[PATCH 1/4] KVM: MMU: rename 'sp->root_count' to 'sp->active_count'

Xiao Guangrong
2010-09-20T14:18:48Z

Now, sp->root_count is only used by the root sp, in the later patch, we will increase
it to keep unsync sp alive while it's out of 'kvm->mmu_lock''s protection, so rename the
name to fits its use

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/include/asm/kvm_host.h | 7 ++++++-
arch/x86/kvm/mmu.c | 20 ++++++++++----------
arch/x86/kvm/mmutrace.h | 8 ++++----
3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8c5779d..55abc76 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -206,7 +206,12 @@ struct kvm_mmu_page {
DECLARE_BITMAP(slot_bitmap, KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS);
bool multimapped; /* More than one parent_pte? */
bool unsync;
- int root_count; /* Currently serving as active root */
+ /*
+ * if active_count > 0, it means that this page is not freed
+ * immediately, it's used by active root and unsync pages which
+ * out of kvm->mmu_lock's protection currently.
+ */
+ int active_count;
unsigned int unsync_children;
union {
u64 *parent_pte; /* !multimapped */
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 3ce56bf..839852d 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -1683,7 +1683,7 @@ static int kvm_mmu_prepare_zap_page(struct kvm *kvm, struct kvm_mmu_page *sp,
unaccount_shadowed(kvm, sp->gfn);
if (sp->unsync)
kvm_unlink_unsync_page(kvm, sp);
- if (!sp->root_count) {
+ if (!sp->active_count) {
/* Count self */
ret++;
list_move(&sp->link, invalid_list);
@@ -1709,7 +1709,7 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm,

do {
sp = list_first_entry(invalid_list, struct kvm_mmu_page, link);
- WARN_ON(!sp->role.invalid || sp->root_count);
+ WARN_ON(!sp->role.invalid || sp->active_count);
kvm_mmu_free_page(kvm, sp);
} while (!list_empty(invalid_list));

@@ -2326,8 +2326,8 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu)
hpa_t root = vcpu->arch.mmu.root_hpa;

sp = page_header(root);
- --sp->root_count;
- if (!sp->root_count && sp->role.invalid) {
+ --sp->active_count;
+ if (!sp->active_count && sp->role.invalid) {
kvm_mmu_prepare_zap_page(vcpu->kvm, sp, &invalid_list);
kvm_mmu_commit_zap_page(vcpu->kvm, &invalid_list);
}
@@ -2341,8 +2341,8 @@ static void mmu_free_roots(struct kvm_vcpu *vcpu)
if (root) {
root &= PT64_BASE_ADDR_MASK;
sp = page_header(root);
- --sp->root_count;
- if (!sp->root_count && sp->role.invalid)
+ --sp->active_count;
+ if (!sp->active_count && sp->role.invalid)
kvm_mmu_prepare_zap_page(vcpu->kvm, sp,
&invalid_list);
}
@@ -2375,7 +2375,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
kvm_mmu_free_some_pages(vcpu);
sp = kvm_mmu_get_page(vcpu, 0, 0, PT64_ROOT_LEVEL,
1, ACC_ALL, NULL);
- ++sp->root_count;
+ ++sp->active_count;
spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.root_hpa = __pa(sp->spt);
} else if (vcpu->arch.mmu.shadow_root_level == PT32E_ROOT_LEVEL) {
@@ -2389,7 +2389,7 @@ static int mmu_alloc_direct_roots(struct kvm_vcpu *vcpu)
PT32_ROOT_LEVEL, 1, ACC_ALL,
NULL);
root = __pa(sp->spt);
- ++sp->root_count;
+ ++sp->active_count;
spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.pae_root[i] = root | PT_PRESENT_MASK;
vcpu->arch.mmu.root_hpa = __pa(vcpu->arch.mmu.pae_root);
@@ -2426,7 +2426,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL,
0, ACC_ALL, NULL);
root = __pa(sp->spt);
- ++sp->root_count;
+ ++sp->active_count;
spin_unlock(&vcpu->kvm->mmu_lock);
vcpu->arch.mmu.root_hpa = root;
return 0;
@@ -2461,7 +2461,7 @@ static int mmu_alloc_shadow_roots(struct kvm_vcpu *vcpu)
PT32_ROOT_LEVEL, 0,
ACC_ALL, NULL);
root = __pa(sp->spt);
- ++sp->root_count;
+ ++sp->active_count;
spin_unlock(&vcpu->kvm->mmu_lock);

vcpu->arch.mmu.pae_root[i] = root | pm_mask;
diff --git a/arch/x86/kvm/mmutrace.h b/arch/x86/kvm/mmutrace.h
index b60b4fd..70c8bfd 100644
--- a/arch/x86/kvm/mmutrace.h
+++ b/arch/x86/kvm/mmutrace.h
@@ -10,13 +10,13 @@
#define KVM_MMU_PAGE_FIELDS \
__field(__u64, gfn) \
__field(__u32, role) \
- __field(__u32, root_count) \
+ __field(__u32, active_count) \
__field(bool, unsync)

#define KVM_MMU_PAGE_ASSIGN(sp) \
__entry->gfn = sp->gfn; \
__entry->role = sp->role.word; \
- __entry->root_count = sp->root_count; \
+ __entry->active_count = sp->active_count; \
__entry->unsync = sp->unsync;

#define KVM_MMU_PAGE_PRINTK() ({ \
@@ -29,7 +29,7 @@
role.word = __entry->role; \
\
trace_seq_printf(p, "sp gfn %llx %u%s q%u%s %s%s" \
- " %snxe root %u %s%c", \
+ " %snxe active %u %s%c", \
__entry->gfn, role.level, \
role.cr4_pae ? " pae" : "", \
role.quadrant, \
@@ -37,7 +37,7 @@
access_str[role.access], \
role.invalid ? " invalid" : "", \
role.nxe ? "" : "!", \
- __entry->root_count, \
+ __entry->active_count, \
__entry->unsync ? "unsync" : "sync", 0); \
ret; \
})
--
1.7.0.4