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authorPaolo Bonzini <pbonzini@redhat.com>2021-03-31 14:45:19 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2021-03-31 14:45:41 +0300
commit825e34d3c9e21ad1243b4464d23739de3c63a48b (patch)
treed31ae5ffb1277c2cef0c2ae717a1fe841449697e /arch
parent6fb3084ab5d9331cfadf07c59cf4a0bd4059bf4a (diff)
parent33a3164161fc86b9cc238f7f2aa2ccb1d5559b1c (diff)
downloadlinux-825e34d3c9e21ad1243b4464d23739de3c63a48b.tar.xz
Merge commit 'kvm-tdp-fix-flushes' into kvm-master
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/mmu/mmu.c9
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.c26
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.h24
3 files changed, 42 insertions, 17 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index d75524bc8423..486aa94ecf1d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5884,6 +5884,7 @@ static void kvm_recover_nx_lpages(struct kvm *kvm)
struct kvm_mmu_page *sp;
unsigned int ratio;
LIST_HEAD(invalid_list);
+ bool flush = false;
ulong to_zap;
rcu_idx = srcu_read_lock(&kvm->srcu);
@@ -5905,19 +5906,19 @@ static void kvm_recover_nx_lpages(struct kvm *kvm)
lpage_disallowed_link);
WARN_ON_ONCE(!sp->lpage_disallowed);
if (is_tdp_mmu_page(sp)) {
- kvm_tdp_mmu_zap_gfn_range(kvm, sp->gfn,
- sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level));
+ flush = kvm_tdp_mmu_zap_sp(kvm, sp);
} else {
kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
WARN_ON_ONCE(sp->lpage_disallowed);
}
if (need_resched() || rwlock_needbreak(&kvm->mmu_lock)) {
- kvm_mmu_commit_zap_page(kvm, &invalid_list);
+ kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
cond_resched_rwlock_write(&kvm->mmu_lock);
+ flush = false;
}
}
- kvm_mmu_commit_zap_page(kvm, &invalid_list);
+ kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
write_unlock(&kvm->mmu_lock);
srcu_read_unlock(&kvm->srcu, rcu_idx);
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 462b1f71c77f..018d82e73e31 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -86,7 +86,7 @@ static inline struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm,
list_for_each_entry(_root, &_kvm->arch.tdp_mmu_roots, link)
static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
- gfn_t start, gfn_t end, bool can_yield);
+ gfn_t start, gfn_t end, bool can_yield, bool flush);
void kvm_tdp_mmu_free_root(struct kvm *kvm, struct kvm_mmu_page *root)
{
@@ -99,7 +99,7 @@ void kvm_tdp_mmu_free_root(struct kvm *kvm, struct kvm_mmu_page *root)
list_del(&root->link);
- zap_gfn_range(kvm, root, 0, max_gfn, false);
+ zap_gfn_range(kvm, root, 0, max_gfn, false, false);
free_page((unsigned long)root->spt);
kmem_cache_free(mmu_page_header_cache, root);
@@ -668,20 +668,21 @@ static inline bool tdp_mmu_iter_cond_resched(struct kvm *kvm,
* 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.
+ * operation can cause a soft lockup. Note, in some use cases a flush may be
+ * required by prior actions. Ensure the pending flush is performed prior to
+ * yielding.
*/
static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
- gfn_t start, gfn_t end, bool can_yield)
+ gfn_t start, gfn_t end, bool can_yield, bool flush)
{
struct tdp_iter iter;
- bool flush_needed = false;
rcu_read_lock();
tdp_root_for_each_pte(iter, root, start, end) {
if (can_yield &&
- tdp_mmu_iter_cond_resched(kvm, &iter, flush_needed)) {
- flush_needed = false;
+ tdp_mmu_iter_cond_resched(kvm, &iter, flush)) {
+ flush = false;
continue;
}
@@ -699,11 +700,11 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
continue;
tdp_mmu_set_spte(kvm, &iter, 0);
- flush_needed = true;
+ flush = true;
}
rcu_read_unlock();
- return flush_needed;
+ return flush;
}
/*
@@ -712,13 +713,14 @@ static bool zap_gfn_range(struct kvm *kvm, struct kvm_mmu_page *root,
* 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)
+bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, gfn_t start, gfn_t end,
+ bool can_yield)
{
struct kvm_mmu_page *root;
bool flush = false;
for_each_tdp_mmu_root_yield_safe(kvm, root)
- flush |= zap_gfn_range(kvm, root, start, end, true);
+ flush = zap_gfn_range(kvm, root, start, end, can_yield, flush);
return flush;
}
@@ -930,7 +932,7 @@ static int zap_gfn_range_hva_wrapper(struct kvm *kvm,
struct kvm_mmu_page *root, gfn_t start,
gfn_t end, unsigned long unused)
{
- return zap_gfn_range(kvm, root, start, end, false);
+ return zap_gfn_range(kvm, root, start, end, false, false);
}
int kvm_tdp_mmu_zap_hva_range(struct kvm *kvm, unsigned long start,
diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
index 3b761c111bff..31096ece9b14 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.h
+++ b/arch/x86/kvm/mmu/tdp_mmu.h
@@ -8,7 +8,29 @@
hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu);
void kvm_tdp_mmu_free_root(struct kvm *kvm, struct kvm_mmu_page *root);
-bool kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, gfn_t start, gfn_t end);
+bool __kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, gfn_t start, gfn_t end,
+ bool can_yield);
+static inline bool kvm_tdp_mmu_zap_gfn_range(struct kvm *kvm, gfn_t start,
+ gfn_t end)
+{
+ return __kvm_tdp_mmu_zap_gfn_range(kvm, start, end, true);
+}
+static inline bool kvm_tdp_mmu_zap_sp(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ gfn_t end = sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level);
+
+ /*
+ * Don't allow yielding, as the caller may have a flush pending. Note,
+ * if mmu_lock is held for write, zapping will never yield in this case,
+ * but explicitly disallow it for safety. The TDP MMU does not yield
+ * until it has made forward progress (steps sideways), and when zapping
+ * a single shadow page that it's guaranteed to see (thus the mmu_lock
+ * requirement), its "step sideways" will always step beyond the bounds
+ * of the shadow page's gfn range and stop iterating before yielding.
+ */
+ lockdep_assert_held_write(&kvm->mmu_lock);
+ return __kvm_tdp_mmu_zap_gfn_range(kvm, sp->gfn, end, false);
+}
void kvm_tdp_mmu_zap_all(struct kvm *kvm);
int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,