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-rw-r--r--arch/x86/kvm/mmu/mmu.c120
-rw-r--r--arch/x86/kvm/mmu/paging_tmpl.h3
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.c38
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.h5
4 files changed, 91 insertions, 75 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 3be9beea838d..e2e1d012df22 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1582,7 +1582,7 @@ bool kvm_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range)
flush = kvm_handle_gfn_range(kvm, range, kvm_unmap_rmapp);
if (is_tdp_mmu_enabled(kvm))
- flush |= kvm_tdp_mmu_unmap_gfn_range(kvm, range, flush);
+ flush = kvm_tdp_mmu_unmap_gfn_range(kvm, range, flush);
return flush;
}
@@ -1936,7 +1936,11 @@ static void mmu_audit_disable(void) { }
static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
{
- return sp->role.invalid ||
+ if (sp->role.invalid)
+ return true;
+
+ /* TDP MMU pages due not use the MMU generation. */
+ return !sp->tdp_mmu_page &&
unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen);
}
@@ -2173,10 +2177,10 @@ static void shadow_walk_init_using_root(struct kvm_shadow_walk_iterator *iterato
iterator->shadow_addr = root;
iterator->level = vcpu->arch.mmu->shadow_root_level;
- if (iterator->level == PT64_ROOT_4LEVEL &&
+ if (iterator->level >= PT64_ROOT_4LEVEL &&
vcpu->arch.mmu->root_level < PT64_ROOT_4LEVEL &&
!vcpu->arch.mmu->direct_map)
- --iterator->level;
+ iterator->level = PT32E_ROOT_LEVEL;
if (iterator->level == PT32E_ROOT_LEVEL) {
/*
@@ -3976,6 +3980,20 @@ out_retry:
return true;
}
+/*
+ * Returns true if the page fault is stale and needs to be retried, i.e. if the
+ * root was invalidated by a memslot update or a relevant mmu_notifier fired.
+ */
+static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
+ struct kvm_page_fault *fault, int mmu_seq)
+{
+ if (is_obsolete_sp(vcpu->kvm, to_shadow_page(vcpu->arch.mmu->root_hpa)))
+ return true;
+
+ return fault->slot &&
+ mmu_notifier_retry_hva(vcpu->kvm, mmu_seq, fault->hva);
+}
+
static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
{
bool is_tdp_mmu_fault = is_tdp_mmu(vcpu->arch.mmu);
@@ -4013,8 +4031,9 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
else
write_lock(&vcpu->kvm->mmu_lock);
- if (fault->slot && mmu_notifier_retry_hva(vcpu->kvm, mmu_seq, fault->hva))
+ if (is_page_fault_stale(vcpu, fault, mmu_seq))
goto out_unlock;
+
r = make_mmu_pages_available(vcpu);
if (r)
goto out_unlock;
@@ -4855,7 +4874,7 @@ void kvm_init_shadow_npt_mmu(struct kvm_vcpu *vcpu, unsigned long cr0,
struct kvm_mmu *context = &vcpu->arch.guest_mmu;
struct kvm_mmu_role_regs regs = {
.cr0 = cr0,
- .cr4 = cr4,
+ .cr4 = cr4 & ~X86_CR4_PKE,
.efer = efer,
};
union kvm_mmu_role new_role;
@@ -4919,7 +4938,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
context->direct_map = false;
update_permission_bitmask(context, true);
- update_pkru_bitmask(context);
+ context->pkru_mask = 0;
reset_rsvds_bits_mask_ept(vcpu, context, execonly);
reset_ept_shadow_zero_bits_mask(vcpu, context, execonly);
}
@@ -5025,6 +5044,14 @@ void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu)
/*
* Invalidate all MMU roles to force them to reinitialize as CPUID
* information is factored into reserved bit calculations.
