for (level = root_level; level >= leaf; level--)
+ pr_cont(", spte[%d] = 0x%llx", level, sptes[level]);
+ pr_cont("\n");
+}
+EXPORT_SYMBOL_GPL(kvm_mmu_print_sptes);
+
static void __kvm_mmu_invalidate_addr(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
u64 addr, hpa_t root_hpa)
{
@@ -6173,7 +6206,10 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu)
vcpu->arch.mmu_page_header_cache.kmem_cache = mmu_page_header_cache;
vcpu->arch.mmu_page_header_cache.gfp_zero = __GFP_ZERO;
- vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
+ vcpu->arch.mmu_shadow_page_cache.init_value =
+ SHADOW_NONPRESENT_VALUE;
+ if (!vcpu->arch.mmu_shadow_page_cache.init_value)
+ vcpu->arch.mmu_shadow_page_cache.gfp_zero = __GFP_ZERO;
vcpu->arch.mmu = &vcpu->arch.root_mmu;
vcpu->arch.walk_mmu = &vcpu->arch.root_mmu;
@@ -6316,6 +6352,7 @@ static bool kvm_has_zapped_obsolete_pages(struct kvm *kvm)
void kvm_mmu_init_vm(struct kvm *kvm)
{
+ kvm->arch.shadow_mmio_value = shadow_mmio_value;
INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
INIT_LIST_HEAD(&kvm->arch.zapped_obsolete_pages);
INIT_LIST_HEAD(&kvm->arch.possible_nx_huge_pages);
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 5390a591a5..ce2fcd19ba 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -190,7 +190,7 @@ static inline bool is_nx_huge_page_enabled(struct kvm *kvm)
struct kvm_page_fault {
/* arguments to kvm_mmu_do_page_fault. */
const gpa_t addr;
- const u32 error_code;
+ const u64 error_code;
const bool prefetch;
/* Derived from error_code. */
@@ -279,8 +279,16 @@ enum {
RET_PF_SPURIOUS,
};
+static inline void kvm_mmu_prepare_memory_fault_exit(struct kvm_vcpu *vcpu,
+ struct kvm_page_fault *fault)
+{
+ kvm_prepare_memory_fault_exit(vcpu, fault->gfn << PAGE_SHIFT,
+ PAGE_SIZE, fault->write, fault->exec,
+ fault->is_private);
+}
+
static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
- u32 err, bool prefetch, int *emulation_type)
+ u64 err, bool prefetch, int *emulation_type)
{
struct kvm_page_fault fault = {
.addr = cr2_or_gpa,
@@ -298,7 +306,10 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
.max_level = KVM_MAX_HUGEPAGE_LEVEL,
.req_level = PG_LEVEL_4K,
.goal_level = PG_LEVEL_4K,
- .is_private = kvm_mem_is_private(vcpu->kvm, cr2_or_gpa >> PAGE_SHIFT),
+ .is_private = err & PFERR_PRIVATE_ACCESS,
+
+ .pfn = KVM_PFN_ERR_FAULT,
+ .hva = KVM_HVA_ERR_BAD,
};
int r;
@@ -320,6 +331,17 @@ static inline int kvm_mmu_do_page_fault(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
else
r = vcpu->arch.mmu->page_fault(vcpu, &fault);
+ /*
+ * Not sure what's happening, but punt to userspace and hope that
+ * they can fix it by changing memory to shared, or they can
+ * provide a better error.
+ */
+ if (r == RET_PF_EMULATE && fault.is_private) {
+ pr_warn_ratelimited("kvm: unexpected emulation request on private memory\n");
+ kvm_mmu_prepare_memory_fault_exit(vcpu, &fault);
+ return -EFAULT;
+ }
+
if (fault.write_fault_to_shadow_pgtable && emulation_type)
*emulation_type |= EMULTYPE_WRITE_PF_TO_SP;
diff --git a/arch/x86/kvm/mmu/mmutrace.h b/arch/x86/kvm/mmu/mmutrace.h
index ae86820cef..195d98bc8d 100644
--- a/arch/x86/kvm/mmu/mmutrace.h
+++ b/arch/x86/kvm/mmu/mmutrace.h
@@ -260,7 +260,7 @@ TRACE_EVENT(
TP_STRUCT__entry(
__field(int, vcpu_id)
__field(gpa_t, cr2_or_gpa)
- __field(u32, error_code)
+ __field(u64, error_code)
__field(u64 *, sptep)
__field(u64, old_spte)
__field(u64, new_spte)
diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
index f6448284c1..561c331fd6 100644
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -41,7 +41,7 @@ bool kvm_page_track_write_tracking_enabled(struct kvm *kvm)
void kvm_page_track_free_memslot(struct kvm_memory_slot *slot)
{
- kvfree(slot->arch.gfn_write_track);
+ vfree(slot->arch.gfn_write_track);
slot->arch.gfn_write_track = NULL;
}
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 4d4e98fe4f..d3dbcf382e 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -497,21 +497,21 @@ error:
* The other bits are set to 0.
