From: Marcelo Tosatti <[EMAIL PROTECTED]>
Allow guest pagetables to go out of sync.
Signed-off-by: Marcelo Tosatti <[EMAIL PROTECTED]>
Signed-off-by: Avi Kivity <[EMAIL PROTECTED]>
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 57c7580..9fd0259 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -147,6 +147,10 @@ struct kvm_shadow_walk {
u64 addr, u64 *spte, int level);
};
+struct kvm_unsync_walk {
+ int (*entry) (struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk);
+};
+
typedef int (*mmu_parent_walk_fn) (struct kvm_vcpu *vcpu, struct kvm_mmu_page
*sp);
static struct kmem_cache *pte_chain_cache;
@@ -908,6 +912,41 @@ static void nonpaging_invlpg(struct kvm_vcpu *vcpu, gva_t
gva)
{
}
+static int mmu_unsync_walk(struct kvm_mmu_page *sp,
+ struct kvm_unsync_walk *walker)
+{
+ int i, ret;
+
+ if (!sp->unsync_children)
+ return 0;
+
+ for (i = 0; i < PT64_ENT_PER_PAGE; ++i) {
+ u64 ent = sp->spt[i];
+
+ if (is_shadow_present_pte(ent)) {
+ struct kvm_mmu_page *child;
+ child = page_header(ent & PT64_BASE_ADDR_MASK);
+
+ if (child->unsync_children) {
+ ret = mmu_unsync_walk(child, walker);
+ if (ret)
+ return ret;
+ }
+
+ if (child->unsync) {
+ ret = walker->entry(child, walker);
+ if (ret)
+ return ret;
+ }
+ }
+ }
+
+ if (i == PT64_ENT_PER_PAGE)
+ sp->unsync_children = 0;
+
+ return 0;
+}
+
static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm *kvm, gfn_t gfn)
{
unsigned index;
@@ -928,6 +967,59 @@ static struct kvm_mmu_page *kvm_mmu_lookup_page(struct kvm
*kvm, gfn_t gfn)
return NULL;
}
+static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ WARN_ON(!sp->unsync);
+ sp->unsync = 0;
+ --kvm->stat.mmu_unsync;
+}
+
+static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
+
+static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+ if (sp->role.glevels != vcpu->arch.mmu.root_level) {
+ kvm_mmu_zap_page(vcpu->kvm, sp);
+ return 1;
+ }
+
+ rmap_write_protect(vcpu->kvm, sp->gfn);
+ if (vcpu->arch.mmu.sync_page(vcpu, sp)) {
+ kvm_mmu_zap_page(vcpu->kvm, sp);
+ return 1;
+ }
+
+ kvm_mmu_flush_tlb(vcpu);
+ kvm_unlink_unsync_page(vcpu->kvm, sp);
+ return 0;
+}
+
+struct sync_walker {
+ struct kvm_vcpu *vcpu;
+ struct kvm_unsync_walk walker;
+};
+
+static int mmu_sync_fn(struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk)
+{
+ struct sync_walker *sync_walk = container_of(walk, struct sync_walker,
+ walker);
+ struct kvm_vcpu *vcpu = sync_walk->vcpu;
+
+ kvm_sync_page(vcpu, sp);
+ return (need_resched() || spin_needbreak(&vcpu->kvm->mmu_lock));
+}
+
+static void mmu_sync_children(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+ struct sync_walker walker = {
+ .walker = { .entry = mmu_sync_fn, },
+ .vcpu = vcpu,
+ };
+
+ while (mmu_unsync_walk(sp, &walker.walker))
+ cond_resched_lock(&vcpu->kvm->mmu_lock);
+}
+
static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
gfn_t gfn,
gva_t gaddr,
@@ -941,7 +1033,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct
kvm_vcpu *vcpu,
unsigned quadrant;
struct hlist_head *bucket;
struct kvm_mmu_page *sp;
- struct hlist_node *node;
+ struct hlist_node *node, *tmp;
role.word = 0;
role.glevels = vcpu->arch.mmu.root_level;
@@ -957,8 +1049,18 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct
kvm_vcpu *vcpu,
gfn, role.word);
index = kvm_page_table_hashfn(gfn);
bucket = &vcpu->kvm->arch.mmu_page_hash[index];
- hlist_for_each_entry(sp, node, bucket, hash_link)
- if (sp->gfn == gfn && sp->role.word == role.word) {