+ *
+ * Correctly handling multiple vCPU models with respect to paging and
+ * physical address properties) in a single VM would require tracking
+ * all relevant CPUID information in kvm_mmu_page_role. That is very
+ * undesirable as it would increase the memory requirements for
+ * gfn_track (see struct kvm_mmu_page_role comments). For now that
+ * problem is swept under the rug; KVM's CPUID API is horrific and
+ * it's all but impossible to solve it without introducing a new API.
*/
vcpu->arch.root_mmu.mmu_role.ext.valid = 0;
vcpu->arch.guest_mmu.mmu_role.ext.valid = 0;
@@ -5032,24 +5059,10 @@ void kvm_mmu_after_set_cpuid(struct kvm_vcpu *vcpu)
kvm_mmu_reset_context(vcpu);
/*
- * KVM does not correctly handle changing guest CPUID after KVM_RUN, as
- * MAXPHYADDR, GBPAGES support, AMD reserved bit behavior, etc.. aren't
- * tracked in kvm_mmu_page_role. As a result, KVM may miss guest page
- * faults due to reusing SPs/SPTEs. Alert userspace, but otherwise
- * sweep the problem under the rug.
- *
- * KVM's horrific CPUID ABI makes the problem all but impossible to
- * solve, as correctly handling multiple vCPU models (with respect to
- * paging and physical address properties) in a single VM would require
- * tracking all relevant CPUID information in kvm_mmu_page_role. That
- * is very undesirable as it would double the memory requirements for
- * gfn_track (see struct kvm_mmu_page_role comments), and in practice
- * no sane VMM mucks with the core vCPU model on the fly.
+ * Changing guest CPUID after KVM_RUN is forbidden, see the comment in
+ * kvm_arch_vcpu_ioctl().
*/
- if (vcpu->arch.last_vmentry_cpu != -1) {
- pr_warn_ratelimited("KVM: KVM_SET_CPUID{,2} after KVM_RUN may cause guest instability\n");
- pr_warn_ratelimited("KVM: KVM_SET_CPUID{,2} will fail after KVM_RUN starting with Linux 5.16\n");
- }
+ KVM_BUG_ON(vcpu->arch.last_vmentry_cpu != -1, vcpu->kvm);
}
void kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
@@ -5369,7 +5382,7 @@ void kvm_mmu_invalidate_gva(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
void kvm_mmu_invlpg(struct kvm_vcpu *vcpu, gva_t gva)
{
- kvm_mmu_invalidate_gva(vcpu, vcpu->arch.mmu, gva, INVALID_PAGE);
+ kvm_mmu_invalidate_gva(vcpu, vcpu->arch.walk_mmu, gva, INVALID_PAGE);
++vcpu->stat.invlpg;
}
EXPORT_SYMBOL_GPL(kvm_mmu_invlpg);
@@ -5854,8 +5867,6 @@ restart:
void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
const struct kvm_memory_slot *slot)
{
- bool flush = false;
-
if (kvm_memslots_have_rmaps(kvm)) {
write_lock(&kvm->mmu_lock);
/*
@@ -5863,17 +5874,14 @@ void kvm_mmu_zap_collapsible_sptes(struct kvm *kvm,
* logging at a 4k granularity and never creates collapsible
* 2m SPTEs during dirty logging.
*/
- flush = slot_handle_level_4k(kvm, slot, kvm_mmu_zap_collapsible_spte, true);
- if (flush)
+ if (slot_handle_level_4k(kvm, slot, kvm_mmu_zap_collapsible_spte, true))
kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
write_unlock(&kvm->mmu_lock);
}
if (is_tdp_mmu_enabled(kvm)) {
read_lock(&kvm->mmu_lock);
- flush = kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot, flush);
- if (flush)
- kvm_arch_flush_remote_tlbs_memslot(kvm, slot);
+ kvm_tdp_mmu_zap_collapsible_sptes(kvm, slot);
read_unlock(&kvm->mmu_lock);
}
}
@@ -6182,23 +6190,46 @@ void kvm_mmu_module_exit(void)
mmu_audit_disable();
}
+/*
+ * Calculate the effective recovery period, accounting for '0' meaning "let KVM
+ * select a halving time of 1 hour". Returns true if recovery is enabled.