*/
if (!(errcode & PFERR_RSVD_MASK)) {
- vcpu->arch.exit_qualification &= (EPT_VIOLATION_GVA_IS_VALID |
- EPT_VIOLATION_GVA_TRANSLATED);
+ walker->fault.exit_qualification = 0;
+
if (write_fault)
- vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_WRITE;
+ walker->fault.exit_qualification |= EPT_VIOLATION_ACC_WRITE;
if (user_fault)
- vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_READ;
+ walker->fault.exit_qualification |= EPT_VIOLATION_ACC_READ;
if (fetch_fault)
- vcpu->arch.exit_qualification |= EPT_VIOLATION_ACC_INSTR;
+ walker->fault.exit_qualification |= EPT_VIOLATION_ACC_INSTR;
/*
* Note, pte_access holds the raw RWX bits from the EPTE, not
* ACC_*_MASK flags!
*/
- vcpu->arch.exit_qualification |= (pte_access & VMX_EPT_RWX_MASK) <<
- EPT_VIOLATION_RWX_SHIFT;
+ walker->fault.exit_qualification |= (pte_access & VMX_EPT_RWX_MASK) <<
+ EPT_VIOLATION_RWX_SHIFT;
}
#endif
walker->fault.address = addr;
@@ -911,7 +911,7 @@ static int FNAME(sync_spte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int
gpa_t pte_gpa;
gfn_t gfn;
- if (WARN_ON_ONCE(!sp->spt[i]))
+ if (WARN_ON_ONCE(sp->spt[i] == SHADOW_NONPRESENT_VALUE))
return 0;
first_pte_gpa = FNAME(get_level1_sp_gpa)(sp);
@@ -933,13 +933,13 @@ static int FNAME(sync_spte)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, int
return 0;
/*
- * Drop the SPTE if the new protections would result in a RWX=0
- * SPTE or if the gfn is changing. The RWX=0 case only affects
- * EPT with execute-only support, i.e. EPT without an effective
- * "present" bit, as all other paging modes will create a
- * read-only SPTE if pte_access is zero.
+ * Drop the SPTE if the new protections result in no effective
+ * "present" bit or if the gfn is changing. The former case
+ * only affects EPT with execute-only support with pte_access==0;
+ * all other paging modes will create a read-only SPTE if
+ * pte_access is zero.
*/
- if ((!pte_access && !shadow_present_mask) ||
+ if ((pte_access | shadow_present_mask) == SHADOW_NONPRESENT_VALUE ||
gfn != kvm_mmu_page_get_gfn(sp, i)) {
drop_spte(vcpu->kvm, &sp->spt[i]);
return 1;
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c
index 4a599130e9..a5e014d7bc 100644
--- a/arch/x86/kvm/mmu/spte.c
+++ b/arch/x86/kvm/mmu/spte.c
@@ -74,10 +74,10 @@ u64 make_mmio_spte(struct kvm_vcpu *vcpu, u64 gfn, unsigned int access)
u64 spte = generation_mmio_spte_mask(gen);
u64 gpa = gfn << PAGE_SHIFT;
- WARN_ON_ONCE(!shadow_mmio_value);
+ WARN_ON_ONCE(!vcpu->kvm->arch.shadow_mmio_value);
access &= shadow_mmio_access_mask;
- spte |= shadow_mmio_value | access;
+ spte |= vcpu->kvm->arch.shadow_mmio_value | access;
spte |= gpa | shadow_nonpresent_or_rsvd_mask;
spte |= (gpa & shadow_nonpresent_or_rsvd_mask)
<< SHADOW_NONPRESENT_OR_RSVD_MASK_LEN;
@@ -144,19 +144,19 @@ bool make_spte(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp,
u64 spte = SPTE_MMU_PRESENT_MASK;
bool wrprot = false;
- WARN_ON_ONCE(!pte_access && !shadow_present_mask);
+ /*
+ * For the EPT case, shadow_present_mask has no RWX bits set if
+ * exec-only page table entries are supported. In that case,
+ * ACC_USER_MASK and shadow_user_mask are used to represent
+ * read access. See FNAME(gpte_access) in paging_tmpl.h.