+ hlist_for_each_entry_safe(sp, node, tmp, bucket, hash_link)
+ if (sp->gfn == gfn) {
+ if (sp->unsync)
+ if (kvm_sync_page(vcpu, sp))
+ continue;
+
+ if (sp->role.word != role.word)
+ continue;
+
+ if (sp->unsync_children)
+ set_bit(KVM_REQ_MMU_SYNC, &vcpu->requests);
+
mmu_page_add_parent_pte(vcpu, sp, parent_pte);
pgprintk("%s: found\n", __func__);
return sp;
@@ -1078,14 +1180,47 @@ static void kvm_mmu_unlink_parents(struct kvm *kvm,
struct kvm_mmu_page *sp)
}
}
+struct zap_walker {
+ struct kvm_unsync_walk walker;
+ struct kvm *kvm;
+ int zapped;
+};
+
+static int mmu_zap_fn(struct kvm_mmu_page *sp, struct kvm_unsync_walk *walk)
+{
+ struct zap_walker *zap_walk = container_of(walk, struct zap_walker,
+ walker);
+ kvm_mmu_zap_page(zap_walk->kvm, sp);
+ zap_walk->zapped = 1;
+ return 0;
+}
+
+static int mmu_zap_unsync_children(struct kvm *kvm, struct kvm_mmu_page *sp)
+{
+ struct zap_walker walker = {
+ .walker = { .entry = mmu_zap_fn, },
+ .kvm = kvm,
+ .zapped = 0,
+ };
+
+ if (sp->role.level == PT_PAGE_TABLE_LEVEL)
+ return 0;
+ mmu_unsync_walk(sp, &walker.walker);
+ return walker.zapped;
+}
+
static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
+ int ret;
++kvm->stat.mmu_shadow_zapped;
+ ret = mmu_zap_unsync_children(kvm, sp);
kvm_mmu_page_unlink_children(kvm, sp);
kvm_mmu_unlink_parents(kvm, sp);
kvm_flush_remote_tlbs(kvm);
if (!sp->role.invalid && !sp->role.metaphysical)
unaccount_shadowed(kvm, sp->gfn);
+ if (sp->unsync)
+ kvm_unlink_unsync_page(kvm, sp);
if (!sp->root_count) {
hlist_del(&sp->hash_link);
kvm_mmu_free_page(kvm, sp);
@@ -1095,7 +1230,7 @@ static int kvm_mmu_zap_page(struct kvm *kvm, struct
kvm_mmu_page *sp)
kvm_reload_remote_mmus(kvm);
}
kvm_mmu_reset_last_pte_updated(kvm);
- return 0;
+ return ret;
}
/*
@@ -1201,10 +1336,58 @@ struct page *gva_to_page(struct kvm_vcpu *vcpu, gva_t
gva)
return page;
}
+static int unsync_walk_fn(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+ sp->unsync_children = 1;
+ return 1;
+}
+
+static int kvm_unsync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
+{
+ unsigned index;
+ struct hlist_head *bucket;
+ struct kvm_mmu_page *s;
+ struct hlist_node *node, *n;
+
+ index = kvm_page_table_hashfn(sp->gfn);
+ bucket = &vcpu->kvm->arch.mmu_page_hash[index];
+ /* don't unsync if pagetable is shadowed with multiple roles */
+ hlist_for_each_entry_safe(s, node, n, bucket, hash_link) {
+ if (s->gfn != sp->gfn || s->role.metaphysical)
+ continue;
+ if (s->role.word != sp->role.word)
+ return 1;
+ }
+ mmu_parent_walk(vcpu, sp, unsync_walk_fn);
+ ++vcpu->kvm->stat.mmu_unsync;
+ sp->unsync = 1;
+ mmu_convert_notrap(sp);
+ return 0;
+}
+
+static int mmu_need_write_protect(struct kvm_vcpu *vcpu, gfn_t gfn,
+ bool can_unsync)
+{
+ struct kvm_mmu_page *shadow;
+
+ shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
+ if (shadow) {
+ if (shadow->role.level != PT_PAGE_TABLE_LEVEL)
+ return 1;
+ if (shadow->unsync)
+ return 0;
+ if (can_unsync)
+ return kvm_unsync_page(vcpu, shadow);
+ return 1;
+ }
+ return 0;
+}
+
static int set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
unsigned pte_access, int user_fault,
int write_fault, int dirty, int largepage,
- gfn_t gfn, pfn_t pfn, bool speculative)
+ gfn_t gfn, pfn_t pfn, bool speculative,
+ bool can_unsync)
{
u64 spte;
int ret = 0;
@@ -1231,7 +1414,6 @@ static int set_spte(struct kvm_vcpu *vcpu, u64
*shadow_pte,
if ((pte_access & ACC_WRITE_MASK)
|| (write_fault && !is_write_protection(vcpu) && !user_fault)) {
