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KVM: MMU: split the operations of kvm_mmu_zap_page()

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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: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Xiao Guangrong 2010-06-04 21:53:54 +08:00 committed by Avi Kivity
parent 7ae680eb2d
commit 7775834a23
2 changed files with 44 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
arch/x86/kvm/mmu.c
View File

@ -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)
{
ASSERT(is_empty_shadow_page(sp->spt));
hlist_del(&sp->hash_link);
list_del(&sp->link);
__free_page(virt_to_page(sp->spt));
if (!sp->role.direct)
@ -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_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) \
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)
}
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;
struct mmu_page_path parents;
@ -1544,7 +1550,7 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
struct kvm_mmu_page *sp;
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);
zapped++;
}
@ -1554,16 +1560,16 @@ static int mmu_zap_unsync_children(struct kvm *kvm,
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;
trace_kvm_mmu_zap_page(sp);
trace_kvm_mmu_prepare_zap_page(sp);
++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_unlink_parents(kvm, sp);
kvm_flush_remote_tlbs(kvm);
if (!sp->role.invalid && !sp->role.direct)
unaccount_shadowed(kvm, sp->gfn);
if (sp->unsync)
@ -1571,17 +1577,45 @@ static int kvm_mmu_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp)
if (!sp->root_count) {
/* Count self */
ret++;
hlist_del(&sp->hash_link);
kvm_mmu_free_page(kvm, sp);
list_move(&sp->link, invalid_list);
} else {
sp->role.invalid = 1;
list_move(&sp->link, &kvm->arch.active_mmu_pages);
kvm_reload_remote_mmus(kvm);
}
sp->role.invalid = 1;
kvm_mmu_reset_last_pte_updated(kvm);
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
* Note: if kvm_nr_mmu_pages is too small, you will get dead lock

2
arch/x86/kvm/mmutrace.h
View File

@ -190,7 +190,7 @@ DEFINE_EVENT(kvm_mmu_page_class, kvm_mmu_unsync_page,
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_ARGS(sp)