+ */
+ WARN_ON_ONCE((pte_access | shadow_present_mask) == SHADOW_NONPRESENT_VALUE);
if (sp->role.ad_disabled)
spte |= SPTE_TDP_AD_DISABLED;
else if (kvm_mmu_page_ad_need_write_protect(sp))
spte |= SPTE_TDP_AD_WRPROT_ONLY;
- /*
- * For the EPT case, shadow_present_mask is 0 if hardware
- * supports exec-only page table entries. In that case,
- * ACC_USER_MASK and shadow_user_mask are used to represent
- * read access. See FNAME(gpte_access) in paging_tmpl.h.
- */
spte |= shadow_present_mask;
if (!prefetch)
spte |= spte_shadow_accessed_mask(spte);
@@ -322,22 +322,6 @@ u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled)
return spte;
}
-u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn)
-{
- u64 new_spte;
-
- new_spte = old_spte & ~SPTE_BASE_ADDR_MASK;
- new_spte |= (u64)new_pfn << PAGE_SHIFT;
-
- new_spte &= ~PT_WRITABLE_MASK;
- new_spte &= ~shadow_host_writable_mask;
- new_spte &= ~shadow_mmu_writable_mask;
-
- new_spte = mark_spte_for_access_track(new_spte);
-
- return new_spte;
-}
-
u64 mark_spte_for_access_track(u64 spte)
{
if (spte_ad_enabled(spte))
@@ -429,7 +413,9 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only)
shadow_dirty_mask = has_ad_bits ? VMX_EPT_DIRTY_BIT : 0ull;
shadow_nx_mask = 0ull;
shadow_x_mask = VMX_EPT_EXECUTABLE_MASK;
- shadow_present_mask = has_exec_only ? 0ull : VMX_EPT_READABLE_MASK;
+ /* VMX_EPT_SUPPRESS_VE_BIT is needed for W or X violation. */
+ shadow_present_mask =
+ (has_exec_only ? 0ull : VMX_EPT_READABLE_MASK) | VMX_EPT_SUPPRESS_VE_BIT;
/*
* EPT overrides the host MTRRs, and so KVM must program the desired
* memtype directly into the SPTEs. Note, this mask is just the mask
@@ -446,7 +432,7 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only)
* of an EPT paging-structure entry is 110b (write/execute).
*/
kvm_mmu_set_mmio_spte_mask(VMX_EPT_MISCONFIG_WX_VALUE,
- VMX_EPT_RWX_MASK, 0);
+ VMX_EPT_RWX_MASK | VMX_EPT_SUPPRESS_VE_BIT, 0);
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_ept_masks);
diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index a129951c9a..52fa004a1f 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -3,6 +3,8 @@
#ifndef KVM_X86_MMU_SPTE_H
#define KVM_X86_MMU_SPTE_H
+#include <asm/vmx.h>
+
#include "mmu.h"
#include "mmu_internal.h"
@@ -149,6 +151,22 @@ static_assert(MMIO_SPTE_GEN_LOW_BITS == 8 && MMIO_SPTE_GEN_HIGH_BITS == 11);
#define MMIO_SPTE_GEN_MASK GENMASK_ULL(MMIO_SPTE_GEN_LOW_BITS + MMIO_SPTE_GEN_HIGH_BITS - 1, 0)
+/*
+ * Non-present SPTE value needs to set bit 63 for TDX, in order to suppress
+ * #VE and get EPT violations on non-present PTEs. We can use the
+ * same value also without TDX for both VMX and SVM:
+ *
+ * For SVM NPT, for non-present spte (bit 0 = 0), other bits are ignored.
+ * For VMX EPT, bit 63 is ignored if #VE is disabled. (EPT_VIOLATION_VE=0)
+ * bit 63 is #VE suppress if #VE is enabled. (EPT_VIOLATION_VE=1)
+ */
+#ifdef CONFIG_X86_64
+#define SHADOW_NONPRESENT_VALUE BIT_ULL(63)
+static_assert(!(SHADOW_NONPRESENT_VALUE & SPTE_MMU_PRESENT_MASK));
+#else
+#define SHADOW_NONPRESENT_VALUE 0ULL
+#endif
+
extern u64 __read_mostly shadow_host_writable_mask;
extern u64 __read_mostly shadow_mmu_writable_mask;
extern u64 __read_mostly shadow_nx_mask;
@@ -190,11 +208,11 @@ extern u64 __read_mostly shadow_nonpresent_or_rsvd_mask;
*
* Use a semi-arbitrary value that doesn't set RWX bits, i.e. is not-present on
* both AMD and Intel CPUs, and doesn't set PFN bits, i.e. doesn't create a L1TF
- * vulnerability. Use only low bits to avoid 64-bit immediates.