- struct kvm_mmu_page *shadow;
if (largepage && has_wrprotected_page(vcpu->kvm, gfn)) {
ret = 1;
@@ -1241,8 +1423,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64
*shadow_pte,
spte |= PT_WRITABLE_MASK;
- shadow = kvm_mmu_lookup_page(vcpu->kvm, gfn);
- if (shadow) {
+ if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
pgprintk("%s: found shadow page for %lx, marking ro\n",
__func__, gfn);
ret = 1;
@@ -1260,7 +1441,6 @@ set_pte:
return ret;
}
-
static void mmu_set_spte(struct kvm_vcpu *vcpu, u64 *shadow_pte,
unsigned pt_access, unsigned pte_access,
int user_fault, int write_fault, int dirty,
@@ -1298,7 +1478,7 @@ static void mmu_set_spte(struct kvm_vcpu *vcpu, u64
*shadow_pte,
}
}
if (set_spte(vcpu, shadow_pte, pte_access, user_fault, write_fault,
- dirty, largepage, gfn, pfn, speculative)) {
+ dirty, largepage, gfn, pfn, speculative, true)) {
if (write_fault)
*ptwrite = 1;
kvm_x86_ops->tlb_flush(vcpu);
@@ -1518,10 +1698,6 @@ static void mmu_alloc_roots(struct kvm_vcpu *vcpu)
vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
}
-static void mmu_sync_children(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
-{
-}
-
static void mmu_sync_roots(struct kvm_vcpu *vcpu)
{
int i;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index dc169e8..613ec9a 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -580,7 +580,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct
kvm_mmu_page *sp)
pte_access = sp->role.access & FNAME(gpte_access)(vcpu, gpte);
set_spte(vcpu, &sp->spt[i], pte_access, 0, 0,
is_dirty_pte(gpte), 0, gfn,
- spte_to_pfn(sp->spt[i]), true);
+ spte_to_pfn(sp->spt[i]), true, false);
}
return !nr_present;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index efee85b..1c5864a 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -101,6 +101,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "mmu_flooded", VM_STAT(mmu_flooded) },
{ "mmu_recycled", VM_STAT(mmu_recycled) },
{ "mmu_cache_miss", VM_STAT(mmu_cache_miss) },
+ { "mmu_unsync", VM_STAT(mmu_unsync) },
{ "remote_tlb_flush", VM_STAT(remote_tlb_flush) },
{ "largepages", VM_STAT(lpages) },
{ NULL }
@@ -3120,6 +3121,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct
kvm_run *kvm_run)
if (vcpu->requests) {
if (test_and_clear_bit(KVM_REQ_MIGRATE_TIMER, &vcpu->requests))
__kvm_migrate_timers(vcpu);
+ if (test_and_clear_bit(KVM_REQ_MMU_SYNC, &vcpu->requests))
+ kvm_mmu_sync_roots(vcpu);
if (test_and_clear_bit(KVM_REQ_TLB_FLUSH, &vcpu->requests))
kvm_x86_ops->tlb_flush(vcpu);
if (test_and_clear_bit(KVM_REQ_REPORT_TPR_ACCESS,
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 8ac6719..c61e4ab 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -195,6 +195,8 @@ struct kvm_mmu_page {
*/
int multimapped; /* More than one parent_pte? */
int root_count; /* Currently serving as active root */
+ bool unsync;
+ bool unsync_children;
union {
u64 *parent_pte; /* !multimapped */
struct hlist_head parent_ptes; /* multimapped, kvm_pte_chain */
@@ -371,6 +373,7 @@ struct kvm_vm_stat {
u32 mmu_flooded;
u32 mmu_recycled;
u32 mmu_cache_miss;
+ u32 mmu_unsync;
u32 remote_tlb_flush;
u32 lpages;
};
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 6252802..73b7c52 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -35,6 +35,7 @@
#define KVM_REQ_TRIPLE_FAULT 4
#define KVM_REQ_PENDING_TIMER 5
#define KVM_REQ_UNHALT 6
+#define KVM_REQ_MMU_SYNC 7
struct kvm_vcpu;
extern struct kmem_cache *kvm_vcpu_cache;
--
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