Commit 7775834a authored by Xiao Guangrong's avatar Xiao Guangrong Committed by Avi Kivity

KVM: MMU: split the operations of kvm_mmu_zap_page()

Using kvm_mmu_prepare_zap_page() and kvm_mmu_commit_zap_page() to
split kvm_mmu_zap_page() function, then we can:

- traverse hlist safely
- easily to gather remote tlb flush which occurs during page zapped

Those feature can be used in the later patches
Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 7ae680eb
...@@ -916,6 +916,7 @@ static int is_empty_shadow_page(u64 *spt) ...@@ -916,6 +916,7 @@ static int is_empty_shadow_page(u64 *spt)
static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp) static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{ {
ASSERT(is_empty_shadow_page(sp->spt)); ASSERT(is_empty_shadow_page(sp->spt));
hlist_del(&sp->hash_link);
list_del(&sp->link); list_del(&sp->link);
__free_page(virt_to_page(sp->spt)); __free_page(virt_to_page(sp->spt));
if (!sp->role.direct) if (!sp->role.direct)
...@@ -1200,6 +1201,10 @@ static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp) ...@@ -1200,6 +1201,10 @@ static void kvm_unlink_unsync_page(struct kvm *kvm, struct kvm_mmu_page *sp)
} }
static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp); static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp);
static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
struct list_head *invalid_list);
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
struct list_head *invalid_list);
#define for_each_gfn_sp(kvm, sp, gfn, pos, n) \ #define for_each_gfn_sp(kvm, sp, gfn, pos, n) \
hlist_for_each_entry_safe(sp, pos, n, \ hlist_for_each_entry_safe(sp, pos, n, \
...@@ -1530,7 +1535,8 @@ static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp) ...@@ -1530,7 +1535,8 @@ static void kvm_mmu_unlink_parents(struct kvm *kvm, struct kvm_mmu_page *sp)
} }
static int mmu_zap_unsync_children(struct kvm *kvm, static int mmu_zap_unsync_children(struct kvm *kvm,
struct kvm_mmu_page *parent) struct kvm_mmu_page *parent,
struct list_head *invalid_list)
{ {
int i, zapped = 0; int i, zapped = 0;
struct mmu_page_path parents; struct mmu_page_path parents;
...@@ -1544,7 +1550,7 @@ static int mmu_zap_unsync_children(struct kvm *kvm, ...@@ -1544,7 +1550,7 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
struct kvm_mmu_page *sp; struct kvm_mmu_page *sp;
for_each_sp(pages, sp, parents, i) { for_each_sp(pages, sp, parents, i) {
kvm_mmu_zap_page(kvm, sp); kvm_mmu_prepare_zap_page(kvm, sp, invalid_list);
mmu_pages_clear_parents(&parents); mmu_pages_clear_parents(&parents);
zapped++; zapped++;
} }
...@@ -1554,16 +1560,16 @@ static int mmu_zap_unsync_children(struct kvm *kvm, ...@@ -1554,16 +1560,16 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
return zapped; return zapped;
} }
static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp) static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
struct list_head *invalid_list)
{ {
int ret; int ret;
trace_kvm_mmu_zap_page(sp); trace_kvm_mmu_prepare_zap_page(sp);
++kvm->stat.mmu_shadow_zapped; ++kvm->stat.mmu_shadow_zapped;
ret = mmu_zap_unsync_children(kvm, sp); ret = mmu_zap_unsync_children(kvm, sp, invalid_list);
kvm_mmu_page_unlink_children(kvm, sp); kvm_mmu_page_unlink_children(kvm, sp);
kvm_mmu_unlink_parents(kvm, sp); kvm_mmu_unlink_parents(kvm, sp);
kvm_flush_remote_tlbs(kvm);
if (!sp->role.invalid && !sp->role.direct) if (!sp->role.invalid && !sp->role.direct)
unaccount_shadowed(kvm, sp->gfn); unaccount_shadowed(kvm, sp->gfn);
if (sp->unsync) if (sp->unsync)
...@@ -1571,17 +1577,45 @@ static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp) ...@@ -1571,17 +1577,45 @@ static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
if (!sp->root_count) { if (!sp->root_count) {
/* Count self */ /* Count self */
ret++; ret++;
hlist_del(&sp->hash_link); list_move(&sp->link, invalid_list);
kvm_mmu_free_page(kvm, sp);
} else { } else {
sp->role.invalid = 1;
list_move(&sp->link, &kvm->arch.active_mmu_pages); list_move(&sp->link, &kvm->arch.active_mmu_pages);
kvm_reload_remote_mmus(kvm); kvm_reload_remote_mmus(kvm);
} }
sp->role.invalid = 1;
kvm_mmu_reset_last_pte_updated(kvm); kvm_mmu_reset_last_pte_updated(kvm);
return ret; return ret;
} }
static void kvm_mmu_commit_zap_page(struct kvm *kvm,
struct list_head *invalid_list)
{
struct kvm_mmu_page *sp;
if (list_empty(invalid_list))
return;
kvm_flush_remote_tlbs(kvm);
do {
sp = list_first_entry(invalid_list, struct kvm_mmu_page, link);
WARN_ON(!sp->role.invalid || sp->root_count);
kvm_mmu_free_page(kvm, sp);
} while (!list_empty(invalid_list));
}
static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
{
LIST_HEAD(invalid_list);
int ret;
ret = kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
kvm_mmu_commit_zap_page(kvm, &invalid_list);
return ret;
}
/* /*
* Changing the number of mmu pages allocated to the vm * Changing the number of mmu pages allocated to the vm
* Note: if kvm_nr_mmu_pages is too small, you will get dead lock * Note: if kvm_nr_mmu_pages is too small, you will get dead lock
......
...@@ -190,7 +190,7 @@ DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_unsync_page, ...@@ -190,7 +190,7 @@ DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_unsync_page,
TP_ARGS(sp) TP_ARGS(sp)
); );
DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_zap_page, DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_prepare_zap_page,
TP_PROTO(struct kvm_mmu_page *sp), TP_PROTO(struct kvm_mmu_page *sp),
TP_ARGS(sp) TP_ARGS(sp)
......
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