+ * vulnerability.
*
* Only used by the TDP MMU.
*/
-#define REMOVED_SPTE 0x5a0ULL
+#define REMOVED_SPTE (SHADOW_NONPRESENT_VALUE | 0x5a0ULL)
/* Removed SPTEs must not be misconstrued as shadow present PTEs. */
static_assert(!(REMOVED_SPTE & SPTE_MMU_PRESENT_MASK));
@@ -249,9 +267,9 @@ static inline struct kvm_mmu_page *root_to_sp(hpa_t root)
return spte_to_child_sp(root);
}
-static inline bool is_mmio_spte(u64 spte)
+static inline bool is_mmio_spte(struct kvm *kvm, u64 spte)
{
- return (spte & shadow_mmio_mask) == shadow_mmio_value &&
+ return (spte & shadow_mmio_mask) == kvm->arch.shadow_mmio_value &&
likely(enable_mmio_caching);
}
@@ -260,6 +278,13 @@ static inline bool is_shadow_present_pte(u64 pte)
return !!(pte & SPTE_MMU_PRESENT_MASK);
}
+static inline bool is_ept_ve_possible(u64 spte)
+{
+ return (shadow_present_mask & VMX_EPT_SUPPRESS_VE_BIT) &&
+ !(spte & VMX_EPT_SUPPRESS_VE_BIT) &&
+ (spte & VMX_EPT_RWX_MASK) != VMX_EPT_MISCONFIG_WX_VALUE;
+}
+
/*
* Returns true if A/D bits are supported in hardware and are enabled by KVM.
* When enabled, KVM uses A/D bits for all non-nested MMUs. Because L1 can
@@ -496,8 +521,6 @@ static inline u64 restore_acc_track_spte(u64 spte)
return spte;
}
-u64 kvm_mmu_changed_pte_notifier_make_spte(u64 old_spte, kvm_pfn_t new_pfn);
-
void __init kvm_mmu_spte_module_init(void);
void kvm_mmu_reset_all_pte_masks(void);
diff --git a/arch/x86/kvm/mmu/tdp_iter.h b/arch/x86/kvm/mmu/tdp_iter.h
index fae559559a..2880fd392e 100644
--- a/arch/x86/kvm/mmu/tdp_iter.h
+++ b/arch/x86/kvm/mmu/tdp_iter.h
@@ -21,11 +21,13 @@ static inline u64 kvm_tdp_mmu_read_spte(tdp_ptep_t sptep)
static inline u64 kvm_tdp_mmu_write_spte_atomic(tdp_ptep_t sptep, u64 new_spte)
{
+ KVM_MMU_WARN_ON(is_ept_ve_possible(new_spte));
return xchg(rcu_dereference(sptep), new_spte);
}
static inline void __kvm_tdp_mmu_write_spte(tdp_ptep_t sptep, u64 new_spte)
{
+ KVM_MMU_WARN_ON(is_ept_ve_possible(new_spte));
WRITE_ONCE(*rcu_dereference(sptep), new_spte);
}
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 04c1f0957f..36539c1b36 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -495,8 +495,8 @@ static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
* impact the guest since both the former and current SPTEs
* are nonpresent.
*/
- if (WARN_ON_ONCE(!is_mmio_spte(old_spte) &&
- !is_mmio_spte(new_spte) &&
+ if (WARN_ON_ONCE(!is_mmio_spte(kvm, old_spte) &&
+ !is_mmio_spte(kvm, new_spte) &&
!is_removed_spte(new_spte)))
pr_err("Unexpected SPTE change! Nonpresent SPTEs\n"
"should not be replaced with another,\n"
@@ -530,6 +530,31 @@ static void handle_changed_spte(struct kvm *kvm, int as_id, gfn_t gfn,
kvm_set_pfn_accessed(spte_to_pfn(old_spte));
}
+static inline int __tdp_mmu_set_spte_atomic(struct tdp_iter *iter, u64 new_spte)
+{
+ u64 *sptep = rcu_dereference(iter->sptep);
+
+ /*
+ * The caller is responsible for ensuring the old SPTE is not a REMOVED
+ * SPTE. KVM should never attempt to zap or manipulate a REMOVED SPTE,
+ * and pre-checking before inserting a new SPTE is advantageous as it
+ * avoids unnecessary work.