+ */
+static bool calc_nx_huge_pages_recovery_period(uint *period)
+{
+ /*
+ * Use READ_ONCE to get the params, this may be called outside of the
+ * param setters, e.g. by the kthread to compute its next timeout.
+ */
+ bool enabled = READ_ONCE(nx_huge_pages);
+ uint ratio = READ_ONCE(nx_huge_pages_recovery_ratio);
+
+ if (!enabled || !ratio)
+ return false;
+
+ *period = READ_ONCE(nx_huge_pages_recovery_period_ms);
+ if (!*period) {
+ /* Make sure the period is not less than one second. */
+ ratio = min(ratio, 3600u);
+ *period = 60 * 60 * 1000 / ratio;
+ }
+ return true;
+}
+
static int set_nx_huge_pages_recovery_param(const char *val, const struct kernel_param *kp)
{
bool was_recovery_enabled, is_recovery_enabled;
uint old_period, new_period;
int err;
- was_recovery_enabled = nx_huge_pages_recovery_ratio;
- old_period = nx_huge_pages_recovery_period_ms;
+ was_recovery_enabled = calc_nx_huge_pages_recovery_period(&old_period);
err = param_set_uint(val, kp);
if (err)
return err;
- is_recovery_enabled = nx_huge_pages_recovery_ratio;
- new_period = nx_huge_pages_recovery_period_ms;
+ is_recovery_enabled = calc_nx_huge_pages_recovery_period(&new_period);
- if (READ_ONCE(nx_huge_pages) && is_recovery_enabled &&
+ if (is_recovery_enabled &&
(!was_recovery_enabled || old_period > new_period)) {
struct kvm *kvm;
@@ -6262,18 +6293,13 @@ static void kvm_recover_nx_lpages(struct kvm *kvm)
static long get_nx_lpage_recovery_timeout(u64 start_time)
{
- uint ratio = READ_ONCE(nx_huge_pages_recovery_ratio);
- uint period = READ_ONCE(nx_huge_pages_recovery_period_ms);
+ bool enabled;
+ uint period;
- if (!period && ratio) {
- /* Make sure the period is not less than one second. */
- ratio = min(ratio, 3600u);
- period = 60 * 60 * 1000 / ratio;
- }
+ enabled = calc_nx_huge_pages_recovery_period(&period);
- return READ_ONCE(nx_huge_pages) && ratio
- ? start_time + msecs_to_jiffies(period) - get_jiffies_64()
- : MAX_SCHEDULE_TIMEOUT;
+ return enabled ? start_time + msecs_to_jiffies(period) - get_jiffies_64()
+ : MAX_SCHEDULE_TIMEOUT;
}
static int kvm_nx_lpage_recovery_worker(struct kvm *kvm, uintptr_t data)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index f87d36898c44..708a5d297fe1 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -911,7 +911,8 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
r = RET_PF_RETRY;
write_lock(&vcpu->kvm->mmu_lock);
- if (fault->slot && mmu_notifier_retry_hva(vcpu->kvm, mmu_seq, fault->hva))
+
+ if (is_page_fault_stale(vcpu, fault, mmu_seq))
goto out_unlock;
kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index a54c3491af42..1db8496259ad 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -317,9 +317,6 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt,
struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(pt));
int level = sp->role.level;
gfn_t base_gfn = sp->gfn;
- u64 old_child_spte;
- u64 *sptep;
- gfn_t gfn;
int i;
trace_kvm_mmu_prepare_zap_page(sp);
@@ -327,8 +324,9 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt,
tdp_mmu_unlink_page(kvm, sp, shared);
for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
- sptep = rcu_dereference(pt) + i;
- gfn = base_gfn + i * KVM_PAGES_PER_HPAGE(level);
+ u64 *sptep = rcu_dereference(pt) + i;
+ gfn_t gfn = base_gfn + i * KVM_PAGES_PER_HPAGE(level);
+ u64 old_child_spte;
if (shared) {
/*
@@ -374,7 +372,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt,
shared);
}
- kvm_flush_remote_tlbs_with_address(kvm, gfn,
+ kvm_flush_remote_tlbs_with_address(kvm, base_gfn,
KVM_PAGES_PER_HPAGE(level + 1));
call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback);
@@ -1033,9 +1031,9 @@ bool kvm_tdp_mmu_unmap_gfn_range(struct kvm *kvm, struct kvm_gfn_range *range,
{
struct kvm_mmu_page *root;
- for_each_tdp_mmu_root(kvm, root, range->slot->as_id)
- flush |= zap_gfn_range(kvm, root, range->start, range->end,
- range->may_block, flush, false);
+ for_each_tdp_mmu_root_yield_safe(kvm, root, range->slot->as_id, false)
+ flush = zap_gfn_range(kvm, root, range->start, range->end,
+ range->may_block, flush, false);
return flush;
}
@@ -1364,10 +1362,9 @@ void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm,
* Clear leaf entries which could be replaced by large mappings, for
* GFNs within the slot.