+ */
+ WARN_ON_ONCE(iter->yielded || is_removed_spte(iter->old_spte));
+
+ /*
+ * Note, fast_pf_fix_direct_spte() can also modify TDP MMU SPTEs and
+ * does not hold the mmu_lock. On failure, i.e. if a different logical
+ * CPU modified the SPTE, try_cmpxchg64() updates iter->old_spte with
+ * the current value, so the caller operates on fresh data, e.g. if it
+ * retries tdp_mmu_set_spte_atomic()
+ */
+ if (!try_cmpxchg64(sptep, &iter->old_spte, new_spte))
+ return -EBUSY;
+
+ return 0;
+}
+
/*
* tdp_mmu_set_spte_atomic - Set a TDP MMU SPTE atomically
* and handle the associated bookkeeping. Do not mark the page dirty
@@ -551,27 +576,13 @@ static inline int tdp_mmu_set_spte_atomic(struct kvm *kvm,
struct tdp_iter *iter,
u64 new_spte)
{
- u64 *sptep = rcu_dereference(iter->sptep);
-
- /*
- * The caller is responsible for ensuring the old SPTE is not a REMOVED
- * SPTE. KVM should never attempt to zap or manipulate a REMOVED SPTE,
- * and pre-checking before inserting a new SPTE is advantageous as it
- * avoids unnecessary work.
- */
- WARN_ON_ONCE(iter->yielded || is_removed_spte(iter->old_spte));
+ int ret;
lockdep_assert_held_read(&kvm->mmu_lock);
- /*
- * Note, fast_pf_fix_direct_spte() can also modify TDP MMU SPTEs and
- * does not hold the mmu_lock. On failure, i.e. if a different logical
- * CPU modified the SPTE, try_cmpxchg64() updates iter->old_spte with
- * the current value, so the caller operates on fresh data, e.g. if it
- * retries tdp_mmu_set_spte_atomic()
- */
- if (!try_cmpxchg64(sptep, &iter->old_spte, new_spte))
- return -EBUSY;
+ ret = __tdp_mmu_set_spte_atomic(iter, new_spte);
+ if (ret)
+ return ret;
handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
new_spte, iter->level, true);
@@ -584,13 +595,17 @@ static inline int tdp_mmu_zap_spte_atomic(struct kvm *kvm,
{
int ret;
+ lockdep_assert_held_read(&kvm->mmu_lock);
+
/*
- * Freeze the SPTE by setting it to a special,
- * non-present value. This will stop other threads from
- * immediately installing a present entry in its place
- * before the TLBs are flushed.
+ * Freeze the SPTE by setting it to a special, non-present value. This
+ * will stop other threads from immediately installing a present entry
+ * in its place before the TLBs are flushed.
+ *
+ * Delay processing of the zapped SPTE until after TLBs are flushed and
+ * the REMOVED_SPTE is replaced (see below).
*/
- ret = tdp_mmu_set_spte_atomic(kvm, iter, REMOVED_SPTE);
+ ret = __tdp_mmu_set_spte_atomic(iter, REMOVED_SPTE);
if (ret)
return ret;
@@ -599,11 +614,19 @@ static inline int tdp_mmu_zap_spte_atomic(struct kvm *kvm,
/*
* No other thread can overwrite the removed SPTE as they must either
* wait on the MMU lock or use tdp_mmu_set_spte_atomic() which will not
- * overwrite the special removed SPTE value. No bookkeeping is needed
- * here since the SPTE is going from non-present to non-present. Use
- * the raw write helper to avoid an unnecessary check on volatile bits.
+ * overwrite the special removed SPTE value. Use the raw write helper to
+ * avoid an unnecessary check on volatile bits.
*/
- __kvm_tdp_mmu_write_spte(iter->sptep, 0);
+ __kvm_tdp_mmu_write_spte(iter->sptep, SHADOW_NONPRESENT_VALUE);
+
+ /*
+ * Process the zapped SPTE after flushing TLBs, and after replacing
+ * REMOVED_SPTE with 0. This minimizes the amount of time vCPUs are
+ * blocked by the REMOVED_SPTE and reduces contention on the child
+ * SPTEs.
+ */
+ handle_changed_spte(kvm, iter->as_id, iter->gfn, iter->old_spte,
+ SHADOW_NONPRESENT_VALUE, iter->level, true);
return 0;
}
@@ -740,8 +763,8 @@ retry:
continue;
if (!shared)
- tdp_mmu_iter_set_spte(kvm, &iter, 0);
- else if (tdp_mmu_set_spte_atomic(kvm, &iter, 0))
+ tdp_mmu_iter_set_spte(kvm, &iter, SHADOW_NONPRESENT_VALUE);
+ else if (tdp_mmu_set_spte_atomic(kvm, &iter, SHADOW_NONPRESENT_VALUE))
goto retry;
}
}
@@ -808,8 +831,8 @@ bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
if (WARN_ON_ONCE(!is_shadow_present_pte(old_spte)))
return false;
- tdp_mmu_set_spte(kvm, kvm_mmu_page_as_id(sp), sp->ptep, old_spte, 0,
- sp->gfn, sp->role.level + 1);
+ tdp_mmu_set_spte(kvm, kvm_mmu_page_as_id(sp), sp->ptep, old_spte,
+ SHADOW_NONPRESENT_VALUE, sp->gfn, sp->role.level + 1);
return true;
}
@@ -843,7 +866,7 @@ static bool tdp_mmu_zap_leafs(struct kvm *kvm, struct kvm_mmu_page *root,
!is_last_spte(iter.old_spte, iter.level))
continue;
- tdp_mmu_iter_set_spte(kvm, &iter, 0);
+ tdp_mmu_iter_set_spte(kvm, &iter, SHADOW_NONPRESENT_VALUE);
/*
* Zappings SPTEs in invalid roots doesn't require a TLB flush,
@@ -1028,7 +1051,7 @@ static int tdp_mmu_map_handle_target_level(struct kvm_vcpu *vcpu,
}
/* If a MMIO SPTE is installed, the MMIO will need to be emulated. */
- if (unlikely(is_mmio_spte(new_spte))) {
+ if (unlikely(is_mmio_spte(vcpu->kvm, new_spte))) {
vcpu->stat.pf_mmio_spte_created++;
trace_mark_mmio_spte(rcu_dereference(iter->sptep), iter->gfn,
new_spte);
@@ -1258,52 +1281,6 @@ bool kvm_tdp_mmu_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
return kvm_tdp_mmu_handle_gfn(kvm, range, test_age_gfn);
}
-static bool set_spte_gfn(struct kvm *kvm, struct tdp_iter *iter,
- struct kvm_gfn_range *range)
-{
- u64 new_spte;
-
- /* Huge pages aren't expected to be modified without first being zapped. */
- WARN_ON_ONCE(pte_huge(range->arg.pte) || range->start + 1 != range->end);
-
- if (iter->level != PG_LEVEL_4K ||
- !is_shadow_present_pte(iter->old_spte))
- return false;
-
- /*
- * Note, when changing a read-only SPTE, it's not strictly necessary to
- * zero the SPTE before setting the new PFN, but doing so preserves the
- * invariant that the PFN of a present * leaf SPTE can never change.
- * See handle_changed_spte().
- */
- tdp_mmu_iter_set_spte(kvm, iter, 0);
-
- if (!pte_write(range->arg.pte)) {
- new_spte = kvm_mmu_changed_pte_notifier_make_spte(iter->old_spte,
- pte_pfn(range->arg.pte));
-
- tdp_mmu_iter_set_spte(kvm, iter, new_spte);
- }
-
- return true;
-}
-
-/*
- * 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.
- */
-bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range)
-{
- /*
- * No need to handle the remote TLB flush under RCU protection, the
- * target SPTE _must_ be a leaf SPTE, i.e. cannot result in freeing a
- * shadow page. See the WARN on pfn_changed in handle_changed_spte().
- */
- return kvm_tdp_mmu_handle_gfn(kvm, range, set_spte_gfn);
-}
-
/*
* Remove write access from all SPTEs at or above min_level that map GFNs
* [start, end). Returns true if an SPTE has been changed and the TLBs need to
diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
index 6e1ea04ca8..58b55e61bd 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.h
+++ b/arch/x86/kvm/mmu/tdp_mmu.h
@@ -31,7 +31,6 @@ bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range,
bool flush);
bool kvm_tdp_mmu_age_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range);
bool kvm_tdp_mmu_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range);
-bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range);
bool kvm_tdp_mmu_wrprot_slot(struct kvm *kvm,
const struct kvm_memory_slot *slot, int min_level);