*/
-static bool zap_collapsible_spte_range(struct kvm *kvm,
+static void zap_collapsible_spte_range(struct kvm *kvm,
struct kvm_mmu_page *root,
- const struct kvm_memory_slot *slot,
- bool flush)
+ const struct kvm_memory_slot *slot)
{
gfn_t start = slot->base_gfn;
gfn_t end = start + slot->npages;
@@ -1378,10 +1375,8 @@ static bool zap_collapsible_spte_range(struct kvm *kvm,
tdp_root_for_each_pte(iter, root, start, end) {
retry:
- if (tdp_mmu_iter_cond_resched(kvm, &iter, flush, true)) {
- flush = false;
+ if (tdp_mmu_iter_cond_resched(kvm, &iter, false, true))
continue;
- }
if (!is_shadow_present_pte(iter.old_spte) ||
!is_last_spte(iter.old_spte, iter.level))
@@ -1393,6 +1388,7 @@ retry:
pfn, PG_LEVEL_NUM))
continue;
+ /* Note, a successful atomic zap also does a remote TLB flush. */
if (!tdp_mmu_zap_spte_atomic(kvm, &iter)) {
/*
* The iter must explicitly re-read the SPTE because
@@ -1401,30 +1397,24 @@ retry:
iter.old_spte = READ_ONCE(*rcu_dereference(iter.sptep));
goto retry;
}
- flush = true;
}
rcu_read_unlock();
-
- return flush;
}
/*
* Clear non-leaf entries (and free associated page tables) which could
* be replaced by large mappings, for GFNs within the slot.
*/
-bool kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
- const struct kvm_memory_slot *slot,
- bool flush)
+void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
+ const struct kvm_memory_slot *slot)
{
struct kvm_mmu_page *root;
lockdep_assert_held_read(&kvm->mmu_lock);
for_each_tdp_mmu_root_yield_safe(kvm, root, slot->as_id, true)
- flush = zap_collapsible_spte_range(kvm, root, slot, flush);
-
- return flush;
+ zap_collapsible_spte_range(kvm, root, slot);
}
/*
diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
index 476b133544dd..3899004a5d91 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.h
+++ b/arch/x86/kvm/mmu/tdp_mmu.h
@@ -64,9 +64,8 @@ void kvm_tdp_mmu_clear_dirty_pt_masked(struct kvm *kvm,
struct kvm_memory_slot *slot,
gfn_t gfn, unsigned long mask,
bool wrprot);
-bool kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
- const struct kvm_memory_slot *slot,
- bool flush);
+void kvm_tdp_mmu_zap_collapsible_sptes(struct kvm *kvm,
+ const struct kvm_memory_slot *slot);
bool kvm_tdp_mmu_write_protect_gfn(struct kvm *kvm,
struct kvm_memory_slot *slot, gfn_t gfn,
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-01 19:24:58 +0000